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// Copyright 2015-2016 Mozilla Foundation. See the COPYRIGHT
// file at the top-level directory of this distribution.
//
// Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or
// https://www.apache.org/licenses/LICENSE-2.0> or the MIT license
// <LICENSE-MIT or https://opensource.org/licenses/MIT>, at your
// option. This file may not be copied, modified, or distributed
// except according to those terms.
use handles::*;
use data::*;
use variant::*;
use super::*;
pub struct Big5Decoder {
lead: u8,
}
impl Big5Decoder {
pub fn new() -> VariantDecoder {
VariantDecoder::Big5(Big5Decoder { lead: 0 })
}
fn plus_one_if_lead(&self, byte_length: usize) -> usize {
byte_length +
if self.lead == 0 {
0
} else {
1
}
}
pub fn max_utf16_buffer_length(&self, byte_length: usize) -> usize {
// If there is a lead but the next byte isn't a valid trail, an
// error is generated for the lead (+1). Then another iteration checks
// space, which needs +1 to account for the possibility of astral
// output or combining pair.
self.plus_one_if_lead(byte_length) + 1
}
pub fn max_utf8_buffer_length_without_replacement(&self, byte_length: usize) -> usize {
// No need to account for REPLACEMENT CHARACTERS.
// Cases:
// ASCII: 1 to 1
// Valid pair: 2 to 2, 2 to 3 or 2 to 4, i.e. worst case 2 to 4
// lead set and first byte is trail: 1 to 4 worst case
//
// When checking for space for the last byte:
// no lead: the last byte must be ASCII (or fatal error): 1 to 1
// lead set: space for 4 bytes was already checked when reading the
// lead, hence the last lead and the last trail together are worst
// case 2 to 4.
//
// If lead set and the input is a single trail byte, the worst-case
// output is 4, so we need to add one before multiplying if lead is
// set.
self.plus_one_if_lead(byte_length) * 2
}
pub fn max_utf8_buffer_length(&self, byte_length: usize) -> usize {
// If there is a lead but the next byte isn't a valid trail, an
// error is generated for the lead (+(1*3)). Then another iteration
// checks space, which needs +3 to account for the possibility of astral
// output or combining pair. In between start and end, the worst case
// is that every byte is bad: *3.
3 * self.plus_one_if_lead(byte_length) + 3
}
decoder_functions!({},
{
if self.lead != 0 {
self.lead = 0;
return (DecoderResult::Malformed(1, 0),
src_consumed,
dest.written());
}
},
{
if self.lead == 0 {
if b <= 0x7f {
// TODO optimize ASCII run
destination_handle.write_ascii(b);
continue;
}
if b >= 0x81 && b <= 0xFE {
self.lead = b;
continue;
}
return (DecoderResult::Malformed(1, 0),
unread_handle.consumed(),
destination_handle.written());
}
let lead = self.lead as usize;
self.lead = 0;
let offset = if b < 0x7F {
0x40usize
} else {
0x62usize
};
if (b >= 0x40 && b <= 0x7E) || (b >= 0xA1 && b <= 0xFE) {
let pointer = (lead as usize - 0x81usize) * 157usize +
(b as usize - offset);
match pointer {
1133 => {
destination_handle.write_big5_combination(0x00CAu16,
0x0304u16);
continue;
}
1135 => {
destination_handle.write_big5_combination(0x00CAu16,
0x030Cu16);
continue;
}
1164 => {
destination_handle.write_big5_combination(0x00EAu16,
0x0304u16);
continue;
}
1166 => {
destination_handle.write_big5_combination(0x00EAu16,
0x030Cu16);
continue;
}
_ => {
let low_bits = big5_low_bits(pointer);
if low_bits != 0 {
if big5_is_astral(pointer) {
destination_handle.write_astral(low_bits as u32 |
0x20000u32);
continue;
}
destination_handle.write_bmp_excl_ascii(low_bits);
continue;
}
}
}
}
if b <= 0x7F {
return (DecoderResult::Malformed(1, 0),
unread_handle.unread(),
destination_handle.written());
}
return (DecoderResult::Malformed(2, 0),
unread_handle.consumed(),
destination_handle.written());
},
self,
src_consumed,
dest,
b,
destination_handle,
unread_handle,
check_space_astral);
}
pub struct Big5Encoder;
impl Big5Encoder {
pub fn new(encoding: &'static Encoding) -> Encoder {
Encoder::new(encoding, VariantEncoder::Big5(Big5Encoder))
}
pub fn max_buffer_length_from_utf16_without_replacement(&self, u16_length: usize) -> usize {
// Astral: 2 to 2
// ASCII: 1 to 1
// Other: 1 to 2
2 * u16_length
}
pub fn max_buffer_length_from_utf8_without_replacement(&self, byte_length: usize) -> usize {
// Astral: 4 to 2
// Upper BMP: 3 to 2
// Lower BMP: 2 to 2
// ASCII: 1 to 1
byte_length
}
encoder_functions!({},
{
if c <= '\u{7F}' {
// TODO optimize ASCII run
destination_handle.write_one(c as u8);
continue;
}
let high_bits = c as u32 & 0xFF0000;
let (low_bits, is_astral) = if high_bits == 0 {
(c as u16, false)
} else if high_bits == 0x20000 {
((c as u32 & 0xFFFF) as u16, true)
} else {
// Only BMP and Plane 2 are potentially mappable.
