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decoder.rs
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decoder.rs
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//! rust-compression
//!
//! # Licensing
//! This Source Code is subject to the terms of the Mozilla Public License
//! version 2.0 (the "License"). You can obtain a copy of the License at
//! <http://mozilla.org/MPL/2.0/>.
#[cfg(not(feature = "std"))]
use alloc::string::String;
#[cfg(not(feature = "std"))]
use alloc::vec::Vec;
use bitio::direction::left::Left;
use bitio::reader::BitRead;
use bitset::BitArray;
use bzip2::error::BZip2Error;
use bzip2::mtf::MtfPositionDecoder;
use bzip2::{HEADER_0, HEADER_h, BZ_G_SIZE, HEADER_B, HEADER_Z};
use core::hash::{BuildHasher, Hasher};
use crc32::{BuiltinDigest, IEEE_NORMAL};
use huffman::decoder::HuffmanDecoder;
use traits::decoder::Decoder;
const BZ2_R_NUMS: [usize; 512] = [
619, 720, 127, 481, 931, 816, 813, 233, 566, 247, 985, 724, 205, 454, 863,
491, 741, 242, 949, 214, 733, 859, 335, 708, 621, 574, 73, 654, 730, 472,
419, 436, 278, 496, 867, 210, 399, 680, 480, 51, 878, 465, 811, 169, 869,
675, 611, 697, 867, 561, 862, 687, 507, 283, 482, 129, 807, 591, 733, 623,
150, 238, 59, 379, 684, 877, 625, 169, 643, 105, 170, 607, 520, 932, 727,
476, 693, 425, 174, 647, 73, 122, 335, 530, 442, 853, 695, 249, 445, 515,
909, 545, 703, 919, 874, 474, 882, 500, 594, 612, 641, 801, 220, 162, 819,
984, 589, 513, 495, 799, 161, 604, 958, 533, 221, 400, 386, 867, 600, 782,
382, 596, 414, 171, 516, 375, 682, 485, 911, 276, 98, 553, 163, 354, 666,
933, 424, 341, 533, 870, 227, 730, 475, 186, 263, 647, 537, 686, 600, 224,
469, 68, 770, 919, 190, 373, 294, 822, 808, 206, 184, 943, 795, 384, 383,
461, 404, 758, 839, 887, 715, 67, 618, 276, 204, 918, 873, 777, 604, 560,
951, 160, 578, 722, 79, 804, 96, 409, 713, 940, 652, 934, 970, 447, 318,
353, 859, 672, 112, 785, 645, 863, 803, 350, 139, 93, 354, 99, 820, 908,
609, 772, 154, 274, 580, 184, 79, 626, 630, 742, 653, 282, 762, 623, 680,
81, 927, 626, 789, 125, 411, 521, 938, 300, 821, 78, 343, 175, 128, 250,
170, 774, 972, 275, 999, 639, 495, 78, 352, 126, 857, 956, 358, 619, 580,
124, 737, 594, 701, 612, 669, 112, 134, 694, 363, 992, 809, 743, 168, 974,
944, 375, 748, 52, 600, 747, 642, 182, 862, 81, 344, 805, 988, 739, 511,
655, 814, 334, 249, 515, 897, 955, 664, 981, 649, 113, 974, 459, 893, 228,
433, 837, 553, 268, 926, 240, 102, 654, 459, 51, 686, 754, 806, 760, 493,
403, 415, 394, 687, 700, 946, 670, 656, 610, 738, 392, 760, 799, 887, 653,
978, 321, 576, 617, 626, 502, 894, 679, 243, 440, 680, 879, 194, 572, 640,
724, 926, 56, 204, 700, 707, 151, 457, 449, 797, 195, 791, 558, 945, 679,
297, 59, 87, 824, 713, 663, 412, 693, 342, 606, 134, 108, 571, 364, 631,
212, 174, 643, 304, 329, 343, 97, 430, 751, 497, 314, 983, 374, 822, 928,
140, 206, 73, 263, 980, 736, 876, 478, 430, 305, 170, 514, 364, 692, 829,
82, 855, 953, 676, 246, 369, 970, 294, 750, 807, 827, 150, 790, 288, 923,
804, 378, 215, 828, 592, 281, 565, 555, 710, 82, 896, 831, 547, 261, 524,
462, 293, 465, 502, 56, 661, 821, 976, 991, 658, 869, 905, 758, 745, 193,
768, 550, 608, 933, 378, 286, 215, 979, 792, 961, 61, 688, 793, 644, 986,
403, 106, 366, 905, 644, 372, 567, 466, 434, 645, 210, 389, 550, 919, 135,
780, 773, 635, 389, 707, 100, 626, 958, 165, 504, 920, 176, 193, 713, 857,
265, 203, 50, 668, 108, 645, 990, 626, 197, 510, 357, 358, 850, 858, 364,
936, 638,
];
struct BlockRandomise {
