1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128 129 130 131 132 133 134 135 136 137 138 139 140 141 142 143 144 145 146 147 148 149 150 151 152 153 154 155 156 157 158 159 160 161 162 163 164 165 166 167 168 169 170 171 172 173 174 175 176 177 178 179 180 181 182 183 184 185 186 187 188 189 190 191 192 193 194 195 196 197 198 199 200 201 202 203 204 205 206 207 208 209 210 211 212 213 214 215 216 217 218 219 220 221 222 223 224 225 226 227 228 229 230 231 232 233 234 235 236 237 238 239 240 241 242 243 244 245 246 247 248 249 250 251 252 253 254 255 256 257 258 259 260 261 262 263 264 265 266 267 268 269 270 271 272 273 274 275 276 277 278 279 280 281 282 283 284 285
|
/********************************************************************
* This file was modified from the libogg distribution for *
* inclusion into libkate *
********************************************************************/
/********************************************************************
* *
* THIS FILE IS PART OF THE OggVorbis SOFTWARE CODEC SOURCE CODE. *
* USE, DISTRIBUTION AND REPRODUCTION OF THIS LIBRARY SOURCE IS *
* GOVERNED BY A BSD-STYLE SOURCE LICENSE INCLUDED WITH THIS SOURCE *
* IN 'COPYING'. PLEASE READ THESE TERMS BEFORE DISTRIBUTING. *
* *
* THE OggVorbis SOURCE CODE IS (C) COPYRIGHT 1994-2002 *
* by the Xiph.Org Foundation http://www.xiph.org/ *
* *
********************************************************************
function: packing variable sized words into an octet stream
last mod: $Id: kate_bitwise.c,v 1.3 2008/08/05 20:14:21 lyrian Exp $
********************************************************************/
/* We're 'LSb' endian; if we write a word but read individual bits,
then we'll read the lsb first */
#define KATE_INTERNAL
#include "kate_internal.h"
#ifdef HAVE_STRING_H
#include <string.h>
#endif
#ifdef HAVE_STDLIB_H
#include <stdlib.h>
#endif
#include "kate_bitwise.h"
#define BUFFER_INCREMENT 256
static const unsigned long mask[]=
{0x00000000,0x00000001,0x00000003,0x00000007,0x0000000f,
0x0000001f,0x0000003f,0x0000007f,0x000000ff,0x000001ff,
0x000003ff,0x000007ff,0x00000fff,0x00001fff,0x00003fff,
0x00007fff,0x0000ffff,0x0001ffff,0x0003ffff,0x0007ffff,
0x000fffff,0x001fffff,0x003fffff,0x007fffff,0x00ffffff,
0x01ffffff,0x03ffffff,0x07ffffff,0x0fffffff,0x1fffffff,
0x3fffffff,0x7fffffff,0xffffffff };
void kate_pack_writeinit(kate_pack_buffer *b){
memset(b,0,sizeof(*b));
b->ptr=b->buffer=kate_malloc(BUFFER_INCREMENT);
b->buffer[0]='\0';
b->storage=BUFFER_INCREMENT;
}
void kate_pack_writetrunc(kate_pack_buffer *b,long bits){
long bytes=bits>>3;
bits-=bytes*8;
b->ptr=b->buffer+bytes;
b->endbit=bits;
b->endbyte=bytes;
*b->ptr&=mask[bits];
}
/* Takes only up to 32 bits. */
void kate_pack_write(kate_pack_buffer *b,unsigned long value,int bits){
if(b->endbyte+4>=b->storage){
b->buffer=kate_realloc(b->buffer,b->storage+BUFFER_INCREMENT);
b->storage+=BUFFER_INCREMENT;
b->ptr=b->buffer+b->endbyte;
}
value&=mask[bits];
bits+=b->endbit;
b->ptr[0]|=value<<b->endbit;
if(bits>=8){
b->ptr[1]=(unsigned char)(value>>(8-b->endbit));
if(bits>=16){
b->ptr[2]=(unsigned char)(value>>(16-b->endbit));
