1 use nihav_core::io::byteio::*;
2 use nihav_core::codecs::{EncoderResult, EncoderError};
10 pub struct TokenSeq<T: PartialEq> {
12 pub seq: &'static [EncSeq],
16 macro_rules! bit_entry {
17 (T; $idx:expr) => {EncSeq {bit: true, idx: $idx }};
18 (F; $idx:expr) => {EncSeq {bit: false, idx: $idx }};
22 macro_rules! bit_seq {
23 ($val: expr; $( $bit:tt),* ; $( $idx:expr),* ) => {
29 bit_entry!($bit; $idx),
36 pub struct BoolEncoder<'a, 'b> {
37 bw: &'a mut ByteWriter<'b>,
45 impl<'a, 'b> BoolEncoder<'a, 'b> {
46 pub fn new(bw: &'a mut ByteWriter<'b>) -> Self {
56 pub fn put_bool(&mut self, bit: bool, prob: u8) -> EncoderResult<()> {
57 let split = 1 + (((self.range - 1) * u32::from(prob)) >> 8);
70 fn flush_run(&mut self, overflow: bool) -> EncoderResult<()> {
72 self.bw.write_byte(self.saved + (overflow as u8))?;
74 for _ in 1..self.run {
75 self.bw.write_byte(0xFF)?;
78 for _ in 1..self.run {
79 self.bw.write_byte(0)?;
86 fn renorm(&mut self) -> EncoderResult<()> {
87 let bits = (self.range.leading_zeros() & 7) as u8;
89 if self.bits + bits < 23 {
94 if (self.bits == 23) && ((self.val >> 31) != 0) {
95 self.flush_run(true)?;
100 let tbyte = (self.val >> 24) as u8;
101 let nbyte = (self.val >> 16) as u8;
103 self.flush_run(false)?;
105 self.bw.write_byte(tbyte)?;
113 self.val &= 0xFFFFFF;
120 pub fn flush(mut self) -> EncoderResult<()> {
121 self.flush_run(false)?;
122 self.val <<= 24 - self.bits;
123 self.bw.write_u32be(self.val)?;
127 pub fn put_bits(&mut self, val: u32, len: u8) -> EncoderResult<()> {
128 let mut mask = 1 << (len - 1);
130 self.put_bool((val & mask) != 0, 128)?;
135 pub fn put_probability(&mut self, prob: u8) -> EncoderResult<()> {
136 self.put_bits(u32::from(prob >> 1), 7)
138 pub fn encode_probability(&mut self, new: u8, old: u8, prob: u8) -> EncoderResult<()> {
139 self.put_bool(new != old, prob)?;
141 self.put_probability(new)?;
145 pub fn write_el<T: PartialEq>(&mut self, el: T, tree: &[TokenSeq<T>], probs: &[u8]) -> EncoderResult<()> {
146 for entry in tree.iter() {
148 for seq in entry.seq.iter() {
149 self.put_bool(seq.bit, probs[seq.idx as usize])?;
154 Err(EncoderError::Bug)
158 pub struct Estimator {}
162 pub fn new() -> Self { Self{} }
163 pub fn write_el<T: PartialEq>(&self, el: T, tree: &[TokenSeq<T>], probs: &mut [ProbCounter]) {
164 for entry in tree.iter() {
166 for seq in entry.seq.iter() {
167 probs[seq.idx as usize].add(seq.bit);
173 pub fn est_nits(bit: bool, prob: u8) -> u32 {
175 u32::from(PROB_BITS[prob as usize])
177 u32::from(PROB_BITS[256 - (prob as usize)])
180 pub fn nits_to_bits(nits: u32) -> u32 { (nits + 7) >> 3 }