n2go: usize,
t_pos: usize,
}
impl BlockRandomise {
pub fn new() -> Self {
Self {
n2go: 0,
t_pos: 0,
}
}
pub fn reset(&mut self) {
self.n2go = 0;
self.t_pos = 0;
}
pub fn next(&mut self) -> bool {
if self.n2go == 0 {
self.n2go = BZ2_R_NUMS[self.t_pos];
self.t_pos += 1;
if self.t_pos == 512 {
self.t_pos = 0;
}
}
self.n2go -= 1;
self.n2go == 1
}
}
pub struct BZip2Decoder {
block_no: usize,
block_size_100k: usize,
combined_crc: u32,
block_crc: u32,
block_crc_digest: BuiltinDigest,
tt: Vec<u32>,
n_block_used: usize,
t_pos: u32,
block_randomise: BlockRandomise,
block_randomised: bool,
result_count: usize,
result_wrote_count: usize,
result_charactor: u8,
stream_no: usize,
}
impl Default for BZip2Decoder {
fn default() -> Self {
Self::new()
}
}
impl BZip2Decoder {
const RUN_A: u16 = 0;
const RUN_B: u16 = 1;
pub fn new() -> Self {
Self {
block_no: 0,
block_size_100k: 0,
combined_crc: 0,
block_crc: 0,
block_crc_digest: IEEE_NORMAL.build_hasher(),
tt: Vec::new(),
n_block_used: 0,
t_pos: 0,
block_randomise: BlockRandomise::new(),
block_randomised: false,
result_count: 0,
result_wrote_count: 0,
result_charactor: 0,
stream_no: 1,
}
}
fn read_u8<R: BitRead<Left>>(reader: &mut R) -> Result<u8, String> {
reader.read_bits(8).map(|x| x.data())
}
fn read_u32<R: BitRead<Left>>(reader: &mut R) -> Result<u32, String> {
reader.read_bits(32).map(|x| x.data())
}
fn check_u8<R: BitRead<Left>>(
reader: &mut R,
value: u8,
) -> Result<bool, String> {
Self::read_u8(reader).map(|x| x == value)
}
fn init_block<R: BitRead<Left>>(
&mut self,
reader: &mut R,
) -> Result<bool, BZip2Error> {
loop {
if self.block_no == 0 {
let magic_err = if self.stream_no == 1 {
BZip2Error::DataErrorMagicFirst
} else {
BZip2Error::DataErrorMagic
};
try!(Self::check_u8(reader, HEADER_B).map_err(|_| magic_err));
try!(Self::check_u8(reader, HEADER_Z).map_err(|_| magic_err));
try!(Self::check_u8(reader, HEADER_h).map_err(|_| magic_err));
self.block_size_100k = {
let b = try!(
Self::read_u8(reader)
.map_err(|_| BZip2Error::UnexpectedEof)
);
if b < 1 + HEADER_0 || b > 9 + HEADER_0 {
return Err(magic_err);
}
usize::from(b - HEADER_0)
};
} else {
let data_block_crc = self.block_crc_digest.finish() as u32;
debug!(
" {{0x{:08x}, 0x{:08x}}}]",
self.block_crc, data_block_crc
);
if data_block_crc != self.block_crc {
return Err(BZip2Error::DataError);
}
self.combined_crc = ((self.combined_crc << 1)
| (self.combined_crc >> 31))
^ self.block_crc;
self.block_crc_digest = IEEE_NORMAL.build_hasher();
}
let block_head_byte = try!(
Self::read_u8(reader).map_err(|_| BZip2Error::UnexpectedEof)
);
if block_head_byte == 0x31 {
try!(
Self::check_u8(reader, 0x41)
.map_err(|_| BZip2Error::DataError)
);
try!(
Self::check_u8(reader, 0x59)
.map_err(|_| BZip2Error::DataError)
);
try!(
Self::check_u8(reader, 0x26)
.map_err(|_| BZip2Error::DataError)
);
try!(
Self::check_u8(reader, 0x53)
.map_err(|_| BZip2Error::DataError)
);
try!(
Self::check_u8(reader, 0x59)
.map_err(|_| BZip2Error::DataError)
);
self.block_no += 1;
debug!(" [{}: huff+mtf ", self.block_no);
self.block_crc = try!(
Self::read_u32(reader)
.map_err(|_| BZip2Error::UnexpectedEof)
);
self.block_randomised = try!(
reader
.read_bits::<u8>(1)
.map_err(|_| BZip2Error::UnexpectedEof)
).data() == 1;
let orig_pos = try!(
reader
.read_bits::<u32>(24)
.map_err(|_| BZip2Error::UnexpectedEof)
).data() as usize;
if orig_pos > 10 + 100_000 * self.block_size_100k {
return Err(BZip2Error::DataError);
}
/*--- Receive the mapping table ---*/
