514b8adacd
Just an intermediate change set to simplify merges. Reordering several uncompressed header bits, code restructuring + minor cleanups. Change-Id: I28272f520762f8c4e3ad230ae39fff5102ba5c0d
55 lines
1.5 KiB
C
55 lines
1.5 KiB
C
/*
|
|
* 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.
|
|
*/
|
|
|
|
#ifndef VP9_READ_BIT_BUFFER_
|
|
#define VP9_READ_BIT_BUFFER_
|
|
|
|
#include <limits.h>
|
|
|
|
#include "vpx/vpx_integer.h"
|
|
|
|
typedef void (*vp9_rb_error_handler)(void *data, int bit_offset);
|
|
|
|
struct vp9_read_bit_buffer {
|
|
const uint8_t *bit_buffer;
|
|
const uint8_t *bit_buffer_end;
|
|
size_t bit_offset;
|
|
|
|
void *error_handler_data;
|
|
vp9_rb_error_handler error_handler;
|
|
};
|
|
|
|
static size_t vp9_rb_bytes_read(struct vp9_read_bit_buffer *rb) {
|
|
return rb->bit_offset / CHAR_BIT + (rb->bit_offset % CHAR_BIT > 0);
|
|
}
|
|
|
|
static int vp9_rb_read_bit(struct vp9_read_bit_buffer *rb) {
|
|
const int off = rb->bit_offset;
|
|
const int p = off / CHAR_BIT;
|
|
const int q = CHAR_BIT - 1 - off % CHAR_BIT;
|
|
if (rb->bit_buffer + p >= rb->bit_buffer_end) {
|
|
rb->error_handler(rb->error_handler_data, rb->bit_offset);
|
|
return 0;
|
|
} else {
|
|
const int bit = (rb->bit_buffer[p] & (1 << q)) >> q;
|
|
rb->bit_offset = off + 1;
|
|
return bit;
|
|
}
|
|
}
|
|
|
|
static int vp9_rb_read_literal(struct vp9_read_bit_buffer *rb, int bits) {
|
|
int value = 0, bit;
|
|
for (bit = bits - 1; bit >= 0; bit--)
|
|
value |= vp9_rb_read_bit(rb) << bit;
|
|
return value;
|
|
}
|
|
|
|
#endif // VP9_READ_BIT_BUFFER_
|