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// Copyright 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
// option. This file may not be copied, modified, or distributed
// except according to those terms.
use super::*;
use crate::data::*;
use crate::handles::*;
use crate::variant::*;
// Rust 1.14.0 requires the following despite the asterisk above.
use super::in_inclusive_range32;
pub struct Big5Decoder {
lead: Option<u8>,
}
impl Big5Decoder {
pub fn new() -> VariantDecoder {
VariantDecoder::Big5(Big5Decoder { lead: None })
}
pub fn in_neutral_state(&self) -> bool {
self.lead.is_none()
}
fn plus_one_if_lead(&self, byte_length: usize) -> Option<usize> {
byte_length.checked_add(match self.lead {
None => 0,
Some(_) => 1,
})
}
pub fn max_utf16_buffer_length(&self, byte_length: usize) -> Option<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.
checked_add(1, self.plus_one_if_lead(byte_length))
}
pub fn max_utf8_buffer_length_without_replacement(&self, byte_length: usize) -> Option<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.
//
// Finally, add two so that if input is non-zero, the output is at
// least 4.
checked_add(2, checked_mul(2, self.plus_one_if_lead(byte_length)))
}
pub fn max_utf8_buffer_length(&self, byte_length: usize) -> Option<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.
checked_add(3, checked_mul(3, self.plus_one_if_lead(byte_length)))
}
ascii_compatible_two_byte_decoder_functions!(
{
// If lead is between 0x81 and 0xFE, inclusive,
// subtract offset 0x81.
let non_ascii_minus_offset =
non_ascii.wrapping_sub(0x81);
if non_ascii_minus_offset > (0xFE - 0x81) {
return (DecoderResult::Malformed(1, 0),
source.consumed(),
handle.written());
}
non_ascii_minus_offset
},
{
// If trail is between 0x40 and 0x7E, inclusive,
// subtract offset 0x40. Else if trail is
// between 0xA1 and 0xFE, inclusive, subtract
// offset 0x62.
// TODO: Find out which range is more probable.
let mut trail_minus_offset =
byte.wrapping_sub(0x40);
if trail_minus_offset > (0x7E - 0x40) {
let trail_minus_range_start =
byte.wrapping_sub(0xA1);
if trail_minus_range_start >
(0xFE - 0xA1) {
if byte < 0x80 {
return (DecoderResult::Malformed(1, 0),
unread_handle_trail.unread(),
handle.written());
}
return (DecoderResult::Malformed(2, 0),
unread_handle_trail.consumed(),
handle.written());
}
trail_minus_offset = byte - 0x62;
}
let pointer = lead_minus_offset as usize *
157usize +
trail_minus_offset as usize;
let rebased_pointer = pointer.wrapping_sub(942);
let low_bits = big5_low_bits(rebased_pointer);
if low_bits == 0 {
match pointer {
1133 => {
handle.write_big5_combination(0x00CAu16,
0x0304u16)
}
1135 => {
handle.write_big5_combination(0x00CAu16,
0x030Cu16)
}
1164 => {
handle.write_big5_combination(0x00EAu16,
0x0304u16)
}
1166 => {
handle.write_big5_combination(0x00EAu16,
0x030Cu16)
}
_ => {
if byte < 0x80 {
return (DecoderResult::Malformed(1, 0),
unread_handle_trail.unread(),
handle.written());
}
return (DecoderResult::Malformed(2, 0),
unread_handle_trail.consumed(),
handle.written());
}
}
} else if big5_is_astral(rebased_pointer) {
handle.write_astral(u32::from(low_bits) |
0x20000u32)
} else {
handle.write_bmp_excl_ascii(low_bits)
}
},
self,
non_ascii,
byte,
lead_minus_offset,
unread_handle_trail,
source,
handle,
'outermost,
copy_ascii_from_check_space_astral,
check_space_astral,
false);
}
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,
) -> Option<usize> {
// Astral: 2 to 2
// ASCII: 1 to 1
// Other: 1 to 2
u16_length.checked_mul(2)
}
pub fn max_buffer_length_from_utf8_without_replacement(
&self,
byte_length: usize,
) -> Option<usize> {
// Astral: 4 to 2
// Upper BMP: 3 to 2
// Lower BMP: 2 to 2
// ASCII: 1 to 1
byte_length.checked_add(1)
}
ascii_compatible_encoder_functions!(
{
// For simplicity, unified ideographs
// in the pointer range 11206...11212 are handled
// as Level 1 Hanzi.