let seq2unseq = {
let mut in_use16 = BitArray::new(16);
for i in 0..16 {
in_use16.set(
i,
try!(
reader
.read_bits::<u8>(1)
.map_err(|_| BZip2Error::UnexpectedEof)
).data() == 1,
);
}
let mut ret = Vec::with_capacity(256);
for (i, _) in
in_use16.iter().enumerate().filter(|&(_, x)| x)
{
for j in 0..16 {
if try!(
reader
.read_bits::<u8>(1)
.map_err(|_| BZip2Error::UnexpectedEof)
).data() == 1
{
ret.push(i * 16 + j)
}
}
}
ret
};
if seq2unseq.is_empty() {
return Err(BZip2Error::DataError);
}
let alpha_size = seq2unseq.len() + 2;
/*--- Now the selectors ---*/
let n_groups = try!(
reader
.read_bits(3)
.map_err(|_| BZip2Error::UnexpectedEof)
).data();
if n_groups < 2 || n_groups > 6 {
return Err(BZip2Error::DataError);
}
let n_selectors = try!(
reader
.read_bits(15)
.map_err(|_| BZip2Error::UnexpectedEof)
).data();
if n_selectors < 1 {
return Err(BZip2Error::DataError);
}
let mut selector = Vec::with_capacity(n_selectors);
{
let mut selector_mtf_dec =
MtfPositionDecoder::new(n_groups);
for _ in 0..n_selectors {
let mut j = 0;
while try!(
reader
.read_bits::<u8>(1)
.map_err(|_| BZip2Error::UnexpectedEof)
).data() != 0
{
j += 1;
if j >= n_groups {
return Err(BZip2Error::DataError);
}
}
/*--- Undo the MTF values for the selectors. ---*/
selector.push(selector_mtf_dec.pop(j));
}
}
let mut len = vec![vec![0; alpha_size]; n_groups];
/*--- Now the coding tables ---*/
for t in &mut len {
let mut curr = try!(
reader
.read_bits::<u8>(5)
.map_err(|_| BZip2Error::UnexpectedEof)
).data();
for i in t.iter_mut() {
while try!(
reader
.read_bits::<u8>(1)
.map_err(|_| BZip2Error::UnexpectedEof)
).data() != 0
{
if curr < 1 || curr > 20 {
return Err(BZip2Error::DataError);
}
if try!(
reader
.read_bits::<u8>(1)
.map_err(|_| BZip2Error::UnexpectedEof)
).data() == 0
{
curr += 1;
} else {
curr -= 1;
}
}
*i = curr;
}
}
/*--- Create the Huffman decoding tables ---*/
let mut code = Vec::with_capacity(n_groups);
for l in &len {
code.push(try!(
HuffmanDecoder::<Left>::new(l, 12)
.map_err(|_| BZip2Error::DataError)
));
}
/*--- Now the MTF values ---*/
let eob = alpha_size as u16 - 1;
let nblock_max = 100_000 * self.block_size_100k;
let mut unzftab = vec![0; 257]; // LF-mapping Table
self.tt.clear();
self.tt.reserve_exact(nblock_max);
{
let mut group_no = 0;
let mut group_pos = 0;
let mut n = 1;
let mut es = 0;
let mut mtf_decoder =
MtfPositionDecoder::new(seq2unseq.len());
loop {
if group_pos == 0 {
group_no += 1;
if group_no > n_selectors {
return Err(BZip2Error::DataError);
}
group_pos = BZ_G_SIZE;
}
group_pos -= 1;
let next_sym = try!(
try!(
code[selector[group_no - 1]]
.dec(reader)
.map_err(|_| BZip2Error::DataError)
).ok_or_else(|| BZip2Error::DataError)
);
if es > 0 && next_sym != Self::RUN_A
&& next_sym != Self::RUN_B
{
let uc = seq2unseq[mtf_decoder.pop(0)];
unzftab[uc + 1] += es;
for _ in 0..es {
self.tt.push(uc as u32);
}
if self.tt.len() >= nblock_max {
return Err(BZip2Error::DataError);
}
n = 1;
es = 0;
}
if next_sym == eob {
break;
}
/* Check that N doesn't get too big, so that es
doesn't go negative. The maximum value that can
be RUNA/RUNB encoded is equal to the block size
(post the initial RLE), viz, 900k, so bounding N
at 2 million should guard against overflow
without rejecting any legitimate inputs. */
if n >= 2 * 1024 * 1024 {
return Err(BZip2Error::DataError);
}
if next_sym == Self::RUN_A {
es += n;
n <<= 1;
} else if next_sym == Self::RUN_B {
n <<= 1;
es += n;
} else {
if self.tt.len() >= nblock_max {
