lpi (Lode's Programming Interface) Code

/*
LodePNG version 20080117

Copyright (c) 2005-2008 Lode Vandevenne

This software is provided 'as-is', without any express or implied
warranty. In no event will the authors be held liable for any damages
arising from the use of this software.

Permission is granted to anyone to use this software for any purpose,
including commercial applications, and to alter it and redistribute it
freely, subject to the following restrictions:

    1. The origin of this software must not be misrepresented; you must not
    claim that you wrote the original software. If you use this software
    in a product, an acknowledgment in the product documentation would be
    appreciated but is not required.

    2. Altered source versions must be plainly marked as such, and must not be
    misrepresented as being the original software.

    3. This notice may not be removed or altered from any source
    distribution.
*/

/*
The manual and changelog can be found in the header file "lodepng.h"
You are free to name this file lodepng.cpp or lodepng.c depending on your usage.
*/

#include "lodepng.h"

#define VERSION_STRING "20080117"

/* ////////////////////////////////////////////////////////////////////////// */
/* / Tools For C                                                            / */
/* ////////////////////////////////////////////////////////////////////////// */

/*
About these tools (vector, uivector, ucvector and string):
-LodePNG was originally written in C++. The vectors replace the std::vectors that were used in the C++ version.
-The string tools are tailor made for LodePNG and avoid problems with compilers that declare things like strncat as deprecated.
-They're not used in the interface, only internally in this file, so all their functions are made static.
*/

typedef struct vector
{
  void* data;
  size_t size; /*in groups of bytes depending on type*/
  size_t allocsize; /*in bytes*/
  unsigned typesize; /*sizeof the type you store in data*/
} vector;

static void vector_resize(vector* p, size_t size)
{
  if(size * p->typesize > p->allocsize)
  {
    size_t newsize = size * p->typesize * 2;
    void* data = realloc(p->data, newsize);
    if(data)
    {
      p->allocsize = newsize;
      p->data = data;
      p->size = size;
    }
  }
  else p->size = size;
}

static void vector_resized(vector* p, size_t size, void dtor(void*)) /*resize and use destructor on elements if it gets smaller*/
{
  size_t i;
  if(size < p->size) for(i = size; i < p->size; i++) dtor(&((char*)(p->data))[i * p->typesize]);
  vector_resize(p, size);
}

static void vector_cleanup(void* p)
{
  ((vector*)p)->size = ((vector*)p)->allocsize = 0;
  free(((vector*)p)->data);
  ((vector*)p)->data = NULL;
}

static void vector_cleanupd(vector* p, void dtor(void*)) /*clear and use destructor on elements*/
{
  vector_resized(p, 0, dtor);
  vector_cleanup(p);
}

static void vector_init(vector* p, unsigned typesize)
{
  p->data = NULL;
  p->size = p->allocsize = 0;
  p->typesize = typesize;
}

static void vector_swap(vector* p, vector* q) /*they're supposed to have the same typesize*/
{
  size_t tmp;
  void* tmpp;
  tmp = p->size; p->size = q->size; q->size = tmp;
  tmp = p->allocsize; p->allocsize = q->allocsize; q->allocsize = tmp;
  tmpp = p->data; p->data = q->data; q->data = tmpp;
}

static void* vector_get(vector* p, size_t index)
{
  return &((char*)p->data)[index * p->typesize];
}

/* /////////////////////////////////////////////////////////////////////////// */

typedef struct uivector
{
  unsigned* data;
  size_t size; /*size in number of unsigned longs*/
  size_t allocsize; /*allocated size in bytes*/
} uivector;

static void uivector_cleanup(void* p)
{
  ((uivector*)p)->size = ((uivector*)p)->allocsize = 0;
  free(((uivector*)p)->data);
  ((uivector*)p)->data = NULL;
}

static void uivector_resize(uivector* p, size_t size)
{
  if(size * sizeof(unsigned) > p->allocsize)
  {
    size_t newsize = size * sizeof(unsigned) * 2;
    void* data = realloc(p->data, newsize);
    if(data)
    {
      p->allocsize = newsize;
      p->data = (unsigned*)data;
      p->size = size;
    }
  }
  else p->size = size;
}

static void uivector_resizev(uivector* p, size_t size, unsigned value) /*resize and give all new elements the value*/
{
  size_t oldsize = p->size, i;
  uivector_resize(p, size);
  for(i = oldsize; i < size; i++) p->data[i] = value;
}

static void uivector_init(uivector* p)
{
  p->data = NULL;
  p->size = p->allocsize = 0;
}

static void uivector_push_back(uivector* p, unsigned c)
{
  uivector_resize(p, p->size + 1);
  p->data[p->size - 1] = c;
}

static void uivector_copy(uivector* p, const uivector* q) /*copy q to p*/
{
  size_t i;
  uivector_resize(p, q->size);
  for(i = 0; i < q->size; i++) p->data[i] = q->data[i];
}

static void uivector_swap(uivector* p, uivector* q)
{
  size_t tmp;
  unsigned* tmpp;
  tmp = p->size; p->size = q->size; q->size = tmp;
  tmp = p->allocsize; p->allocsize = q->allocsize; q->allocsize = tmp;
  tmpp = p->data; p->data = q->data; q->data = tmpp;
}

/* /////////////////////////////////////////////////////////////////////////// */

typedef struct ucvector
{
  unsigned char* data;
  size_t size; /*used size*/
  size_t allocsize; /*allocated size*/
} ucvector;

static void ucvector_cleanup(void* p)
{
  ((ucvector*)p)->size = ((ucvector*)p)->allocsize = 0;
  free(((ucvector*)p)->data);
  ((ucvector*)p)->data = NULL;
}

static void ucvector_resize(ucvector* p, size_t size)
{
  if(size * sizeof(unsigned) > p->allocsize)
  {
    size_t newsize = size * sizeof(unsigned) * 2;
    void* data = realloc(p->data, newsize);
    if(data)
    {
      p->allocsize = newsize;
      p->data = (unsigned char*)data;
      p->size = size;
    }
  }
  else p->size = size;
}

static void ucvector_resizev(ucvector* p, size_t size, unsigned char value) /*resize and give all new elements the value*/
{
  size_t oldsize = p->size, i;
  ucvector_resize(p, size);
  for(i = oldsize; i < size; i++) p->data[i] = value;
}

static void ucvector_init(ucvector* p)
{
  p->data = NULL;
  p->size = p->allocsize = 0;
}

/*you can both convert from vector to buffer&size and vica versa*/
static void ucvector_init_buffer(ucvector* p, unsigned char* buffer, size_t size)
{
  p->data = buffer;
  p->allocsize = p->size = size;
}

static void ucvector_push_back(ucvector* p, unsigned char c)
{
  ucvector_resize(p, p->size + 1);
  p->data[p->size - 1] = c;
}

/* /////////////////////////////////////////////////////////////////////////// */

static unsigned string_resize(char** out, size_t size) /*returns 1 if success, 0 if failure ==> nothing done*/
{
  char* data = (char*)realloc(*out, size + 1);
  if(data)
  {
    data[size] = 0; /*null termination char*/
    *out = data;
  }
  return data != 0;
}

static void string_init(char** out) /*init a {char*, size_t} pair for use as string*/
{
  *out = NULL;
  string_resize(out, 0);
}

static void string_cleanup(char** out) /*free the above pair again*/
{
  free(*out);
  *out = NULL;
}

static void string_set(char** out, const char* in)
{
  size_t insize = strlen(in), i = 0;
  if(string_resize(out, insize)) for(i = 0; i < insize; i++) (*out)[i] = in[i];
}

#if 0
static void string_concat(char** out, const char* in) /*concatenate*/
{
  size_t insize, outsize, i;
  if(!(*out)) return;
  insize = strlen(in);
  outsize = strlen(*out);
  if(string_resize(out, outsize + insize)) for(i = 0; i < insize; i++) (*out)[outsize + i] = in[i];
}
#endif

static unsigned string_equal(const char* a, const char* b)
{
  size_t asize, bsize, i;
  asize = strlen(a);
  bsize = strlen(b);
  if(asize != bsize) return 0;
  for(i = 0; i < asize; i++) if(a[i] != b[i]) return 0;
  return 1;
}

/* ////////////////////////////////////////////////////////////////////////// */
/* / Reading and writing single bits and bytes from/to stream for Deflate   / */
/* ////////////////////////////////////////////////////////////////////////// */

static void addBitToStream(size_t* bitpointer, ucvector* bitstream, unsigned char bit)
{
  if((*bitpointer) % 8 == 0) ucvector_push_back(bitstream, 0); /*add a new byte at the end*/
  (bitstream->data[bitstream->size - 1]) |= (bit << ((*bitpointer) & 0x7)); /*earlier bit of huffman code is in a lesser significant bit of an earlier byte*/
  (*bitpointer)++;
}

static void addBitsToStream(size_t* bitpointer, ucvector* bitstream, unsigned value, size_t nbits)
{
  size_t i;
  for(i = 0; i < nbits; i++) addBitToStream(bitpointer, bitstream, (unsigned char)((value >> i) & 1));
}

static void addBitsToStreamReversed(size_t* bitpointer, ucvector* bitstream, unsigned value, size_t nbits)
{
  size_t i;
  for(i = 0; i < nbits; i++) addBitToStream(bitpointer, bitstream, (unsigned char)((value >> (nbits - 1 - i)) & 1));
}

static unsigned char readBitFromStream(size_t* bitpointer, const unsigned char* bitstream)
{
  unsigned char result = (unsigned char)((bitstream[(*bitpointer) >> 3] >> ((*bitpointer) & 0x7)) & 1);
  (*bitpointer)++;
  return result;
}

static unsigned readBitsFromStream(size_t* bitpointer, const unsigned char* bitstream, size_t nbits)
{
  unsigned result = 0, i;
  for(i = 0; i < nbits; i++) result += ((unsigned)readBitFromStream(bitpointer, bitstream)) << i;
  return result;
}

/* ////////////////////////////////////////////////////////////////////////// */
/* / Deflate - Huffman                                                      / */
/* ////////////////////////////////////////////////////////////////////////// */

static const unsigned FIRST_LENGTH_CODE_INDEX = 257;
static const unsigned LAST_LENGTH_CODE_INDEX = 285;
static const unsigned NUM_DEFLATE_CODE_SYMBOLS = 288; /*256 literals, the end code, some length codes, and 2 unused codes*/
static const unsigned NUM_DISTANCE_SYMBOLS = 32; /*the distance codes have their own symbols, 30 used, 2 unused*/
#define               NUM_CODE_LENGTH_CODES 19 /*the code length codes. 0-15: code lengths, 16: copy previous 3-6 times, 17: 3-10 zeros, 18: 11-138 zeros*/

static const unsigned LENGTHBASE[29] /*the base lengths represented by codes 257-285*/
  = {3, 4, 5, 6, 7, 8, 9, 10, 11, 13, 15, 17, 19, 23, 27, 31, 35, 43, 51, 59, 67, 83, 99, 115, 131, 163, 195, 227, 258};
static const unsigned LENGTHEXTRA[29] /*the extra bits used by codes 257-285 (added to base length)*/
  = {0, 0, 0, 0, 0, 0, 0,  0,  1,  1,  1,  1,  2,  2,  2,  2,  3,  3,  3,  3,  4,  4,  4,   4,   5,   5,   5,   5,   0};
static const unsigned DISTANCEBASE[30] /*the base backwards distances (the bits of distance codes appear after length codes and use their own huffman tree)*/
  = {1, 2, 3, 4, 5, 7, 9, 13, 17, 25, 33, 49, 65, 97, 129, 193, 257, 385, 513, 769, 1025, 1537, 2049, 3073, 4097, 6145, 8193, 12289, 16385, 24577};
static const unsigned DISTANCEEXTRA[30] /*the extra bits of backwards distances (added to base)*/
  = {0, 0, 0, 0, 1, 1, 2,  2,  3,  3,  4,  4,  5,  5,   6,   6,   7,   7,   8,   8,    9,    9,   10,   10,   11,   11,   12,    12,    13,    13};
static const unsigned CLCL[NUM_CODE_LENGTH_CODES] /*the order in which "code length alphabet code lengths" are stored, out of this the huffman tree of the dynamic huffman tree lengths is generated*/
  = {16, 17, 18, 0, 8, 7, 9, 6, 10, 5, 11, 4, 12, 3, 13, 2, 14, 1, 15};

/* /////////////////////////////////////////////////////////////////////////// */

/*terminology used for the package-merge algorithm and the coin collector's problem*/
typedef struct Coin /*a coin can be multiple coins (when they're merged)*/
{
  uivector symbols; /*type: unsigned*/
  float weight; /*the sum of all weights in this coin*/
} Coin;

static void Coin_init(Coin* c)
{
  uivector_init(&c->symbols);
}

static void Coin_cleanup(void* c) /*void* so that this dtor can be given as function pointer to the vector resize function*/
{
  uivector_cleanup(&((Coin*)c)->symbols);
}

static void Coin_copy(Coin* c1, const Coin* c2)
{
  c1->weight = c2->weight;
  uivector_copy(&c1->symbols, &c2->symbols);
}

static void addCoins(Coin* c1, const Coin* c2)
{
  unsigned i;
  for(i = 0; i < c2->symbols.size; i++) uivector_push_back(&c1->symbols, c2->symbols.data[i]);
  c1->weight += c2->weight;
}

static void Coin_sort(Coin* data, size_t amount) /*combsort*/
{
  size_t gap = amount;
  unsigned char swapped = 0;
  while(gap > 1 || swapped)
  {
    size_t i;
    gap = (gap * 10) / 13; /*shrink factor 1.3*/
    if(gap == 9 || gap == 10) gap = 11; /*combsort11*/
    if(gap < 1) gap = 1;
    swapped = 0;
    for(i = 0; i < amount - gap; i++)
    {
      size_t j = i + gap;
      if(data[j].weight < data[i].weight)
      {
        float temp = data[j].weight; data[j].weight = data[i].weight; data[i].weight = temp;
        uivector_swap(&data[i].symbols, &data[j].symbols);
        swapped = 1;
      }
    }
  }
}

typedef struct HuffmanTree
{
  uivector tree2d;
  uivector tree1d;
  uivector lengths; /*the lengths of the codes of the 1d-tree*/
  unsigned maxbitlen; /*maximum number of bits a single code can get*/
  unsigned numcodes; /*number of symbols in the alphabet = number of codes*/
} HuffmanTree;

static void HuffmanTree_init(HuffmanTree* tree)
{
  uivector_init(&tree->tree2d);
  uivector_init(&tree->tree1d);
  uivector_init(&tree->lengths);
}

static void HuffmanTree_cleanup(HuffmanTree* tree)
{
  uivector_cleanup(&tree->tree2d);
  uivector_cleanup(&tree->tree1d);
  uivector_cleanup(&tree->lengths);
}

/*the tree representation used by the decoder. return value is error*/
static unsigned HuffmanTree_make2DTree(HuffmanTree* tree)
{
  unsigned nodefilled = 0; /*up to which node it is filled*/
  unsigned treepos = 0; /*position in the tree (1 of the numcodes columns)*/
  unsigned n, i;
  
  uivector_resize(&tree->tree2d, tree->numcodes * 2);
  /*convert tree1d[] to tree2d[][]. In the 2D array, a value of 32767 means uninited, a value >= numcodes is an address to another bit, a value < numcodes is a code. The 2 rows are the 2 possible bit values (0 or 1), there are as many columns as codes - 1
  a good huffmann tree has N * 2 - 1 nodes, of which N - 1 are internal nodes. Here, the internal nodes are stored (what their 0 and 1 option point to). There is only memory for such good tree currently, if there are more nodes (due to too long length codes), error 55 will happen*/
  for(n = 0;  n < tree->numcodes * 2; n++) tree->tree2d.data[n] = 32767; /*32767 here means the tree2d isn't filled there yet*/

  for(n = 0; n < tree->numcodes; n++) /*the codes*/
  for(i = 0; i < tree->lengths.data[n]; i++) /*the bits for this code*/
  {
    unsigned char bit = (unsigned char)((tree->tree1d.data[n] >> (tree->lengths.data[n] - i - 1)) & 1);
    if(treepos > tree->numcodes - 2) return 55; /*error 55: oversubscribed; see description in header*/
    if(tree->tree2d.data[2 * treepos + bit] == 32767) /*not yet filled in*/
    {
      if(i + 1 == tree->lengths.data[n]) /*last bit*/
      {
        tree->tree2d.data[2 * treepos + bit] = n; /*put the current code in it*/
        treepos = 0;
      }
      else /*put address of the next step in here, first that address has to be found of course (it's just nodefilled + 1)...*/
      {
        nodefilled++;
        tree->tree2d.data[2 * treepos + bit] = nodefilled + tree->numcodes; /*addresses encoded with numcodes added to it*/
        treepos = nodefilled;
      }
    }
    else treepos = tree->tree2d.data[2 * treepos + bit] - tree->numcodes;
  }
  for(n = 0;  n < tree->numcodes * 2; n++) if(tree->tree2d.data[n] == 32767) tree->tree2d.data[n] = 0; /*remove possible remaining 32767's*/
  
  return 0;
}

static unsigned HuffmanTree_makeFromLengths2(HuffmanTree* tree) /*given that numcodes, lengths and maxbitlen are already filled in correctly. return value is error.*/
{
  uivector blcount;
  uivector nextcode;
  unsigned bits, n;
  
  uivector_init(&blcount);
  uivector_init(&nextcode);
  
  uivector_resize(&tree->tree1d, tree->numcodes);
  uivector_resizev(&blcount, tree->maxbitlen + 1, 0);
  uivector_resizev(&nextcode, tree->maxbitlen + 1, 0);
  
  /*step 1: count number of instances of each code length*/
  for(bits = 0; bits < tree->numcodes; bits++) blcount.data[tree->lengths.data[bits]]++;
  /*step 2: generate the nextcode values*/
  for(bits = 1; bits <= tree->maxbitlen; bits++) nextcode.data[bits] = (nextcode.data[bits - 1] + blcount.data[bits - 1]) << 1;
  /*step 3: generate all the codes*/
  for(n = 0; n < tree->numcodes; n++) if(tree->lengths.data[n] != 0) tree->tree1d.data[n] = nextcode.data[tree->lengths.data[n]]++;
  uivector_cleanup(&blcount);
  uivector_cleanup(&nextcode);
  
  return HuffmanTree_make2DTree(tree);
}

/*given the code lengths (as stored in the PNG file), generate the tree as defined by Deflate. maxbitlen is the maximum bits that a code in the tree can have. return value is error.*/
static unsigned HuffmanTree_makeFromLengths(HuffmanTree* tree, const unsigned* bitlen, size_t numcodes, unsigned maxbitlen)
{
  unsigned i;
  uivector_resize(&tree->lengths, numcodes);
  for(i = 0; i < numcodes; i++) tree->lengths.data[i] = bitlen[i];
  tree->numcodes = (unsigned)numcodes; /*number of symbols*/
  tree->maxbitlen = maxbitlen;
  return HuffmanTree_makeFromLengths2(tree);
}

/*Decodes a symbol from the tree
if decoded is true, then result contains the symbol, otherwise it contains something unspecified (because the symbol isn't fully decoded yet)
bit is the bit that was just read from the stream
you have to decode a full symbol (let the decode function return true) before you can try to decode another one, otherwise the state isn't reset
return value is error.*/
static unsigned HuffmanTree_decode(const HuffmanTree* tree, unsigned* decoded, unsigned* result, unsigned* treepos, unsigned char bit)
{
  if((*treepos) >= tree->numcodes) return 11; /*error: it appeared outside the codetree*/
  
