428 lines
15 KiB
Rust
428 lines
15 KiB
Rust
// Copyright Mozilla Foundation. See the COPYRIGHT
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// file at the top-level directory of this distribution.
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//
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// Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or
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// https://www.apache.org/licenses/LICENSE-2.0> or the MIT license
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// <LICENSE-MIT or https://opensource.org/licenses/MIT>, at your
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// option. This file may not be copied, modified, or distributed
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// except according to those terms.
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use super::*;
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use crate::data::*;
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use crate::handles::*;
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use crate::variant::*;
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// Rust 1.14.0 requires the following despite the asterisk above.
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use super::in_inclusive_range32;
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pub struct Big5Decoder {
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lead: Option<u8>,
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}
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impl Big5Decoder {
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pub fn new() -> VariantDecoder {
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VariantDecoder::Big5(Big5Decoder { lead: None })
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}
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pub fn in_neutral_state(&self) -> bool {
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self.lead.is_none()
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}
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fn plus_one_if_lead(&self, byte_length: usize) -> Option<usize> {
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byte_length.checked_add(match self.lead {
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None => 0,
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Some(_) => 1,
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})
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}
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pub fn max_utf16_buffer_length(&self, byte_length: usize) -> Option<usize> {
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// If there is a lead but the next byte isn't a valid trail, an
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// error is generated for the lead (+1). Then another iteration checks
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// space, which needs +1 to account for the possibility of astral
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// output or combining pair.
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checked_add(1, self.plus_one_if_lead(byte_length))
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}
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pub fn max_utf8_buffer_length_without_replacement(&self, byte_length: usize) -> Option<usize> {
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// No need to account for REPLACEMENT CHARACTERS.
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// Cases:
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// ASCII: 1 to 1
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// Valid pair: 2 to 2, 2 to 3 or 2 to 4, i.e. worst case 2 to 4
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// lead set and first byte is trail: 1 to 4 worst case
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//
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// When checking for space for the last byte:
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// no lead: the last byte must be ASCII (or fatal error): 1 to 1
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// lead set: space for 4 bytes was already checked when reading the
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// lead, hence the last lead and the last trail together are worst
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// case 2 to 4.
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//
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// If lead set and the input is a single trail byte, the worst-case
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// output is 4, so we need to add one before multiplying if lead is
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// set.
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//
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// Finally, add two so that if input is non-zero, the output is at
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// least 4.
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checked_add(2, checked_mul(2, self.plus_one_if_lead(byte_length)))
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}
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pub fn max_utf8_buffer_length(&self, byte_length: usize) -> Option<usize> {
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// If there is a lead but the next byte isn't a valid trail, an
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// error is generated for the lead (+(1*3)). Then another iteration
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// checks space, which needs +3 to account for the possibility of astral
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// output or combining pair. In between start and end, the worst case
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// is that every byte is bad: *3.
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checked_add(3, checked_mul(3, self.plus_one_if_lead(byte_length)))
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}
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ascii_compatible_two_byte_decoder_functions!(
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{
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// If lead is between 0x81 and 0xFE, inclusive,
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// subtract offset 0x81.
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let non_ascii_minus_offset =
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non_ascii.wrapping_sub(0x81);
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if non_ascii_minus_offset > (0xFE - 0x81) {
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return (DecoderResult::Malformed(1, 0),
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source.consumed(),
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handle.written());
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}
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non_ascii_minus_offset
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},
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{
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// If trail is between 0x40 and 0x7E, inclusive,
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// subtract offset 0x40. Else if trail is
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// between 0xA1 and 0xFE, inclusive, subtract
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// offset 0x62.
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// TODO: Find out which range is more probable.
