michael@0: /*
michael@0:  *  Copyright (c) 2010 The WebM project authors. All Rights Reserved.
michael@0:  *
michael@0:  *  Use of this source code is governed by a BSD-style license
michael@0:  *  that can be found in the LICENSE file in the root of the source
michael@0:  *  tree. An additional intellectual property rights grant can be found
michael@0:  *  in the file PATENTS.  All contributing project authors may
michael@0:  *  be found in the AUTHORS file in the root of the source tree.
michael@0:  */
michael@0: 
michael@0: 
michael@0: /****************************************************************************
michael@0: *
michael@0: *   Module Title :     boolhuff.h
michael@0: *
michael@0: *   Description  :     Bool Coder header file.
michael@0: *
michael@0: ****************************************************************************/
michael@0: #ifndef __INC_BOOLHUFF_H
michael@0: #define __INC_BOOLHUFF_H
michael@0: 
michael@0: #include "vpx_ports/mem.h"
michael@0: #include "vpx/internal/vpx_codec_internal.h"
michael@0: 
michael@0: typedef struct
michael@0: {
michael@0:     unsigned int lowvalue;
michael@0:     unsigned int range;
michael@0:     int count;
michael@0:     unsigned int pos;
michael@0:     unsigned char *buffer;
michael@0:     unsigned char *buffer_end;
michael@0:     struct vpx_internal_error_info *error;
michael@0: 
michael@0:     /* Variables used to track bit costs without outputing to the bitstream */
michael@0:     unsigned int  measure_cost;
michael@0:     unsigned long bit_counter;
michael@0: } BOOL_CODER;
michael@0: 
michael@0: extern void vp8_start_encode(BOOL_CODER *bc, unsigned char *buffer, unsigned char *buffer_end);
michael@0: 
michael@0: extern void vp8_encode_value(BOOL_CODER *br, int data, int bits);
michael@0: extern void vp8_stop_encode(BOOL_CODER *bc);
michael@0: extern const unsigned int vp8_prob_cost[256];
michael@0: 
michael@0: 
michael@0: DECLARE_ALIGNED(16, extern const unsigned char, vp8_norm[256]);
michael@0: 
michael@0: static int validate_buffer(const unsigned char *start,
michael@0:                            size_t               len,
michael@0:                            const unsigned char *end,
michael@0:                            struct vpx_internal_error_info *error)
michael@0: {
michael@0:     if (start + len > start && start + len < end)
michael@0:         return 1;
michael@0:     else
michael@0:         vpx_internal_error(error, VPX_CODEC_CORRUPT_FRAME,
michael@0:             "Truncated packet or corrupt partition ");
michael@0: 
michael@0:     return 0;
michael@0: }
michael@0: static void vp8_encode_bool(BOOL_CODER *br, int bit, int probability)
michael@0: {
michael@0:     unsigned int split;
michael@0:     int count = br->count;
michael@0:     unsigned int range = br->range;
michael@0:     unsigned int lowvalue = br->lowvalue;
michael@0:     register unsigned int shift;
michael@0: 
michael@0: #ifdef VP8_ENTROPY_STATS
michael@0: #if defined(SECTIONBITS_OUTPUT)
michael@0: 
michael@0:     if (bit)
michael@0:         Sectionbits[active_section] += vp8_prob_cost[255-probability];
michael@0:     else
michael@0:         Sectionbits[active_section] += vp8_prob_cost[probability];
michael@0: 
michael@0: #endif
michael@0: #endif
michael@0: 
michael@0:     split = 1 + (((range - 1) * probability) >> 8);
michael@0: 
michael@0:     range = split;
michael@0: 
michael@0:     if (bit)
michael@0:     {
michael@0:         lowvalue += split;
michael@0:         range = br->range - split;
michael@0:     }
michael@0: 
michael@0:     shift = vp8_norm[range];
michael@0: 
michael@0:     range <<= shift;
michael@0:     count += shift;
michael@0: 
michael@0:     if (count >= 0)
michael@0:     {
michael@0:         int offset = shift - count;
michael@0: 
michael@0:         if ((lowvalue << (offset - 1)) & 0x80000000)
michael@0:         {
michael@0:             int x = br->pos - 1;
michael@0: 
michael@0:             while (x >= 0 && br->buffer[x] == 0xff)
michael@0:             {
michael@0:                 br->buffer[x] = (unsigned char)0;
michael@0:                 x--;
michael@0:             }
michael@0: 
michael@0:             br->buffer[x] += 1;
michael@0:         }
michael@0: 
michael@0:         validate_buffer(br->buffer + br->pos, 1, br->buffer_end, br->error);
michael@0:         br->buffer[br->pos++] = (lowvalue >> (24 - offset));
michael@0: 
michael@0:         lowvalue <<= offset;
michael@0:         shift = count;
michael@0:         lowvalue &= 0xffffff;
michael@0:         count -= 8 ;
michael@0:     }
michael@0: 
michael@0:     lowvalue <<= shift;
michael@0:     br->count = count;
michael@0:     br->lowvalue = lowvalue;
michael@0:     br->range = range;
michael@0: }
michael@0: 
michael@0: #endif