  (*result) = tree->tree2d.data[2 * (*treepos) + bit];
  (*decoded) = ((*result) < tree->numcodes);

  if(*decoded) (*treepos) = 0;
  else (*treepos) = (*result) - tree->numcodes;
  
  return 0;
}

static void HuffmanTree_fillInCoins(vector* coins, const unsigned* frequencies, unsigned numcodes, size_t sum)
{
  unsigned i;
  for(i = 0; i < numcodes; i++)
  {
    Coin* coin;
    if(frequencies[i] == 0) continue; /*it's important to exclude symbols that aren't present*/
    vector_resize(coins, coins->size + 1);
    coin = (Coin*)(vector_get(coins, coins->size - 1));
    Coin_init(coin);
    coin->weight = frequencies[i] / (float)sum;
    uivector_push_back(&coin->symbols, i);
  }
  if(coins->size) Coin_sort((Coin*)coins->data, coins->size);
}

static unsigned HuffmanTree_makeFromFrequencies(HuffmanTree* tree, const unsigned* frequencies, size_t numcodes, unsigned maxbitlen)
{
  unsigned i, j;
  size_t sum = 0, numpresent = 0;
  unsigned error = 0;
  
  vector prev_row; /*type Coin, the previous row of coins*/
  vector coins; /*type Coin, the coins of the currently calculated row*/
  
  tree->maxbitlen = maxbitlen;
  
  for(i = 0; i < numcodes; i++)
  {
    if(frequencies[i] > 0)
    {
      numpresent++;
      sum += frequencies[i];
    }
  }

  tree->numcodes = (unsigned)numcodes; /*number of symbols*/
  uivector_resize(&tree->lengths, 0);
  uivector_resizev(&tree->lengths, tree->numcodes, 0);
  
  if(numpresent == 0) /*there are no symbols at all, in that case add one symbol of value 0 to the tree (see RFC 1951 section 3.2.7) */
  {
    return HuffmanTree_makeFromLengths2(tree);
  }
  else if(numpresent == 1) /*the package merge algorithm gives wrong results if there's only one symbol (theoretically 0 bits would then suffice, but we need a proper symbol for zlib)*/
  {
    for(i = 0; i < numcodes; i++) if(frequencies[i]) tree->lengths.data[i] = 1;
    return HuffmanTree_makeFromLengths2(tree);
  }
  
  vector_init(&coins, sizeof(Coin));
  vector_init(&prev_row, sizeof(Coin));

  /*Package-Merge algorithm represented by coin collector's problem
  For every symbol, maxbitlen coins will be created*/
  
  /*first row, lowest denominator*/
  HuffmanTree_fillInCoins(&coins, frequencies, tree->numcodes, sum);
  for(j = 1; j <= maxbitlen; j++) /*each of the remaining rows*/
  {
    vector_swap(&coins, &prev_row); /*swap instead of copying*/
    vector_resized(&coins, 0, Coin_cleanup);

    for(i = 0; i + 1 < prev_row.size; i += 2)
    {
      vector_resize(&coins, coins.size + 1);
      Coin_init((Coin*)vector_get(&coins, coins.size - 1));
      Coin_copy((Coin*)vector_get(&coins, coins.size - 1), (Coin*)vector_get(&prev_row, i));
      addCoins((Coin*)vector_get(&coins, coins.size - 1), (Coin*)vector_get(&prev_row, i + 1)); /*merge the coins into packages*/
    }
    if(j < maxbitlen)
    {
      HuffmanTree_fillInCoins(&coins, frequencies, tree->numcodes, sum);
    }
  }
  
  /*keep the coins with lowest weight, so that they add up to the amount of symbols - 1*/
  vector_resized(&coins, numpresent - 1, Coin_cleanup);
  
  /*calculate the lenghts of each symbol, as the amount of times a coin of each symbol is used*/
  for(i = 0; i < coins.size; i++)
  {
    Coin* coin = (Coin*)vector_get(&coins, i);
    for(j = 0; j < coin->symbols.size; j++) tree->lengths.data[coin->symbols.data[j]]++;
  }
  
  error = HuffmanTree_makeFromLengths2(tree);
  
  vector_cleanupd(&coins, Coin_cleanup);
  vector_cleanupd(&prev_row, Coin_cleanup);
  
  return error;
}

static unsigned HuffmanTree_getCode(const HuffmanTree* tree, unsigned index) { return tree->tree1d.data[index]; }
static unsigned HuffmanTree_getLength(const HuffmanTree* tree, unsigned index) { return tree->lengths.data[index]; }

/*get the tree of a deflated block with fixed tree, as specified in the deflate specification*/
static unsigned generateFixedTree(HuffmanTree* tree)
{
  unsigned i, error;
  uivector bitlen;
  uivector_init(&bitlen);
  uivector_resize(&bitlen, NUM_DEFLATE_CODE_SYMBOLS);
    
  /*288 possible codes: 0-255=literals, 256=endcode, 257-285=lengthcodes, 286-287=unused*/
  for(i =   0; i <= 143; i++) bitlen.data[i] = 8;
  for(i = 144; i <= 255; i++) bitlen.data[i] = 9;
  for(i = 256; i <= 279; i++) bitlen.data[i] = 7;
  for(i = 280; i <= 287; i++) bitlen.data[i] = 8;
  
  error = HuffmanTree_makeFromLengths(tree, bitlen.data, NUM_DEFLATE_CODE_SYMBOLS, 15);
  uivector_cleanup(&bitlen);
  return error;
}

static unsigned generateDistanceTree(HuffmanTree* tree)
{
  unsigned i, error;
  uivector bitlen;
  uivector_init(&bitlen);
  uivector_resize(&bitlen, NUM_DISTANCE_SYMBOLS);
  
  /*there are 32 distance codes, but 30-31 are unused*/
  for(i = 0; i < NUM_DISTANCE_SYMBOLS; i++) bitlen.data[i] = 5;
  
  error = HuffmanTree_makeFromLengths(tree, bitlen.data, NUM_DISTANCE_SYMBOLS, 15);
  uivector_cleanup(&bitlen);
  return error;
}

static unsigned huffmanDecodeSymbol(unsigned int* error, const unsigned char* in, size_t* bp, const HuffmanTree* codetree, size_t inlength)
{
  unsigned treepos = 0;
  unsigned decoded;
  unsigned ct;
  for(;;)
  {
    unsigned char bit;
    if(((*bp) & 0x07) == 0 && ((*bp) >> 3) > inlength) { *error = 10; return 0; } /*error: end of input memory reached without endcode*/
    bit = readBitFromStream(bp, in);
    *error = HuffmanTree_decode(codetree, &decoded, &ct, &treepos, bit);
    if(*error) return 0; /*stop, an error happened*/
    if(decoded) return ct;
  }
}

/* ////////////////////////////////////////////////////////////////////////// */
/* / Inflator                                                               / */
/* ////////////////////////////////////////////////////////////////////////// */

/*get the tree of a deflated block with fixed tree, as specified in the deflate specification*/
static void getTreeInflateFixed(HuffmanTree* tree, HuffmanTree* treeD)
{
  /*error checking not done, this is fixed stuff, it works, it doesn't depend on the image*/
  generateFixedTree(tree);
  generateDistanceTree(treeD);
}

/*get the tree of a deflated block with dynamic tree, the tree itself is also Huffman compressed with a known tree*/
static unsigned getTreeInflateDynamic(HuffmanTree* codetree, HuffmanTree* codetreeD, HuffmanTree* codelengthcodetree,
                                      const unsigned char* in, size_t* bp, size_t inlength)
{
  /*make sure that length values that aren't filled in will be 0, or a wrong tree will be generated*/
  /*C-code note: use no "return" between ctor and dtor of an uivector!*/
  unsigned error;
  unsigned n, HLIT, HDIST, HCLEN, i;
  uivector bitlen;
  uivector bitlenD;
  uivector codelengthcode;
  
  if((*bp) >> 3 >= inlength - 2) { return 49; } /*the bit pointer is or will go past the memory*/

  HLIT =  readBitsFromStream(bp, in, 5) + FIRST_LENGTH_CODE_INDEX; /*number of literal/length codes + 257. Unlike the spec, the value 257 is added to it here already*/
  HDIST = readBitsFromStream(bp, in, 5) + 1; /*number of distance codes. Unlike the spec, the value 1 is added to it here already*/
  HCLEN = readBitsFromStream(bp, in, 4) + 4; /*number of code length codes. Unlike the spec, the value 4 is added to it here already*/
  
  /*read the code length codes out of 3 * (amount of code length codes) bits*/
  uivector_init(&codelengthcode);
  uivector_resize(&codelengthcode, NUM_CODE_LENGTH_CODES);
  for(i = 0; i < NUM_CODE_LENGTH_CODES; i++)
  {
    if(i < HCLEN) codelengthcode.data[CLCL[i]] = readBitsFromStream(bp, in, 3);
    else codelengthcode.data[CLCL[i]] = 0; /*if not, it must stay 0*/
  }
  
  error = HuffmanTree_makeFromLengths(codelengthcodetree, codelengthcode.data, codelengthcode.size, 7);
  uivector_cleanup(&codelengthcode);
  if(error) return error;
  
  /*now we can use this tree to read the lengths for the tree that this function will return*/
  uivector_init(&bitlen);
  uivector_resizev(&bitlen, NUM_DEFLATE_CODE_SYMBOLS, 0);
  uivector_init(&bitlenD);
  uivector_resizev(&bitlenD, NUM_DISTANCE_SYMBOLS, 0);
  i = 0;
  while(i < HLIT + HDIST) /*i is the current symbol we're reading in the part that contains the code lengths of lit/len codes and dist codes*/
  {
    unsigned code = huffmanDecodeSymbol(&error, in, bp, codelengthcodetree, inlength);
    if(error) break;
    
    if(code <= 15) /*a length code*/
    {
      if(i < HLIT) bitlen.data[i] = code;
      else bitlenD.data[i - HLIT] = code;
      i++;
    }
    else if(code == 16) /*repeat previous*/
    {
      unsigned replength = 3; /*read in the 2 bits that indicate repeat length (3-6)*/
      unsigned value; /*set value to the previous code*/
      
      if((*bp) >> 3 >= inlength) { error = 50; break; } /*error, bit pointer jumps past memory*/
      
      replength += readBitsFromStream(bp, in, 2);
      
      if((i - 1) < HLIT) value = bitlen.data[i - 1];
      else value = bitlenD.data[i - HLIT - 1];
      /*repeat this value in the next lengths*/
      for(n = 0; n < replength; n++)
      {
        if(i >= HLIT + HDIST) { error = 13; break; } /*error: i is larger than the amount of codes*/
        if(i < HLIT) bitlen.data[i] = value;
        else bitlenD.data[i - HLIT] = value;
        i++;
      }
    }
    else if(code == 17) /*repeat "0" 3-10 times*/
    {
      unsigned replength = 3; /*read in the bits that indicate repeat length*/
      if((*bp) >> 3 >= inlength) { error = 50; break; } /*error, bit pointer jumps past memory*/

      replength += readBitsFromStream(bp, in, 3);
      
      /*repeat this value in the next lengths*/
      for(n = 0; n < replength; n++)
      {
        if(i >= HLIT + HDIST) { error = 14; break; } /*error: i is larger than the amount of codes*/
        if(i < HLIT) bitlen.data[i] = 0;
        else bitlenD.data[i - HLIT] = 0;
        i++;
      }
    }
    else if(code == 18) /*repeat "0" 11-138 times*/
    {
      unsigned replength = 11; /*read in the bits that indicate repeat length*/

      if((*bp) >> 3 >= inlength) { error = 50; break; } /*error, bit pointer jumps past memory*/

      replength += readBitsFromStream(bp, in, 7);
      
      /*repeat this value in the next lengths*/
      for(n = 0; n < replength; n++)
      {
        if(i >= HLIT + HDIST) { error = 15; break; } /*error: i is larger than the amount of codes*/
        if(i < HLIT) bitlen.data[i] = 0;
        else bitlenD.data[i - HLIT] = 0;
        i++;
      }
    }
    else { error = 16; break; } /*error: somehow an unexisting code appeared. This can never happen.*/
  }
  
  if(!error && bitlen.data[256] == 0) { error = 64; } /*the length of the end code 256 must be larger than 0*/
  
  /*now we've finally got HLIT and HDIST, so generate the code trees, and the function is done*/
  if(!error) error = HuffmanTree_makeFromLengths(codetree, &bitlen.data[0], bitlen.size, 15);
  if(!error) error = HuffmanTree_makeFromLengths(codetreeD, &bitlenD.data[0], bitlenD.size, 15);
  
  uivector_cleanup(&bitlen);
  uivector_cleanup(&bitlenD);
  
  return error;
}

/*inflate a block with dynamic of fixed Huffman tree*/
static unsigned inflateHuffmanBlock(ucvector* out, const unsigned char* in, size_t* bp, size_t* pos, size_t inlength, unsigned btype)
{
  unsigned endreached = 0, error = 0;
  HuffmanTree codetree; /*287, the code tree for Huffman codes*/
  HuffmanTree codetreeD; /*31, the code tree for distance codes*/
  
  HuffmanTree_init(&codetree);
  HuffmanTree_init(&codetreeD);
  
  if(btype == 1) getTreeInflateFixed(&codetree, &codetreeD);
  else if(btype == 2)
  {
    HuffmanTree codelengthcodetree; /*18, the code tree for code length codes*/
    HuffmanTree_init(&codelengthcodetree);
    error = getTreeInflateDynamic(&codetree, &codetreeD, &codelengthcodetree, in, bp, inlength);
    HuffmanTree_cleanup(&codelengthcodetree);
  }
  
  while(!endreached && !error)
  {
    unsigned code = huffmanDecodeSymbol(&error, in, bp, &codetree, inlength);
    if(error) break; /*some error happened in the above function*/
    if(code == 256) /*end code*/
    {
      endreached = 1;
    }
    else if(code <= 255) /*literal symbol*/
    {
      if((*pos) >= out->size) ucvector_resize(out, ((*pos) + 1) * 2); /*reserve more room at once*/
      out->data[(*pos)] = (unsigned char)(code);
      (*pos)++;
    }
    else if(code >= FIRST_LENGTH_CODE_INDEX && code <= LAST_LENGTH_CODE_INDEX) /*length code*/
    {
      /*part 1: get length base*/
      size_t length = LENGTHBASE[code - FIRST_LENGTH_CODE_INDEX];
      unsigned codeD, distance, numextrabitsD;
      size_t start, forward, backward, numextrabits;
      
      /*part 2: get extra bits and add the value of that to length*/
      numextrabits = LENGTHEXTRA[code - FIRST_LENGTH_CODE_INDEX];
      if(((*bp) >> 3) >= inlength) { error = 51; break; } /*error, bit pointer will jump past memory*/
      length += readBitsFromStream(bp, in, numextrabits);
      
      /*part 3: get distance code*/
      codeD = huffmanDecodeSymbol(&error, in, bp, &codetreeD, inlength);
      if(error) break;
      if(codeD > 29) { error = 18; break; } /*error: invalid distance code (30-31 are never used)*/
      distance = DISTANCEBASE[codeD];
      
      /*part 4: get extra bits from distance*/
      numextrabitsD = DISTANCEEXTRA[codeD];

      if(((*bp) >> 3) >= inlength) { error = 51; break; } /*error, bit pointer will jump past memory*/
      distance += readBitsFromStream(bp, in, numextrabitsD);
      
      /*part 5: fill in all the out[n] values based on the length and dist*/
      start = (*pos);
      backward = start - distance;
      
      if((*pos) + length >= out->size) ucvector_resize(out, ((*pos) + length) * 2); /*reserve more room at once*/
      
      for(forward = 0; forward < length; forward++)
      {
        out->data[(*pos)] = out->data[backward];
        (*pos)++;
        backward++;
        if(backward >= start) backward = start - distance;
      }
    }
  }
  
  HuffmanTree_cleanup(&codetree);
  HuffmanTree_cleanup(&codetreeD);
  
  return error;
}

static unsigned inflateNoCompression(ucvector* out, const unsigned char* in, size_t* bp, size_t* pos, size_t inlength)
{
  /*go to first boundary of byte*/
  size_t p;
  unsigned LEN, NLEN, n, error = 0;
  while(((*bp) & 0x7) != 0) (*bp)++;
  p = (*bp) / 8; /*byte position*/
  
  /*read LEN (2 bytes) and NLEN (2 bytes)*/
  if(p >= inlength - 4) return 52; /*error, bit pointer will jump past memory*/
  LEN = in[p] + 256 * in[p + 1]; p += 2;
  NLEN = in[p] + 256 * in[p + 1]; p += 2;
  
  /*check if 16-bit NLEN is really the one's complement of LEN*/
  if(LEN + NLEN != 65535) return 21; /*error: NLEN is not one's complement of LEN*/

  if((*pos) + LEN >= out->size) ucvector_resize(out, (*pos) + LEN);
  
  /*read the literal data: LEN bytes are now stored in the out buffer*/
  if(p + LEN > inlength) return 23; /*error: reading outside of in buffer*/
  for(n = 0; n < LEN; n++) out->data[(*pos)++] = in[p++];
  
  (*bp) = p * 8;
  
  return error;
}

/*inflate the deflated data (cfr. deflate spec); return value is the error*/
unsigned LodeFlate_inflate(ucvector* out, const unsigned char* in, size_t insize, size_t inpos)
{
  size_t bp = 0; /*bit pointer in the "in" data, current byte is bp >> 3, current bit is bp & 0x7 (from lsb to msb of the byte)*/
  unsigned BFINAL = 0;
  size_t pos = 0; /*byte position in the out buffer*/
  
  unsigned error = 0;
  
  while(!BFINAL)
  {
    unsigned BTYPE;
    if(bp >> 3 >= insize) return 52; /*error, bit pointer will jump past memory*/
    BFINAL = readBitFromStream(&bp, &in[inpos]);
    BTYPE = 1 * readBitFromStream(&bp, &in[inpos]); BTYPE += 2 * readBitFromStream(&bp, &in[inpos]);

    if(BTYPE == 3) return 20; /*error: invalid BTYPE*/
    else if(BTYPE == 0) /*no compression*/
    {
      error = inflateNoCompression(out, &in[inpos], &bp, &pos, insize);
    }
    else /*compression, BTYPE 01 or 10*/
    {
      error = inflateHuffmanBlock(out, &in[inpos], &bp, &pos, insize, BTYPE);
    }
    if(error) return error;
  }
  
  ucvector_resize(out, pos); /*Only now we know the true size of out, resize it to that*/
  
  return error;
}

/* ////////////////////////////////////////////////////////////////////////// */
/* / Deflator                                                               / */
/* ////////////////////////////////////////////////////////////////////////// */

static const size_t MAX_SUPPORTED_DEFLATE_LENGTH = 258;

/*bitlen is the size in bits of the code*/
static void addHuffmanSymbol(size_t* bp, ucvector* compressed, unsigned code, unsigned bitlen)
{
  addBitsToStreamReversed(bp, compressed, code, bitlen);
}

/*search the index in the array, that has the largest value smaller than or equal to the given value, given array must be sorted (if no value is smaller, it returns the size of the given array)*/
static size_t searchCodeIndex(const unsigned* array, size_t array_size, size_t value)
{
  /*linear search implementation*/
  /*for(size_t i = 1; i < array_size; i++) if(array[i] > value) return i - 1;
  return array_size - 1;*/
  
  /*binary search implementation (not that much faster) (precondition: array_size > 0)*/
  size_t left  = 1;
  size_t right = array_size - 1;
  while(left <= right)
  {
    size_t mid = (left + right) / 2;
    if(array[mid] <= value) left = mid + 1; /*the value to find is more to the right*/
    else if(array[mid - 1] > value) right = mid - 1; /*the value to find is more to the left*/
    else return mid - 1;
  }
  return array_size - 1;
}

static void addLengthDistance(uivector* values, size_t length, size_t distance)
{
  /*values in encoded vector are those used by deflate:
  0-255: literal bytes
  256: end
  257-285: length/distance pair (length code, followed by extra length bits, distance code, extra distance bits)
  286-287: invalid*/

  unsigned length_code = (unsigned)searchCodeIndex(LENGTHBASE, 29, length);
  unsigned extra_length = (unsigned)(length - LENGTHBASE[length_code]);
  unsigned dist_code = (unsigned)searchCodeIndex(DISTANCEBASE, 30, distance);
  unsigned extra_distance = (unsigned)(distance - DISTANCEBASE[dist_code]);
  
  uivector_push_back(values, length_code + FIRST_LENGTH_CODE_INDEX);
  uivector_push_back(values, extra_length);
  uivector_push_back(values, dist_code);
  uivector_push_back(values, extra_distance);
}

