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/*
* Copyright (c) 2013 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 file in the root of the source
* tree. An additional intellectual property rights grant can be found
* in the file PATENTS. All contributing project authors may
* be found in the AUTHORS file in the root of the source tree.
*/
#include <assert.h>
#include <limits.h>
#include <stdlib.h>
#include "./vpx_config.h"
#include "./bitwriter_buffer.h"
void vpx_wb_init(struct vpx_write_bit_buffer *wb, uint8_t *bit_buffer,
size_t size) {
wb->error = 0;
wb->bit_offset = 0;
wb->size = size;
wb->bit_buffer = bit_buffer;
}
int vpx_wb_has_error(const struct vpx_write_bit_buffer *wb) {
return wb->error;
}
size_t vpx_wb_bytes_written(const struct vpx_write_bit_buffer *wb) {
assert(!wb->error);
return wb->bit_offset / CHAR_BIT + (wb->bit_offset % CHAR_BIT > 0);
}
void vpx_wb_write_bit(struct vpx_write_bit_buffer *wb, int bit) {
if (wb->error) return;
const int off = (int)wb->bit_offset;
const int p = off / CHAR_BIT;
const int q = CHAR_BIT - 1 - off % CHAR_BIT;
if ((size_t)p >= wb->size) {
wb->error = 1;
return;
}
if (q == CHAR_BIT - 1) {
wb->bit_buffer[p] = bit << q;
} else {
assert((wb->bit_buffer[p] & (1 << q)) == 0);
wb->bit_buffer[p] |= bit << q;
}
wb->bit_offset = off + 1;
}
void vpx_wb_write_literal(struct vpx_write_bit_buffer *wb, int data, int bits) {
int bit;
for (bit = bits - 1; bit >= 0; bit--) vpx_wb_write_bit(wb, (data >> bit) & 1);
}
void vpx_wb_write_inv_signed_literal(struct vpx_write_bit_buffer *wb, int data,
int bits) {
vpx_wb_write_literal(wb, abs(data), bits);
vpx_wb_write_bit(wb, data < 0);
}
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