use super::super::alloc::{Allocator, SliceWrapper, SliceWrapperMut};
use super::backward_references::BrotliEncoderParams;
use super::input_pair::{InputPair, InputReference, InputReferenceMut};
use super::interface;
use super::ir_interpret::{push_base, IRInterpreter};
use super::prior_eval::DEFAULT_SPEED;
use super::util::{floatX, FastLog2u16};
const NIBBLE_PRIOR_SIZE: usize = 16;
pub const STRIDE_PRIOR_SIZE: usize = 256 * 256 * NIBBLE_PRIOR_SIZE * 2;
pub fn local_init_cdfs(cdfs: &mut [u16]) {
for (index, item) in cdfs.iter_mut().enumerate() {
*item = 4 + 4 * (index as u16 & 0x0f);
}
}
#[allow(unused_variables)]
fn stride_lookup_lin(
stride_byte: u8,
selected_context: u8,
actual_context: usize,
high_nibble: Option<u8>,
) -> usize {
if let Some(nibble) = high_nibble {
1 + 2 * (actual_context | ((stride_byte as usize & 0xf) << 8) | ((nibble as usize) << 12))
} else {
2 * (actual_context | ((stride_byte as usize) << 8))
}
}
struct CDF<'a> {
cdf: &'a mut [u16],
}
struct Stride1Prior {}
impl Stride1Prior {
fn lookup_lin(
stride_byte: u8,
selected_context: u8,
actual_context: usize,
high_nibble: Option<u8>,
) -> usize {
stride_lookup_lin(stride_byte, selected_context, actual_context, high_nibble)
}
fn lookup_mut(
data: &mut [u16],
stride_byte: u8,
selected_context: u8,
actual_context: usize,
high_nibble: Option<u8>,
) -> CDF {
let index = Self::lookup_lin(stride_byte, selected_context, actual_context, high_nibble)
* NIBBLE_PRIOR_SIZE;
CDF::from(data.split_at_mut(index).1.split_at_mut(16).0)
}
}
impl<'a> CDF<'a> {
pub fn cost(&self, nibble_u8: u8) -> floatX {
assert_eq!(self.cdf.len(), 16);
let nibble = nibble_u8 as usize & 0xf;
let mut pdf = self.cdf[nibble];
if nibble_u8 != 0 {
pdf -= self.cdf[nibble - 1];
}
FastLog2u16(self.cdf[15]) - FastLog2u16(pdf)
}
pub fn update(&mut self, nibble_u8: u8, speed: (u16, u16)) {
assert_eq!(self.cdf.len(), 16);
for nib_range in (nibble_u8 as usize & 0xf)..16 {
self.cdf[nib_range] += speed.0;
}
if self.cdf[15] >= speed.1 {
const CDF_BIAS: [u16; 16] = [1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16];
for nibble_index in 0..16 {
let tmp = &mut self.cdf[nibble_index];
*tmp = (tmp.wrapping_add(CDF_BIAS[nibble_index]))
.wrapping_sub(tmp.wrapping_add(CDF_BIAS[nibble_index]) >> 2);
}
}
}
}
impl<'a> From<&'a mut [u16]> for CDF<'a> {
fn from(cdf: &'a mut [u16]) -> CDF<'a> {
assert_eq!(cdf.len(), 16);
CDF { cdf }
}
}
pub struct StrideEval<
'a,
Alloc: alloc::Allocator<u16> + alloc::Allocator<u32> + alloc::Allocator<floatX> + 'a,
> {
input: InputPair<'a>,
alloc: &'a mut Alloc,
context_map: &'a interface::PredictionModeContextMap<InputReferenceMut<'a>>,
block_type: u8,
local_byte_offset: usize,
stride_priors: [<Alloc as Allocator<u16>>::AllocatedMemory; 8],
score: <Alloc as Allocator<floatX>>::AllocatedMemory,
cur_score_epoch: usize,
stride_speed: [(u16, u16); 2],
cur_stride: u8,
}
impl<'a, Alloc: alloc::Allocator<u16> + alloc::Allocator<u32> + alloc::Allocator<floatX> + 'a>