#if 0
/*the "brute force" version of the encodeLZ7 algorithm, not used anymore, kept here for reference*/
static void encodeLZ77_brute(uivector* out, const unsigned char* in, size_t size, unsigned windowSize)
{
  size_t pos;
  /*using pointer instead of vector for input makes it faster when NOT using optimization when compiling; no influence if optimization is used*/
  for(pos = 0; pos < size; pos++)
  {
    size_t length = 0, offset = 0; /*the length and offset found for the current position*/
    size_t max_offset = pos < windowSize ? pos : windowSize; /*how far back to test*/
    size_t current_offset;
  
    /**search for the longest string**/
    for(current_offset = 1; current_offset < max_offset; current_offset++) /*search backwards through all possible distances (=offsets)*/
    {
      size_t backpos = pos - current_offset;
      if(in[backpos] == in[pos])
      {
        /*test the next characters*/
        size_t current_length = 1;
        size_t backtest = backpos + 1;
        size_t foretest = pos + 1;
        while(foretest < size && in[backtest] == in[foretest] && current_length < MAX_SUPPORTED_DEFLATE_LENGTH) /*maximum supporte length by deflate is max length*/
        {
          if(backpos >= pos) backpos -= current_offset; /*continue as if we work on the decoded bytes after pos by jumping back before pos*/
          current_length++;
          backtest++;
          foretest++;
        }
        if(current_length > length)
        {
          length = current_length; /*the longest length*/
          offset = current_offset; /*the offset that is related to this longest length*/
          if(current_length == MAX_SUPPORTED_DEFLATE_LENGTH) break; /*you can jump out of this for loop once a length of max length is found (gives significant speed gain)*/
        }
      }
    }
    
    /**encode it as length/distance pair or literal value**/
    if(length < 3) /*only lengths of 3 or higher are supported as length/distance pair*/
    {
      uivector_push_back(out, in[pos]);
    }
    else
    {
      addLengthDistance(out, length, offset);
      pos += (length - 1);
    }
  } /*end of the loop through each character of input*/
}
#endif

static const unsigned HASH_NUM_VALUES = 65536;
static const unsigned HASH_NUM_CHARACTERS = 6;
static const unsigned HASH_SHIFT = 2;
/*
Good and fast values: HASH_NUM_VALUES=65536, HASH_NUM_CHARACTERS=6, HASH_SHIFT=2
making HASH_NUM_CHARACTERS larger (like 8), makes the file size larger but is a bit faster
making HASH_NUM_CHARACTERS smaller (like 3), makes the file size smaller but is slower
*/

static unsigned getHash(const unsigned char* data, size_t size, size_t pos)
{
  unsigned result = 0;
  size_t amount, i;
  if(pos >= size) return 0;
  amount = HASH_NUM_CHARACTERS; if(pos + amount >= size) amount = size - pos;
  for(i = 0; i < amount; i++) result ^= (data[pos + i] << (i * HASH_SHIFT));
  return result % HASH_NUM_VALUES;
}

/*LZ77-encode the data using a hash table technique to let it encode faster.*/
static void encodeLZ77(uivector* out, const unsigned char* in, size_t size, unsigned windowSize)
{
  /**generate hash table**/
  /*table represents what would be an std::vector<std::vector<unsigned> > in C++*/
  vector table; /*HASH_NUM_VALUES uivectors*/
  uivector tablepos1;
  uivector tablepos2;
  
  unsigned pos, i;
  
  vector_init(&table, sizeof(uivector));
  vector_resize(&table, HASH_NUM_VALUES);
  for(i = 0; i < HASH_NUM_VALUES; i++)
  {
    uivector* v = (uivector*)vector_get(&table, i);
    uivector_init(v);
  }

  /*remember start and end positions in the tables to searching in*/
  uivector_init(&tablepos1);
  uivector_resizev(&tablepos1, HASH_NUM_VALUES, 0);
  uivector_init(&tablepos2);
  uivector_resizev(&tablepos2, HASH_NUM_VALUES, 0);
  
  for(pos = 0; pos < size; pos++)
  {
    unsigned length = 0, offset = 0; /*the length and offset found for the current position*/
    unsigned max_offset = pos < windowSize ? pos : windowSize; /*how far back to test*/
    
    unsigned tablepos;
  
    /*/search for the longest string*/
    /*first find out where in the table to start (the first value that is in the range from "pos - max_offset" to "pos")*/
    unsigned hash = getHash(in, size, pos);
    uivector_push_back((uivector*)vector_get(&table, hash), pos);
    
    while(((uivector*)vector_get(&table, hash))->data[tablepos1.data[hash]] < pos - max_offset) tablepos1.data[hash]++; /*it now points to the first value in the table for which the index is larger than or equal to pos - max_offset*/
    while(((uivector*)vector_get(&table, hash))->data[tablepos2.data[hash]] < pos) tablepos2.data[hash]++; /*it now points to the first value in the table for which the index is larger than or equal to pos*/

    for(tablepos = tablepos2.data[hash] - 1; tablepos >= tablepos1.data[hash] && tablepos < tablepos2.data[hash]; tablepos--)
    {
      unsigned backpos = ((uivector*)vector_get(&table, hash))->data[tablepos];
      unsigned current_offset = pos - backpos;

      /*test the next characters*/
      unsigned current_length = 0;
      unsigned backtest = backpos;
      unsigned foretest = pos;
      while(foretest < size && in[backtest] == in[foretest] && current_length < MAX_SUPPORTED_DEFLATE_LENGTH) /*maximum supporte length by deflate is max length*/
      {
        if(backpos >= pos) backpos -= current_offset; /*continue as if we work on the decoded bytes after pos by jumping back before pos*/
        current_length++;
        backtest++;
        foretest++;
      }
      if(current_length > length)
      {
        length = current_length; /*the longest length*/
        offset = current_offset; /*the offset that is related to this longest length*/
        if(current_length == MAX_SUPPORTED_DEFLATE_LENGTH) break; /*you can jump out of this for loop once a length of max length is found (gives significant speed gain)*/
      }
    }
    
    /**encode it as length/distance pair or literal value**/
    if(length < 3) /*only lengths of 3 or higher are supported as length/distance pair*/
    {
      uivector_push_back(out, in[pos]);
    }
    else
    {
      unsigned j;
      addLengthDistance(out, length, offset);
      /*pos += (length - 1);*/
      for(j = 0; j < length - 1; j++)
      {
        pos++;
        uivector_push_back((uivector*)vector_get(&table, getHash(in, size, pos)), pos);
      }
    }
  } /*end of the loop through each character of input*/
  
  /*cleanup*/
  for(i = 0; i < table.size; i++)
  {
    uivector* v = (uivector*)vector_get(&table, i);
    uivector_cleanup(v);
  }
  vector_cleanup(&table);
  uivector_cleanup(&tablepos1);
  uivector_cleanup(&tablepos2);
}

/* /////////////////////////////////////////////////////////////////////////// */

void LodeZlib_DeflateSettings_init(LodeZlib_DeflateSettings* settings)
{
  settings->btype = 2; /*compress with dynamic huffman tree (not in the mathematical sense, just not the predefined one)*/
  settings->useLZ77 = 1;
  settings->windowSize = 2048; /*this is a good tradeoff between speed and compression ratio*/
}

const LodeZlib_DeflateSettings LodeZlib_defaultDeflateSettings = {2, 1, 2048};

static unsigned deflateNoCompression(ucvector* out, const unsigned char* data, size_t datasize)
{
  /*non compressed deflate block data: 1 bit BFINAL,2 bits BTYPE,(5 bits): it jumps to start of next byte, 2 bytes LEN, 2 bytes NLEN, LEN bytes literal DATA*/
  
  size_t i, j, numdeflateblocks = datasize / 65536 + 1;
  unsigned datapos = 0;
  for(i = 0; i < numdeflateblocks; i++)
  {
    unsigned BFINAL, BTYPE, LEN, NLEN;
    unsigned char firstbyte;
    
    BFINAL = (i == numdeflateblocks - 1);
    BTYPE = 0;
    
    firstbyte = (unsigned char)(BFINAL + ((BTYPE & 1) << 1) + ((BTYPE & 2) << 1));
    ucvector_push_back(out, firstbyte);
    
    LEN = 65535;
    if(datasize - datapos < 65535) LEN = (unsigned)datasize - datapos;
    NLEN = 65535 - LEN;
    
    ucvector_push_back(out, (unsigned char)(LEN % 256));
    ucvector_push_back(out, (unsigned char)(LEN / 256));
    ucvector_push_back(out, (unsigned char)(NLEN % 256));
    ucvector_push_back(out, (unsigned char)(NLEN / 256));

    /*Decompressed data*/
    for(j = 0; j < 65535 && datapos < datasize; j++)
    {
      ucvector_push_back(out, data[datapos++]);
    }
  }
  
  return 0;
}

/*write the encoded data, using lit/len as well as distance codes*/
static void writeLZ77data(size_t* bp, ucvector* out, const uivector* lz77_encoded, const HuffmanTree* codes, const HuffmanTree* codesD)
{
  size_t i = 0;
  for(i = 0; i < lz77_encoded->size; i++)
  {
    unsigned val = lz77_encoded->data[i];
    addHuffmanSymbol(bp, out, HuffmanTree_getCode(codes, val), HuffmanTree_getLength(codes, val));
    if(val > 256) /*for a length code, 3 more things have to be added*/
    {
      unsigned length_index = val - FIRST_LENGTH_CODE_INDEX;
      unsigned n_length_extra_bits = LENGTHEXTRA[length_index];
      unsigned length_extra_bits = lz77_encoded->data[++i];
      
      unsigned distance_code = lz77_encoded->data[++i];
      
      unsigned distance_index = distance_code;
      unsigned n_distance_extra_bits = DISTANCEEXTRA[distance_index];
      unsigned distance_extra_bits = lz77_encoded->data[++i];
      
      addBitsToStream(bp, out, length_extra_bits, n_length_extra_bits);
      addHuffmanSymbol(bp, out, HuffmanTree_getCode(codesD, distance_code), HuffmanTree_getLength(codesD, distance_code));
      addBitsToStream(bp, out, distance_extra_bits, n_distance_extra_bits);
    }
  }
}

static unsigned deflateDynamic(ucvector* out, const unsigned char* data, size_t datasize, const LodeZlib_DeflateSettings* settings)
{
  /*
  after the BFINAL and BTYPE, the dynamic block consists out of the following:
  - 5 bits HLIT, 5 bits HDIST, 4 bits HCLEN
  - (HCLEN+4)*3 bits code lengths of code length alphabet
  - HLIT + 257 code lenghts of lit/length alphabet (encoded using the code length alphabet, + possible repetition codes 16, 17, 18)
  - HDIST + 1 code lengths of distance alphabet (encoded using the code length alphabet, + possible repetition codes 16, 17, 18)
  - compressed data
  - 256 (end code)
  */
  
  unsigned error = 0;
  
  uivector lz77_encoded;
  HuffmanTree codes; /*tree for literal values and length codes*/
  HuffmanTree codesD; /*tree for distance codes*/
  HuffmanTree codelengthcodes;
  uivector frequencies;
  uivector frequenciesD;
  uivector amounts; /*the amounts in the "normal" order*/
  uivector lldl;
  uivector lldll; /*lit/len & dist code lenghts*/
  uivector clcls;
  
  unsigned BFINAL = 1; /*make only one block... the first and final one*/
  size_t numcodes, numcodesD, i, bp = 0; /*the bit pointer*/
  unsigned HLIT, HDIST, HCLEN;
  
  uivector_init(&lz77_encoded);
  HuffmanTree_init(&codes);
  HuffmanTree_init(&codesD);
  HuffmanTree_init(&codelengthcodes);
  uivector_init(&frequencies);
  uivector_init(&frequenciesD);
  uivector_init(&amounts);
  uivector_init(&lldl);
  uivector_init(&lldll);
  uivector_init(&clcls);
  
  while(!error) /*the goto-avoiding while construct: break out to go to the cleanup phase, a break at the end makes sure the while is never repeated*/
  {
    if(settings->useLZ77) encodeLZ77(&lz77_encoded, data, datasize, settings->windowSize); /*LZ77 encoded*/
    else
    {
      uivector_resize(&lz77_encoded, datasize);
      for(i = 0; i < datasize; i++) lz77_encoded.data[i] = data[i]; /*no LZ77, but still will be Huffman compressed*/
    }
    
    uivector_resizev(&frequencies, 286, 0);
    uivector_resizev(&frequenciesD, 30, 0);
    for(i = 0; i < lz77_encoded.size; i++)
    {
      unsigned symbol = lz77_encoded.data[i];
      frequencies.data[symbol]++;
      if(symbol > 256)
      {
        unsigned dist = lz77_encoded.data[i + 2];
        frequenciesD.data[dist]++;
        i += 3;
      }
    }
    frequencies.data[256] = 1; /*there will be exactly 1 end code, at the end of the block*/
    
    error = HuffmanTree_makeFromFrequencies(&codes, frequencies.data, frequencies.size, 15);
    if(error) break;
    error = HuffmanTree_makeFromFrequencies(&codesD, frequenciesD.data, frequenciesD.size, 15);
    if(error) break;
    
    addBitToStream(&bp, out, BFINAL);
    addBitToStream(&bp, out, 0); /*first bit of BTYPE "dynamic"*/
    addBitToStream(&bp, out, 1); /*second bit of BTYPE "dynamic"*/
  
    numcodes = codes.numcodes; if(numcodes > 286) numcodes = 286;
    numcodesD = codesD.numcodes; if(numcodesD > 30) numcodesD = 30;
    for(i = 0; i < numcodes; i++) uivector_push_back(&lldll, HuffmanTree_getLength(&codes, (unsigned)i));
    for(i = 0; i < numcodesD; i++) uivector_push_back(&lldll, HuffmanTree_getLength(&codesD, (unsigned)i));
    
    /*make lldl smaller by using repeat codes 16 (copy length 3-6 times), 17 (3-10 zeroes), 18 (11-138 zeroes)*/
    for(i = 0; i < (unsigned)lldll.size; i++)
    {
      unsigned j = 0;
      while(i + j + 1 < (unsigned)lldll.size && lldll.data[i + j + 1] == lldll.data[i]) j++;
      
      if(lldll.data[i] == 0 && j >= 2)
      {
        j++; /*include the first zero*/
        if(j <= 10) { uivector_push_back(&lldl, 17); uivector_push_back(&lldl, j - 3); }
        else
        {
          if(j > 138) j = 138;
          uivector_push_back(&lldl, 18); uivector_push_back(&lldl, j - 11);
        }
        i += (j - 1);
      }
      else if(j >= 3)
      {
        size_t k;
        unsigned num = j / 6, rest = j % 6;
        uivector_push_back(&lldl, lldll.data[i]);
        for(k = 0; k < num; k++) { uivector_push_back(&lldl, 16); uivector_push_back(&lldl,    6 - 3); }
        if(rest >= 3)            { uivector_push_back(&lldl, 16); uivector_push_back(&lldl, rest - 3); }
        else j -= rest;
        i += j;
      }
      else uivector_push_back(&lldl, lldll.data[i]);
    }
    
    /*generate huffmantree for the length codes of lit/len and dist codes*/
    uivector_resizev(&amounts, 19, 0); /*16 possible lengths (0-15) and 3 repeat codes (16, 17 and 18)*/
    for(i = 0; i < lldl.size; i++)
    {
      amounts.data[lldl.data[i]]++;
      if(lldl.data[i] >= 16) i++; /*after a repeat code come the bits that specify the amount, those don't need to be in the amounts calculation*/
    }
    
    error = HuffmanTree_makeFromFrequencies(&codelengthcodes, amounts.data, amounts.size, 7);
    if(error) break;
    
    uivector_resize(&clcls, 19);
    for(i = 0; i < 19; i++) clcls.data[i] = HuffmanTree_getLength(&codelengthcodes, CLCL[i]); /*lenghts of code length tree is in the order as specified by deflate*/
    while(clcls.data[clcls.size - 1] == 0 && clcls.size > 4) uivector_resize(&clcls, clcls.size - 1); /*remove zeros at the end, but minimum size must be 4*/
    
    /*write the HLIT, HDIST and HCLEN values*/
    HLIT = (unsigned)(numcodes - 257);
    HDIST = (unsigned)(numcodesD - 1);
    HCLEN = (unsigned)clcls.size - 4;
    addBitsToStream(&bp, out, HLIT, 5);
    addBitsToStream(&bp, out, HDIST, 5);
    addBitsToStream(&bp, out, HCLEN, 4);
    
    /*write the code lenghts of the code length alphabet*/
    for(i = 0; i < HCLEN + 4; i++) addBitsToStream(&bp, out, clcls.data[i], 3);
  
    /*write the lenghts of the lit/len AND the dist alphabet*/
    for(i = 0; i < lldl.size; i++)
    {
      addHuffmanSymbol(&bp, out, HuffmanTree_getCode(&codelengthcodes, lldl.data[i]), HuffmanTree_getLength(&codelengthcodes, lldl.data[i]));
      /*extra bits of repeat codes*/
      if(lldl.data[i] == 16) addBitsToStream(&bp, out, lldl.data[++i], 2);
      else if(lldl.data[i] == 17) addBitsToStream(&bp, out, lldl.data[++i], 3);
      else if(lldl.data[i] == 18) addBitsToStream(&bp, out, lldl.data[++i], 7);
    }
    
    /*write the compressed data symbols*/
    writeLZ77data(&bp, out, &lz77_encoded, &codes, &codesD);
    if(HuffmanTree_getLength(&codes, 256) == 0) { error = 64; break; } /*the length of the end code 256 must be larger than 0*/
    addHuffmanSymbol(&bp, out, HuffmanTree_getCode(&codes, 256), HuffmanTree_getLength(&codes, 256)); /*end code*/
    
    break; /*end of error-while*/
  }
  
  /*cleanup*/
  uivector_cleanup(&lz77_encoded);
  HuffmanTree_cleanup(&codes);
  HuffmanTree_cleanup(&codesD);
  HuffmanTree_cleanup(&codelengthcodes);
  uivector_cleanup(&frequencies);
  uivector_cleanup(&frequenciesD);
  uivector_cleanup(&amounts);
  uivector_cleanup(&lldl);
  uivector_cleanup(&lldll);
  uivector_cleanup(&clcls);
  
  return error;
}

static unsigned deflateFixed(ucvector* out, const unsigned char* data, size_t datasize, const LodeZlib_DeflateSettings* settings)
{
  HuffmanTree codes; /*tree for literal values and length codes*/
  HuffmanTree codesD; /*tree for distance codes*/
  
  unsigned BFINAL = 1; /*make only one block... the first and final one*/
  size_t i, bp = 0; /*the bit pointer*/
  
  HuffmanTree_init(&codes);
  HuffmanTree_init(&codesD);
  
  generateFixedTree(&codes);
  generateDistanceTree(&codesD);
  
  addBitToStream(&bp, out, BFINAL);
  addBitToStream(&bp, out, 1); /*first bit of BTYPE*/
  addBitToStream(&bp, out, 0); /*second bit of BTYPE*/
  
  if(settings->useLZ77) /*LZ77 encoded*/
  {
    uivector lz77_encoded;
    uivector_init(&lz77_encoded);
    encodeLZ77(&lz77_encoded, data, datasize, settings->windowSize);
    writeLZ77data(&bp, out, &lz77_encoded, &codes, &codesD);
    uivector_cleanup(&lz77_encoded);
  }
  else /*no LZ77, but still will be Huffman compressed*/
  {
    for(i = 0; i < datasize; i++) addHuffmanSymbol(&bp, out, HuffmanTree_getCode(&codes, data[i]), HuffmanTree_getLength(&codes, data[i]));
  }
  addHuffmanSymbol(&bp, out, HuffmanTree_getCode(&codes, 256), HuffmanTree_getLength(&codes, 256)); /*"end" code*/
  
