/* *  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. */ /**************************************************************************** * *   Module Title :     boolhuff.h * *   Description  :     Bool Coder header file. * ****************************************************************************/#ifndef VPX_VP8_ENCODER_BOOLHUFF_H_#define VPX_VP8_ENCODER_BOOLHUFF_H_ #include "vpx_ports/mem.h"#include "vpx/internal/vpx_codec_internal.h" #ifdef __cplusplusextern "C" {#endif typedef struct {  unsigned int lowvalue;  unsigned int range;  int count;  unsigned int pos;  unsigned char *buffer;  unsigned char *buffer_end;  struct vpx_internal_error_info *error;} BOOL_CODER; void vp8_start_encode(BOOL_CODER *bc, unsigned char *source,                      unsigned char *source_end); void vp8_encode_value(BOOL_CODER *bc, int data, int bits);void vp8_stop_encode(BOOL_CODER *bc);extern const unsigned int vp8_prob_cost[256]; DECLARE_ALIGNED(16, extern const unsigned char, vp8_norm[256]); static int validate_buffer(const unsigned char *start, size_t len,                           const unsigned char *end,                           struct vpx_internal_error_info *error) {  if (start + len > start && start + len < end) {    return 1;  } else {    vpx_internal_error(error, VPX_CODEC_CORRUPT_FRAME,                       "Truncated packet or corrupt partition ");  }   return 0;}static void vp8_encode_bool(BOOL_CODER *bc, int bit, int probability) {  unsigned int split;  int count = bc->count;  unsigned int range = bc->range;  unsigned int lowvalue = bc->lowvalue;  int shift;   split = 1 + (((range - 1) * probability) >> 8);   range = split;   if (bit) {    lowvalue += split;    range = bc->range - split;  }   shift = vp8_norm[range];   range <<= shift;  count += shift;   if (count >= 0) {    int offset = shift - count;     if ((lowvalue << (offset - 1)) & 0x80000000) {      int x = bc->pos - 1;       while (x >= 0 && bc->buffer[x] == 0xff) {        bc->buffer[x] = (unsigned char)0;        x--;      }       bc->buffer[x] += 1;    }     validate_buffer(bc->buffer + bc->pos, 1, bc->buffer_end, bc->error);    bc->buffer[bc->pos++] = (lowvalue >> (24 - offset) & 0xff);     lowvalue <<= offset;    shift = count;    lowvalue &= 0xffffff;    count -= 8;  }   lowvalue <<= shift;  bc->count = count;  bc->lowvalue = lowvalue;  bc->range = range;} #ifdef __cplusplus}  // extern "C"#endif #endif  // VPX_VP8_ENCODER_BOOLHUFF_H_