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|
use nihav_core::codecs::*;
use nihav_core::io::bitreader::*;
use nihav_core::io::codebook::*;
/// Bitstream reader.
#[derive(Debug,Clone)]
pub struct QdmBitReader<'a> {
cache: u32,
bits: u8,
pos: usize,
src: &'a [u8],
}
#[allow(clippy::identity_op)]
#[allow(dead_code)]
impl<'a> QdmBitReader<'a> {
pub fn new(src: &'a [u8]) -> Self {
Self{ cache: 0, pos: 0, bits: 0, src }
}
pub fn tell(&self) -> usize {
self.pos * 8 - (self.bits as usize)
}
pub fn left(&self) -> isize {
((self.src.len() as isize) - (self.pos as isize)) * 8 + (self.bits as isize)
}
fn refill(&mut self) {
while self.bits <= 24 {
let byte = if self.pos < self.src.len() {
self.pos += 1;
self.src[self.pos - 1]
} else {
self.pos += 1;
0
};
self.cache |= u32::from(byte) << self.bits;
self.bits += 8;
}
}
fn read_cache(&mut self, nbits: u8) -> u32 {
((1 << nbits) - 1) & self.cache
}
fn skip_cache(&mut self, nbits: u8) {
self.cache >>= nbits;
self.bits -= nbits;
}
fn reset_cache(&mut self) {
self.bits = 0;
self.cache = 0;
}
pub fn read(&mut self, nbits: u8) -> u32 {
if nbits == 0 { return 0; }
if nbits > 32 { return 0; }
if self.bits < nbits {
self.refill();
}
let res = self.read_cache(nbits);
self.skip_cache(nbits);
res
}
pub fn read_bool(&mut self) -> bool {
if self.bits < 1 {
self.refill();
}
let res = self.read_cache(1);
self.skip_cache(1);
res == 1
}
pub fn peek(&mut self, nbits: u8) -> u32 {
if nbits > 32 { return 0 }
if self.bits < nbits { self.refill(); }
self.read_cache(nbits)
}
pub fn skip(&mut self, nbits: u32) {
if u32::from(self.bits) >= nbits {
self.skip_cache(nbits as u8);
return;
}
let mut skip_bits = nbits - u32::from(self.bits);
self.reset_cache();
self.pos += ((skip_bits / 32) * 4) as usize;
skip_bits &= 0x1F;
self.refill();
if skip_bits > 0 {
self.skip_cache(skip_bits as u8);
}
}
}
impl<'a, S: Copy> CodebookReader<S> for QdmBitReader<'a> {
#[allow(unused_variables)]
fn read_cb(&mut self, cb: &Codebook<S>) -> CodebookResult<S> {
let mut esc = true;
let mut idx = 0;
let mut lut_bits = cb.lut_bits;
while esc {
let lut_idx = (self.peek(lut_bits) as usize) + (idx as usize);
if cb.table[lut_idx] == TABLE_FILL_VALUE { return Err(CodebookError::InvalidCode); }
let bits = cb.table[lut_idx] & 0x7F;
esc = (cb.table[lut_idx] & 0x80) != 0;
idx = (cb.table[lut_idx] >> 8) as usize;
let skip_bits = if esc { u32::from(lut_bits) } else { bits };
self.skip(skip_bits as u32);
lut_bits = bits as u8;
}
Ok(cb.syms[idx])
}
}
pub fn to_signed(val: i32) -> i32 {
if (val & 1) != 0 {
(val + 1) >> 1
} else {
-(val >> 1)
}
}
pub trait QdmcCodeReader {
fn read_code(&mut self, cb: &Codebook<u8>) -> DecoderResult<u32>;
fn read_code_long(&mut self, cb: &Codebook<u8>) -> DecoderResult<u32>;
}
impl<'a> QdmcCodeReader for BitReader<'a> {
fn read_code(&mut self, cb: &Codebook<u8>) -> DecoderResult<u32> {
let idx = self.read_cb(cb)?;
if idx > 0 {
Ok(u32::from(idx - 1))
} else {
let len = (self.read(3)? as u8) + 1;
let val = self.read(len)?;
Ok(val)
}
}
fn read_code_long(&mut self, cb: &Codebook<u8>) -> DecoderResult<u32> {
let idx = self.read_code(cb)? as usize;
validate!(idx < ESCAPE_PREFIX.len());
let add = self.read((idx >> 2) as u8)?;
Ok(ESCAPE_PREFIX[idx] + add)
}
}
impl<'a> QdmcCodeReader for QdmBitReader<'a> {
fn read_code(&mut self, cb: &Codebook<u8>) -> DecoderResult<u32> {
let idx = self.read_cb(cb)?;
if idx > 0 {
Ok(u32::from(idx - 1))
} else {
let len = (self.read(3) as u8) + 1;
let val = self.read(len);
Ok(val)
}
}
fn read_code_long(&mut self, cb: &Codebook<u8>) -> DecoderResult<u32> {
let idx = self.read_code(cb)? as usize;
validate!(idx < ESCAPE_PREFIX.len());
let add = self.read((idx >> 2) as u8);
Ok(ESCAPE_PREFIX[idx] + add)
}
}
const ESCAPE_PREFIX: [u32; 65] = [
0x00000, 0x00001, 0x00002, 0x00003, 0x00004, 0x00006, 0x00008, 0x0000A,
0x0000C, 0x00010, 0x00014, 0x00018, 0x0001C, 0x00024, 0x0002C, 0x00034,
0x0003C, 0x0004C, 0x0005C, 0x0006C, 0x0007C, 0x0009C, 0x000BC, 0x000DC,
0x000FC, 0x0013C, 0x0017C, 0x001BC, 0x001FC, 0x0027C, 0x002FC, 0x0037C,
0x003FC, 0x004FC, 0x005FC, 0x006FC, 0x007FC, 0x009FC, 0x00BFC, 0x00DFC,
0x00FFC, 0x013FC, 0x017FC, 0x01BFC, 0x01FFC, 0x027FC, 0x02FFC, 0x037FC,
0x03FFC, 0x04FFC, 0x05FFC, 0x06FFC, 0x07FFC, 0x09FFC, 0x0BFFC, 0x0DFFC,
0x0FFFC, 0x13FFC, 0x17FFC, 0x1BFFC, 0x1FFFC, 0x27FFC, 0x2FFFC, 0x37FFC,
0x3FFFC
];
pub struct RNG {
pub seed: u32,
}
impl RNG {
pub fn new() -> Self { Self { seed: 0 } }
pub fn next(&mut self) -> u32 {
self.seed = self.seed.wrapping_mul(0x343FD).wrapping_add(0x269EC3);
self.seed
}
pub fn next_float(&mut self) -> f32 {
self.next();
((((self.seed >> 16) & 0x7FFF) as f32) - 16384.0) / 16384.0
}
}
#[derive(Clone,Copy)]
pub struct Tone {
pub ch: u8,
pub phase: u8,
pub offset: u8,
pub freq: u16,
pub amp_idx: u8,
}
pub const MAX_TONES: usize = 8192;
|