  /*cleanup*/
  HuffmanTree_cleanup(&codes);
  HuffmanTree_cleanup(&codesD);
  
  return 0;
}

unsigned LodeFlate_deflate(ucvector* out, const unsigned char* data, size_t datasize, const LodeZlib_DeflateSettings* settings)
{
  unsigned error = 0;
  if(settings->btype == 0) error = deflateNoCompression(out, data, datasize);
  else if(settings->btype == 1) error = deflateFixed(out, data, datasize, settings);
  else if(settings->btype == 2) error = deflateDynamic(out, data, datasize, settings);
  else error = 61;
  return error;
}

/* ////////////////////////////////////////////////////////////////////////// */
/* / Adler32                                                                  */
/* ////////////////////////////////////////////////////////////////////////// */

static unsigned update_adler32(unsigned adler, const unsigned char* data, unsigned len)
{
   unsigned s1 = adler & 0xffff;
   unsigned s2 = (adler >> 16) & 0xffff;
   
  while(len > 0)
  {
    /*at least 5550 sums can be done before the sums overflow, saving us from a lot of module divisions*/
    unsigned amount = len > 5550 ? 5550 : len;
    len -= amount;
    while(amount > 0)
    {
      s1 = (s1 + *data++);
      s2 = (s2 + s1);
      amount--;
    }
    s1 %= 65521;
    s2 %= 65521;
  }
  
  return (s2 << 16) | s1;
}

/*Return the adler32 of the bytes data[0..len-1]*/
static unsigned adler32(const unsigned char* data, unsigned len)
{
  return update_adler32(1L, data, len);
}

/* ////////////////////////////////////////////////////////////////////////// */
/* / Reading and writing single bits and bytes from/to stream for Zlib      / */
/* ////////////////////////////////////////////////////////////////////////// */

void LodeZlib_add32bitInt(ucvector* buffer, unsigned value)
{
  ucvector_push_back(buffer, (unsigned char)((value >> 24) & 0xff));
  ucvector_push_back(buffer, (unsigned char)((value >> 16) & 0xff));
  ucvector_push_back(buffer, (unsigned char)((value >>  8) & 0xff));
  ucvector_push_back(buffer, (unsigned char)((value      ) & 0xff));
}

unsigned LodeZlib_read32bitInt(const unsigned char* buffer)
{
  return (buffer[0] << 24) | (buffer[1] << 16) | (buffer[2] << 8) | buffer[3];
}

/* ////////////////////////////////////////////////////////////////////////// */
/* / Zlib                                                                   / */
/* ////////////////////////////////////////////////////////////////////////// */

void LodeZlib_DecompressSettings_init(LodeZlib_DecompressSettings* settings)
{
  settings->ignoreAdler32 = 0;
}

const LodeZlib_DecompressSettings LodeZlib_defaultDecompressSettings = {0};

unsigned LodeZlib_decompress(unsigned char** out, size_t* outsize, const unsigned char* in, size_t insize, const LodeZlib_DecompressSettings* settings)
{
  unsigned error = 0;
  unsigned CM, CINFO, FDICT;
  ucvector outv;
  
  if(insize < 2) { error = 53; return error; } /*error, size of zlib data too small*/
  /*read information from zlib header*/
  if((in[0] * 256 + in[1]) % 31 != 0) { error = 24; return error; } /*error: 256 * in[0] + in[1] must be a multiple of 31, the FCHECK value is supposed to be made that way*/

  CM = in[0] & 15;
  CINFO = (in[0] >> 4) & 15;
  /*FCHECK = in[1] & 31; //FCHECK is already tested above*/
  FDICT = (in[1] >> 5) & 1;
  /*FLEVEL = (in[1] >> 6) & 3; //not really important, all it does it to give a compiler warning about unused variable, we don't care what encoding setting the encoder used*/
  
  if(CM != 8 || CINFO > 7) { error = 25; return error; } /*error: only compression method 8: inflate with sliding window of 32k is supported by the PNG spec*/
  if(FDICT != 0) { error = 26; return error; } /*error: the specification of PNG says about the zlib stream: "The additional flags shall not specify a preset dictionary."*/
  
  ucvector_init_buffer(&outv, *out, *outsize); /*ucvector-controlled version of the output buffer, for dynamic array*/
  error = LodeFlate_inflate(&outv, in, insize, 2);
  *out = outv.data;
  *outsize = outv.size;
  if(error != 0) return error;
  
  if(!settings->ignoreAdler32)
  {
    unsigned ADLER32 = LodeZlib_read32bitInt(&in[insize - 4]);
    unsigned checksum = adler32(outv.data, (unsigned)outv.size);
    if(checksum != ADLER32) { error = 58; return error; }
  }
  
  return error;
}

unsigned LodeZlib_compress(unsigned char** out, size_t* outsize, const unsigned char* in, size_t insize, const LodeZlib_DeflateSettings* settings)
{
  /*initially, *out must be NULL and outsize 0, if you just give some random *out that's pointing to a non allocated buffer, this'll crash*/
  ucvector deflatedata, outv;
  size_t i;
  unsigned error;
  
  unsigned ADLER32;
  /*zlib data: 1 byte CMF (CM+CINFO), 1 byte FLG, deflate data, 4 byte ADLER32 checksum of the Decompressed data*/
  unsigned CMF = 120; /*0b01111000: CM 8, CINFO 7. With CINFO 7, any window size up to 32768 can be used.*/
  unsigned FLEVEL = 0;
  unsigned FDICT = 0;
  unsigned CMFFLG = 256 * CMF + FDICT * 32 + FLEVEL * 64;
  unsigned FCHECK = 31 - CMFFLG % 31;
  CMFFLG += FCHECK;
  
  ucvector_init_buffer(&outv, *out, *outsize); /*ucvector-controlled version of the output buffer, for dynamic array*/
  
  ucvector_push_back(&outv, (unsigned char)(CMFFLG / 256));
  ucvector_push_back(&outv, (unsigned char)(CMFFLG % 256));
  
  ucvector_init(&deflatedata);
  error = LodeFlate_deflate(&deflatedata, in, insize, settings);
  
  if(!error)
  {
    ADLER32 = adler32(in, (unsigned)insize);
    for(i = 0; i < deflatedata.size; i++) ucvector_push_back(&outv, deflatedata.data[i]);
    ucvector_cleanup(&deflatedata);
    LodeZlib_add32bitInt(&outv, ADLER32);
  }
  
  *out = outv.data;
  *outsize = outv.size;
  
  return error;
}



/* ////////////////////////////////////////////////////////////////////////// */
/* ////////////////////////////////////////////////////////////////////////// */
/* ////////////////////////////////////////////////////////////////////////// */
/* ////////////////////////////////////////////////////////////////////////// */
/* ////////////////////////////////////////////////////////////////////////// */
/* // End of Zlib related code, now comes the PNG related code that uses it// */
/* ////////////////////////////////////////////////////////////////////////// */
/* ////////////////////////////////////////////////////////////////////////// */
/* ////////////////////////////////////////////////////////////////////////// */
/* ////////////////////////////////////////////////////////////////////////// */
/* ////////////////////////////////////////////////////////////////////////// */



/*
The two functions below (LodePNG_decompress and LodePNG_compress) directly call the
LodeZlib_decompress and LodeZlib_compress functions. The only purpose of the functions
below, is to provide the ability to let LodePNG use a different Zlib encoder by only
changing the two functions below, instead of changing it inside the vareous places
in the other LodePNG functions.

*out must be NULL and *outsize must be 0 initially, and after the function is done,
*out must point to the decompressed data, *outsize must be the size of it, and must
be the size of the useful data in bytes, not the alloc size.
*/

static unsigned LodePNG_decompress(unsigned char** out, size_t* outsize, const unsigned char* in, size_t insize, const LodeZlib_DecompressSettings* settings)
{
  return LodeZlib_decompress(out, outsize, in, insize, settings);
}

static unsigned LodePNG_compress(unsigned char** out, size_t* outsize, const unsigned char* in, size_t insize, const LodeZlib_DeflateSettings* settings)
{
  return LodeZlib_compress(out, outsize, in, insize, settings);
}


/* ////////////////////////////////////////////////////////////////////////// */
/* / CRC32                                                                  / */
/* ////////////////////////////////////////////////////////////////////////// */

static unsigned Crc32_crc_table_computed = 0;
static unsigned Crc32_crc_table[256];

/*Make the table for a fast CRC.*/
static void Crc32_make_crc_table(void)
{
  unsigned c, k, n;
  for(n = 0; n < 256; n++)
  {
    c = n;
    for(k = 0; k < 8; k++)
    {
      if(c & 1) c = 0xedb88320L ^ (c >> 1);
      else c = c >> 1;
    }
    Crc32_crc_table[n] = c;
  }
  Crc32_crc_table_computed = 1;
}

/*Update a running CRC with the bytes buf[0..len-1]--the CRC should be 
initialized to all 1's, and the transmitted value is the 1's complement of the
final running CRC (see the crc() routine below).*/
static unsigned Crc32_update_crc(const unsigned char* buf, unsigned crc, size_t len)
{
  unsigned c = crc;
  size_t n;

  if(!Crc32_crc_table_computed) Crc32_make_crc_table();
  for(n = 0; n < len; n++)
  {
    c = Crc32_crc_table[(c ^ buf[n]) & 0xff] ^ (c >> 8);
  }
  return c;
}

/*Return the CRC of the bytes buf[0..len-1].*/
static unsigned Crc32_crc(const unsigned char* buf, size_t len)
{
  return Crc32_update_crc(buf, 0xffffffffL, len) ^ 0xffffffffL;
}

/* ////////////////////////////////////////////////////////////////////////// */
/* / Reading and writing single bits and bytes from/to stream for LodePNG   / */
/* ////////////////////////////////////////////////////////////////////////// */

static unsigned char readBitFromReversedStream(size_t* bitpointer, const unsigned char* bitstream)
{
  unsigned char result = (unsigned char)((bitstream[(*bitpointer) >> 3] >> (7 - ((*bitpointer) & 0x7))) & 1);
  (*bitpointer)++;
  return result;
}

static unsigned readBitsFromReversedStream(size_t* bitpointer, const unsigned char* bitstream, size_t nbits)
{
  unsigned result = 0;
  size_t i;
  for(i = nbits - 1; i < nbits; i--) result += (unsigned)readBitFromReversedStream(bitpointer, bitstream) << i;
  return result;
}

static void setBitOfReversedStream0(size_t* bitpointer, unsigned char* bitstream, unsigned char bit)
{
  /*the current bit in bitstream must be 0 for this to work*/
  if(bit) bitstream[(*bitpointer) >> 3] |=  (bit << (7 - ((*bitpointer) & 0x7))); /*earlier bit of huffman code is in a lesser significant bit of an earlier byte*/
  (*bitpointer)++;
}

static void setBitOfReversedStream(size_t* bitpointer, unsigned char* bitstream, unsigned char bit)
{
  /*the current bit in bitstream may be 0 or 1 for this to work*/
  if(bit == 0) bitstream[(*bitpointer) >> 3] &=  (unsigned char)(~(1 << (7 - ((*bitpointer) & 0x7))));
  else bitstream[(*bitpointer) >> 3] |=  (1 << (7 - ((*bitpointer) & 0x7)));
  (*bitpointer)++;
}

static unsigned LodePNG_read32bitInt(const unsigned char* buffer)
{
  return (buffer[0] << 24) | (buffer[1] << 16) | (buffer[2] << 8) | buffer[3];
}

static void LodePNG_add32bitInt(ucvector* buffer, unsigned value)
{
  ucvector_push_back(buffer, (unsigned char)((value >> 24) & 0xff));
  ucvector_push_back(buffer, (unsigned char)((value >> 16) & 0xff));
  ucvector_push_back(buffer, (unsigned char)((value >>  8) & 0xff));
  ucvector_push_back(buffer, (unsigned char)((value      ) & 0xff));
}

/* ////////////////////////////////////////////////////////////////////////// */
/* / Color types and such                                                   / */
/* ////////////////////////////////////////////////////////////////////////// */

/*return type is a LodePNG error code*/
static unsigned checkColorValidity(unsigned colorType, unsigned bd) /*bd = bitDepth*/
{
  switch(colorType)
  {
    case 0: if(!(bd == 1 || bd == 2 || bd == 4 || bd == 8 || bd == 16)) return 37; break; /*grey*/
    case 2: if(!(                                 bd == 8 || bd == 16)) return 37; break; /*RGB*/
    case 3: if(!(bd == 1 || bd == 2 || bd == 4 || bd == 8            )) return 37; break; /*palette*/
    case 4: if(!(                                 bd == 8 || bd == 16)) return 37; break; /*grey + alpha*/
    case 6: if(!(                                 bd == 8 || bd == 16)) return 37; break; /*RGBA*/
    default: return 31;
  }
  return 0; /*allowed color type / bits combination*/
}

static unsigned getNumColorChannels(unsigned colorType)
{
  switch(colorType)
  {
    case 0: return 1; /*grey*/
    case 2: return 3; /*RGB*/
    case 3: return 1; /*palette*/
    case 4: return 2; /*grey + alpha*/
    case 6: return 4; /*RGBA*/
  }
  return 0; /*unexisting color type*/
}

static unsigned getBpp(unsigned colorType, unsigned bitDepth)
{
  return getNumColorChannels(colorType) * bitDepth; /*bits per pixel is amount of channels * bits per channel*/
}

/* ////////////////////////////////////////////////////////////////////////// */

void LodePNG_InfoColor_init(LodePNG_InfoColor* info)
{
  info->key_defined = 0;
  info->colorType = 6;
  info->bitDepth = 8;
  info->palette = 0;
  info->palettesize = 0;
}

void LodePNG_InfoColor_cleanup(LodePNG_InfoColor* info)
{
  LodePNG_InfoColor_clearPalette(info);
}

void LodePNG_InfoColor_clearPalette(LodePNG_InfoColor* info)
{
  if(info->palette) free(info->palette);
  info->palettesize = 0;
}

void LodePNG_InfoColor_addPalette(LodePNG_InfoColor* info, unsigned char r, unsigned char g, unsigned char b, unsigned char a)
{
  unsigned char* data;
  /*the same resize technique as C++ std::vectors is used, and here it's made so that for a palette with the max of 256 colors, it'll have the exact alloc size*/
  if(!(info->palettesize & (info->palettesize - 1))) /*if palettesize is 0 or a power of two*/
  {
    /*allocated data must be at least 4* palettesize (for 4 color bytes)*/
    size_t alloc_size = info->palettesize == 0 ? 4 : info->palettesize * 4 * 2;
    data = (unsigned char*)realloc(info->palette, alloc_size);
    if(!data) return;
    else info->palette = data;
  }
  info->palette[4 * info->palettesize + 0] = r;
  info->palette[4 * info->palettesize + 1] = g;
  info->palette[4 * info->palettesize + 2] = b;
  info->palette[4 * info->palettesize + 3] = a;
  info->palettesize++;
}

unsigned LodePNG_InfoColor_getBpp(const LodePNG_InfoColor* info) { return getBpp(info->colorType, info->bitDepth); } /*calculate bits per pixel out of colorType and bitDepth*/
unsigned LodePNG_InfoColor_getChannels(const LodePNG_InfoColor* info) { return getNumColorChannels(info->colorType); }
unsigned LodePNG_InfoColor_isGreyscaleType(const LodePNG_InfoColor* info) { return info->colorType == 0 || info->colorType == 4; }
unsigned LodePNG_InfoColor_isAlphaType(const LodePNG_InfoColor* info) { return (info->colorType & 4) != 0; }

unsigned LodePNG_InfoColor_equal(const LodePNG_InfoColor* info1, const LodePNG_InfoColor* info2)
{
  return info1->colorType == info2->colorType
      && info1->bitDepth  == info2->bitDepth; /*palette and color key not compared*/
}

void LodePNG_InfoPng_init(LodePNG_InfoPng* info)
{
  LodePNG_InfoColor_init(&info->color);
  info->background_defined = 0;
  info->interlaceMethod = 0;
  info->compressionMethod = 0;
  info->filterMethod = 0;
  
  info->num_texts = 0;
  info->text_keys = NULL;
  info->text_strings = NULL;
}

void LodePNG_InfoPng_cleanup(LodePNG_InfoPng* info)
{
  LodePNG_InfoColor_cleanup(&info->color);
  LodePNG_InfoPng_clearText(info);
}

void LodePNG_InfoPng_clearText(LodePNG_InfoPng* info)
{
  size_t i;
  for(i = 0; i < info->num_texts; i++)
    {
    string_cleanup(&info->text_keys[i]);
    string_cleanup(&info->text_strings[i]);
    }
  free(info->text_keys);
  free(info->text_strings);
}

void LodePNG_InfoPng_addText(LodePNG_InfoPng* info, const char* key, const char* str) /*push back both texts at once*/
{
  char** new_keys = (char**)(realloc(info->text_keys, sizeof(char*) * (info->num_texts + 1)));
  char** new_strings = (char**)(realloc(info->text_strings, sizeof(char*) * (info->num_texts + 1)));
  if(!new_keys || !new_strings) return;
  
  info->num_texts++;
  info->text_keys = new_keys;
  info->text_strings = new_strings;
  
  string_init(&info->text_keys[info->num_texts - 1]);
  string_set(&info->text_keys[info->num_texts - 1], key);
  
  string_init(&info->text_strings[info->num_texts - 1]);
  string_set(&info->text_strings[info->num_texts - 1], str);
}

void LodePNG_InfoColor_copy(LodePNG_InfoColor* dest, const LodePNG_InfoColor* source)
{
  size_t i;
  LodePNG_InfoColor_cleanup(dest);
  *dest = *source;
  dest->palette = (unsigned char*)malloc(source->palettesize * 4);
  for(i = 0; i < source->palettesize * 4; i++) dest->palette[i] = source->palette[i];
}

void LodePNG_InfoPng_copy(LodePNG_InfoPng* dest, const LodePNG_InfoPng* source)
{
  size_t i = 0;
  LodePNG_InfoPng_cleanup(dest);
  *dest = *source;
  LodePNG_InfoColor_init(&dest->color);
  LodePNG_InfoColor_copy(&dest->color, &source->color);
  dest->text_keys = 0;
  dest->text_strings = 0;
  dest->num_texts = 0;
  for(i = 0; i < source->num_texts; i++) LodePNG_InfoPng_addText(dest, source->text_keys[i], source->text_strings[i]);
}

void LodePNG_InfoRaw_init(LodePNG_InfoRaw* info)
{
  LodePNG_InfoColor_init(&info->color);
}

void LodePNG_InfoRaw_cleanup(LodePNG_InfoRaw* info)
{
  LodePNG_InfoColor_cleanup(&info->color);
}

void LodePNG_InfoRaw_copy(LodePNG_InfoRaw* dest, const LodePNG_InfoRaw* source)
{
  LodePNG_InfoRaw_cleanup(dest);
  *dest = *source;
  LodePNG_InfoColor_init(&dest->color);
  LodePNG_InfoColor_copy(&dest->color, &source->color);
}