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let mut trail_minus_offset =
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byte.wrapping_sub(0x40);
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if trail_minus_offset > (0x7E - 0x40) {
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let trail_minus_range_start =
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byte.wrapping_sub(0xA1);
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if trail_minus_range_start >
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(0xFE - 0xA1) {
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if byte < 0x80 {
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return (DecoderResult::Malformed(1, 0),
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unread_handle_trail.unread(),
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handle.written());
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}
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return (DecoderResult::Malformed(2, 0),
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unread_handle_trail.consumed(),
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handle.written());
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}
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trail_minus_offset = byte - 0x62;
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}
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let pointer = lead_minus_offset as usize *
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157usize +
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trail_minus_offset as usize;
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let rebased_pointer = pointer.wrapping_sub(942);
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let low_bits = big5_low_bits(rebased_pointer);
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if low_bits == 0 {
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match pointer {
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1133 => {
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handle.write_big5_combination(0x00CAu16,
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0x0304u16)
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}
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1135 => {
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handle.write_big5_combination(0x00CAu16,
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0x030Cu16)
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}
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1164 => {
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handle.write_big5_combination(0x00EAu16,
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0x0304u16)
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}
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1166 => {
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handle.write_big5_combination(0x00EAu16,
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0x030Cu16)
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}
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_ => {
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if byte < 0x80 {
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return (DecoderResult::Malformed(1, 0),
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unread_handle_trail.unread(),
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handle.written());
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}
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return (DecoderResult::Malformed(2, 0),
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unread_handle_trail.consumed(),
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handle.written());
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}
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}
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} else if big5_is_astral(rebased_pointer) {
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handle.write_astral(u32::from(low_bits) |
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0x20000u32)
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} else {
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handle.write_bmp_excl_ascii(low_bits)
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}
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},
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self,
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non_ascii,
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byte,
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lead_minus_offset,
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unread_handle_trail,
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source,
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handle,
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'outermost,
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copy_ascii_from_check_space_astral,
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check_space_astral,
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false);
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}
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pub struct Big5Encoder;
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impl Big5Encoder {
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pub fn new(encoding: &'static Encoding) -> Encoder {
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Encoder::new(encoding, VariantEncoder::Big5(Big5Encoder))
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}
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pub fn max_buffer_length_from_utf16_without_replacement(
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&self,
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u16_length: usize,
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) -> Option<usize> {
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// Astral: 2 to 2
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// ASCII: 1 to 1
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// Other: 1 to 2
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u16_length.checked_mul(2)
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}
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pub fn max_buffer_length_from_utf8_without_replacement(
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&self,
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byte_length: usize,
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) -> Option<usize> {
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// Astral: 4 to 2
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// Upper BMP: 3 to 2
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// Lower BMP: 2 to 2
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// ASCII: 1 to 1
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byte_length.checked_add(1)
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}
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ascii_compatible_encoder_functions!(
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{
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// For simplicity, unified ideographs
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// in the pointer range 11206...11212 are handled
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// as Level 1 Hanzi.
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if let Some((lead, trail)) = big5_level1_hanzi_encode(bmp) {
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handle.write_two(lead, trail)
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} else {
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let pointer = if let Some(pointer) = big5_box_encode(bmp) {
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pointer
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} else if let Some(pointer) = big5_other_encode(bmp) {
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pointer
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} else {
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return (
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EncoderResult::unmappable_from_bmp(bmp),
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source.consumed(),
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handle.written(),
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);
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};
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let lead = pointer / 157 + 0x81;
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let remainder = pointer % 157;
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let trail = if remainder < 0x3F {
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remainder + 0x40
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} else {
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remainder + 0x62
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};
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handle.write_two(lead as u8, trail as u8)
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}
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},
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{
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if in_inclusive_range32(astral as u32, 0x2008A, 0x2F8A6) {
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if let Some(rebased_pointer) = big5_astral_encode(astral as u16) {
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// big5_astral_encode returns rebased pointer,
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// so adding 0x87 instead of 0x81.
