dtourolle
77a1925bac
The crate as crates.io publishes it, minus .cargo-ok, its Cargo.lock and data/testdata (13 MB of sample files only its own tests read). Not yet routed through [patch.crates-io]; the next commit is the patch.
485 lines
12 KiB
Rust
485 lines
12 KiB
Rust
use std::slice::Chunks;
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use crate::bits::*;
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#[derive(Debug, Clone)]
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pub struct BitPumpLSB<'a> {
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buffer: Chunks<'a, u8>,
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bits: u64,
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nbits: u32,
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}
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impl<'a> BitPumpLSB<'a> {
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pub fn new(src: &'a [u8]) -> Self {
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Self {
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buffer: src.chunks(size_of::<u32>()),
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bits: 0,
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nbits: 0,
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}
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}
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/// Refill internal bit buffer - Little-Endian
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///
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/// For fast refill, we can simply take a whole u32 value out.
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/// For slow refill, there may be 1, 2 or 3 bytes left in buffer. We need
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/// to collect them manually.
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fn refill(&mut self) -> (u32, u32) {
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if let Some(chunk) = self.buffer.next() {
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if chunk.len() == 4 {
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// Fast refill
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let bits: u32 = u32::from_le_bytes([chunk[0], chunk[1], chunk[2], chunk[3]]);
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(bits, u32::BITS)
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} else {
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// Slow refill
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chunk
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.into_iter()
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.rev()
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.fold((0, 0), |(bits, bit_cnt), x| ((bits << 8) | *x as u32, bit_cnt + 8))
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}
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} else {
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panic!("Can't refill bitpump, buffer exhausted");
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}
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}
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}
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#[derive(Debug, Clone)]
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pub struct BitPumpMSB<'a> {
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buffer: Chunks<'a, u8>,
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bits: u64,
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nbits: u32,
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}
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impl<'a> BitPumpMSB<'a> {
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pub fn new(src: &'a [u8]) -> Self {
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Self {
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buffer: src.chunks(size_of::<u32>()),
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bits: 0,
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nbits: 0,
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}
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}
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/// Refill internal bit buffer - Big-Endian
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///
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/// For fast refill, we can simply take a whole u32 value out.
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/// For slow refill, there may be 1, 2 or 3 bytes left in buffer. We need
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/// to collect them manually.
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fn refill(&mut self) -> (u32, u32) {
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if let Some(chunk) = self.buffer.next() {
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if chunk.len() == 4 {
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// Fast refill
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let bits: u32 = u32::from_be_bytes([chunk[0], chunk[1], chunk[2], chunk[3]]);
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(bits, u32::BITS)
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} else {
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// Slow refill
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chunk.into_iter().fold((0, 0), |(bits, bit_cnt), x| ((bits << 8) | *x as u32, bit_cnt + 8))
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}
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} else {
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panic!("Can't refill bitpump, buffer exhausted");
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}
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}
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}
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#[derive(Debug, Clone)]
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pub struct BitPumpMSB32<'a> {
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buffer: Chunks<'a, u8>,
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pos: usize,
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bits: u64,
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nbits: u32,
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}
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impl<'a> BitPumpMSB32<'a> {
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pub fn new(src: &'a [u8]) -> Self {
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Self {
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buffer: src.chunks(size_of::<u32>()),
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pos: 0,
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bits: 0,
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nbits: 0,
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}
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}
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/// Refill internal bit buffer - Little-Endian
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///
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/// For fast refill, we can simply take a whole u32 value out.
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/// For slow refill, there may be 1, 2 or 3 bytes left in buffer. We need
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/// to collect them manually.
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fn refill(&mut self) -> (u32, u32) {
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if let Some(chunk) = self.buffer.next() {
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if chunk.len() == 4 {
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// Fast refill
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let bits: u32 = u32::from_le_bytes([chunk[0], chunk[1], chunk[2], chunk[3]]);
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(bits, u32::BITS)
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} else {
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// Slow refill
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chunk
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.into_iter()
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.rev()
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.fold((0, 0), |(bits, bit_cnt), x| ((bits << 8) | *x as u32, bit_cnt + 8))
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}
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} else {
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panic!("Can't refill bitpump, buffer exhausted");
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}
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}
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#[inline(always)]
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pub fn get_pos(&self) -> usize {
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self.pos - ((self.nbits >> 3) as usize)
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}
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}
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#[derive(Debug, Copy, Clone)]
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pub struct BitPumpJPEG<'a> {
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buffer: &'a [u8],
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pos: usize,
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bits: u64,
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nbits: u32,
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finished: bool,
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}
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impl<'a> BitPumpJPEG<'a> {
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pub fn new(src: &'a [u8]) -> Self {
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Self {
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buffer: src,
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pos: 0,
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bits: 0,
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nbits: 0,
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finished: false,
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}
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}
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}
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pub trait BitPump {
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fn peek_bits(&mut self, num: u32) -> u32;
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fn consume_bits(&mut self, num: u32);
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#[inline(always)]
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fn get_bits(&mut self, num: u32) -> u32 {
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if num == 0 {
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return 0;
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}
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let val = self.peek_bits(num);
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self.consume_bits(num);
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val
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}
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#[inline(always)]
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fn peek_ibits(&mut self, num: u32) -> i32 {
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self.peek_bits(num) as i32
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}
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#[inline(always)]
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fn get_ibits(&mut self, num: u32) -> i32 {
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self.get_bits(num) as i32
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}
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// Sign extend ibits
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#[inline(always)]
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fn get_ibits_sextended(&mut self, num: u32) -> i32 {
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let val = self.get_ibits(num);
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val.wrapping_shl(32 - num).wrapping_shr(32 - num)
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}
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/// Count the leading zeroes block-wise in 31 bits
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/// per block and returns the count.
