The Tor Browser / file comparison
comparison: media/libvpx/vp9/decoder/vp9_read_bit_buffer.h
media/libvpx/vp9/decoder/vp9_read_bit_buffer.h
- branch
- TOR_BUG_9701
- changeset 10
- ac0c01689b40
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| -1:000000000000 | 0:599f8939b00b |
|---|---|
| 1 /* | |
| 2 * Copyright (c) 2013 The WebM project authors. All Rights Reserved. | |
| 3 * | |
| 4 * Use of this source code is governed by a BSD-style license | |
| 5 * that can be found in the LICENSE file in the root of the source | |
| 6 * tree. An additional intellectual property rights grant can be found | |
| 7 * in the file PATENTS. All contributing project authors may | |
| 8 * be found in the AUTHORS file in the root of the source tree. | |
| 9 */ | |
| 10 | |
| 11 #ifndef VP9_DECODER_VP9_READ_BIT_BUFFER_H_ | |
| 12 #define VP9_DECODER_VP9_READ_BIT_BUFFER_H_ | |
| 13 | |
| 14 #include <limits.h> | |
| 15 | |
| 16 #include "vpx/vpx_integer.h" | |
| 17 | |
| 18 typedef void (*vp9_rb_error_handler)(void *data, size_t bit_offset); | |
| 19 | |
| 20 struct vp9_read_bit_buffer { | |
| 21 const uint8_t *bit_buffer; | |
| 22 const uint8_t *bit_buffer_end; | |
| 23 size_t bit_offset; | |
| 24 | |
| 25 void *error_handler_data; | |
| 26 vp9_rb_error_handler error_handler; | |
| 27 }; | |
| 28 | |
| 29 static size_t vp9_rb_bytes_read(struct vp9_read_bit_buffer *rb) { | |
| 30 return rb->bit_offset / CHAR_BIT + (rb->bit_offset % CHAR_BIT > 0); | |
| 31 } | |
| 32 | |
| 33 static int vp9_rb_read_bit(struct vp9_read_bit_buffer *rb) { | |
| 34 const size_t off = rb->bit_offset; | |
| 35 const size_t p = off / CHAR_BIT; | |
| 36 const int q = CHAR_BIT - 1 - (int)off % CHAR_BIT; | |
| 37 if (rb->bit_buffer + p >= rb->bit_buffer_end) { | |
| 38 rb->error_handler(rb->error_handler_data, rb->bit_offset); | |
| 39 return 0; | |
| 40 } else { | |
| 41 const int bit = (rb->bit_buffer[p] & (1 << q)) >> q; | |
| 42 rb->bit_offset = off + 1; | |
| 43 return bit; | |
| 44 } | |
| 45 } | |
| 46 | |
| 47 static int vp9_rb_read_literal(struct vp9_read_bit_buffer *rb, int bits) { | |
| 48 int value = 0, bit; | |
| 49 for (bit = bits - 1; bit >= 0; bit--) | |
| 50 value |= vp9_rb_read_bit(rb) << bit; | |
| 51 return value; | |
| 52 } | |
| 53 | |
| 54 static int vp9_rb_read_signed_literal(struct vp9_read_bit_buffer *rb, | |
| 55 int bits) { | |
| 56 const int value = vp9_rb_read_literal(rb, bits); | |
| 57 return vp9_rb_read_bit(rb) ? -value : value; | |
| 58 } | |
| 59 | |
| 60 #endif // VP9_DECODER_VP9_READ_BIT_BUFFER_H_ |
