| 1 | use nihav_core::io::byteio::*; |
| 2 | use nihav_core::codecs::{EncoderResult, EncoderError}; |
| 3 | use super::models::*; |
| 4 | |
| 5 | pub struct EncSeq { |
| 6 | pub bit: bool, |
| 7 | pub idx: u8, |
| 8 | } |
| 9 | |
| 10 | pub struct TokenSeq<T: PartialEq> { |
| 11 | pub val: T, |
| 12 | pub seq: &'static [EncSeq], |
| 13 | } |
| 14 | |
| 15 | #[macro_export] |
| 16 | macro_rules! bit_entry { |
| 17 | (T; $idx:expr) => {EncSeq {bit: true, idx: $idx }}; |
| 18 | (F; $idx:expr) => {EncSeq {bit: false, idx: $idx }}; |
| 19 | } |
| 20 | |
| 21 | #[macro_export] |
| 22 | macro_rules! bit_seq { |
| 23 | ($val: expr; $( $bit:tt),* ; $( $idx:expr),* ) => { |
| 24 | TokenSeq { |
| 25 | val: $val, |
| 26 | seq: |
| 27 | &[ |
| 28 | $( |
| 29 | bit_entry!($bit; $idx), |
| 30 | )* |
| 31 | ] |
| 32 | } |
| 33 | }; |
| 34 | } |
| 35 | |
| 36 | pub struct BoolEncoder<'a, 'b> { |
| 37 | bw: &'a mut ByteWriter<'b>, |
| 38 | val: u32, |
| 39 | range: u32, |
| 40 | bits: u8, |
| 41 | saved: u8, |
| 42 | run: usize, |
| 43 | } |
| 44 | |
| 45 | impl<'a, 'b> BoolEncoder<'a, 'b> { |
| 46 | pub fn new(bw: &'a mut ByteWriter<'b>) -> Self { |
| 47 | Self { |
| 48 | bw, |
| 49 | val: 0, |
| 50 | range: 255, |
| 51 | bits: 0, |
| 52 | saved: 0, |
| 53 | run: 0, |
| 54 | } |
| 55 | } |
| 56 | pub fn put_bool(&mut self, bit: bool, prob: u8) -> EncoderResult<()> { |
| 57 | let split = 1 + (((self.range - 1) * u32::from(prob)) >> 8); |
| 58 | if bit { |
| 59 | self.range -= split; |
| 60 | self.val += split; |
| 61 | } else { |
| 62 | self.range = split; |
| 63 | } |
| 64 | |
| 65 | if self.range < 128 { |
| 66 | self.renorm()?; |
| 67 | } |
| 68 | Ok(()) |
| 69 | } |
| 70 | fn flush_run(&mut self, overflow: bool) -> EncoderResult<()> { |
| 71 | if self.run > 0 { |
| 72 | self.bw.write_byte(self.saved + (overflow as u8))?; |
| 73 | if !overflow { |
| 74 | for _ in 1..self.run { |
| 75 | self.bw.write_byte(0xFF)?; |
| 76 | } |
| 77 | } else { |
| 78 | for _ in 1..self.run { |
| 79 | self.bw.write_byte(0)?; |
| 80 | } |
| 81 | } |
| 82 | self.run = 0; |
| 83 | } |
| 84 | Ok(()) |
| 85 | } |
| 86 | fn renorm(&mut self) -> EncoderResult<()> { |
| 87 | let bits = (self.range.leading_zeros() & 7) as u8; |
| 88 | self.range <<= bits; |
| 89 | if self.bits + bits < 23 { |
| 90 | self.bits += bits; |
| 91 | self.val <<= bits; |
| 92 | } else { |
| 93 | for _ in 0..bits { |
| 94 | if (self.bits == 23) && ((self.val >> 31) != 0) { |
| 95 | self.flush_run(true)?; |
| 96 | } |
| 97 | self.val <<= 1; |
| 98 | self.bits += 1; |
| 99 | if self.bits == 24 { |
| 100 | let tbyte = (self.val >> 24) as u8; |
| 101 | let nbyte = (self.val >> 16) as u8; |
| 102 | if tbyte < 0xFF { |
| 103 | self.flush_run(false)?; |
| 104 | if nbyte < 0xFE { |
| 105 | self.bw.write_byte(tbyte)?; |
| 106 | } else { |
| 107 | self.saved = tbyte; |
| 108 | self.run = 1; |
| 109 | } |
| 110 | } else { |
| 111 | self.run += 1; |
| 112 | } |
| 113 | self.val &= 0xFFFFFF; |
| 114 | self.bits -= 8; |
| 115 | } |
| 116 | } |
| 117 | } |
| 118 | Ok(()) |
| 119 | } |
| 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)?; |
| 124 | Ok(()) |
| 125 | } |
| 126 | |
| 127 | pub fn put_bits(&mut self, val: u32, len: u8) -> EncoderResult<()> { |
| 128 | let mut mask = 1 << (len - 1); |
| 129 | while mask != 0 { |
| 130 | self.put_bool((val & mask) != 0, 128)?; |
| 131 | mask >>= 1; |
| 132 | } |
| 133 | Ok(()) |
| 134 | } |
| 135 | pub fn put_probability(&mut self, prob: u8) -> EncoderResult<()> { |
| 136 | self.put_bits(u32::from(prob >> 1), 7) |
| 137 | } |
| 138 | pub fn encode_probability(&mut self, new: u8, old: u8, prob: u8) -> EncoderResult<()> { |
| 139 | self.put_bool(new != old, prob)?; |
| 140 | if new != old { |
| 141 | self.put_probability(new)?; |
| 142 | } |
| 143 | Ok(()) |
| 144 | } |
| 145 | pub fn write_el<T: PartialEq>(&mut self, el: T, tree: &[TokenSeq<T>], probs: &[u8]) -> EncoderResult<()> { |
| 146 | for entry in tree.iter() { |
| 147 | if entry.val == el { |
| 148 | for seq in entry.seq.iter() { |
| 149 | self.put_bool(seq.bit, probs[seq.idx as usize])?; |
| 150 | } |
| 151 | return Ok(()); |
| 152 | } |
| 153 | } |
| 154 | Err(EncoderError::Bug) |
| 155 | } |
| 156 | } |
| 157 | |
| 158 | pub struct Estimator {} |
| 159 | |
| 160 | #[allow(dead_code)] |
| 161 | impl 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() { |
| 165 | if entry.val == el { |
| 166 | for seq in entry.seq.iter() { |
| 167 | probs[seq.idx as usize].add(seq.bit); |
| 168 | } |
| 169 | return; |
| 170 | } |
| 171 | } |
| 172 | } |
| 173 | pub fn est_nits(bit: bool, prob: u8) -> u32 { |
| 174 | if !bit { |
| 175 | u32::from(PROB_BITS[prob as usize]) |
| 176 | } else { |
| 177 | u32::from(PROB_BITS[256 - (prob as usize)]) |
| 178 | } |
| 179 | } |
| 180 | pub fn nits_to_bits(nits: u32) -> u32 { (nits + 7) >> 3 } |
| 181 | } |