1
  2
  3
  4
  5
  6
  7
  8
  9
 10
 11
 12
 13
 14
 15
 16
 17
 18
 19
 20
 21
 22
 23
 24
 25
 26
 27
 28
 29
 30
 31
 32
 33
 34
 35
 36
 37
 38
 39
 40
 41
 42
 43
 44
 45
 46
 47
 48
 49
 50
 51
 52
 53
 54
 55
 56
 57
 58
 59
 60
 61
 62
 63
 64
 65
 66
 67
 68
 69
 70
 71
 72
 73
 74
 75
 76
 77
 78
 79
 80
 81
 82
 83
 84
 85
 86
 87
 88
 89
 90
 91
 92
 93
 94
 95
 96
 97
 98
 99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163

// This is a part of rust-encoding.
// Copyright (c) 2013-2015, Kang Seonghoon.
// See README.md and LICENSE.txt for details.

//! 7-bit ASCII encoding.

use std::mem;
use std::convert::Into;
use types::*;

/**
 * ASCII, also known as ISO/IEC 646:US.
 *
 * It is both a basis and a lowest common denominator of many other encodings
 * including UTF-8, which Rust internally assumes.
 */
#[derive(Clone, Copy)]
pub struct ASCIIEncoding;

impl Encoding for ASCIIEncoding {
    fn name(&self) -> &'static str { "ascii" }
    fn raw_encoder(&self) -> Box<RawEncoder> { ASCIIEncoder::new() }
    fn raw_decoder(&self) -> Box<RawDecoder> { ASCIIDecoder::new() }
}

/// An encoder for ASCII.
#[derive(Clone, Copy)]
pub struct ASCIIEncoder;

impl ASCIIEncoder {
    pub fn new() -> Box<RawEncoder> { Box::new(ASCIIEncoder) }
}

impl RawEncoder for ASCIIEncoder {
    fn from_self(&self) -> Box<RawEncoder> { ASCIIEncoder::new() }
    fn is_ascii_compatible(&self) -> bool { true }

    fn raw_feed(&mut self, input: &str, output: &mut ByteWriter) -> (usize, Option<CodecError>) {
        output.writer_hint(input.len());

        match input.as_bytes().iter().position(|&ch| ch >= 0x80) {
            Some(first_error) => {
                output.write_bytes(&input.as_bytes()[..first_error]);
                let len = input[first_error..].chars().next().unwrap().len_utf8();
                (first_error, Some(CodecError {
                    upto: (first_error + len) as isize, cause: "unrepresentable character".into()
                }))
            }
            None => {
                output.write_bytes(input.as_bytes());
                (input.len(), None)
            }
        }
    }

    fn raw_finish(&mut self, _output: &mut ByteWriter) -> Option<CodecError> {
        None
    }
}

/// A decoder for ASCII.
#[derive(Clone, Copy)]
pub struct ASCIIDecoder;

impl ASCIIDecoder {
    pub fn new() -> Box<RawDecoder> { Box::new(ASCIIDecoder) }
}

impl RawDecoder for ASCIIDecoder {
    fn from_self(&self) -> Box<RawDecoder> { ASCIIDecoder::new() }
    fn is_ascii_compatible(&self) -> bool { true }

    fn raw_feed(&mut self, input: &[u8], output: &mut StringWriter) -> (usize, Option<CodecError>) {
        output.writer_hint(input.len());

        fn write_ascii_bytes(output: &mut StringWriter, buf: &[u8]) {
            output.write_str(unsafe {mem::transmute(buf)});
        }

        match input.iter().position(|&ch| ch >= 0x80) {
            Some(first_error) => {
                write_ascii_bytes(output, &input[..first_error]);
                (first_error, Some(CodecError {
                    upto: first_error as isize + 1, cause: "invalid sequence".into()
                }))
            }
            None => {
                write_ascii_bytes(output, input);
                (input.len(), None)
            }
        }
    }

    fn raw_finish(&mut self, _output: &mut StringWriter) -> Option<CodecError> {
        None
    }
}

#[cfg(test)]
mod tests {
    extern crate test;
    use super::ASCIIEncoding;
    use testutils;
    use types::*;

    #[test]
    fn test_encoder() {
        let mut e = ASCIIEncoding.raw_encoder();
        assert_feed_ok!(e, "A", "", [0x41]);
        assert_feed_ok!(e, "BC", "", [0x42, 0x43]);
        assert_feed_ok!(e, "", "", []);
        assert_feed_err!(e, "", "\u{a0}", "", []);
        assert_feed_err!(e, "X", "\u{a0}", "Z", [0x58]);
        assert_finish_ok!(e, []);
    }

    #[test]
    fn test_decoder() {
        let mut d = ASCIIEncoding.raw_decoder();
        assert_feed_ok!(d, [0x41], [], "A");
        assert_feed_ok!(d, [0x42, 0x43], [], "BC");
        assert_feed_ok!(d, [], [], "");
        assert_feed_err!(d, [], [0xa0], [], "");
        assert_feed_err!(d, [0x58], [0xa0], [0x5a], "X");
        assert_finish_ok!(d, "");
    }

    #[bench]
    fn bench_encode(bencher: &mut test::Bencher) {
        let s = testutils::ASCII_TEXT;
        bencher.bytes = s.len() as u64;
        bencher.iter(|| test::black_box({
            ASCIIEncoding.encode(s, EncoderTrap::Strict)
        }))
    }

    #[bench]
    fn bench_decode(bencher: &mut test::Bencher) {
        let s = testutils::ASCII_TEXT.as_bytes();
        bencher.bytes = s.len() as u64;
        bencher.iter(|| test::black_box({
            ASCIIEncoding.decode(s, DecoderTrap::Strict)
        }))
    }

    #[bench]
    fn bench_encode_replace(bencher: &mut test::Bencher) {
        let s = testutils::KOREAN_TEXT;
        bencher.bytes = s.len() as u64;
        bencher.iter(|| test::black_box({
            ASCIIEncoding.encode(s, EncoderTrap::Replace)
        }))
    }

    #[bench]
    fn bench_decode_replace(bencher: &mut test::Bencher) {
        let s = testutils::KOREAN_TEXT.as_bytes();
        bencher.bytes = s.len() as u64;
        bencher.iter(|| test::black_box({
            ASCIIEncoding.decode(s, DecoderTrap::Replace)
        }))
    }
}