| /* |
| * Copyright (c) 2010 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 VPX_VPX_DSP_BITWRITER_H_ |
| #define VPX_VPX_DSP_BITWRITER_H_ |
| |
| #include <stdio.h> |
| |
| #include "vpx_ports/compiler_attributes.h" |
| #include "vpx_ports/mem.h" |
| |
| #include "vpx_dsp/prob.h" |
| #if CONFIG_BITSTREAM_DEBUG |
| #include "vpx_util/vpx_debug_util.h" |
| #endif // CONFIG_BITSTREAM_DEBUG |
| |
| #ifdef __cplusplus |
| extern "C" { |
| #endif |
| |
| typedef struct vpx_writer { |
| unsigned int lowvalue; |
| unsigned int range; |
| int count; |
| unsigned int pos; |
| uint8_t *buffer; |
| } vpx_writer; |
| |
| void vpx_start_encode(vpx_writer *br, uint8_t *source); |
| void vpx_stop_encode(vpx_writer *br); |
| |
| static INLINE VPX_NO_UNSIGNED_SHIFT_CHECK void vpx_write(vpx_writer *br, |
| int bit, |
| int probability) { |
| unsigned int split; |
| int count = br->count; |
| unsigned int range = br->range; |
| unsigned int lowvalue = br->lowvalue; |
| int shift; |
| |
| #if CONFIG_BITSTREAM_DEBUG |
| /* |
| int queue_r = 0; |
| int frame_idx_r = 0; |
| int queue_w = bitstream_queue_get_write(); |
| int frame_idx_w = bitstream_queue_get_frame_write(); |
| if (frame_idx_w == frame_idx_r && queue_w == queue_r) { |
| fprintf(stderr, "\n *** bitstream queue at frame_idx_w %d queue_w %d\n", |
| frame_idx_w, queue_w); |
| assert(0); |
| } |
| */ |
| bitstream_queue_push(bit, probability); |
| #endif |
| |
| split = 1 + (((range - 1) * probability) >> 8); |
| |
| range = split; |
| |
| if (bit) { |
| lowvalue += split; |
| range = br->range - split; |
| } |
| |
| shift = vpx_norm[range]; |
| |
| range <<= shift; |
| count += shift; |
| |
| if (count >= 0) { |
| int offset = shift - count; |
| |
| if ((lowvalue << (offset - 1)) & 0x80000000) { |
| int x = br->pos - 1; |
| |
| while (x >= 0 && br->buffer[x] == 0xff) { |
| br->buffer[x] = 0; |
| x--; |
| } |
| |
| br->buffer[x] += 1; |
| } |
| |
| br->buffer[br->pos++] = (lowvalue >> (24 - offset)) & 0xff; |
| lowvalue <<= offset; |
| shift = count; |
| lowvalue &= 0xffffff; |
| count -= 8; |
| } |
| |
| lowvalue <<= shift; |
| br->count = count; |
| br->lowvalue = lowvalue; |
| br->range = range; |
| } |
| |
| static INLINE void vpx_write_bit(vpx_writer *w, int bit) { |
| vpx_write(w, bit, 128); // vpx_prob_half |
| } |
| |
| static INLINE void vpx_write_literal(vpx_writer *w, int data, int bits) { |
| int bit; |
| |
| for (bit = bits - 1; bit >= 0; bit--) vpx_write_bit(w, 1 & (data >> bit)); |
| } |
| |
| #define vpx_write_prob(w, v) vpx_write_literal((w), (v), 8) |
| |
| #ifdef __cplusplus |
| } // extern "C" |
| #endif |
| |
| #endif // VPX_VPX_DSP_BITWRITER_H_ |