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/// All zero bits are consumed.
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#[inline(always)]
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fn consume_zerobits(&mut self) -> u32 {
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// Take one bit less because leading_zeros() is undefined
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// when all bits in register are zero.
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const BITS_PER_LOOP: u32 = u32::BITS - 1;
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let mut count = 0;
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// Count-and-skip all the leading `0`s.
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loop {
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let batch: u32 = (self.peek_bits(BITS_PER_LOOP) << 1) | 0x1;
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let n = batch.leading_zeros();
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self.consume_bits(n);
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count += n;
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if n != BITS_PER_LOOP {
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break;
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}
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}
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count
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}
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}
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impl<'a> BitPump for BitPumpLSB<'a> {
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#[inline(always)]
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fn peek_bits(&mut self, num: u32) -> u32 {
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if num > self.nbits {
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let (inbits, bit_cnt) = self.refill();
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self.bits = (((inbits as u64) << 32) | (self.bits << (32 - self.nbits))) >> (32 - self.nbits);
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self.nbits += bit_cnt;
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}
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(self.bits & (0x0ffffffffu64 >> (32 - num))) as u32
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}
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#[inline(always)]
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fn consume_bits(&mut self, num: u32) {
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self.nbits -= num;
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self.bits >>= num;
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}
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}
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impl<'a> BitPump for BitPumpMSB<'a> {
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#[inline(always)]
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fn peek_bits(&mut self, num: u32) -> u32 {
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if num > self.nbits {
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let (inbits, bit_cnt) = self.refill();
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self.bits = (self.bits << bit_cnt) | inbits as u64;
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self.nbits += bit_cnt;
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}
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(self.bits >> (self.nbits - num)) as u32
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}
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#[inline(always)]
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fn consume_bits(&mut self, num: u32) {
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self.nbits -= num;
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self.bits &= (1 << self.nbits) - 1;
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}
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}
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impl<'a> BitPump for BitPumpMSB32<'a> {
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#[inline(always)]
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fn peek_bits(&mut self, num: u32) -> u32 {
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if num > self.nbits {
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let (inbits, bit_cnt) = self.refill();
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self.bits = (self.bits << 32) | inbits as u64;
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self.nbits += bit_cnt;
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self.pos += bit_cnt as usize / 8;
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}
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(self.bits >> (self.nbits - num)) as u32
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}
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#[inline(always)]
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fn consume_bits(&mut self, num: u32) {
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self.nbits -= num;
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self.bits &= (1 << self.nbits) - 1;
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}
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}
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impl<'a> BitPump for BitPumpJPEG<'a> {
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#[inline(always)]
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fn peek_bits(&mut self, num: u32) -> u32 {
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if num > self.nbits && !self.finished {
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if (self.buffer.len() >= 4)
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&& self.pos < self.buffer.len() - 4
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&& self.buffer[self.pos + 0] != 0xff
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&& self.buffer[self.pos + 1] != 0xff
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&& self.buffer[self.pos + 2] != 0xff
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&& self.buffer[self.pos + 3] != 0xff
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{
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let inbits: u64 = BEu32(self.buffer, self.pos) as u64;
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self.bits = (self.bits << 32) | inbits;
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self.pos += 4;
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self.nbits += 32;
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} else {
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// Read 32 bits the hard way
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let mut read_bytes = 0;
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while read_bytes < 4 && !self.finished {
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let byte = {
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if self.pos >= self.buffer.len() {
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self.finished = true;
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0
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} else {
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let nextbyte = self.buffer[self.pos];
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if nextbyte != 0xff {
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nextbyte
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} else if self.buffer[self.pos + 1] == 0x00 {
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self.pos += 1; // Skip the extra byte used to mark 255
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nextbyte
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} else {
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self.finished = true;
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0
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}
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}
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};
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self.bits = (self.bits << 8) | (byte as u64);
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self.pos += 1;
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self.nbits += 8;
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read_bytes += 1;
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}
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}
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}
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if num > self.nbits && self.finished {
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// Stuff with zeroes to not fail to read
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self.bits <<= 32;
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self.nbits += 32;
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}
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(self.bits >> (self.nbits - num)) as u32
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}
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#[inline(always)]
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fn consume_bits(&mut self, num: u32) {
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debug_assert!(num <= self.nbits);
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self.nbits -= num;
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self.bits &= (1 << self.nbits) - 1;
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}
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}
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#[derive(Debug, Copy, Clone)]
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pub struct ByteStream<'a> {
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buffer: &'a [u8],
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pos: usize,
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endian: Endian,
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}
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impl<'a> ByteStream<'a> {
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pub fn new(src: &'a [u8], endian: Endian) -> Self {
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Self { buffer: src, pos: 0, endian }
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}