/* ////////////////////////////////////////////////////////////////////////// */

/*
converts from any color type to 24-bit or 32-bit (later maybe more supported). return value = LodePNG error code
the out buffer must have (w * h * bpp + 7) / 8 bytes, where bpp is the bits per pixel of the output color type (LodePNG_InfoColor_getBpp)
for < 8 bpp images, there may _not_ be padding bits at the end of scanlines.
*/
unsigned LodePNG_convert(unsigned char* out, const unsigned char* in, LodePNG_InfoColor* infoOut, LodePNG_InfoColor* infoIn, unsigned w, unsigned h)
{
  const size_t numpixels = w * h; /*amount of pixels*/
  const unsigned OUT_BYTES = LodePNG_InfoColor_getBpp(infoOut) / 8; /*bytes per pixel in the output image*/
  const unsigned OUT_ALPHA = LodePNG_InfoColor_isAlphaType(infoOut); /*use 8-bit alpha channel*/
  
  size_t i, c, bp = 0; /*bitpointer, used by less-than-8-bit color types*/
  
  /*cases where in and out already have the same format*/
  if(LodePNG_InfoColor_equal(infoIn, infoOut))
  {
    size_t i, size = (w * h * LodePNG_InfoColor_getBpp(infoIn) + 7) / 8;
    for(i = 0; i < size; i++) out[i] = in[i];
    return 0;
  }

  if((infoOut->colorType == 2 || infoOut->colorType == 6) && infoOut->bitDepth == 8)
  {
    if(infoIn->bitDepth == 8)
    {
      switch(infoIn->colorType)
      {
        case 0: /*greyscale color*/
          for(i = 0; i < numpixels; i++)
          {
            if(OUT_ALPHA) out[OUT_BYTES * i + 3] = 255;
            out[OUT_BYTES * i + 0] = out[OUT_BYTES * i + 1] = out[OUT_BYTES * i + 2] = in[i];
            if(OUT_ALPHA && infoIn->key_defined && in[i] == infoIn->key_r) out[OUT_BYTES * i + 3] = 0;
          }
        break;
        case 2: /*RGB color*/
          for(i = 0; i < numpixels; i++)
          {
            if(OUT_ALPHA) out[OUT_BYTES * i + 3] = 255;
            for(c = 0; c < 3; c++) out[OUT_BYTES * i + c] = in[3 * i + c];
            if(OUT_ALPHA && infoIn->key_defined == 1 && in[3 * i + 0] == infoIn->key_r && in[3 * i + 1] == infoIn->key_g && in[3 * i + 2] == infoIn->key_b) out[OUT_BYTES * i + 3] = 0;
          }
        break;
        case 3: /*indexed color (palette)*/
          for(i = 0; i < numpixels; i++)
          {
            if(OUT_ALPHA) out[OUT_BYTES * i + 3] = 255;
            if(in[i] >= infoIn->palettesize) return 46;
            for(c = 0; c < OUT_BYTES; c++) out[OUT_BYTES * i + c] = infoIn->palette[4 * in[i] + c]; /*get rgb colors from the palette*/
          }
        break;
        case 4: /*greyscale with alpha*/
          for(i = 0; i < numpixels; i++)
          {
            out[OUT_BYTES * i + 0] = out[OUT_BYTES * i + 1] = out[OUT_BYTES * i + 2] = in[2 * i + 0];
            if(OUT_ALPHA) out[OUT_BYTES * i + 3] = in[2 * i + 1];
          }
        break;
        case 6: /*RGB with alpha*/
          for(i = 0; i < numpixels; i++)
          {
            for(c = 0; c < OUT_BYTES; c++) out[OUT_BYTES * i + c] = in[4 * i + c];
          }
        break;
        default: break;
      }
    }
    else if(infoIn->bitDepth == 16)
    {
      switch(infoIn->colorType)
      {
        case 0: /*greyscale color*/
          for(i = 0; i < numpixels; i++)
          {
            if(OUT_ALPHA) out[OUT_BYTES * i + 3] = 255;
            out[OUT_BYTES * i + 0] = out[OUT_BYTES * i + 1] = out[OUT_BYTES * i + 2] = in[2 * i];
            if(OUT_ALPHA && infoIn->key_defined && 256U * in[i] + in[i + 1] == infoIn->key_r) out[OUT_BYTES * i + 3] = 0;
          }
        break;
        case 2: /*RGB color*/
          for(i = 0; i < numpixels; i++)
          {
            if(OUT_ALPHA) out[OUT_BYTES * i + 3] = 255;
            for(c = 0; c < 3; c++) out[OUT_BYTES * i + c] = in[6 * i + 2 * c];
            if(OUT_ALPHA && infoIn->key_defined && 256U * in[6 * i + 0] + in[6 * i + 1] == infoIn->key_r && 256U * in[6 * i + 2] + in[6 * i + 3] == infoIn->key_g && 256U * in[6 * i + 4] + in[6 * i + 5] == infoIn->key_b) out[OUT_BYTES * i + 3] = 0;
          }
        break;
        case 4: /*greyscale with alpha*/
          for(i = 0; i < numpixels; i++)
          {
            out[OUT_BYTES * i + 0] = out[OUT_BYTES * i + 1] = out[OUT_BYTES * i + 2] = in[4 * i]; /*most significant byte*/
            if(OUT_ALPHA) out[OUT_BYTES * i + 3] = in[4 * i + 2];
          }
        break;
        case 6: /*RGB with alpha*/
          for(i = 0; i < numpixels; i++)
          {
            for(c = 0; c < OUT_BYTES; c++) out[OUT_BYTES * i + c] = in[8 * i + 2 * c];
          }
          break;
        default: break;
      }
    }
    else /*infoIn->bitDepth is less than 8 bit per channel*/
    {
      switch(infoIn->colorType)
      {
        case 0: /*greyscale color*/
          for(i = 0; i < numpixels; i++)
          {
            unsigned value = readBitsFromReversedStream(&bp, in, infoIn->bitDepth);
            if(OUT_ALPHA) out[OUT_BYTES * i + 3] = 255;
            if(OUT_ALPHA && infoIn->key_defined && value && ((1U << infoIn->bitDepth) - 1U) == infoIn->key_r && ((1U << infoIn->bitDepth) - 1U)) out[OUT_BYTES * i + 3] = 0;
            value = (value * 255) / ((1 << infoIn->bitDepth) - 1); /*scale value from 0 to 255*/
            out[OUT_BYTES * i + 0] = out[OUT_BYTES * i + 1] = out[OUT_BYTES * i + 2] = (unsigned char)(value);
          }
        break;
        case 3: /*indexed color (palette)*/
          for(i = 0; i < numpixels; i++)
          {
            unsigned value = readBitsFromReversedStream(&bp, in, infoIn->bitDepth);
            if(OUT_ALPHA) out[OUT_BYTES * i + 3] = 255;
            if(value >= infoIn->palettesize) return 47;
            for(c = 0; c < OUT_BYTES; c++) out[OUT_BYTES * i + c] = infoIn->palette[4 * value + c]; /*get rgb colors from the palette*/
          }
        break;
        default: break;
      }
    }
  }
  else if(LodePNG_InfoColor_isGreyscaleType(infoOut) && infoOut->bitDepth == 8) /*conversion from greyscale to greyscale*/
  {
    if(!LodePNG_InfoColor_isGreyscaleType(infoIn)) return 62;
    if(infoIn->bitDepth == 8)
    {
      switch(infoIn->colorType)
      {
        case 0: /*greyscale color*/
          for(i = 0; i < numpixels; i++)
          {
            if(OUT_ALPHA) out[OUT_BYTES * i + 1] = 255;
            out[OUT_BYTES * i] = in[i];
            if(OUT_ALPHA && infoIn->key_defined && in[i] == infoIn->key_r) out[OUT_BYTES * i + 1] = 0;
          }
        break;
        case 4: /*greyscale with alpha*/
          for(i = 0; i < numpixels; i++)
          {
            out[OUT_BYTES * i + 0] = in[2 * i + 0];
            if(OUT_ALPHA) out[OUT_BYTES * i + 1] = in[2 * i + 1];
          }
        break;
        default: return 31;
      }
    }
    else if(infoIn->bitDepth == 16)
    {
      switch(infoIn->colorType)
      {
        case 0: /*greyscale color*/
          for(i = 0; i < numpixels; i++)
          {
            if(OUT_ALPHA) out[OUT_BYTES * i + 1] = 255;
            out[OUT_BYTES * i] = in[2 * i];
            if(OUT_ALPHA && infoIn->key_defined && 256U * in[i] + in[i + 1] == infoIn->key_r) out[OUT_BYTES * i + 1] = 0;
          }
        break;
        case 4: /*greyscale with alpha*/
          for(i = 0; i < numpixels; i++)
          {
            out[OUT_BYTES * i] = in[4 * i]; /*most significant byte*/
            if(OUT_ALPHA) out[OUT_BYTES * i + 1] = in[4 * i + 2]; /*most significant byte*/
          }
        break;
        default: return 31;
      }
    }
    else /*infoIn->bitDepth is less than 8 bit per channel*/
    {
      if(infoIn->colorType != 0) return 31; /*colorType 0 is the only greyscale type with < 8 bits per channel*/

      for(i = 0; i < numpixels; i++)
      {
        unsigned value = readBitsFromReversedStream(&bp, in, infoIn->bitDepth);
        if(OUT_ALPHA) out[OUT_BYTES * i + 1] = 255;
        if(OUT_ALPHA && infoIn->key_defined && value && ((1U << infoIn->bitDepth) - 1U) == infoIn->key_r && ((1U << infoIn->bitDepth) - 1U)) out[OUT_BYTES * i + 1] = 0;
        value = (value * 255) / ((1 << infoIn->bitDepth) - 1); /*scale value from 0 to 255*/
        out[OUT_BYTES * i] = (unsigned char)(value);
      }
    }
  }
  else return 59;
  
  return 0;
}

/*Paeth predicter, used by PNG filter type 4*/
static int paethPredictor(int a, int b, int c)
{
  int p = a + b - c;
  int pa = p > a ? p - a : a - p;
  int pb = p > b ? p - b : b - p;
  int pc = p > c ? p - c : c - p;
  
  if(pa <= pb && pa <= pc) return a;
  else if(pb <= pc) return b;
  else return c;
}

/*shared values used by multiple Adam7 related functions*/

static const unsigned ADAM7_IX[7] = { 0, 4, 0, 2, 0, 1, 0 }; /*x start values*/
static const unsigned ADAM7_IY[7] = { 0, 0, 4, 0, 2, 0, 1 }; /*y start values*/
static const unsigned ADAM7_DX[7] = { 8, 8, 4, 4, 2, 2, 1 }; /*x delta values*/
static const unsigned ADAM7_DY[7] = { 8, 8, 8, 4, 4, 2, 2 }; /*y delta values*/

static void Adam7_getpassvalues(unsigned passw[7], unsigned passh[7], size_t filter_passstart[8], size_t padded_passstart[8], size_t passstart[8], unsigned w, unsigned h, unsigned bpp)
{
  /*the passstart values have 8 values: the 8th one actually indicates the byte after the end of the 7th (= last) pass*/
  unsigned i;
  
  /*calculate width and height in pixels of each pass*/
  for(i = 0; i < 7; i++)
  {
    passw[i] = (w + ADAM7_DX[i] - ADAM7_IX[i] - 1) / ADAM7_DX[i];
    passh[i] = (h + ADAM7_DY[i] - ADAM7_IY[i] - 1) / ADAM7_DY[i];
    if(passw[i] == 0) passh[i] = 0;
    if(passh[i] == 0) passw[i] = 0;
  }
  
  filter_passstart[0] = padded_passstart[0] = passstart[0] = 0;
  for(i = 0; i < 7; i++)
  {
    filter_passstart[i + 1] = filter_passstart[i] + ((passw[i] && passh[i]) ? passh[i] * (1 + (passw[i] * bpp + 7) / 8) : 0); /*if passw[i] is 0, it's 0 bytes, not 1 (no filtertype-byte)*/
    padded_passstart[i + 1] = padded_passstart[i] + passh[i] * ((passw[i] * bpp + 7) / 8); /*bits padded if needed to fill full byte at end of each scanline*/
    passstart[i + 1] = passstart[i] + (passh[i] * passw[i] * bpp + 7) / 8; /*only padded at end of reduced image*/
  }
}

/* ////////////////////////////////////////////////////////////////////////// */
/* / PNG Decoder                                                            / */
/* ////////////////////////////////////////////////////////////////////////// */

/*read the information from the header and store it in the LodePNG_Info. return value is error*/
void LodePNG_inspect(LodePNG_Decoder* decoder, const unsigned char* in, size_t inlength)
{
  if(inlength == 0 || in == 0) { decoder->error = 48; return; } /*the given data is empty*/
  if(inlength < 29) { decoder->error = 27; return; } /*error: the data length is smaller than the length of the header*/
  
  /*when decoding a new PNG image, make sure all parameters created after previous decoding are reset*/
  LodePNG_InfoPng_cleanup(&decoder->infoPng);
  LodePNG_InfoPng_init(&decoder->infoPng);
  decoder->error = 0;

  if(in[0] != 137 || in[1] != 80 || in[2] != 78 || in[3] != 71 || in[4] != 13 || in[5] != 10 || in[6] != 26 || in[7] != 10) { decoder->error = 28; return; } /*error: the first 8 bytes are not the correct PNG signature*/
  if(in[12] != 'I' || in[13] != 'H' || in[14] != 'D' || in[15] != 'R') { decoder->error = 29; return; } /*error: it doesn't start with a IHDR chunk!*/
  
  /*read the values given in the header*/
  decoder->infoPng.width = LodePNG_read32bitInt(&in[16]);
  decoder->infoPng.height = LodePNG_read32bitInt(&in[20]);
  decoder->infoPng.color.bitDepth = in[24];
  decoder->infoPng.color.colorType = in[25];
  decoder->infoPng.compressionMethod = in[26];
  decoder->infoPng.filterMethod = in[27];
  decoder->infoPng.interlaceMethod = in[28];

  if(!decoder->settings.ignoreCrc)
  {
    unsigned CRC = LodePNG_read32bitInt(&in[29]);
    unsigned checksum = Crc32_crc(&in[12], 17);
    if(CRC != checksum) { decoder->error = 57; return; }
  }
  
  if(decoder->infoPng.compressionMethod != 0) { decoder->error = 32; return; } /*error: only compression method 0 is allowed in the specification*/
  if(decoder->infoPng.filterMethod != 0)      { decoder->error = 33; return; } /*error: only filter method 0 is allowed in the specification*/
  if(decoder->infoPng.interlaceMethod > 1)    { decoder->error = 34; return; } /*error: only interlace methods 0 and 1 exist in the specification*/
  
  decoder->error = checkColorValidity(decoder->infoPng.color.colorType, decoder->infoPng.color.bitDepth);
}

static unsigned unfilterScanline(unsigned char* recon, const unsigned char* scanline, const unsigned char* precon, size_t bytewidth, unsigned char filterType, size_t length)
{
  /*
  For PNG filter method 0
  unfilter a PNG image scanline by scanline. when the pixels are smaller than 1 byte, the filter works byte per byte (bytewidth = 1)
  precon is the previous unfiltered scanline, recon the result, scanline the current one
  the incoming scanlines do NOT include the filtertype byte, that one is given in the parameter filterType instead
  recon and scanline MAY be the same memory address! precon must be disjoint.
  */
  
  size_t i;
  switch(filterType)
  {
    case 0:
      for(i = 0; i < length; i++) recon[i] = scanline[i];
      break;
    case 1:
      for(i =         0; i < bytewidth; i++) recon[i] = scanline[i];
      for(i = bytewidth; i <    length; i++) recon[i] = scanline[i] + recon[i - bytewidth];
      break;
    case 2: 
      if(precon) for(i = 0; i < length; i++) recon[i] = scanline[i] + precon[i];
      else       for(i = 0; i < length; i++) recon[i] = scanline[i];
      break;
    case 3:
      if(precon)
      {
        for(i =         0; i < bytewidth; i++) recon[i] = scanline[i] + precon[i] / 2;
        for(i = bytewidth; i <    length; i++) recon[i] = scanline[i] + ((recon[i - bytewidth] + precon[i]) / 2);
      }
      else
      {
        for(i =         0; i < bytewidth; i++) recon[i] = scanline[i];
        for(i = bytewidth; i <    length; i++) recon[i] = scanline[i] + recon[i - bytewidth] / 2;
      }
      break;
    case 4:
      if(precon)
      {
        for(i =         0; i < bytewidth; i++) recon[i] = (unsigned char)(scanline[i] + paethPredictor(0, precon[i], 0));
        for(i = bytewidth; i <    length; i++) recon[i] = (unsigned char)(scanline[i] + paethPredictor(recon[i - bytewidth], precon[i], precon[i - bytewidth]));
      }
      else
      {
        for(i =         0; i < bytewidth; i++) recon[i] = scanline[i];
        for(i = bytewidth; i <    length; i++) recon[i] = (unsigned char)(scanline[i] + paethPredictor(recon[i - bytewidth], 0, 0));
      }
      break;
    default: return 36; /*error: unexisting filter type given*/
  }
  return 0;
}

static unsigned unfilter(unsigned char* out, const unsigned char* in, unsigned w, unsigned h, unsigned bpp)
{
  /*
  For PNG filter method 0
  this function unfilters a single image (e.g. without interlacing this is called once, with Adam7 it's called 7 times)
  out must have enough bytes allocated already, in must have the scanlines + 1 filtertype byte per scanline
  w and h are image dimensions or dimensions of reduced image, bpp is bits per pixel
  in and out are allowed to be the same memory address!
  */
  
  unsigned y;
  unsigned char* prevline = 0;
  
  size_t bytewidth = (bpp + 7) / 8; /*bytewidth is used for filtering, is 1 when bpp < 8, number of bytes per pixel otherwise*/
  size_t linebytes = (w * bpp + 7) / 8;
  
  for(y = 0; y < h; y++)
  {
    size_t outindex = linebytes * y;
    size_t inindex = (1 + linebytes) * y; /*the extra filterbyte added to each row*/
    unsigned char filterType = in[inindex];
    
    unsigned error = unfilterScanline(&out[outindex], &in[inindex + 1], prevline, bytewidth, filterType, linebytes);
    if(error) return error;
    
    prevline = &out[outindex];
  }
  
  return 0;
}

static void Adam7_deinterlace(unsigned char* out, const unsigned char* in, unsigned w, unsigned h, unsigned bpp)
{
  /*Note: this function works on image buffers WITHOUT padding bits at end of scanlines with non-multiple-of-8 bit amounts, only between reduced images is padding
  out must be big enough AND must be 0 everywhere if bpp < 8 in the current implementation (because that's likely a little bit faster)*/
  unsigned passw[7], passh[7]; size_t filter_passstart[8], padded_passstart[8], passstart[8];
  unsigned i;

  Adam7_getpassvalues(passw, passh, filter_passstart, padded_passstart, passstart, w, h, bpp);
  
  if(bpp >= 8)
  {
    for(i = 0; i < 7; i++)
    {
      unsigned x, y, b;
      size_t bytewidth = bpp / 8;
      for(y = 0; y < passh[i]; y++)
      for(x = 0; x < passw[i]; x++)
      {
        size_t pixelinstart = passstart[i] + (y * passw[i] + x) * bytewidth;
        size_t pixeloutstart = ((ADAM7_IY[i] + y * ADAM7_DY[i]) * w + ADAM7_IX[i] + x * ADAM7_DX[i]) * bytewidth;
        for(b = 0; b < bytewidth; b++)
        {
          out[pixeloutstart + b] = in[pixelinstart + b];
        }
      }
    }
  }
  else /*bpp < 8: Adam7 with pixels < 8 bit is a bit trickier: with bit pointers*/
  {
    for(i = 0; i < 7; i++)
    {
      unsigned x, y, b;
      unsigned ilinebits = bpp * passw[i];
      unsigned olinebits = bpp * w;
      size_t obp, ibp; /*bit pointers (for out and in buffer)*/
      for(y = 0; y < passh[i]; y++)
      for(x = 0; x < passw[i]; x++)
      {
        ibp = (8 * passstart[i]) + (y * ilinebits + x * bpp);
        obp = (ADAM7_IY[i] + y * ADAM7_DY[i]) * olinebits + (ADAM7_IX[i] + x * ADAM7_DX[i]) * bpp;
        for(b = 0; b < bpp; b++)
        {
          unsigned char bit = readBitFromReversedStream(&ibp, in);
          setBitOfReversedStream0(&obp, out, bit); /*note that this function assumes the out buffer is completely 0, use setBitOfReversedStream otherwise*/
        }
      }
    }
  }
}

static void removePaddingBits(unsigned char* out, const unsigned char* in, size_t olinebits, size_t ilinebits, unsigned h)
{
  /*
  After filtering there are still padding bits if scanlines have non multiple of 8 bit amounts. They need to be removed (except at last scanline of (Adam7-reduced) image) before working with pure image buffers for the Adam7 code, the color convert code and the output to the user.
  in and out are allowed to be the same buffer, in may also be higher but still overlapping; in must have >= ilinebits*h bits, out must have >= olinebits*h bits, olinebits must be <= ilinebits
  also used to move bits after earlier such operations happened, e.g. in a sequence of reduced images from Adam7
  only useful if (ilinebits - olinebits) is a value in the range 1..7
  */
  unsigned y;
  size_t diff = ilinebits - olinebits;
  size_t obp = 0, ibp = 0; /*bit pointers*/
  for(y = 0; y < h; y++)
  {
    size_t x;
    for(x = 0; x < olinebits; x++)
    {
      unsigned char bit = readBitFromReversedStream(&ibp, in);
      setBitOfReversedStream(&obp, out, bit);
    }
    ibp += diff;
  }
}