StrideEval<'a, Alloc>
{
pub fn new(
alloc: &'a mut Alloc,
input: InputPair<'a>,
prediction_mode: &'a interface::PredictionModeContextMap<InputReferenceMut<'a>>,
params: &BrotliEncoderParams,
) -> Self {
let do_alloc = true;
let mut stride_speed = prediction_mode.stride_context_speed();
if stride_speed[0] == (0, 0) {
stride_speed[0] = params.literal_adaptation[0]
}
if stride_speed[0] == (0, 0) {
stride_speed[0] = DEFAULT_SPEED;
}
if stride_speed[1] == (0, 0) {
stride_speed[1] = params.literal_adaptation[1]
}
if stride_speed[1] == (0, 0) {
stride_speed[1] = stride_speed[0];
}
let score = if do_alloc {
<Alloc as Allocator<floatX>>::alloc_cell(alloc, 8 * 4) } else {
<Alloc as Allocator<floatX>>::AllocatedMemory::default()
};
let stride_priors = if do_alloc {
[
<Alloc as Allocator<u16>>::alloc_cell(alloc, STRIDE_PRIOR_SIZE),
<Alloc as Allocator<u16>>::alloc_cell(alloc, STRIDE_PRIOR_SIZE),
<Alloc as Allocator<u16>>::alloc_cell(alloc, STRIDE_PRIOR_SIZE),
<Alloc as Allocator<u16>>::alloc_cell(alloc, STRIDE_PRIOR_SIZE),
<Alloc as Allocator<u16>>::alloc_cell(alloc, STRIDE_PRIOR_SIZE),
<Alloc as Allocator<u16>>::alloc_cell(alloc, STRIDE_PRIOR_SIZE),
<Alloc as Allocator<u16>>::alloc_cell(alloc, STRIDE_PRIOR_SIZE),
<Alloc as Allocator<u16>>::alloc_cell(alloc, STRIDE_PRIOR_SIZE),
]
} else {
[
<Alloc as Allocator<u16>>::AllocatedMemory::default(),
<Alloc as Allocator<u16>>::AllocatedMemory::default(),
<Alloc as Allocator<u16>>::AllocatedMemory::default(),
<Alloc as Allocator<u16>>::AllocatedMemory::default(),
<Alloc as Allocator<u16>>::AllocatedMemory::default(),
<Alloc as Allocator<u16>>::AllocatedMemory::default(),
<Alloc as Allocator<u16>>::AllocatedMemory::default(),
<Alloc as Allocator<u16>>::AllocatedMemory::default(),
]
};
let mut ret = StrideEval::<Alloc> {
input,
context_map: prediction_mode,
block_type: 0,
alloc,
cur_stride: 1,
cur_score_epoch: 0,
local_byte_offset: 0,
stride_priors,
score,
stride_speed,
};
for stride_prior in ret.stride_priors.iter_mut() {
local_init_cdfs(stride_prior.slice_mut());
}
ret
}
pub fn alloc(&mut self) -> &mut Alloc {
self.alloc
}
pub fn choose_stride(&self, stride_data: &mut [u8]) {
assert_eq!(stride_data.len(), self.cur_score_epoch);
assert!(self.score.slice().len() > stride_data.len());
assert!(self.score.slice().len() > (stride_data.len() << 3) + 7 + 8);
for (index, choice) in stride_data.iter_mut().enumerate() {
let choices = self
.score
.slice()
.split_at((1 + index) << 3)
.1
.split_at(8)
.0;
let mut best_choice: u8 = 0;
let mut best_score = choices[0];
for (cur_index, cur_score) in choices.iter().enumerate() {
if *cur_score + 2.0 < best_score {
best_score = *cur_score;
best_choice = cur_index as u8;
}
}
*choice = best_choice;
}
}
pub fn num_types(&self) -> usize {
self.cur_score_epoch
}
fn update_cost_base(
&mut self,
stride_prior: [u8; 8],
selected_bits: u8,
cm_prior: usize,
literal: u8,
) {
type CurPrior = Stride1Prior;
{
for i in 0..8 {
let mut cdf = CurPrior::lookup_mut(