return Err(BZip2Error::DataError);
}
let uc = seq2unseq
[mtf_decoder.pop(next_sym as usize - 1)];
unzftab[uc + 1] += 1;
self.tt.push(uc as u32);
}
}
}
/* Now we know what nblock is, we can do a better sanity
check on s->origPtr. */
if orig_pos >= self.tt.len() {
return Err(BZip2Error::DataError);
}
/*-- Set up cftab to facilitate generation of T^(-1) --*/
/* Actually generate cftab. */
if unzftab[0] != 0 {
return Err(BZip2Error::DataError);
}
for i in 1..unzftab.len() {
// /* Check: unzftab entries in range. */
// if (unzftab[i] < 0 || unzftab[i] > nblock)
// throw new InvalidDataException();
unzftab[i] += unzftab[i - 1];
/* Check: cftab entries non-descending. */
if unzftab[i - 1] > unzftab[i] {
return Err(BZip2Error::DataError);
}
}
/* Check: cftab entries in range. */
if unzftab[unzftab.len() - 1] != self.tt.len() {
return Err(BZip2Error::DataError);
}
debug!("rt+rld");
/*-- compute the T^(-1) vector --*/
for i in 0..self.tt.len() {
let uc = (self.tt[i] & 0xFF) as usize;
self.tt[unzftab[uc]] |= (i as u32) << 8;
unzftab[uc] += 1;
}
self.t_pos = self.tt[orig_pos] >> 8;
self.n_block_used = 0;
if self.block_randomised {
self.block_randomise.reset();
}
self.result_count = 0;
self.result_wrote_count = 0;
return Ok(true);
} else if block_head_byte == 0x17 {
try!(
Self::check_u8(reader, 0x72)
.map_err(|_| BZip2Error::DataError)
);
try!(
Self::check_u8(reader, 0x45)
.map_err(|_| BZip2Error::DataError)
);
try!(
Self::check_u8(reader, 0x38)
.map_err(|_| BZip2Error::DataError)
);
try!(
Self::check_u8(reader, 0x50)
.map_err(|_| BZip2Error::DataError)
);
try!(
Self::check_u8(reader, 0x90)
.map_err(|_| BZip2Error::DataError)
);
let stored_combind_crc = try!(
Self::read_u32(reader)
.map_err(|_| BZip2Error::UnexpectedEof)
);
debug!(
" combined CRCs: stored = 0x{:08x}, computed = 0x{:08x}",
stored_combind_crc, self.combined_crc
);
if stored_combind_crc != self.combined_crc {
return Err(BZip2Error::DataError);
}
reader.skip_to_next_byte();
let next = try!(
reader
.peek_bits::<usize>(8)
.map_err(|_| BZip2Error::Unexpected)
);
if next.len() == 8 {
self.block_no = 0;
self.combined_crc = 0;
self.stream_no += 1;
} else {
return Ok(false);
}
} else {
return Err(BZip2Error::DataError);
}
}
}
fn get_next_lfm(&mut self) -> Result<u8, BZip2Error> {
let mut position = self.t_pos;
/* c_tPos is unsigned, hence test < 0 is pointless. */
if position >= 100_000 * self.block_size_100k as u32 {
return Err(BZip2Error::DataError);
}
position = self.tt[position as usize];
let mut k0 = position as u8;
self.t_pos = position >> 8;
self.n_block_used += 1;
if self.block_randomised {
k0 ^= if self.block_randomise.next() {
1
} else {
0
};
}
Ok(k0)
}
}
impl<R> Decoder<R> for BZip2Decoder
where
R: BitRead<Left>,
{
type Error = BZip2Error;
type Output = u8;
fn next(&mut self, iter: &mut R) -> Result<Option<u8>, Self::Error> {
if self.result_count == self.result_wrote_count {
if self.n_block_used == self.tt.len()
&& !try!(self.init_block(iter))
{
return Ok(None);
}
let buffer = try!(self.get_next_lfm());
if buffer == self.result_charactor && self.result_count < 4 {
self.result_count += 1;
self.result_wrote_count += 1;
} else {
self.result_charactor = buffer;
self.result_count = 1;
self.result_wrote_count = 1;
}
if self.result_count == 4 {
self.result_count += usize::from(try!(self.get_next_lfm()));
}
} else {
self.result_wrote_count += 1;
}
self.block_crc_digest
.write_u8(self.result_charactor);
Ok(Some(self.result_charactor))
}
}