/*---------------------------------------------------------------------------------------------
* Copyright (c) Microsoft Corporation. All rights reserved.
* Licensed under the Apache License, Version 2.0. See LICENSE.txt in the project root for license information.
* This software incorporates material from third parties. See NOTICE.txt for details.
*--------------------------------------------------------------------------------------------*/
/*
* Copyright (c) 2010 The WebM project authors. All Rights Reserved.
*
* Use of this source code is governed by a BSD-style license
* that can be found in the LICENSE banner below
* An additional intellectual property rights grant can be found
* in the file PATENTS. All contributing project authors may
* be found in the VPX_AUTHORS file in this directory
*/
/*
Copyright (c) 2010, Google Inc. All rights reserved.
Redistribution and use in source and binary forms, with or without modification, are permitted provided that the following conditions are met:
Redistributions of source code must retain the above copyright notice, this list of conditions and the following disclaimer.
Redistributions in binary form must reproduce the above copyright notice, this list of conditions and the following disclaimer in the documentation and/or other materials provided with the distribution.
Neither the name of Google nor the names of its contributors may be used to endorse or promote products derived from this software without specific prior written permission.
THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS “AS IS” AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
*/
use std::io::{Result, Write};
use crate::metrics::{Metrics, ModelComponent};
#[cfg(feature = "compression_stats")]
use crate::metrics::ModelStatsCollector;
use super::{branch::Branch, simple_hash::SimpleHash};
pub struct VPXBoolWriter<W> {
low_value: u32,
range: u32,
count: i32,
writer: W,
buffer: Vec<u8>,
model_statistics: Metrics,
pub hash: SimpleHash,
}
impl<W: Write> VPXBoolWriter<W> {
pub fn new(writer: W) -> Result<Self> {
let mut retval = VPXBoolWriter {
low_value: 0,
range: 255,
count: -24,
buffer: Vec::new(),
writer: writer,
model_statistics: Metrics::default(),
hash: SimpleHash::new(),
};
let mut dummy_branch = Branch::new();
retval.put(false, &mut dummy_branch, ModelComponent::Dummy)?;
Ok(retval)
}
pub fn drain_stats(&mut self) -> Metrics {
self.model_statistics.drain()
}
#[inline(never)]
pub fn put_grid<const A: usize, const B: usize>(
&mut self,
v: u8,
branches: &mut [[Branch; B]; A],
cmp: ModelComponent,
) -> Result<()> {
assert!(1 << (A - 1) == B);
let mut index = A - 1;
let mut serialized_so_far = 0;
loop {
let cur_bit = (v & (1 << index)) != 0;
self.put(
cur_bit,
&mut branches[index as usize][serialized_so_far],
cmp,
)?;
serialized_so_far <<= 1;
serialized_so_far |= cur_bit as usize;
if index == 0 {
break;
}
index -= 1;
}
Ok(())
}
#[inline(never)]
pub fn put_n_bits<const A: usize>(
&mut self,
bits: usize,
num_bits: usize,
branches: &mut [Branch; A],
cmp: ModelComponent,
) -> Result<()> {
let mut i: i32 = (num_bits - 1) as i32;
while i >= 0 {
self.put((bits & (1 << i)) != 0, &mut branches[i as usize], cmp)?;
i -= 1;
}
Ok(())
}
#[inline(never)]
pub fn put_unary_encoded<const A: usize>(
&mut self,
v: usize,
branches: &mut [Branch; A],
cmp: ModelComponent,
) -> Result<()> {
assert!(v <= A);
for i in 0..A {
let cur_bit = v != i;
self.put(cur_bit, &mut branches[i], cmp)?;
if !cur_bit {
break;
}
}
Ok(())
}
#[inline(always)]
pub fn put(&mut self, value: bool, branch: &mut Branch, _cmp: ModelComponent) -> Result<()> {
#[cfg(feature = "detailed_tracing")]
{
// used to detect divergences between the C++ and rust versions
self.hash.hash(branch.get_u64());
self.hash.hash(self.low_value);
self.hash.hash(self.count);
self.hash.hash(self.range);
let hashed_value = self.hash.get();
//if hashedValue == 0xe35c28fd
{
print!("({0}:{1:x})", value as u8, hashed_value);
if hashed_value % 8 == 0 {
println!();
}
}
}
let probability = branch.get_probability() as u32;
let mut tmp_range = self.range;
let split = 1 + (((tmp_range - 1) * probability) >> 8);
let mut tmp_low_value = self.low_value;
if value {
branch.record_and_update_true_obs();
tmp_low_value += split;
tmp_range -= split;
} else {
branch.record_and_update_false_obs();
tmp_range = split;
}
//lookup tables are best avoided in modern CPUs
//let mut shift = VPX_NORM[tmp_range as usize] as i32;
let mut shift = tmp_range.leading_zeros() as i32 - 24;
#[cfg(feature = "compression_stats")]
{
self.model_statistics
.record_compression_stats(_cmp, 1, i64::from(shift));
}
tmp_range <<= shift;
let mut tmp_count = self.count;
tmp_count += shift;
if tmp_count >= 0 {
let offset = shift - tmp_count;
if ((tmp_low_value << (offset - 1)) & 0x80000000) != 0 {
let mut x = self.buffer.len() - 1;
while self.buffer[x] == 0xFF {
self.buffer[x] = 0;
assert!(x > 0);
x -= 1;
}
self.buffer[x] += 1;
}
self.buffer.push((tmp_low_value >> (24 - offset)) as u8);
tmp_low_value <<= offset;
shift = tmp_count;
tmp_low_value &= 0xffffff;
tmp_count -= 8;
}
tmp_low_value <<= shift;
self.count = tmp_count;
self.low_value = tmp_low_value;
self.range = tmp_range;
// check if we're out of buffer space, if yes - send the buffer to output,
if self.buffer.len() > 65536 - 128 {
self.flush_non_final_data()?;
}
Ok(())
}
pub fn finish(&mut self) -> Result<()> {
for _i in 0..32 {
let mut dummy_branch = Branch::new();
self.put(false, &mut dummy_branch, ModelComponent::Dummy)?;
}
// Ensure there's no ambigous collision with any index marker bytes
if (self.buffer.last().unwrap() & 0xe0) == 0xc0 {
self.buffer.push(0);
}
self.writer.write_all(&self.buffer[..])?;
Ok(())
}
/// When buffer is full and is going to be sent to output, preserve buffer data that
/// is not final and should carried over to the next buffer.
fn flush_non_final_data(&mut self) -> Result<()> {
// carry over buffer data that might be not final
let mut i = self.buffer.len() - 1;
while self.buffer[i] == 0xFF {
assert!(i > 0);
i -= 1;
}
self.writer.write_all(&self.buffer[..i])?;
self.buffer.drain(..i);
Ok(())
}
}