/*out must be buffer big enough to contain full image, and in must contain the full decompressed data from the IDAT chunks*/
static unsigned postProcessScanlines(unsigned char* out, unsigned char* in, const LodePNG_InfoPng* infoPng) /*return value is error*/
{
  /*
  This function converts the filtered-padded-interlaced data into pure 2D image buffer with the PNG's colortype. Steps:
  *) if no Adam7: 1) unfilter 2) remove padding bits (= posible extra bits per scanline if bpp < 8)
  *) if adam7: 1) 7x unfilter 2) 7x remove padding bits 3) Adam7_deinterlace
  NOTE: the in buffer will be overwritten with intermediate data!
  */
  unsigned bpp = LodePNG_InfoColor_getBpp(&infoPng->color);
  unsigned w = infoPng->width;
  unsigned h = infoPng->height;
  unsigned error = 0;
  
  if(infoPng->interlaceMethod == 0)
  {
    if(bpp < 8 && w * bpp != ((w * bpp + 7) / 8) * 8)
    {
      error = unfilter(in, in, w, h, bpp);
      if(error) return error;
      removePaddingBits(out, in, w * bpp, ((w * bpp + 7) / 8) * 8, h);
    }
    else error = unfilter(out, in, w, h, bpp); /*we can immediatly filter into the out buffer, no other steps needed*/
  }
  else /*interlaceMethod is 1 (Adam7)*/
  {
    unsigned passw[7], passh[7]; size_t filter_passstart[8], padded_passstart[8], passstart[8];
    unsigned i;
    
    Adam7_getpassvalues(passw, passh, filter_passstart, padded_passstart, passstart, w, h, bpp);
    
    for(i = 0; i < 7; i++)
    {
      error = unfilter(&in[padded_passstart[i]], &in[filter_passstart[i]], passw[i], passh[i], bpp);
      if(error) return error;
      if(bpp < 8) /*TODO: possible efficiency improvement: if in this reduced image the bits fit nicely in 1 scanline, move bytes instead of bits or move not at all*/
      {
        /*remove padding bits in scanlines; after this there still may be padding bits between the different reduced images: each reduced image still starts nicely at a byte*/
        removePaddingBits(&in[passstart[i]], &in[padded_passstart[i]], passw[i] * bpp, ((passw[i] * bpp + 7) / 8) * 8, passh[i]);
      }
    }
    
    Adam7_deinterlace(out, in, w, h, bpp);
  }
  
  return error;
}

/*read a PNG, the result will be in the same color type as the PNG (hence "generic")*/
static void decodeGeneric(LodePNG_Decoder* decoder, unsigned char** out, size_t* outsize, const unsigned char* in, size_t size)
{
  unsigned char IEND = 0;
  unsigned known_type = 1;
  size_t i, pos = 33; /*first byte of the first chunk after the header*/
  ucvector idat; /*the data from idat chunks*/
  
  /*provide some proper output values if error will happen*/
  *out = 0;
  *outsize = 0;
  
  if(size == 0 || in == 0) { decoder->error = 48; return; } /*the given data is empty*/

  LodePNG_inspect(decoder, in, size); /*reads header and resets other parameters in decoder->infoPng*/
  if(decoder->error) return;

  ucvector_init(&idat);
  
  while(!IEND) /*loop through the chunks, ignoring unknown chunks and stopping at IEND chunk. IDAT data is put at the start of the in buffer*/
  {
    size_t chunkLength; /*length of the data of the chunk, excluding the length bytes, chunk type and CRC bytes*/
    /*get chunk length*/
    if(pos + 8 >= size) { decoder->error = 30; break; } /*error: size of the in buffer too small to contain next chunk*/
    chunkLength = LodePNG_read32bitInt(&in[pos]); pos += 4;
    if(chunkLength > 2147483647) { decoder->error = 63; break; }
    if(pos + chunkLength >= size) { decoder->error = 35; break; } /*error: size of the in buffer too small to contain next chunk*/
    /*IDAT chunk, containing compressed image data*/
    if(in[pos + 0] == 'I' && in[pos + 1] == 'D' && in[pos + 2] == 'A' && in[pos + 3] == 'T')
    {
      size_t oldsize = idat.size;
      pos += 4;
      ucvector_resize(&idat, oldsize + chunkLength);
      for(i = 0; i < chunkLength; i++) idat.data[oldsize + i] = in[pos + i];
      pos += chunkLength;
    }
    /*IEND chunk*/
    else if(in[pos + 0] == 'I' && in[pos + 1] == 'E' && in[pos + 2] == 'N' && in[pos + 3] == 'D')
    {
      pos += 4;
      IEND = 1;
    }
    /*palette chunk (PLTE)*/
    else if(in[pos + 0] == 'P' && in[pos + 1] == 'L' && in[pos + 2] == 'T' && in[pos + 3] == 'E')
    {
      pos += 4; /*go after the 4 letters*/
      if(decoder->infoPng.color.palette) free(decoder->infoPng.color.palette);
      decoder->infoPng.color.palettesize = chunkLength / 3;
      decoder->infoPng.color.palette = (unsigned char*)malloc(4 * decoder->infoPng.color.palettesize);
      if(!decoder->infoPng.color.palette) decoder->infoPng.color.palettesize = 0; /*malloc failed...*/
      if(decoder->infoPng.color.palettesize > 256) { decoder->error = 38; break; } /*error: palette too big*/
      for(i = 0; i < decoder->infoPng.color.palettesize; i++)
      {
        decoder->infoPng.color.palette[4 * i + 0] = in[pos++]; /*R*/
        decoder->infoPng.color.palette[4 * i + 1] = in[pos++]; /*G*/
        decoder->infoPng.color.palette[4 * i + 2] = in[pos++]; /*B*/
        decoder->infoPng.color.palette[4 * i + 3] = 255; /*alpha*/
      }
    }
    /*palette transparency chunk (tRNS)*/
    else if(in[pos + 0] == 't' && in[pos + 1] == 'R' && in[pos + 2] == 'N' && in[pos + 3] == 'S')
    {
      pos += 4; /*go after the 4 letters*/
      if(decoder->infoPng.color.colorType == 3)
      {
        if(chunkLength > decoder->infoPng.color.palettesize) { decoder->error = 39; break; } /*error: more alpha values given than there are palette entries*/
        for(i = 0; i < chunkLength; i++) decoder->infoPng.color.palette[4 * i + 3] = in[pos++];
      }
      else if(decoder->infoPng.color.colorType == 0)
      {
        if(chunkLength != 2) { decoder->error = 40; break; } /*error: this chunk must be 2 bytes for greyscale image*/
        decoder->infoPng.color.key_defined = 1;
        decoder->infoPng.color.key_r = decoder->infoPng.color.key_g = decoder->infoPng.color.key_b = 256 * in[pos] + in[pos + 1]; pos += 2;
      }
      else if(decoder->infoPng.color.colorType == 2)
      {
        if(chunkLength != 6) { decoder->error = 41; break; } /*error: this chunk must be 6 bytes for RGB image*/
        decoder->infoPng.color.key_defined = 1;
        decoder->infoPng.color.key_r = 256 * in[pos] + in[pos + 1]; pos += 2;
        decoder->infoPng.color.key_g = 256 * in[pos] + in[pos + 1]; pos += 2;
        decoder->infoPng.color.key_b = 256 * in[pos] + in[pos + 1]; pos += 2;
      }
      else { decoder->error = 42; break; } /*error: tRNS chunk not allowed for other color models*/
    }
    /*background color chunk (bKGD)*/
    else if(in[pos + 0] == 'b' && in[pos + 1] == 'K' && in[pos + 2] == 'G' && in[pos + 3] == 'D')
    {
      pos += 4; /*go after the 4 letters*/
      if(decoder->infoPng.color.colorType == 3)
      {
        if(chunkLength != 1) { decoder->error = 43; break; } /*error: this chunk must be 1 byte for indexed color image*/
        decoder->infoPng.background_defined = 1;
        decoder->infoPng.background_r = decoder->infoPng.background_g = decoder->infoPng.background_g = in[pos++];
      }
      else if(decoder->infoPng.color.colorType == 0 || decoder->infoPng.color.colorType == 4)
      {
        if(chunkLength != 2) { decoder->error = 44; break; } /*error: this chunk must be 2 bytes for greyscale image*/
        decoder->infoPng.background_defined = 1;
        decoder->infoPng.background_r = decoder->infoPng.background_g = decoder->infoPng.background_b = 256 * in[pos] + in[pos + 1]; pos += 2;
      }
      else if(decoder->infoPng.color.colorType == 2 || decoder->infoPng.color.colorType == 6)
      {
        if(chunkLength != 6) { decoder->error = 45; break; } /*error: this chunk must be 6 bytes for greyscale image*/
        decoder->infoPng.background_defined = 1;
        decoder->infoPng.background_r = 256 * in[pos] + in[pos + 1]; pos += 2;
        decoder->infoPng.background_g = 256 * in[pos] + in[pos + 1]; pos += 2;
        decoder->infoPng.background_b = 256 * in[pos] + in[pos + 1]; pos += 2;
      }
    }
    /*text chunk (tEXt)*/
    else if(in[pos + 0] == 't' && in[pos + 1] == 'E' && in[pos + 2] == 'X' && in[pos + 3] == 't')
    {
      pos += 4; /*go after the 4 letters*/
      if(decoder->settings.readTextChunks)
      {
        size_t chunk_end = pos + chunkLength, stringlength;
        char *key, *str;
        
        for(i = pos, stringlength = 0; i < chunk_end && in[i] != 0; i++) stringlength++;
        key = (char*)malloc(stringlength + 1);
        key[stringlength] = 0;
        for(i = 0; i < stringlength; i++) key[i] = in[pos + i];
        pos += stringlength + 1;
        
        stringlength = chunk_end - pos;
        str = (char*)malloc(stringlength + 1);
        str[stringlength] = 0;
        for(i = 0; i < stringlength; i++) str[i] = in[pos + i];
        pos += stringlength; /*post must be at chunk_end here*/

        LodePNG_InfoPng_addText(&decoder->infoPng, key, str);
        free(key);
        free(str);
      }
    }
    /*compressed text chunk (zTXt)*/
    else if(in[pos + 0] == 'z' && in[pos + 1] == 'T' && in[pos + 2] == 'X' && in[pos + 3] == 't')
    {
      pos += 4; /*go after the 4 letters*/
      if(decoder->settings.readTextChunks)
      {
        size_t chunk_end = pos + chunkLength, length;
        char *key = 0;
        ucvector decoded;
        
        ucvector_init(&decoded);
        
        while(!decoder->error) /*not really a while loop, only used to break on error*/
        {
          for(i = pos, length = 0; i < chunk_end && in[i] != 0; i++) length++;
          key = (char*)malloc(length + 1);
          key[length] = 0;
          for(i = 0; i < length; i++) key[i] = in[pos + i];
          pos += length + 1;
          if(in[pos] != 0) { decoder->error = 72; break; }
          pos++;
          
          length = chunk_end - pos;
          decoder->error = LodePNG_decompress(&decoded.data, &decoded.size, (unsigned char*)(&in[pos]), length, &decoder->settings.zlibsettings);
          if(decoder->error) break;
          ucvector_push_back(&decoded, 0);
          pos += length; /*post must be at chunk_end here*/

          LodePNG_InfoPng_addText(&decoder->infoPng, key, (char*)decoded.data);
          
          break;
        }

        free(key);
        ucvector_cleanup(&decoded);
        
        if(decoder->error) break;
      }
      else pos += chunkLength;
    }
    else /*it's not an implemented chunk type, so ignore it: skip over the data*/
    {
      if(!(in[pos + 0] & 32)) { decoder->error = 69; break; } /*error: unknown critical chunk (5th bit of first byte of chunk type is 0)*/
      pos += (chunkLength + 4); /*skip 4 letters and uninterpreted data of unimplemented chunk*/
      known_type = 0;
    }
    
    if(!decoder->settings.ignoreCrc && known_type) /*check CRC if wanted, only on known chunk types*/
    {
      unsigned CRC = LodePNG_read32bitInt(&in[pos]);
      size_t chunkStart = pos - chunkLength - 4; /*the CRC is taken of the data and the 4 chunk type letters, not the length*/
      unsigned checksum = Crc32_crc(&in[chunkStart], chunkLength + 4);
      if(CRC != checksum) { decoder->error = 57; break; }
    }
    pos += 4; /*step over CRC*/
  }
  
  if(!decoder->error)
  {
    ucvector scanlines;
    ucvector_init(&scanlines);
    ucvector_resize(&scanlines, ((decoder->infoPng.width * (decoder->infoPng.height * LodePNG_InfoColor_getBpp(&decoder->infoPng.color) + 7)) / 8) + decoder->infoPng.height); /*maximum final image length is already reserved in the vector's length - this is not really necessary*/
    decoder->error = LodePNG_decompress(&scanlines.data, &scanlines.size, idat.data, idat.size, &decoder->settings.zlibsettings); /*decompress with the Zlib decompressor*/
    
    if(!decoder->error)
    {
      ucvector outv;
      ucvector_init(&outv);
      ucvector_resizev(&outv, (decoder->infoPng.height * decoder->infoPng.width * LodePNG_InfoColor_getBpp(&decoder->infoPng.color) + 7) / 8, 0);
      decoder->error = postProcessScanlines(outv.data, scanlines.data, &decoder->infoPng);
      *out = outv.data;
      *outsize = outv.size;
    }
    ucvector_cleanup(&scanlines);
  }
  
  ucvector_cleanup(&idat);
}

void LodePNG_decode(LodePNG_Decoder* decoder, unsigned char** out, size_t* outsize, const unsigned char* in, size_t insize)
{
  *out = 0;
  *outsize = 0;
  decodeGeneric(decoder, out, outsize, in, insize);
  if(decoder->error) return;
  if(!decoder->settings.color_convert || LodePNG_InfoColor_equal(&decoder->infoRaw.color, &decoder->infoPng.color))
  {
    /*same color type, no copying or converting of data needed*/
    /*store the infoPng color settings on the infoRaw so that the infoRaw still reflects what colorType
    the raw image has to the end user*/
    if(!decoder->settings.color_convert) LodePNG_InfoColor_copy(&decoder->infoRaw.color, &decoder->infoPng.color);
  }
  else
  {
    /*color conversion needed; sort of copy of the data*/
    unsigned char* data = *out;
    /*size_t datasize = *outsize;*/

    /*TODO: check if this works according to the statement in the documentation: "The converter can convert from greyscale input color type, to 8-bit greyscale or greyscale with alpha"*/
    if(!(decoder->infoRaw.color.colorType == 2 || decoder->infoRaw.color.colorType == 6) && !(decoder->infoRaw.color.bitDepth == 8)) { decoder->error = 56; return; }

    *outsize = (decoder->infoPng.width * decoder->infoPng.height * LodePNG_InfoColor_getBpp(&decoder->infoRaw.color) + 7) / 8;
    *out = (unsigned char*)malloc(*outsize);
    if(!(*out))
    {
      decoder->error = 70;
      *outsize = 0;
    }
    else decoder->error = LodePNG_convert(*out, data, &decoder->infoRaw.color, &decoder->infoPng.color, decoder->infoPng.width, decoder->infoPng.height);
    free(data);
  }
}

unsigned LodePNG_decode32(unsigned char** out, unsigned* w, unsigned* h, const unsigned char* in, size_t insize)
{
  unsigned error;
  size_t dummy_size;
  LodePNG_Decoder decoder;
  LodePNG_Decoder_init(&decoder);
  LodePNG_decode(&decoder, out, &dummy_size, in, insize);
  error = decoder.error;
  *w = decoder.infoPng.width;
  *h = decoder.infoPng.height;
  LodePNG_Decoder_cleanup(&decoder);
  return error;
}

unsigned LodePNG_decode32f(unsigned char** out, unsigned* w, unsigned* h, const char* filename)
{
  unsigned char* buffer;
  size_t buffersize;
  unsigned error;
  LodePNG_loadFile(&buffer, &buffersize, filename);
  error = LodePNG_decode32(out, w, h, buffer, buffersize);
  free(buffer);
  return error;
}

void LodePNG_DecodeSettings_init(LodePNG_DecodeSettings* settings)
{
  settings->color_convert = 1;
  settings->readTextChunks = 1;
  settings->ignoreCrc = 0;
  LodeZlib_DecompressSettings_init(&settings->zlibsettings);
}

void LodePNG_Decoder_init(LodePNG_Decoder* decoder)
{
  LodePNG_DecodeSettings_init(&decoder->settings);
  LodePNG_InfoRaw_init(&decoder->infoRaw);
  LodePNG_InfoPng_init(&decoder->infoPng);
  decoder->error = 1;
}

void LodePNG_Decoder_cleanup(LodePNG_Decoder* decoder)
{
  LodePNG_InfoRaw_cleanup(&decoder->infoRaw);
  LodePNG_InfoPng_cleanup(&decoder->infoPng);
}

void LodePNG_Decoder_copy(LodePNG_Decoder* dest, const LodePNG_Decoder* source)
{
  LodePNG_Decoder_cleanup(dest);
  *dest = *source;
  LodePNG_InfoRaw_init(&dest->infoRaw);
  LodePNG_InfoRaw_copy(&dest->infoRaw, &source->infoRaw);
  LodePNG_InfoPng_init(&dest->infoPng);
  LodePNG_InfoPng_copy(&dest->infoPng, &source->infoPng);
}

/* ////////////////////////////////////////////////////////////////////////// */
/* / PNG Encoder                                                            / */
/* ////////////////////////////////////////////////////////////////////////// */

/*chunkName must be string of 4 characters*/
static void addChunk(ucvector* out, const char* chunkName, unsigned char* data, size_t length)
{
  size_t i;
  unsigned CRC;
  
  /*1: length*/
  LodePNG_add32bitInt(out, (unsigned)length);
  
  /*2: chunk name (4 letters)*/
  ucvector_push_back(out, chunkName[0]);
  ucvector_push_back(out, chunkName[1]);
  ucvector_push_back(out, chunkName[2]);
  ucvector_push_back(out, chunkName[3]);
  
  /*3: the data*/
  for(i = 0; i < length; i++) ucvector_push_back(out, data[i]);
  
  /*4: CRC (of the chunkname characters and the data)*/
  CRC = Crc32_crc(&out->data[out->size - length - 4], length + 4);

  LodePNG_add32bitInt(out, CRC);
}

static void writeSignature(ucvector* out)
{
  /*8 bytes PNG signature*/
  ucvector_push_back(out, 137);
  ucvector_push_back(out, 80);
  ucvector_push_back(out, 78);
  ucvector_push_back(out, 71);
  ucvector_push_back(out, 13);
  ucvector_push_back(out, 10);
  ucvector_push_back(out, 26);
  ucvector_push_back(out, 10);
}

static unsigned writeChunk_IHDR(ucvector* out, unsigned w, unsigned h, unsigned bitDepth, unsigned colorType, unsigned interlaceMethod)
{
  ucvector header;
  ucvector_init(&header);
  