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let lead = rebased_pointer / 157 + 0x87;
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let remainder = rebased_pointer % 157;
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let trail = if remainder < 0x3F {
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remainder + 0x40
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} else {
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remainder + 0x62
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};
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handle.write_two(lead as u8, trail as u8)
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} else {
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return (
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EncoderResult::Unmappable(astral),
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source.consumed(),
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handle.written(),
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);
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}
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} else {
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return (
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EncoderResult::Unmappable(astral),
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source.consumed(),
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handle.written(),
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);
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}
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},
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bmp,
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astral,
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self,
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source,
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handle,
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copy_ascii_to_check_space_two,
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check_space_two,
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false
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);
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}
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// Any copyright to the test code below this comment is dedicated to the
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// Public Domain. http://creativecommons.org/publicdomain/zero/1.0/
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#[cfg(all(test, feature = "alloc"))]
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mod tests {
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use super::super::testing::*;
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use super::super::*;
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fn decode_big5(bytes: &[u8], expect: &str) {
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decode(BIG5, bytes, expect);
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}
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fn encode_big5(string: &str, expect: &[u8]) {
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encode(BIG5, string, expect);
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}
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#[test]
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fn test_big5_decode() {
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// Empty
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decode_big5(b"", &"");
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// ASCII
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decode_big5(&[0x61u8, 0x62u8], &"\u{0061}\u{0062}");
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// Edge cases
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decode_big5(&[0x87u8, 0x40u8], &"\u{43F0}");
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decode_big5(&[0xFEu8, 0xFEu8], &"\u{79D4}");
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decode_big5(&[0xFEu8, 0xFDu8], &"\u{2910D}");
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decode_big5(&[0x88u8, 0x62u8], &"\u{00CA}\u{0304}");
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decode_big5(&[0x88u8, 0x64u8], &"\u{00CA}\u{030C}");
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decode_big5(&[0x88u8, 0x66u8], &"\u{00CA}");
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decode_big5(&[0x88u8, 0xA3u8], &"\u{00EA}\u{0304}");
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decode_big5(&[0x88u8, 0xA5u8], &"\u{00EA}\u{030C}");
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decode_big5(&[0x88u8, 0xA7u8], &"\u{00EA}");
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decode_big5(&[0x99u8, 0xD4u8], &"\u{8991}");
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decode_big5(&[0x99u8, 0xD5u8], &"\u{27967}");
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decode_big5(&[0x99u8, 0xD6u8], &"\u{8A29}");
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// Edge cases surrounded with ASCII
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decode_big5(
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&[0x61u8, 0x87u8, 0x40u8, 0x62u8],
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&"\u{0061}\u{43F0}\u{0062}",
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);
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decode_big5(
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&[0x61u8, 0xFEu8, 0xFEu8, 0x62u8],
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&"\u{0061}\u{79D4}\u{0062}",
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);
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decode_big5(
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&[0x61u8, 0xFEu8, 0xFDu8, 0x62u8],
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&"\u{0061}\u{2910D}\u{0062}",
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);
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decode_big5(
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&[0x61u8, 0x88u8, 0x62u8, 0x62u8],
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&"\u{0061}\u{00CA}\u{0304}\u{0062}",
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);
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decode_big5(
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&[0x61u8, 0x88u8, 0x64u8, 0x62u8],
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&"\u{0061}\u{00CA}\u{030C}\u{0062}",
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);
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decode_big5(
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&[0x61u8, 0x88u8, 0x66u8, 0x62u8],
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&"\u{0061}\u{00CA}\u{0062}",
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);
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decode_big5(
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&[0x61u8, 0x88u8, 0xA3u8, 0x62u8],
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&"\u{0061}\u{00EA}\u{0304}\u{0062}",
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);
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decode_big5(
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&[0x61u8, 0x88u8, 0xA5u8, 0x62u8],
