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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 variant::*;
use super::*;
pub struct Utf16Decoder {
lead_surrogate: u16, // If non-zero and pending_bmp == false, a pending lead surrogate
lead_byte: Option<u8>,
be: bool,
pending_bmp: bool, // if true, lead_surrogate is actually pending BMP
}
impl Utf16Decoder {
pub fn new(big_endian: bool) -> VariantDecoder {
VariantDecoder::Utf16(Utf16Decoder {
lead_surrogate: 0,
lead_byte: None,
be: big_endian,
pending_bmp: false,
})
}
pub fn max_utf16_buffer_length(&self, byte_length: usize) -> Option<usize> {
checked_add(1, checked_div(byte_length.checked_add(1), 2))
}
pub fn max_utf8_buffer_length_without_replacement(&self, byte_length: usize) -> Option<usize> {
checked_add(1,
checked_mul(3, checked_div(byte_length.checked_add(1), 2)))
}
pub fn max_utf8_buffer_length(&self, byte_length: usize) -> Option<usize> {
checked_add(1,
checked_mul(3, checked_div(byte_length.checked_add(1), 2)))
}
decoder_functions!({
if self.pending_bmp {
match dest.check_space_bmp() {
Space::Full(_) => {
return (DecoderResult::OutputFull, 0, 0);
}
Space::Available(destination_handle) => {
destination_handle.write_bmp(self.lead_surrogate);
self.pending_bmp = false;
self.lead_surrogate = 0;
}
}
}
},
{},
{
debug_assert!(!self.pending_bmp);
if self.lead_surrogate != 0 {
self.lead_surrogate = 0;
match self.lead_byte {
None => {
return (DecoderResult::Malformed(2, 0),
src_consumed,
dest.written());
}
Some(_) => {
self.lead_byte = None;
return (DecoderResult::Malformed(3, 0),
src_consumed,
dest.written());
}
}
}
match self.lead_byte {
None => {}
Some(_) => {
self.lead_byte = None;
return (DecoderResult::Malformed(1, 0),
src_consumed,
dest.written());
}
}
},
{
match self.lead_byte {
None => {
self.lead_byte = Some(b);
continue;
}
Some(lead) => {
self.lead_byte = None;
let code_unit = if self.be {
(lead as u16) << 8 | b as u16
} else {
(b as u16) << 8 | (lead as u16)
};
let high_bits = code_unit & 0xFC00u16;
if high_bits == 0xD800u16 {
// high surrogate
if self.lead_surrogate != 0 {
// The previous high surrogate was in
// error and this one becomes the new
// pending one.
self.lead_surrogate = code_unit as u16;
return (DecoderResult::Malformed(2, 2),
unread_handle.consumed(),
destination_handle.written());
}
self.lead_surrogate = code_unit;
continue;
}
if high_bits == 0xDC00u16 {
// low surrogate
if self.lead_surrogate == 0 {
return (DecoderResult::Malformed(2, 0),
unread_handle.consumed(),
destination_handle.written());
}
destination_handle.write_surrogate_pair(self.lead_surrogate,
code_unit);
self.lead_surrogate = 0;
continue;
}
// bmp
if self.lead_surrogate != 0 {
// The previous high surrogate was in
// error and this code unit becomes a
// pending BMP character.
self.lead_surrogate = code_unit;
self.pending_bmp = true;
return (DecoderResult::Malformed(2, 2),
unread_handle.consumed(),
destination_handle.written());
}
destination_handle.write_bmp(code_unit);
continue;
}
}
},
self,
src_consumed,
dest,
source,
b,
destination_handle,
unread_handle,
check_space_astral);
}
// 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_utf_16le(bytes: &[u8], expect: &str) {
decode_without_padding(UTF_16LE, bytes, expect);
}
fn decode_utf_16be(bytes: &[u8], expect: &str) {
decode_without_padding(UTF_16BE, bytes, expect);
}
fn encode_utf_16le(string: &str, expect: &[u8]) {
encode(UTF_16LE, string, expect);
}
fn encode_utf_16be(string: &str, expect: &[u8]) {
encode(UTF_16BE, string, expect);
}
#[test]
fn test_utf_16_decode() {
decode_utf_16le(b"", "");
decode_utf_16be(b"", "");
decode_utf_16le(b"\x61\x00\x62\x00", "\u{0061}\u{0062}");
decode_utf_16be(b"\x00\x61\x00\x62", "\u{0061}\u{0062}");
decode_utf_16le(b"\xFE\xFF\x00\x61\x00\x62", "\u{0061}\u{0062}");
decode_utf_16be(b"\xFF\xFE\x61\x00\x62\x00", "\u{0061}\u{0062}");
decode_utf_16le(b"\x61\x00\x62", "\u{0061}\u{FFFD}");
decode_utf_16be(b"\x00\x61\x00", "\u{0061}\u{FFFD}");
decode_utf_16le(b"\x3D\xD8\xA9", "\u{FFFD}");
decode_utf_16be(b"\xD8\x3D\xDC", "\u{FFFD}");
decode_utf_16le(b"\x3D\xD8\xA9\xDC\x03\x26", "\u{1F4A9}\u{2603}");
decode_utf_16be(b"\xD8\x3D\xDC\xA9\x26\x03", "\u{1F4A9}\u{2603}");
decode_utf_16le(b"\xA9\xDC\x03\x26", "\u{FFFD}\u{2603}");
decode_utf_16be(b"\xDC\xA9\x26\x03", "\u{FFFD}\u{2603}");
decode_utf_16le(b"\x3D\xD8\x03\x26", "\u{FFFD}\u{2603}");
decode_utf_16be(b"\xD8\x3D\x26\x03", "\u{FFFD}\u{2603}");
}
#[test]
fn test_utf_16_encode() {
// Empty
encode_utf_16be("", b"");
encode_utf_16le("", b"");
// Encodes as UTF-8
assert_eq!(UTF_16LE.new_encoder().encoding(), UTF_8);
assert_eq!(UTF_16BE.new_encoder().encoding(), UTF_8);
encode_utf_16le("\u{1F4A9}\u{2603}", "\u{1F4A9}\u{2603}".as_bytes());
encode_utf_16be("\u{1F4A9}\u{2603}", "\u{1F4A9}\u{2603}".as_bytes());
}
}