  LodePNG_add32bitInt(&header, w); /*width*/
  LodePNG_add32bitInt(&header, h); /*height*/
  ucvector_push_back(&header, (unsigned char)bitDepth); /*bit depth*/
  ucvector_push_back(&header, (unsigned char)colorType); /*color type*/
  ucvector_push_back(&header, 0); /*compression method*/
  ucvector_push_back(&header, 0); /*filter method*/
  ucvector_push_back(&header, interlaceMethod); /*interlace method*/
  
  addChunk(out, "IHDR", header.data, header.size);
  ucvector_cleanup(&header);
  
  return 0;
}

static unsigned writeChunk_tEXt(ucvector* out, const char* keyword, const char* textstring)
{
  /*add text chunk*/
  size_t i;
  ucvector text;
  ucvector_init(&text);
  for(i = 0; keyword[i] != 0; i++) ucvector_push_back(&text, (unsigned char)keyword[i]);
  ucvector_push_back(&text, 0);
  for(i = 0; textstring[i] != 0; i++) ucvector_push_back(&text, (unsigned char)textstring[i]);
  /*ucvector_push_back(&text, 0);*/
  addChunk(out, "tEXt", text.data, text.size);
  ucvector_cleanup(&text);
  
  return 0;
}

static unsigned writeChunk_zTXt(ucvector* out, const char* keyword, const char* textstring, LodeZlib_DeflateSettings* zlibsettings)
{
  /*add text chunk*/
  size_t i;
  ucvector data;
  ucvector compressed;
  unsigned error = 0;
  size_t textsize = strlen(textstring);
  
  ucvector_init(&data);
  ucvector_init(&compressed);
  for(i = 0; keyword[i] != 0; i++) ucvector_push_back(&data, (unsigned char)keyword[i]);
  ucvector_push_back(&data, 0); /* 0 termination char*/
  ucvector_push_back(&data, 0); /*compression method: 0*/
  
  error = LodePNG_compress(&compressed.data, &compressed.size, (unsigned char*)textstring, textsize, zlibsettings);
  if(!error)
  {
    for(i = 0; i < compressed.size; i++) ucvector_push_back(&data, compressed.data[i]);
    addChunk(out, "zTXt", data.data, data.size);
  }
  
  ucvector_cleanup(&compressed);
  ucvector_cleanup(&data);
  return error;
}

static unsigned writeChunk_PLTE(ucvector* out, const LodePNG_InfoColor* info)
{
  size_t i;
  ucvector PLTE;
  ucvector_init(&PLTE);
  for(i = 0; i < info->palettesize * 4; i++) if(i % 4 != 3) ucvector_push_back(&PLTE, info->palette[i]); /*add all channels except alpha channel*/
  addChunk(out, "PLTE", PLTE.data, PLTE.size);
  ucvector_cleanup(&PLTE);
  
  return 0;
}

static unsigned writeChunk_tRNS(ucvector* out, const LodePNG_InfoColor* info)
{
  size_t i;
  ucvector tRNS;
  ucvector_init(&tRNS);
  if(info->colorType == 3)
  {
    for(i = 0; i < info->palettesize; i++) ucvector_push_back(&tRNS, info->palette[4 * i + 3]); /*add only alpha channel*/
  }
  else if(info->colorType == 0)
  {
    if(info->key_defined)
    {
      ucvector_push_back(&tRNS, (unsigned char)(info->key_r / 256));
      ucvector_push_back(&tRNS, (unsigned char)(info->key_r % 256));
    }
  }
  else if(info->colorType == 2)
  {
    if(info->key_defined)
    {
      ucvector_push_back(&tRNS, (unsigned char)(info->key_r / 256));
      ucvector_push_back(&tRNS, (unsigned char)(info->key_r % 256));
      ucvector_push_back(&tRNS, (unsigned char)(info->key_g / 256));
      ucvector_push_back(&tRNS, (unsigned char)(info->key_g % 256));
      ucvector_push_back(&tRNS, (unsigned char)(info->key_b / 256));
      ucvector_push_back(&tRNS, (unsigned char)(info->key_b % 256));
    }
  }
  
  addChunk(out, "tRNS", tRNS.data, tRNS.size);
  ucvector_cleanup(&tRNS);
  
  return 0;
}

static unsigned writeChunk_IDAT(ucvector* out, const unsigned char* data, size_t datasize, LodeZlib_DeflateSettings* zlibsettings)
{
  ucvector zlibdata;
  unsigned error = 0;
  
  /*compress with the Zlib compressor*/
  ucvector_init(&zlibdata);
  error = LodePNG_compress(&zlibdata.data, &zlibdata.size, data, datasize, zlibsettings);
  addChunk(out, "IDAT", zlibdata.data, zlibdata.size);
  ucvector_cleanup(&zlibdata);
  
  return error;
}

static unsigned writeChunk_IEND(ucvector* out)
{
  addChunk(out, "IEND", 0, 0);
  
  return 0;
}

static unsigned writeChunk_bKGD(ucvector* out, const LodePNG_InfoPng* info)
{
  ucvector bKGD;
  ucvector_init(&bKGD);
  if(info->color.colorType == 0 || info->color.colorType == 4)
  {
    ucvector_push_back(&bKGD, (unsigned char)(info->background_r / 256));
    ucvector_push_back(&bKGD, (unsigned char)(info->background_r % 256));
  }
  else if(info->color.colorType == 2 || info->color.colorType == 6)
  {
    ucvector_push_back(&bKGD, (unsigned char)(info->background_r / 256));
    ucvector_push_back(&bKGD, (unsigned char)(info->background_r % 256));
    ucvector_push_back(&bKGD, (unsigned char)(info->background_g / 256));
    ucvector_push_back(&bKGD, (unsigned char)(info->background_g % 256));
    ucvector_push_back(&bKGD, (unsigned char)(info->background_b / 256));
    ucvector_push_back(&bKGD, (unsigned char)(info->background_b % 256));
  }
  else if(info->color.colorType == 3)
  {
    ucvector_push_back(&bKGD, (unsigned char)(info->background_r % 256)); /*palette index*/
  }
  
  addChunk(out, "bKGD", bKGD.data, bKGD.size);
  ucvector_cleanup(&bKGD);
  
  return 0;
}

static void filterScanline(unsigned char* out, const unsigned char* scanline, const unsigned char* prevline, size_t length, size_t bytewidth, unsigned char filterType)
{
  size_t i;
  switch(filterType)
  {
    case 0:
      if(prevline) for(i = 0; i < length; i++) out[i] = scanline[i];
      else         for(i = 0; i < length; i++) out[i] = scanline[i];
      break;
    case 1:
      if(prevline)
      {
        for(i =         0; i < bytewidth; i++) out[i] = scanline[i];
        for(i = bytewidth; i < length   ; i++) out[i] = scanline[i] - scanline[i - bytewidth];
      }
      else
      {
        for(i =         0; i < bytewidth; i++) out[i] = scanline[i];
        for(i = bytewidth; i <    length; i++) out[i] = scanline[i] - scanline[i - bytewidth];
      }
      break;
    case 2: 
      if(prevline) for(i = 0; i < length; i++) out[i] = scanline[i] - prevline[i];
      else         for(i = 0; i < length; i++) out[i] = scanline[i];
      break;
    case 3:
      if(prevline)
      {
        for(i =         0; i < bytewidth; i++) out[i] = scanline[i] - prevline[i] / 2;
        for(i = bytewidth; i <    length; i++) out[i] = scanline[i] - ((scanline[i - bytewidth] + prevline[i]) / 2);
      }
      else
      {
        for(i =         0; i < length; i++) out[i] = scanline[i];
        for(i = bytewidth; i < length; i++) out[i] = scanline[i] - scanline[i - bytewidth] / 2;
      }
      break;
    case 4:
      if(prevline)
      {
        for(i =         0; i < bytewidth; i++) out[i] = (unsigned char)(scanline[i] - paethPredictor(0, prevline[i], 0));
        for(i = bytewidth; i <    length; i++) out[i] = (unsigned char)(scanline[i] - paethPredictor(scanline[i - bytewidth], prevline[i], prevline[i - bytewidth]));
      }
      else
      {
        for(i =         0; i < bytewidth; i++) out[i] = scanline[i];
        for(i = bytewidth; i <    length; i++) out[i] = (unsigned char)(scanline[i] - paethPredictor(scanline[i - bytewidth], 0, 0));
      }
      break;
  default: return; /*unexisting filter type given*/
  }
}

static void filter(unsigned char* out, const unsigned char* in, unsigned w, unsigned h, const LodePNG_InfoColor* info)
{
  /*
  For PNG filter method 0
  out must be a buffer with as size: h + (w * h * bpp + 7) / 8, because there are the scanlines with 1 extra byte per scanline
  
  There is a nice heuristic described here: http://www.cs.toronto.edu/~cosmin/pngtech/optipng.html. It says:
   *  If the image type is Palette, or the bit depth is smaller than 8, then do not filter the image (i.e. use fixed filtering, with the filter None).
   * (The other case) If the image type is Grayscale or RGB (with or without Alpha), and the bit depth is not smaller than 8, then use adaptive filtering heuristic as follows: independently for each row, apply all five filters and select the filter that produces the smallest sum of absolute values per row.
  
  Here the above method is used mostly. Note though that it appears to be better to use the adaptive filtering on the plasma 8-bit palette example, but that image isn't the best reference for palette images in general.
  */
  
  unsigned bpp = LodePNG_InfoColor_getBpp(info);
  
  size_t linebytes = (w * bpp + 7) / 8; /*the width of a scanline in bytes, not including the filter type*/
  size_t bytewidth = (bpp + 7) / 8; /*bytewidth is used for filtering, is 1 when bpp < 8, number of bytes per pixel otherwise*/
  
  const unsigned char* prevline = 0;
  unsigned x, y;
  
  unsigned heuristic;
  
  /*choose heuristic as described above*/
  if(info->colorType == 3 || info->bitDepth < 8) heuristic = 0;
  else heuristic = 1;
  
  if(heuristic == 0) /*None filtertype for everything*/
  {
    for(y = 0; y < h; y++)
    {
      size_t outindex = (1 + linebytes) * y; /*the extra filterbyte added to each row*/
      size_t inindex = linebytes * y;
      const unsigned TYPE = 0;
      out[outindex] = TYPE; /*filter type byte*/
      filterScanline(&out[outindex + 1], &in[inindex], prevline, linebytes, bytewidth, TYPE);
      prevline = &in[inindex];
    }
  }
  else if(heuristic == 1) /*adaptive filtering*/
  {
    size_t sum[5];
    ucvector attempt[5]; /*five filtering attempts, one for each filter type*/
    size_t smallest = 0;
    unsigned type, bestType = 0;
    
    for(type = 0; type < 5; type++)
    {
      ucvector_init(&attempt[type]);
      ucvector_resize(&attempt[type], linebytes);
    }
    
    for(y = 0; y < h; y++)
    {
      /*try the 5 filter types*/
      for(type = 0; type < 5; type++)
      {
        filterScanline(attempt[type].data, &in[y * linebytes], prevline, linebytes, bytewidth, type);
        
        /*calculate the sum of the result*/
        sum[type] = 0;
        for(x = 0; x < attempt[type].size; x+=3) sum[type] += attempt[type].data[x]; /*note that not all pixels are checked to speed this up while still having probably the best choice*/
      
        /*check if this is smallest sum (or if type == 0 it's the first case so always store the values)*/
        if(type == 0 || sum[type] < smallest)
        {
          bestType = type;
          smallest = sum[type];
        }
      }
      
      prevline = &in[y * linebytes];
  
      /*now fill the out values*/
      out[y * (linebytes + 1)] = bestType; /*the first byte of a scanline will be the filter type*/
      for(x = 0; x < linebytes; x++) out[y * (linebytes + 1) + 1 + x] = attempt[bestType].data[x];
    }
    
    for(type = 0; type < 5; type++) ucvector_cleanup(&attempt[type]);
  }
  #if 0 /*deflate the scanline with a fixed tree after every filter attempt to see which one deflates best. This is slow, and _does not work as expected_: the heuristic gives smaller result!*/
  else if(heuristic == 2) /*adaptive filtering by using deflate*/
  {
    size_t size[5];
    ucvector attempt[5]; /*five filtering attempts, one for each filter type*/
    size_t smallest;
    unsigned type = 0, bestType = 0;
    unsigned char* dummy;
    LodeZlib_DeflateSettings deflatesettings = LodeZlib_defaultDeflateSettings;
    deflatesettings.btype = 1; /*use fixed tree on the attempts so that the tree is not adapted to the filtertype on purpose, to simulate the true case where the tree is the same for the whole image*/
    for(type = 0; type < 5; type++) { ucvector_init(&attempt[type]); ucvector_resize(&attempt[type], linebytes); }
    for(y = 0; y < h; y++) /*try the 5 filter types*/
    {
      for(type = 0; type < 5; type++)
      {
        filterScanline(attempt[type].data, &in[y * linebytes], prevline, linebytes, bytewidth, type);
        size[type] = 0; dummy = 0;
        LodePNG_compress(&dummy, &size[type], attempt[type].data, attempt[type].size, &deflatesettings);
        free(dummy);
        /*check if this is smallest size (or if type == 0 it's the first case so always store the values)*/
        if(type == 0 || size[type] < smallest) { bestType = type; smallest = size[type]; }
      }
      prevline = &in[y * linebytes];
      out[y * (linebytes + 1)] = bestType; /*the first byte of a scanline will be the filter type*/
      for(x = 0; x < linebytes; x++) out[y * (linebytes + 1) + 1 + x] = attempt[bestType].data[x];
    }
    for(type = 0; type < 5; type++) ucvector_cleanup(&attempt[type]);
  }
  #endif
}

static void addPaddingBits(unsigned char* out, const unsigned char* in, size_t olinebits, size_t ilinebits, unsigned h)
{
  /*The opposite of the removePaddingBits function
  olinebits must be >= ilinebits*/
  unsigned y;
  size_t diff = olinebits - ilinebits;
  size_t obp = 0, ibp = 0; /*bit pointers*/
  for(y = 0; y < h; y++)
  {
    size_t x;
    for(x = 0; x < ilinebits; x++)
    {
      unsigned char bit = readBitFromReversedStream(&ibp, in);
      setBitOfReversedStream(&obp, out, bit);
    }
    /*obp += diff; --> no, fill in some value in the padding bits too, to avoid "Use of uninitialised value of size ###" warning from valgrind*/
    for(x = 0; x < diff; x++) setBitOfReversedStream(&obp, out, 0);
  }
}

static void Adam7_interlace(unsigned char* out, const unsigned char* in, unsigned w, unsigned h, unsigned bpp)
{
  /*Note: this function works on image buffers WITHOUT padding bits at end of scanlines with non-multiple-of-8 bit amounts, only between reduced images is padding*/
  unsigned passw[7], passh[7]; size_t filter_passstart[8], padded_passstart[8], passstart[8];
  unsigned i;

  Adam7_getpassvalues(passw, passh, filter_passstart, padded_passstart, passstart, w, h, bpp);
  
  if(bpp >= 8)
  {
    for(i = 0; i < 7; i++)
    {
      unsigned x, y, b;
      size_t bytewidth = bpp / 8;
      for(y = 0; y < passh[i]; y++)
      for(x = 0; x < passw[i]; x++)
      {
        size_t pixelinstart = ((ADAM7_IY[i] + y * ADAM7_DY[i]) * w + ADAM7_IX[i] + x * ADAM7_DX[i]) * bytewidth;
        size_t pixeloutstart = passstart[i] + (y * passw[i] + x) * bytewidth;
        for(b = 0; b < bytewidth; b++)
        {
          out[pixeloutstart + b] = in[pixelinstart + b];
        }
      }
    }
  }
  else /*bpp < 8: Adam7 with pixels < 8 bit is a bit trickier: with bit pointers*/
  {
    for(i = 0; i < 7; i++)
    {
      unsigned x, y, b;
      unsigned ilinebits = bpp * passw[i];
      unsigned olinebits = bpp * w;
      size_t obp, ibp; /*bit pointers (for out and in buffer)*/
      for(y = 0; y < passh[i]; y++)
      for(x = 0; x < passw[i]; x++)
      {
        ibp = (ADAM7_IY[i] + y * ADAM7_DY[i]) * olinebits + (ADAM7_IX[i] + x * ADAM7_DX[i]) * bpp;
        obp = (8 * passstart[i]) + (y * ilinebits + x * bpp);
        for(b = 0; b < bpp; b++)
        {
          unsigned char bit = readBitFromReversedStream(&ibp, in);
          setBitOfReversedStream(&obp, out, bit);
        }
      }
    }
  }
}

/*out must be buffer big enough to contain uncompressed IDAT chunk data, and in must contain the full image*/
static unsigned preProcessScanlines(unsigned char** out, size_t* outsize, const unsigned char* in, const LodePNG_InfoPng* infoPng) /*return value is error*/
{
  /*
  This function converts the pure 2D image with the PNG's colortype, into filtered-padded-interlaced data. Steps:
  *) if no Adam7: 1) add padding bits (= posible extra bits per scanline if bpp < 8) 2) filter
  *) if adam7: 1) Adam7_interlace 2) 7x add padding bits 3) 7x filter
  */
  unsigned bpp = LodePNG_InfoColor_getBpp(&infoPng->color);
  unsigned w = infoPng->width;
  unsigned h = infoPng->height;
  unsigned error = 0;
  
  if(infoPng->interlaceMethod == 0)
  {
    *outsize = h + (h * ((w * bpp + 7) / 8)); /*image size plus an extra byte per scanline + possible padding bits*/
    *out = (unsigned char*)malloc(*outsize);

    if(bpp < 8 && w * bpp != ((w * bpp + 7) / 8) * 8) /*non multiple of 8 bits per scanline, padding bits needed per scanline*/
    {
      ucvector padded;
      ucvector_init(&padded);
      ucvector_resize(&padded, h * ((w * bpp + 7) / 8));
      addPaddingBits(padded.data, in, ((w * bpp + 7) / 8) * 8, w * bpp, h);
      filter(*out, padded.data, w, h, &infoPng->color);
      ucvector_cleanup(&padded);
    }
    else filter(*out, in, w, h, &infoPng->color); /*we can immediatly filter into the out buffer, no other steps needed*/
  }
  else /*interlaceMethod is 1 (Adam7)*/
  {
    unsigned passw[7], passh[7]; size_t filter_passstart[8], padded_passstart[8], passstart[8];
    unsigned i;
    unsigned char* adam7 = (unsigned char*)malloc((h * w * bpp + 7) / 8);
    
    Adam7_getpassvalues(passw, passh, filter_passstart, padded_passstart, passstart, w, h, bpp);
    
    *outsize = filter_passstart[7]; /*image size plus an extra byte per scanline + possible padding bits*/
    *out = (unsigned char*)malloc(*outsize);
    
    Adam7_interlace(adam7, in, w, h, bpp);
    
    for(i = 0; i < 7; i++)
    {
      if(bpp < 8)
      {
        ucvector padded;
        ucvector_init(&padded);
        ucvector_resize(&padded, h * ((w * bpp + 7) / 8));
        addPaddingBits(&padded.data[padded_passstart[i]], &adam7[passstart[i]], ((passw[i] * bpp + 7) / 8) * 8, passw[i] * bpp, passh[i]);
        
        filter(&(*out)[filter_passstart[i]], &padded.data[padded_passstart[i]], passw[i], passh[i], &infoPng->color);
        
        ucvector_cleanup(&padded);
      }
      else
      {
        filter(&(*out)[filter_passstart[i]], &adam7[padded_passstart[i]], passw[i], passh[i], &infoPng->color);
      }
    }
    
    free(adam7);
  }
  
  return error;
}


/*palette must have 4 * palettesize bytes allocated*/
static unsigned isPaletteFullyOpaque(const unsigned char* palette, size_t palettesize) /*palette given in format RGBARGBARGBARGBA...*/
{
  size_t i;
  for(i = 0; i < palettesize; i++)
  {
    if(palette[4 * i + 3] != 255) return 0;
  }
  return 1;
}

