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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 "./vpx_config.h"
#include "./bitreader_buffer.h"
size_t vpx_rb_bytes_read(struct vpx_read_bit_buffer *rb) {
return (rb->bit_offset + 7) >> 3;
}
int vpx_rb_read_bit(struct vpx_read_bit_buffer *rb) {
const size_t off = rb->bit_offset;
const size_t p = off >> 3;
const int q = 7 - (int)(off & 0x7);
if (rb->bit_buffer + p < rb->bit_buffer_end) {
const int bit = (rb->bit_buffer[p] >> q) & 1;
rb->bit_offset = off + 1;
return bit;
} else {
rb->error_handler(rb->error_handler_data);
return 0;
}
}
int vpx_rb_read_literal(struct vpx_read_bit_buffer *rb, int bits) {
int value = 0, bit;
for (bit = bits - 1; bit >= 0; bit--)
value |= vpx_rb_read_bit(rb) << bit;
return value;
}
int vpx_rb_read_signed_literal(struct vpx_read_bit_buffer *rb,
int bits) {
const int value = vpx_rb_read_literal(rb, bits);
return vpx_rb_read_bit(rb) ? -value : value;
}
int vpx_rb_read_inv_signed_literal(struct vpx_read_bit_buffer *rb,
int bits) {
#if CONFIG_MISC_FIXES
const int nbits = sizeof(unsigned) * 8 - bits - 1;
const unsigned value = (unsigned)vpx_rb_read_literal(rb, bits + 1) << nbits;
return ((int) value) >> nbits;
#else
return vpx_rb_read_signed_literal(rb, bits);
#endif
}
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