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/* n2e_d.c -- implementation of the NRV2E decompression algorithm
This file is part of the UCL data compression library.
Copyright (C) 1996-2004 Markus Franz Xaver Johannes Oberhumer
All Rights Reserved.
The UCL library is free software; you can redistribute it and/or
modify it under the terms of the GNU General Public License as
published by the Free Software Foundation; either version 2 of
the License, or (at your option) any later version.
The UCL library is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
GNU General Public License for more details.
You should have received a copy of the GNU General Public License
along with the UCL library; see the file COPYING.
If not, write to the Free Software Foundation, Inc.,
59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
Markus F.X.J. Oberhumer
<markus@oberhumer.com>
http://www.oberhumer.com/opensource/ucl/
*/
/***********************************************************************
// actual implementation used by a recursive #include
************************************************************************/
#ifdef getbit
#ifdef SAFE
#define fail(x,r) if (x) { *dst_len = olen; return r; }
#else
#define fail(x,r)
#endif
{
ucl_uint32 bb = 0;
#ifdef TEST_OVERLAP
ucl_uint ilen = src_off, olen = 0, last_m_off = 1;
#else
ucl_uint ilen = 0, olen = 0, last_m_off = 1;
#endif
#ifdef SAFE
const ucl_uint oend = *dst_len;
#endif
ACC_UNUSED(wrkmem);
#ifdef TEST_OVERLAP
src_len += src_off;
fail(oend >= src_len, UCL_E_OVERLAP_OVERRUN);
#endif
for (;;)
{
ucl_uint m_off, m_len;
while (getbit(bb))
{
fail(ilen >= src_len, UCL_E_INPUT_OVERRUN);
fail(olen >= oend, UCL_E_OUTPUT_OVERRUN);
#ifdef TEST_OVERLAP
fail(olen > ilen, UCL_E_OVERLAP_OVERRUN);
olen++; ilen++;
#else
dst[olen++] = src[ilen++];
#endif
}
m_off = 1;
for (;;)
{
m_off = m_off*2 + getbit(bb);
fail(ilen >= src_len, UCL_E_INPUT_OVERRUN);
fail(m_off > UCL_UINT32_C(0xffffff) + 3, UCL_E_LOOKBEHIND_OVERRUN);
if (getbit(bb)) break;
m_off = (m_off-1)*2 + getbit(bb);
}
if (m_off == 2)
{
m_off = last_m_off;
m_len = getbit(bb);
}
else
{
fail(ilen >= src_len, UCL_E_INPUT_OVERRUN);
m_off = (m_off-3)*256 + src[ilen++];
if (m_off == UCL_UINT32_C(0xffffffff))
break;
m_len = (m_off ^ UCL_UINT32_C(0xffffffff)) & 1;
m_off >>= 1;
last_m_off = ++m_off;
}
if (m_len)
m_len = 1 + getbit(bb);
else if (getbit(bb))
m_len = 3 + getbit(bb);
else
{
m_len++;
do {
m_len = m_len*2 + getbit(bb);
fail(ilen >= src_len, UCL_E_INPUT_OVERRUN);
fail(m_len >= oend, UCL_E_OUTPUT_OVERRUN);
} while (!getbit(bb));
m_len += 3;
}
m_len += (m_off > 0x500);
fail(olen + m_len > oend, UCL_E_OUTPUT_OVERRUN);
fail(m_off > olen, UCL_E_LOOKBEHIND_OVERRUN);
#ifdef TEST_OVERLAP
olen += m_len + 1;
fail(olen > ilen, UCL_E_OVERLAP_OVERRUN);
#else
{
const ucl_bytep m_pos;
m_pos = dst + olen - m_off;
dst[olen++] = *m_pos++;
do dst[olen++] = *m_pos++; while (--m_len > 0);
}
#endif
}
*dst_len = olen;
return ilen == src_len ? UCL_E_OK : (ilen < src_len ? UCL_E_INPUT_NOT_CONSUMED : UCL_E_INPUT_OVERRUN);
}
#undef fail
#endif /* getbit */
/***********************************************************************
// decompressor entries for the different bit-buffer sizes
************************************************************************/
#ifndef getbit
#include "ucl_conf.h"
#include <ucl/ucl.h>
#include "getbit.h"
UCL_PUBLIC(int)
ucl_nrv2e_decompress_8 ( const ucl_bytep src, ucl_uint src_len,
ucl_bytep dst, ucl_uintp dst_len,
ucl_voidp wrkmem )
{
#define getbit(bb) getbit_8(bb,src,ilen)
#include "n2e_d.c"
#undef getbit
}
UCL_PUBLIC(int)
ucl_nrv2e_decompress_le16 ( const ucl_bytep src, ucl_uint src_len,
ucl_bytep dst, ucl_uintp dst_len,
ucl_voidp wrkmem )
{
#define getbit(bb) getbit_le16(bb,src,ilen)
#include "n2e_d.c"
#undef getbit
}
UCL_PUBLIC(int)
ucl_nrv2e_decompress_le32 ( const ucl_bytep src, ucl_uint src_len,
ucl_bytep dst, ucl_uintp dst_len,
ucl_voidp wrkmem )
{
unsigned bc = 0;
#define getbit(bb) getbit_le32(bb,bc,src,ilen)
#include "n2e_d.c"
#undef getbit
}
#endif /* !getbit */
/*
vi:ts=4:et
*/
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