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&"\u{0061}\u{00EA}\u{030C}\u{0062}",
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);
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decode_big5(
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&[0x61u8, 0x88u8, 0xA7u8, 0x62u8],
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&"\u{0061}\u{00EA}\u{0062}",
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);
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decode_big5(
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&[0x61u8, 0x99u8, 0xD4u8, 0x62u8],
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&"\u{0061}\u{8991}\u{0062}",
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);
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decode_big5(
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&[0x61u8, 0x99u8, 0xD5u8, 0x62u8],
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&"\u{0061}\u{27967}\u{0062}",
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);
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decode_big5(
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&[0x61u8, 0x99u8, 0xD6u8, 0x62u8],
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&"\u{0061}\u{8A29}\u{0062}",
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);
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// Bad sequences
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decode_big5(&[0x80u8, 0x61u8], &"\u{FFFD}\u{0061}");
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decode_big5(&[0xFFu8, 0x61u8], &"\u{FFFD}\u{0061}");
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decode_big5(&[0xFEu8, 0x39u8], &"\u{FFFD}\u{0039}");
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decode_big5(&[0x87u8, 0x66u8], &"\u{FFFD}\u{0066}");
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decode_big5(&[0x81u8, 0x40u8], &"\u{FFFD}\u{0040}");
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decode_big5(&[0x61u8, 0x81u8], &"\u{0061}\u{FFFD}");
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}
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#[test]
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fn test_big5_encode() {
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// Empty
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encode_big5("", b"");
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// ASCII
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encode_big5("\u{0061}\u{0062}", b"\x61\x62");
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if !cfg!(miri) {
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// Miri is too slow
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// Edge cases
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encode_big5("\u{9EA6}\u{0061}", b"麦\x61");
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encode_big5("\u{2626B}\u{0061}", b"𦉫\x61");
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encode_big5("\u{3000}", b"\xA1\x40");
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encode_big5("\u{20AC}", b"\xA3\xE1");
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encode_big5("\u{4E00}", b"\xA4\x40");
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encode_big5("\u{27607}", b"\xC8\xA4");
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encode_big5("\u{FFE2}", b"\xC8\xCD");
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encode_big5("\u{79D4}", b"\xFE\xFE");
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// Not in index
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encode_big5("\u{2603}\u{0061}", b"☃\x61");
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}
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// duplicate low bits
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encode_big5("\u{203B5}", b"\xFD\x6A");
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encode_big5("\u{25605}", b"\xFE\x46");
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// prefer last
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encode_big5("\u{2550}", b"\xF9\xF9");
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}
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#[test]
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#[cfg_attr(miri, ignore)] // Miri is too slow
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fn test_big5_decode_all() {
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let input = include_bytes!("test_data/big5_in.txt");
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let expectation = include_str!("test_data/big5_in_ref.txt");
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let (cow, had_errors) = BIG5.decode_without_bom_handling(input);
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assert!(had_errors, "Should have had errors.");
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assert_eq!(&cow[..], expectation);
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}
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#[test]
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#[cfg_attr(miri, ignore)] // Miri is too slow
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fn test_big5_encode_all() {
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let input = include_str!("test_data/big5_out.txt");
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let expectation = include_bytes!("test_data/big5_out_ref.txt");
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let (cow, encoding, had_errors) = BIG5.encode(input);
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assert!(!had_errors, "Should not have had errors.");
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assert_eq!(encoding, BIG5);
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assert_eq!(&cow[..], &expectation[..]);
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}
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#[test]
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#[cfg_attr(miri, ignore)] // Miri is too slow
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fn test_big5_encode_from_two_low_surrogates() {
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let expectation = b"��";
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let mut output = [0u8; 40];
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let mut encoder = BIG5.new_encoder();
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let (result, read, written, had_errors) =
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encoder.encode_from_utf16(&[0xDC00u16, 0xDEDEu16], &mut output[..], true);
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assert_eq!(result, CoderResult::InputEmpty);
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assert_eq!(read, 2);
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assert_eq!(written, expectation.len());
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assert!(had_errors);
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assert_eq!(&output[..written], expectation);
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}
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}
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