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#[inline(always)]
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pub fn remaining_bytes(&self) -> usize {
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self.buffer.len() - self.pos
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}
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#[inline(always)]
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pub fn get_pos(&self) -> usize {
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self.pos
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}
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#[inline(always)]
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pub fn peek_u8(&self) -> u8 {
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self.buffer[self.pos]
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}
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#[inline(always)]
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pub fn get_u8(&mut self) -> u8 {
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let val = self.peek_u8();
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self.pos += 1;
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val
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}
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#[inline(always)]
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pub fn peek_i8(&self) -> i8 {
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self.buffer[self.pos] as i8
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}
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#[inline(always)]
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pub fn get_i8(&mut self) -> i8 {
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let val = self.peek_i8();
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self.pos += 1;
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val
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}
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#[inline(always)]
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pub fn peek_u16(&self) -> u16 {
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self.endian.read_u16(self.buffer, self.pos)
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}
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#[inline(always)]
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pub fn get_u16(&mut self) -> u16 {
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let val = self.peek_u16();
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self.pos += 2;
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val
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}
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#[inline(always)]
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pub fn peek_i16(&self) -> i16 {
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self.endian.read_i16(self.buffer, self.pos)
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}
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#[inline(always)]
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pub fn get_i16(&mut self) -> i16 {
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let val = self.peek_i16();
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self.pos += 2;
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val
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}
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#[inline(always)]
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pub fn peek_u32(&self) -> u32 {
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self.endian.read_u32(self.buffer, self.pos)
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}
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#[inline(always)]
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pub fn get_u32(&mut self) -> u32 {
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let val = self.peek_u32();
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self.pos += 4;
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val
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}
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#[inline(always)]
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pub fn get_bytes(&mut self, n: usize) -> Vec<u8> {
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let mut val = Vec::with_capacity(n);
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val.extend_from_slice(&self.buffer[self.pos..self.pos + n]);
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self.pos += n;
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val
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}
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// #[inline(always)]
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// pub fn peek_u32(&self) -> u32 { self.endian.ru32(self.buffer, self.pos) }
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// #[inline(always)]
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// pub fn get_u32(&mut self) -> u32 {
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// let val = self.peek_u32();
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// self.pos += 4;
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// val
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// }
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#[inline(always)]
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pub fn consume_bytes(&mut self, num: usize) {
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self.pos += num
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}
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#[inline(always)]
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pub fn skip_to_marker(&mut self) -> Result<usize, String> {
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let mut skip_count = 0;
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while !(self.buffer[self.pos] == 0xFF && self.buffer[self.pos + 1] != 0 && self.buffer[self.pos + 1] != 0xFF) {
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self.pos += 1;
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skip_count += 1;
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if self.pos >= self.buffer.len() {
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return Err("No marker found inside rest of buffer".to_string());
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}
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}
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self.pos += 1; // Make the next byte the marker
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Ok(skip_count + 1)
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}
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}
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/// This pump is for bitstreams where values are stored in LSB bit order.
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/// During refill, bits are converted from LSB to MSB so peaking
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/// is done by reading in MSB mode.
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///
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/// Input bitstream is: 1011 0101 0010 1110...
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/// Output for peek(10) is: 1010 1101 01
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#[derive(Debug, Copy, Clone)]
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pub struct BitPumpReverseBitsMSB<'a> {
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buffer: &'a [u8],
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pos: usize,
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bits: u64,
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nbits: u32,
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}
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impl<'a> BitPumpReverseBitsMSB<'a> {
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pub fn new(src: &'a [u8]) -> Self {
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Self {
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buffer: src,
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pos: 0,
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bits: 0,
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nbits: 0,
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}
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}
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}
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impl<'a> BitPump for BitPumpReverseBitsMSB<'a> {
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#[inline(always)]
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fn peek_bits(&mut self, num: u32) -> u32 {
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debug_assert!(num <= 32);
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if num > self.nbits {
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let mut raw: [u8; 4] = BEu32(self.buffer, self.pos).to_ne_bytes();
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raw[0] = raw[0].reverse_bits();
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raw[1] = raw[1].reverse_bits();
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raw[2] = raw[2].reverse_bits();
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raw[3] = raw[3].reverse_bits();
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let inbits: u64 = u32::from_ne_bytes(raw) as u64;
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self.bits = (self.bits << 32) | inbits;
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self.pos += 4;
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self.nbits += 32;
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}
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(self.bits >> (self.nbits - num)) as u32
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}
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#[inline(always)]
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fn consume_bits(&mut self, num: u32) {
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self.nbits -= num;
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self.bits &= (1 << self.nbits) - 1;
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}
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}
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