if let Some((lead, trail)) = big5_level1_hanzi_encode(bmp) {
handle.write_two(lead, trail)
} else {
let pointer = if let Some(pointer) = big5_box_encode(bmp) {
pointer
} else if let Some(pointer) = big5_other_encode(bmp) {
pointer
} else {
return (
EncoderResult::unmappable_from_bmp(bmp),
source.consumed(),
handle.written(),
);
};
let lead = pointer / 157 + 0x81;
let remainder = pointer % 157;
let trail = if remainder < 0x3F {
remainder + 0x40
} else {
remainder + 0x62
};
handle.write_two(lead as u8, trail as u8)
}
},
{
if in_inclusive_range32(astral as u32, 0x2008A, 0x2F8A6) {
if let Some(rebased_pointer) = big5_astral_encode(astral as u16) {
// big5_astral_encode returns rebased pointer,
// so adding 0x87 instead of 0x81.
let lead = rebased_pointer / 157 + 0x87;
let remainder = rebased_pointer % 157;
let trail = if remainder < 0x3F {
remainder + 0x40
} else {
remainder + 0x62
};
handle.write_two(lead as u8, trail as u8)
} else {
return (
EncoderResult::Unmappable(astral),
source.consumed(),
handle.written(),
);
}
} else {
return (
EncoderResult::Unmappable(astral),
source.consumed(),
handle.written(),
);
}
},
bmp,
astral,
self,
source,
handle,
copy_ascii_to_check_space_two,
check_space_two,
false
);
}
// Any copyright to the test code below this comment is dedicated to the
#[cfg(all(test, feature = "alloc"))]
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");
if !cfg!(miri) {
// Miri is too slow
// 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");
encode_big5("\u{25605}", b"\xFE\x46");
// prefer last
encode_big5("\u{2550}", b"\xF9\xF9");
}
#[test]
#[cfg_attr(miri, ignore)] // Miri is too slow
fn test_big5_decode_all() {
let input = include_bytes!("test_data/big5_in.txt");
let expectation = include_str!("test_data/big5_in_ref.txt");
let (cow, had_errors) = BIG5.decode_without_bom_handling(input);
assert!(had_errors, "Should have had errors.");
assert_eq!(&cow[..], expectation);
}
#[test]
#[cfg_attr(miri, ignore)] // Miri is too slow
fn test_big5_encode_all() {
let input = include_str!("test_data/big5_out.txt");
let expectation = include_bytes!("test_data/big5_out_ref.txt");
let (cow, encoding, had_errors) = BIG5.encode(input);
assert!(!had_errors, "Should not have had errors.");
assert_eq!(encoding, BIG5);
assert_eq!(&cow[..], &expectation[..]);
}
#[test]
#[cfg_attr(miri, ignore)] // Miri is too slow
fn test_big5_encode_from_two_low_surrogates() {
let expectation = b"��";
let mut output = [0u8; 40];
let mut encoder = BIG5.new_encoder();
let (result, read, written, had_errors) =
encoder.encode_from_utf16(&[0xDC00u16, 0xDEDEu16], &mut output[..], true);
assert_eq!(result, CoderResult::InputEmpty);
assert_eq!(read, 2);
assert_eq!(written, expectation.len());
assert!(had_errors);
assert_eq!(&output[..written], expectation);
}
}