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Use dynamic huffman tables to reduse the crate size. #35

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Jan 13, 2018
Merged

Use dynamic huffman tables to reduse the crate size. #35

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159 changes: 29 additions & 130 deletions src/lib.rs
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Original file line number Diff line number Diff line change
Expand Up @@ -557,7 +557,6 @@ use self::State::*;
enum BitsNext {
BlockHeader,
BlockUncompressed,
BlockFixed,
BlockDynHlit,
BlockDynHdist(/* hlit */ u8),
BlockDynHclen(/* hlit */ u8, /* hdist */ u8),
Expand Down Expand Up @@ -769,7 +768,6 @@ impl InflateStream {
let mut stream = BitStream::new(data, state);
macro_rules! ok_state (($state:expr) => ({self.state = Some($state); Ok(stream.used)}));
macro_rules! ok (($next:expr) => (ok_state!(Bits($next, stream.fill()))));
macro_rules! need (($n:expr) => (if !stream.need($n) { return ok!(next); }));
macro_rules! take (
($n:expr => $next:expr) => (match stream.take($n) {
Some(v) => v,
Expand Down Expand Up @@ -815,36 +813,35 @@ impl InflateStream {
ok!(BlockUncompressed)
}
1 => {
// let lit = DynHuffman16::new(&[
// 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, // 0-15
// 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, // 16-31
// 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, // 32-47
// 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, // 48-63
// 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, // 64-79
// 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, // 80-95
// 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, // 96-101
// 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, // 112-127
// 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, // 128-143
// 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, // 144-159
// 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, // 160-175
// 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, // 176-191
// 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, // 192-207
// 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, // 208-223
// 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, // 224-239
// 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, // 240-255
// 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, // 256-271
// 7, 7, 7, 7, 7, 7, 7, 7, // 272-279
// 8, 8, 8, 8, 8, 8, 8, 8, // 280-287
// ]);
// let dist = DynHuffman16::new(&[
// 5, 5, 5, 5, 5, 5, 5, 5,
// 5, 5, 5, 5, 5, 5, 5, 5,
// 5, 5, 5, 5, 5, 5, 5, 5,
// 5, 5, 5, 5, 5, 5, 5, 5
// ]);
// ok!(BlockDyn(lit, dist, 0))
//
ok!(BlockFixed)
// Unwrap is safe because the data is valid.
let lit = DynHuffman16::new(&[
8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, // 0-15
8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, // 16-31
8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, // 32-47
8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, // 48-63
8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, // 64-79
8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, // 80-95
8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, // 96-101
8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, // 112-127
8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, // 128-143
9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, // 144-159
9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, // 160-175
9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, // 176-191
9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, // 192-207
9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, // 208-223
9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, // 224-239
9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, // 240-255
7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, // 256-271
7, 7, 7, 7, 7, 7, 7, 7, // 272-279
8, 8, 8, 8, 8, 8, 8, 8, // 280-287
]).unwrap();
let dist = DynHuffman16::new(&[
5, 5, 5, 5, 5, 5, 5, 5,
5, 5, 5, 5, 5, 5, 5, 5,
5, 5, 5, 5, 5, 5, 5, 5,
5, 5, 5, 5, 5, 5, 5, 5
]).unwrap();
ok!(BlockDyn(lit, dist, 0))
}
2 => ok!(BlockDynHlit),
_ => {
Expand All @@ -862,104 +859,6 @@ impl InflateStream {
}
ok_state!(Uncompressed(len))
}
BlockFixed => {
let mut save;
macro_rules! len_dist2 (($len:expr, $code_const:expr, $code_rev:expr, $bits:expr) => ({
len_dist!($len, $code_const + ($code_rev >> 4), $bits => {stream = save; next}, next);
}));
macro_rules! len (($code:expr, $bits:expr) => ({
let len = 3 + if $bits == 0 { 0 } else { // new_base
4 << $bits
} + ((if $code == 29 {
256
} else {
$code as u16
} - if $bits == 0 { 0 } else { // old_base
$bits * 4 + 4
} - 1) << $bits) + take!($bits => {stream = save; next}) as u16;
let code = take!(5 => {stream = save; next});
debug!(" {:05b}", BIT_REV_U8[(code << 3) as usize]);
match code {
0b00000 | 0b10000 => len_dist2!(len, 0, code, 0),
0b01000 | 0b11000 => len_dist2!(len, 2, code, 0),
0b00100 | 0b10100 => len_dist2!(len, 4, code, 1),
0b01100 | 0b11100 => len_dist2!(len, 6, code, 2),
0b00010 | 0b10010 => len_dist2!(len, 8, code, 3),
0b01010 | 0b11010 => len_dist2!(len, 10, code, 4),
0b00110 | 0b10110 => len_dist2!(len, 12, code, 5),
0b01110 | 0b11110 => len_dist2!(len, 14, code, 6),
0b00001 | 0b10001 => len_dist2!(len, 16, code, 7),
0b01001 | 0b11001 => len_dist2!(len, 18, code, 8),
0b00101 | 0b10101 => len_dist2!(len, 20, code, 9),
0b01101 | 0b11101 => len_dist2!(len, 22, code, 10),
0b00011 | 0b10011 => len_dist2!(len, 24, code, 11),
0b01011 | 0b11011 => len_dist2!(len, 26, code, 12),
0b00111 | 0b10111 => len_dist2!(len, 28, code, 13),
_ => return Err(format!("bad DEFLATE dist code {}", code))
}
}));
loop {
need!(7);
// 0000000 through 0010111
if (stream.state.v & 0b11) == 0b00 &&
(stream.state.v & 0b1100) != 0b1100 {
save = stream.clone();
// FIXME(eddyb) use a 7-bit rev LUT or match the huffman code directly.
let code = BIT_REV_U8[(stream.take(7).unwrap() << 1) as usize];
debug!("{:09b}", code as u16 + 256);
match code {
0 => {
return if self.final_block {
let (len, bytes) = stream.trailing_bytes();
ok_state!(CheckCRC(len, bytes))
} else {
ok!(BlockHeader)
}
}
1...8 => len!(code, 0),
9...12 => len!(code, 1),
13...16 => len!(code, 2),
17...20 => len!(code, 3),
21...23 => len!(code, 4),
_ => return Err(format!("bad DEFLATE len code {}", code as u16 + 256)),
};
continue;
}

