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/*
* Copyright (c) 2016, Alliance for Open Media. All rights reserved
*
* This source code is subject to the terms of the BSD 2 Clause License and
* the Alliance for Open Media Patent License 1.0. If the BSD 2 Clause License
* was not distributed with this source code in the LICENSE file, you can
* obtain it at www.aomedia.org/license/software. If the Alliance for Open
* Media Patent License 1.0 was not distributed with this source code in the
* PATENTS file, you can obtain it at www.aomedia.org/license/patent.
*/
#include <assert.h>
#include <limits.h>
#include <stdlib.h>
#include "config/aom_config.h"
#include "aom_dsp/bitwriter_buffer.h"
int aom_wb_is_byte_aligned(const struct aom_write_bit_buffer *wb) {
return (wb->bit_offset % CHAR_BIT == 0);
}
uint32_t aom_wb_bytes_written(const struct aom_write_bit_buffer *wb) {
return wb->bit_offset / CHAR_BIT + (wb->bit_offset % CHAR_BIT > 0);
}
void aom_wb_write_bit(struct aom_write_bit_buffer *wb, int bit) {
const int off = (int)wb->bit_offset;
const int p = off / CHAR_BIT;
const int q = CHAR_BIT - 1 - off % CHAR_BIT;
if (q == CHAR_BIT - 1) {
// Zero next char and write bit
wb->bit_buffer[p] = bit << q;
} else {
wb->bit_buffer[p] &= ~(1 << q);
wb->bit_buffer[p] |= bit << q;
}
wb->bit_offset = off + 1;
}
void aom_wb_overwrite_bit(struct aom_write_bit_buffer *wb, int bit) {
// Do not zero bytes but overwrite exisiting values
const int off = (int)wb->bit_offset;
const int p = off / CHAR_BIT;
const int q = CHAR_BIT - 1 - off % CHAR_BIT;
wb->bit_buffer[p] &= ~(1 << q);
wb->bit_buffer[p] |= bit << q;
wb->bit_offset = off + 1;
}
void aom_wb_write_literal(struct aom_write_bit_buffer *wb, int data, int bits) {
assert(bits <= 31);
int bit;
for (bit = bits - 1; bit >= 0; bit--) aom_wb_write_bit(wb, (data >> bit) & 1);
}
void aom_wb_write_unsigned_literal(struct aom_write_bit_buffer *wb,
uint32_t data, int bits) {
assert(bits <= 32);
int bit;
for (bit = bits - 1; bit >= 0; bit--) aom_wb_write_bit(wb, (data >> bit) & 1);
}
void aom_wb_overwrite_literal(struct aom_write_bit_buffer *wb, int data,
int bits) {
int bit;
for (bit = bits - 1; bit >= 0; bit--)
aom_wb_overwrite_bit(wb, (data >> bit) & 1);
}
void aom_wb_write_inv_signed_literal(struct aom_write_bit_buffer *wb, int data,
int bits) {
aom_wb_write_literal(wb, data, bits + 1);
}
void aom_wb_write_uvlc(struct aom_write_bit_buffer *wb, uint32_t v) {
int64_t shift_val = ++v;
int leading_zeroes = 1;
assert(shift_val > 0);
while (shift_val >>= 1) leading_zeroes += 2;
aom_wb_write_literal(wb, 0, leading_zeroes >> 1);
aom_wb_write_unsigned_literal(wb, v, (leading_zeroes + 1) >> 1);
}
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