self.stride_priors[i].slice_mut(),
stride_prior[i],
selected_bits,
cm_prior,
None,
);
self.score.slice_mut()[self.cur_score_epoch * 8 + i] += cdf.cost(literal >> 4);
cdf.update(literal >> 4, self.stride_speed[1]);
}
}
{
for i in 0..8 {
let mut cdf = CurPrior::lookup_mut(
self.stride_priors[i].slice_mut(),
stride_prior[i],
selected_bits,
cm_prior,
Some(literal >> 4),
);
self.score.slice_mut()[self.cur_score_epoch * 8 + i] += cdf.cost(literal & 0xf);
cdf.update(literal & 0xf, self.stride_speed[0]);
}
}
}
}
impl<'a, Alloc: alloc::Allocator<u16> + alloc::Allocator<u32> + alloc::Allocator<floatX>> Drop
for StrideEval<'a, Alloc>
{
fn drop(&mut self) {
<Alloc as Allocator<floatX>>::free_cell(self.alloc, core::mem::take(&mut self.score));
for i in 0..8 {
<Alloc as Allocator<u16>>::free_cell(
self.alloc,
core::mem::take(&mut self.stride_priors[i]),
);
}
}
}
impl<'a, Alloc: alloc::Allocator<u16> + alloc::Allocator<u32> + alloc::Allocator<floatX>>
IRInterpreter for StrideEval<'a, Alloc>
{
fn inc_local_byte_offset(&mut self, inc: usize) {
self.local_byte_offset += inc;
}
fn local_byte_offset(&self) -> usize {
self.local_byte_offset
}
fn update_block_type(&mut self, new_type: u8, stride: u8) {
self.block_type = new_type;
self.cur_stride = stride;
self.cur_score_epoch += 1;
if self.cur_score_epoch * 8 + 7 >= self.score.slice().len() {
let new_len = self.score.slice().len() * 2;
let mut new_score = <Alloc as Allocator<floatX>>::alloc_cell(self.alloc, new_len);
for (src, dst) in self.score.slice().iter().zip(
new_score
.slice_mut()
.split_at_mut(self.score.slice().len())
.0
.iter_mut(),
) {
*dst = *src;
}
<Alloc as Allocator<floatX>>::free_cell(
self.alloc,
core::mem::replace(&mut self.score, new_score),
);
}
}
fn block_type(&self) -> u8 {
self.block_type
}
fn literal_data_at_offset(&self, index: usize) -> u8 {
self.input[index]
}
fn literal_context_map(&self) -> &[u8] {
self.context_map.literal_context_map.slice()
}
fn prediction_mode(&self) -> ::interface::LiteralPredictionModeNibble {
self.context_map.literal_prediction_mode()
}
fn update_cost(
&mut self,
stride_prior: [u8; 8],
stride_prior_offset: usize,
selected_bits: u8,
cm_prior: usize,
literal: u8,
) {
let reversed_stride_priors = [
stride_prior[stride_prior_offset & 7],
stride_prior[stride_prior_offset.wrapping_sub(1) & 7],
stride_prior[stride_prior_offset.wrapping_sub(2) & 7],
stride_prior[stride_prior_offset.wrapping_sub(3) & 7],
stride_prior[stride_prior_offset.wrapping_sub(4) & 7],
stride_prior[stride_prior_offset.wrapping_sub(5) & 7],
stride_prior[stride_prior_offset.wrapping_sub(6) & 7],
stride_prior[stride_prior_offset.wrapping_sub(7) & 7],
];
self.update_cost_base(reversed_stride_priors, selected_bits, cm_prior, literal)
}
}
impl<'a, 'b, Alloc: alloc::Allocator<u16> + alloc::Allocator<u32> + alloc::Allocator<floatX>>
interface::CommandProcessor<'b> for StrideEval<'a, Alloc>
{
fn push(&mut self, val: interface::Command<InputReference<'b>>) {
push_base(self, val)
}
}