/*this function checks if the input image given by the user has no transparent pixels*/
static unsigned isFullyOpaque(const unsigned char* image, unsigned w, unsigned h, const LodePNG_InfoColor* info)
{
  /*TODO: When the user specified a color key for the input image, then this function must also check for pixels that are the same as the color key and treat those as transparent.*/

  unsigned i, numpixels = w * h;
  if(info->colorType == 6)
  {
    if(info->bitDepth == 8)
    {
      for(i = 0; i < numpixels; i++) if(image[i * 4 + 3] != 255) return 0;
    }
    else
    {
      for(i = 0; i < numpixels; i++) if(image[i * 8 + 6] != 255 || image[i * 8 + 7] != 255) return 0;
    }
    return 1; /*no single pixel with alpha channel other than 255 found*/
  }
  else if(info->colorType == 4)
  {
    if(info->bitDepth == 8)
    {
      for(i = 0; i < numpixels; i++) if(image[i * 2 + 1] != 255) return 0;
    }
    else
    {
      for(i = 0; i < numpixels; i++) if(image[i * 4 + 2] != 255 || image[i * 4 + 3] != 255) return 0;
    }
    return 1; /*no single pixel with alpha channel other than 255 found*/
  }
  else if(info->colorType == 3)
  {
    /*when there's a palette, we could check every pixel for translucency, but much quicker is to just check the palette*/
    return(isPaletteFullyOpaque(info->palette, info->palettesize));
  }

  return 0; /*color type that isn't supported by this function yet, so assume there is transparency to be safe*/
}

void LodePNG_encode(LodePNG_Encoder* encoder, unsigned char** out, size_t* outsize, const unsigned char* image, unsigned w, unsigned h)
{
  LodePNG_InfoPng internal_infoPng;
  ucvector outv;
  unsigned char* data; /*uncompressed version of the IDAT chunk data*/
  size_t datasize;
  size_t i;
  
  /*provide some proper output values if error will happen*/
  *out = 0;
  *outsize = 0;
  
  encoder->error = 0;
  
  internal_infoPng = encoder->infoPng; /*UNSAFE copy to avoid having to cleanup! but we will only change primitive parameters, and not invoke the cleanup function nor touch the palette's buffer so we use it safely*/
  
  internal_infoPng.width = w;
  internal_infoPng.height = h;
  if(encoder->settings.autoLeaveOutAlphaChannel && isFullyOpaque(image, w, h, &encoder->infoRaw.color))
  {
    /*go to a color type without alpha channel*/
    if(internal_infoPng.color.colorType == 6) internal_infoPng.color.colorType = 2;
    else if(internal_infoPng.color.colorType == 4) internal_infoPng.color.colorType = 0;
  }
  
  if(encoder->settings.zlibsettings.windowSize > 32768) { encoder->error = 60; return; } /*error: windowsize larger than allowed*/
  if(encoder->settings.zlibsettings.btype > 2) { encoder->error = 61; return; } /*error: unexisting btype*/
  if(encoder->infoPng.interlaceMethod > 1) { encoder->error = 71; return; } /*error: unexisting interlace mode*/
  
  if(!LodePNG_InfoColor_equal(&encoder->infoRaw.color, &internal_infoPng.color))
  {
    unsigned char* converted;
    
    if((internal_infoPng.color.colorType != 6 && internal_infoPng.color.colorType != 2) || (internal_infoPng.color.bitDepth != 8)) { encoder->error = 59; return; } /*for the output image, only these types are supported*/
    converted = (unsigned char*)malloc((w * h * LodePNG_InfoColor_getBpp(&internal_infoPng.color) + 7) / 8);
    encoder->error = LodePNG_convert(converted, image, &internal_infoPng.color, &encoder->infoRaw.color, w, h);
    if(!encoder->error) preProcessScanlines(&data, &datasize, converted, &internal_infoPng);/*filter(data.data, converted.data, w, h, LodePNG_InfoColor_getBpp(&internal_infoPng.color));*/
    free(converted);
  }
  else preProcessScanlines(&data, &datasize, image, &internal_infoPng);/*filter(data.data, image, w, h, LodePNG_InfoColor_getBpp(&internal_infoPng.color));*/
  
  ucvector_init(&outv);
  while(!encoder->error) /*not really a while loop, this is only used to break out if an error happens to avoid goto's to do the ucvector cleanup*/
  {
    /*write signature and chunks*/
    writeSignature(&outv);
    /*IHDR*/
    writeChunk_IHDR(&outv, w, h, internal_infoPng.color.bitDepth, internal_infoPng.color.colorType, internal_infoPng.interlaceMethod);
    /*PLTE and tRNS*/
    if(internal_infoPng.color.colorType == 3)
    {
      if(internal_infoPng.color.palettesize == 0 || internal_infoPng.color.palettesize > 256) { encoder->error = 68; break; }
      writeChunk_PLTE(&outv, &internal_infoPng.color);
      if(!isPaletteFullyOpaque(internal_infoPng.color.palette, internal_infoPng.color.palettesize)) writeChunk_tRNS(&outv, &internal_infoPng.color);
    }
    if(encoder->settings.force_palette && (internal_infoPng.color.colorType == 2 || internal_infoPng.color.colorType == 6))
    {
      if(internal_infoPng.color.palettesize == 0 || internal_infoPng.color.palettesize > 256) { encoder->error = 68; break; }
      writeChunk_PLTE(&outv, &internal_infoPng.color);
    }
    if(internal_infoPng.color.key_defined && (internal_infoPng.color.colorType == 0 || internal_infoPng.color.colorType == 2)) writeChunk_tRNS(&outv, &internal_infoPng.color);
    /*bKGD*/
    if(internal_infoPng.background_defined) writeChunk_bKGD(&outv, &internal_infoPng);
    /*IDAT*/
    encoder->error = writeChunk_IDAT(&outv, data, datasize, &encoder->settings.zlibsettings);
    if(encoder->error) break;
    /*tEXt*/
    for(i = 0; i < internal_infoPng.num_texts; i++)
    {
      if(strlen(internal_infoPng.text_keys[i]) > 79) { encoder->error = 66; break; }
      if(strlen(internal_infoPng.text_keys[i]) < 1) { encoder->error = 67; break; }
      if(encoder->settings.text_compression)
        writeChunk_zTXt(&outv, internal_infoPng.text_keys[i], internal_infoPng.text_strings[i], &encoder->settings.zlibsettings);
      else
        writeChunk_tEXt(&outv, internal_infoPng.text_keys[i], internal_infoPng.text_strings[i]);
    }
    /*LodePNG version id*/
    if(encoder->settings.add_id)
    {
      unsigned alread_added_id_text = 0;
      for(i = 0; i < internal_infoPng.num_texts; i++)
        if(string_equal(internal_infoPng.text_keys[i], "LodePNG")) { alread_added_id_text = 1; break; }
      if(alread_added_id_text == 0)
        writeChunk_tEXt(&outv, "LodePNG", VERSION_STRING); /*it's shorter as tEXt than as zTXt chunk*/
    }
    /*IEND*/
    writeChunk_IEND(&outv);
    
    break; /*this isn't really a while loop; no error happened so break out now!*/
  }
  
  free(data);
  /*instead of cleaning the vector up, give it to the output*/
  *out = outv.data;
  *outsize = outv.size;
}

unsigned LodePNG_encode32(unsigned char** out, size_t* outsize, const unsigned char* image, unsigned w, unsigned h)
{
  unsigned error;
  LodePNG_Encoder encoder;
  LodePNG_Encoder_init(&encoder);
  LodePNG_encode(&encoder, out, outsize, image, w, h);
  error = encoder.error;
  LodePNG_Encoder_cleanup(&encoder);
  return error;
}

unsigned LodePNG_encode32f(const char* filename, const unsigned char* image, unsigned w, unsigned h)
{
  unsigned char* buffer;
  size_t buffersize;
  unsigned error = LodePNG_encode32(&buffer, &buffersize, image, w, h);
  LodePNG_saveFile(buffer, buffersize, filename);
  free(buffer);
  return error;
}

void LodePNG_EncodeSettings_init(LodePNG_EncodeSettings* settings)
{
  LodeZlib_DeflateSettings_init(&settings->zlibsettings);
  settings->autoLeaveOutAlphaChannel = 1;
  settings->force_palette = 0;
  settings->add_id = 1;
  settings->text_compression = 0;
}

void LodePNG_Encoder_init(LodePNG_Encoder* encoder)
{
  LodePNG_EncodeSettings_init(&encoder->settings);
  LodePNG_InfoPng_init(&encoder->infoPng);
  LodePNG_InfoRaw_init(&encoder->infoRaw);
  encoder->error = 1;
}

void LodePNG_Encoder_cleanup(LodePNG_Encoder* encoder)
{
  LodePNG_InfoPng_cleanup(&encoder->infoPng);
  LodePNG_InfoRaw_cleanup(&encoder->infoRaw);
}

void LodePNG_Encoder_copy(LodePNG_Encoder* dest, const LodePNG_Encoder* source)
{
  LodePNG_Encoder_cleanup(dest);
  *dest = *source;
  LodePNG_InfoPng_init(&dest->infoPng);
  LodePNG_InfoPng_copy(&dest->infoPng, &source->infoPng);
  LodePNG_InfoRaw_init(&dest->infoRaw);
  LodePNG_InfoRaw_copy(&dest->infoRaw, &source->infoRaw);
}

/* ////////////////////////////////////////////////////////////////////////// */
/* / File IO                                                                / */
/* ////////////////////////////////////////////////////////////////////////// */

void LodePNG_loadFile(unsigned char** out, size_t* outsize, const char* filename) /*designed for loading files from hard disk in a dynamically allocated buffer*/
{
  FILE* file;
  long size;
  
  /*provide some proper output values if error will happen*/
  *out = 0;
  *outsize = 0;

  file = fopen(filename, "rb");
  if(!file) return;

  /*get filesize:*/
  fseek(file , 0 , SEEK_END);
  size = ftell(file);
  rewind(file);
  
  /*read contents of the file into the vector*/
  *outsize = 0;
  *out = (unsigned char*)malloc((size_t)size);
  if(size) (*outsize) = fread(*out, 1, (size_t)size, file);

  fclose (file);
}

/*write given buffer to the file, overwriting the file, it doesn't append to it.*/
void LodePNG_saveFile(const unsigned char* buffer, size_t buffersize, const char* filename)
{
  FILE* file;
  file = fopen(filename, "wb" );
  if(file) fwrite((char*)buffer , 1 , buffersize, file);
  fclose(file);
}

#ifdef __cplusplus
/* ////////////////////////////////////////////////////////////////////////// */
/* / C++ RAII wrapper                                                       / */
/* ////////////////////////////////////////////////////////////////////////// */
namespace LodeZlib
{
  unsigned decompress(std::vector<unsigned char>& out, const std::vector<unsigned char>& in, const LodeZlib_DecompressSettings& settings)
  {
    unsigned char* buffer = 0;
    size_t buffersize = 0;
    unsigned error = LodeZlib_decompress(&buffer, &buffersize, in.empty() ? 0 : &in[0], in.size(), &settings);
    if(buffer)
    {
      out.insert(out.end(), &buffer[0], &buffer[buffersize]);
      free(buffer);
    }
    return error;
  }
  
  unsigned compress(std::vector<unsigned char>& out, const std::vector<unsigned char>& in, const LodeZlib_DeflateSettings& settings)
  {
    unsigned char* buffer = 0;
    size_t buffersize = 0;
    unsigned error = LodeZlib_compress(&buffer, &buffersize, in.empty() ? 0 : &in[0], in.size(), &settings);
    if(buffer)
    {
      out.insert(out.end(), &buffer[0], &buffer[buffersize]);
      free(buffer);
    }
    return error;
  }
}

namespace LodePNG
{
  Decoder::Decoder() { LodePNG_Decoder_init(this); }
  Decoder::~Decoder() { LodePNG_Decoder_cleanup(this); }
  void Decoder::operator=(const LodePNG_Decoder& other) { LodePNG_Decoder_copy(this, &other); }

  bool Decoder::hasError() const { return error != 0; }
  unsigned Decoder::getError() const { return error; }

  unsigned Decoder::getWidth() const { return infoPng.width; }
  unsigned Decoder::getHeight() const { return infoPng.height; }
  unsigned Decoder::getBpp() { return LodePNG_InfoColor_getBpp(&infoPng.color); }
  unsigned Decoder::getChannels() { return LodePNG_InfoColor_getChannels(&infoPng.color); }
  unsigned Decoder::isGreyscaleType() { return LodePNG_InfoColor_isGreyscaleType(&infoPng.color); }
  unsigned Decoder::isAlphaType() { return LodePNG_InfoColor_isAlphaType(&infoPng.color); }
    
  void Decoder::decode(std::vector<unsigned char>& out, const unsigned char* in, size_t insize)
  {
    unsigned char* buffer;
    size_t buffersize;
    LodePNG_decode(this, &buffer, &buffersize, in, insize);
    if(buffer)
    {
      out.insert(out.end(), &buffer[0], &buffer[buffersize]);
      free(buffer);
    }
  }
  
  void Decoder::decode(std::vector<unsigned char>& out, const std::vector<unsigned char>& in)
  {
    decode(out, in.empty() ? 0 : &in[0], in.size());
  }
  
  void Decoder::inspect(const unsigned char* in, size_t size)
  {
    LodePNG_inspect(this, in, size);
  }
  
  void Decoder::inspect(const std::vector<unsigned char>& in)
  {
    inspect(in.empty() ? 0 : &in[0], in.size());
  }
  
  const LodePNG_DecodeSettings& Decoder::getSettings() const { return settings; }
  LodePNG_DecodeSettings& Decoder::getSettings() { return settings; }
  void Decoder::setSettings(const LodePNG_DecodeSettings& settings) { this->settings = settings; }
  
  const LodePNG_InfoPng& Decoder::getInfoPng() const { return infoPng; }
  LodePNG_InfoPng& Decoder::getInfoPng() { return infoPng; }
  void Decoder::setInfoPng(const LodePNG_InfoPng& info) { LodePNG_InfoPng_copy(&this->infoPng, &info); }
  
  const LodePNG_InfoRaw& Decoder::getInfoRaw() const { return infoRaw; }
  LodePNG_InfoRaw& Decoder::getInfoRaw() { return infoRaw; }
  void Decoder::setInfoRaw(const LodePNG_InfoRaw& info) { LodePNG_InfoRaw_copy(&this->infoRaw, &info); }
  
  /* ////////////////////////////////////////////////////////////////////////// */
  
  Encoder::Encoder() { LodePNG_Encoder_init(this); }
  Encoder::~Encoder() { LodePNG_Encoder_cleanup(this); }
  void Encoder::operator=(const LodePNG_Encoder& other) { LodePNG_Encoder_copy(this, &other); }
  
  bool Encoder::hasError() const { return error != 0; }
  unsigned Encoder::getError() const { return error; }
  
  void Encoder::encode(std::vector<unsigned char>& out, const unsigned char* image, unsigned w, unsigned h)
  {
    unsigned char* buffer;
    size_t buffersize;
    LodePNG_encode(this, &buffer, &buffersize, image, w, h);
    if(buffer)
    {
      out.insert(out.end(), &buffer[0], &buffer[buffersize]);
      free(buffer);
    }
  }
  
  void Encoder::encode(std::vector<unsigned char>& out, const std::vector<unsigned char>& image, unsigned w, unsigned h)
  {
    encode(out, image.empty() ? 0 : &image[0], w, h);
  }
  
  void Encoder::clearPalette() { LodePNG_InfoColor_clearPalette(&infoPng.color); }
  void Encoder::addPalette(unsigned char r, unsigned char g, unsigned char b, unsigned char a) { LodePNG_InfoColor_addPalette(&infoPng.color, r, g, b, a); }
  void Encoder::clearText() { LodePNG_InfoPng_clearText(&infoPng); }
  void Encoder::addText(const std::string& key, const std::string& str) { LodePNG_InfoPng_addText(&infoPng, key.c_str(), str.c_str()); }
  
  const LodePNG_EncodeSettings& Encoder::getSettings() const { return settings; }
  LodePNG_EncodeSettings& Encoder::getSettings() { return settings; }
  void Encoder::setSettings(const LodePNG_EncodeSettings& settings) { this->settings = settings; }
  
  const LodePNG_InfoPng& Encoder::getInfoPng() const { return infoPng; }
  LodePNG_InfoPng& Encoder::getInfoPng() { return infoPng; }
  void Encoder::setInfoPng(const LodePNG_InfoPng& info) { LodePNG_InfoPng_copy(&this->infoPng, &info); }
  
  const LodePNG_InfoRaw& Encoder::getInfoRaw() const { return infoRaw; }
  LodePNG_InfoRaw& Encoder::getInfoRaw() { return infoRaw; }
  void Encoder::setInfoRaw(const LodePNG_InfoRaw& info) { LodePNG_InfoRaw_copy(&this->infoRaw, &info); }
  
  /* ////////////////////////////////////////////////////////////////////////// */
  
  void loadFile(std::vector<unsigned char>& buffer, const std::string& filename) //designed for loading files from hard disk in an std::vector
  {
    std::ifstream file(filename.c_str(), std::ios::in|std::ios::binary|std::ios::ate);
  
    /*get filesize*/
    std::streamsize size = 0;
    if(file.seekg(0, std::ios::end).good()) size = file.tellg();
    if(file.seekg(0, std::ios::beg).good()) size -= file.tellg();
  
    /*read contents of the file into the vector*/
    buffer.resize(size_t(size));
    if(size > 0) file.read((char*)(&buffer[0]), size);
  }
  
  /*write given buffer to the file, overwriting the file, it doesn't append to it.*/
  void saveFile(const std::vector<unsigned char>& buffer, const std::string& filename)
  {
    std::ofstream file(filename.c_str(), std::ios::out|std::ios::binary);
    file.write(buffer.empty() ? 0 : (char*)&buffer[0], std::streamsize(buffer.size()));
  }
  
  /* ////////////////////////////////////////////////////////////////////////// */
  
  unsigned decode(std::vector<unsigned char>& out, unsigned& w, unsigned& h, const unsigned char* in, unsigned size, unsigned colorType, unsigned bitDepth)
  {
    Decoder decoder;
    decoder.getInfoRaw().color.colorType = colorType;
    decoder.getInfoRaw().color.bitDepth = bitDepth;
    decoder.decode(out, in, size);
    w = decoder.getWidth();
    h = decoder.getHeight();
    return decoder.getError();
  }
  
  unsigned decode(std::vector<unsigned char>& out, unsigned& w, unsigned& h, const std::vector<unsigned char>& in, unsigned colorType, unsigned bitDepth)
  {
    return decode(out, w, h, in.empty() ? 0 : &in[0], (unsigned)in.size(), colorType, bitDepth);
  }
  
  unsigned decode(std::vector<unsigned char>& out, unsigned& w, unsigned& h, const std::string& filename, unsigned colorType, unsigned bitDepth)
  {
    std::vector<unsigned char> buffer;
    loadFile(buffer, filename);
    return decode(out, w, h, buffer, colorType, bitDepth);
  }
  
  unsigned encode(std::vector<unsigned char>& out, const unsigned char* in, unsigned w, unsigned h, unsigned colorType, unsigned bitDepth)
  {
    Encoder encoder;
    encoder.getInfoRaw().color.colorType = colorType;
    encoder.getInfoRaw().color.bitDepth = bitDepth;
    encoder.encode(out, in, w, h);
    return encoder.getError();
  }
  
  unsigned encode(std::vector<unsigned char>& out, const std::vector<unsigned char>& in, unsigned w, unsigned h, unsigned colorType, unsigned bitDepth)
  {
    return encode(out, in.empty() ? 0 : &in[0], w, h, colorType, bitDepth);
  }
  
  unsigned encode(const std::string& filename, const unsigned char* in, unsigned w, unsigned h, unsigned colorType, unsigned bitDepth)
  {
    std::vector<unsigned char> buffer;
    Encoder encoder;
    encoder.getInfoRaw().color.colorType = colorType;
    encoder.getInfoRaw().color.bitDepth = bitDepth;
    encoder.encode(buffer, in, w, h);
    if(!encoder.hasError()) saveFile(buffer, filename);
    return encoder.getError();
  }
  
  unsigned encode(const std::string& filename, const std::vector<unsigned char>& in, unsigned w, unsigned h, unsigned colorType, unsigned bitDepth)
  {
    return encode(filename, in.empty() ? 0 : &in[0], w, h, colorType, bitDepth);
  }
  
}
#endif /*end of C++ RAII wrapper*/