need!(8);
// 00110000 through 10111111
if (stream.state.v & 0b11) != 0b11 {
save = stream.clone();
// FIXME(eddyb) use a specialized rev LUT with addend.
let code = BIT_REV_U8[(stream.take(8).unwrap()) as usize] - 0b0011_0000;
debug!("{:09b}", code);
push_or!(code, ok!({stream = save; next}));
continue;
}
// 11000000 through 11000111
if (stream.state.v & 0b11100) == 0b00000 {
save = stream.clone();
// FIXME(eddyb) use a 3-bit rev LUT or match the huffman code directly.
let code = 24 + (BIT_REV_U8[stream.take(8).unwrap() as usize] - 0b11000000);
debug!("{:09b}", code as u16 + 256);
match code {
24 => len!(24, 4),
25...28 => len!(code, 5),
29 => len!(29, 0),
_ => return Err(format!("bad DEFLATE len code {}", code as u16 + 256)),
};
continue;
}

need!(9);
// 110010000 through 111111111
save = stream.clone();
// FIXME(eddyb) use a specialized rev LUT with addend.
let code = BIT_REV_U8[(stream.take16(9).unwrap() >> 1) as usize];
debug!("{:09b}", code);
push_or!(code, ok!({stream = save; next}));
}
}
BlockDynHlit => ok!(BlockDynHdist(take!(5) + 1)),
BlockDynHdist(hlit) => ok!(BlockDynHclen(hlit, take!(5) + 1)),
BlockDynHclen(hlit, hdist) => {
Expand Down