return (EncoderResult::Unmappable(c),
unread_handle.consumed(),
destination_handle.written());
};
let pointer = big5_find_pointer(low_bits, is_astral);
if pointer == 0 {
return (EncoderResult::Unmappable(c),
unread_handle.consumed(),
destination_handle.written());
}
let lead = pointer / 157 + 0x81;
let remainder = pointer % 157;
let trail = if remainder < 0x3F {
remainder + 0x40
} else {
remainder + 0x62
};
destination_handle.write_two(lead as u8, trail as u8);
continue;
},
self,
src_consumed,
source,
dest,
c,
destination_handle,
unread_handle,
check_space_two);
}
// Any copyright to the test code below this comment is dedicated to the
// Public Domain. http://creativecommons.org/publicdomain/zero/1.0/
#[cfg(test)]
mod tests {
use super::super::testing::*;
use super::super::*;
fn decode_big5(bytes: &[u8], expect: &str) {
decode(BIG5, bytes, expect);
}
fn encode_big5(string: &str, expect: &[u8]) {
encode(BIG5, string, expect);
}
#[test]
fn test_big5_decode() {
// Empty
decode_big5(b"", &"");
// ASCII
decode_big5(&[0x61u8, 0x62u8], &"\u{0061}\u{0062}");
// Edge cases
decode_big5(&[0x87u8, 0x40u8], &"\u{43F0}");
decode_big5(&[0xFEu8, 0xFEu8], &"\u{79D4}");
decode_big5(&[0xFEu8, 0xFDu8], &"\u{2910D}");
decode_big5(&[0x88u8, 0x62u8], &"\u{00CA}\u{0304}");
decode_big5(&[0x88u8, 0x64u8], &"\u{00CA}\u{030C}");
decode_big5(&[0x88u8, 0x66u8], &"\u{00CA}");
decode_big5(&[0x88u8, 0xA3u8], &"\u{00EA}\u{0304}");
decode_big5(&[0x88u8, 0xA5u8], &"\u{00EA}\u{030C}");
decode_big5(&[0x88u8, 0xA7u8], &"\u{00EA}");
decode_big5(&[0x99u8, 0xD4u8], &"\u{8991}");
decode_big5(&[0x99u8, 0xD5u8], &"\u{27967}");
decode_big5(&[0x99u8, 0xD6u8], &"\u{8A29}");
// Edge cases surrounded with ASCII
decode_big5(&[0x61u8, 0x87u8, 0x40u8, 0x62u8],
&"\u{0061}\u{43F0}\u{0062}");
decode_big5(&[0x61u8, 0xFEu8, 0xFEu8, 0x62u8],
&"\u{0061}\u{79D4}\u{0062}");
decode_big5(&[0x61u8, 0xFEu8, 0xFDu8, 0x62u8],
&"\u{0061}\u{2910D}\u{0062}");
decode_big5(&[0x61u8, 0x88u8, 0x62u8, 0x62u8],
&"\u{0061}\u{00CA}\u{0304}\u{0062}");
decode_big5(&[0x61u8, 0x88u8, 0x64u8, 0x62u8],
&"\u{0061}\u{00CA}\u{030C}\u{0062}");
decode_big5(&[0x61u8, 0x88u8, 0x66u8, 0x62u8],
&"\u{0061}\u{00CA}\u{0062}");
decode_big5(&[0x61u8, 0x88u8, 0xA3u8, 0x62u8],
&"\u{0061}\u{00EA}\u{0304}\u{0062}");
decode_big5(&[0x61u8, 0x88u8, 0xA5u8, 0x62u8],
&"\u{0061}\u{00EA}\u{030C}\u{0062}");
decode_big5(&[0x61u8, 0x88u8, 0xA7u8, 0x62u8],
&"\u{0061}\u{00EA}\u{0062}");
decode_big5(&[0x61u8, 0x99u8, 0xD4u8, 0x62u8],
&"\u{0061}\u{8991}\u{0062}");
decode_big5(&[0x61u8, 0x99u8, 0xD5u8, 0x62u8],
&"\u{0061}\u{27967}\u{0062}");
decode_big5(&[0x61u8, 0x99u8, 0xD6u8, 0x62u8],
&"\u{0061}\u{8A29}\u{0062}");
// Bad sequences
decode_big5(&[0x80u8, 0x61u8], &"\u{FFFD}\u{0061}");
decode_big5(&[0xFFu8, 0x61u8], &"\u{FFFD}\u{0061}");
decode_big5(&[0xFEu8, 0x39u8], &"\u{FFFD}\u{0039}");
decode_big5(&[0x87u8, 0x66u8], &"\u{FFFD}\u{0066}");
decode_big5(&[0x81u8, 0x40u8], &"\u{FFFD}\u{0040}");
decode_big5(&[0x61u8, 0x81u8], &"\u{0061}\u{FFFD}");
}
#[test]
fn test_big5_encode() {
// Empty
encode_big5("", b"");
// ASCII
encode_big5("\u{0061}\u{0062}", b"\x61\x62");
// Edge cases
encode_big5("\u{9EA6}\u{0061}", b"麦\x61");
encode_big5("\u{2626B}\u{0061}", b"𦉫\x61");
encode_big5("\u{3000}", b"\xA1\x40");
encode_big5("\u{20AC}", b"\xA3\xE1");
encode_big5("\u{4E00}", b"\xA4\x40");
encode_big5("\u{27607}", b"\xC8\xA4");
encode_big5("\u{FFE2}", b"\xC8\xCD");
encode_big5("\u{79D4}", b"\xFE\xFE");
// Not in index
encode_big5("\u{2603}\u{0061}", b"☃\x61");
// duplicate low bits
encode_big5("\u{203B5}", b"\xFD\x6A");
// prefer last
encode_big5("\u{2550}", b"\xF9\xF9");
}
}