if(bits>=24){
b->ptr[3]=(unsigned char)(value>>(24-b->endbit));
if(bits>=32){
if(b->endbit)
b->ptr[4]=(unsigned char)(value>>(32-b->endbit));
else
b->ptr[4]=0;
}
}
}
}
b->endbyte+=bits/8;
b->ptr+=bits/8;
b->endbit=bits&7;
}
void kate_pack_writealign(kate_pack_buffer *b){
int bits=8-b->endbit;
if(bits<8)
kate_pack_write(b,0,bits);
}
static void kate_pack_writecopy_helper(kate_pack_buffer *b,
void *source,
long bits,
void (*w)(kate_pack_buffer *,
unsigned long,
int),
int msb){
unsigned char *ptr=(unsigned char *)source;
long bytes=bits/8;
bits-=bytes*8;
if(b->endbit){
int i;
/* unaligned copy. Do it the hard way. */
for(i=0;i<bytes;i++)
w(b,(unsigned long)(ptr[i]),8);
}else{
/* aligned block copy */
if(b->endbyte+bytes+1>=b->storage){
b->storage=b->endbyte+bytes+BUFFER_INCREMENT;
b->buffer=kate_realloc(b->buffer,b->storage);
b->ptr=b->buffer+b->endbyte;
}
memmove(b->ptr,source,bytes);
b->ptr+=bytes;
b->endbyte+=bytes;
*b->ptr=0;
}
if(bits){
if(msb)
w(b,(unsigned long)(ptr[bytes]>>(8-bits)),bits);
else
w(b,(unsigned long)(ptr[bytes]),bits);
}
}
void kate_pack_writecopy(kate_pack_buffer *b,void *source,long bits){
kate_pack_writecopy_helper(b,source,bits,kate_pack_write,0);
}
void kate_pack_reset(kate_pack_buffer *b){
b->ptr=b->buffer;
b->buffer[0]=0;
b->endbit=b->endbyte=0;
}
void kate_pack_writeclear(kate_pack_buffer *b){
kate_free(b->buffer);
memset(b,0,sizeof(*b));
}
void kate_pack_readinit(kate_pack_buffer *b,unsigned char *buf,int bytes){
memset(b,0,sizeof(*b));
b->buffer=b->ptr=buf;
b->storage=bytes;
}
/* Read in bits without advancing the bitptr; bits <= 32 */
long kate_pack_look(kate_pack_buffer *b,int bits){
unsigned long ret;
unsigned long m=mask[bits];
bits+=b->endbit;
if(b->endbyte+4>=b->storage){
/* not the main path */
if(b->endbyte*8+bits>b->storage*8)return(-1);
}
ret=b->ptr[0]>>b->endbit;
if(bits>8){
ret|=b->ptr[1]<<(8-b->endbit);
if(bits>16){
ret|=b->ptr[2]<<(16-b->endbit);
if(bits>24){
ret|=b->ptr[3]<<(24-b->endbit);
if(bits>32 && b->endbit)
ret|=b->ptr[4]<<(32-b->endbit);
}
}
}
return(m&ret);
}
long kate_pack_look1(kate_pack_buffer *b){
if(b->endbyte>=b->storage)return(-1);
return((b->ptr[0]>>b->endbit)&1);
}
void kate_pack_adv(kate_pack_buffer *b,int bits){
bits+=b->endbit;
b->ptr+=bits/8;
b->endbyte+=bits/8;
b->endbit=bits&7;
}
void kate_pack_adv1(kate_pack_buffer *b){
if(++(b->endbit)>7){
b->endbit=0;
b->ptr++;
b->endbyte++;
}
}
/* bits <= 32 */
long kate_pack_read(kate_pack_buffer *b,int bits){
long ret;
unsigned long m=mask[bits];
bits+=b->endbit;
if(b->endbyte+4>=b->storage){
/* not the main path */
ret=-1L;
if(b->endbyte*8+bits>b->storage*8)goto overflow;
}
ret=b->ptr[0]>>b->endbit;
if(bits>8){
ret|=b->ptr[1]<<(8-b->endbit);
if(bits>16){
ret|=b->ptr[2]<<(16-b->endbit);
if(bits>24){
ret|=b->ptr[3]<<(24-b->endbit);
if(bits>32 && b->endbit){
ret|=b->ptr[4]<<(32-b->endbit);
}
}
}
}
ret&=m;
overflow:
b->ptr+=bits/8;
b->endbyte+=bits/8;
b->endbit=bits&7;
return(ret);
}
long kate_pack_read1(kate_pack_buffer *b){
long ret;
if(b->endbyte>=b->storage){
/* not the main path */
ret=-1L;
goto overflow;
}
ret=(b->ptr[0]>>b->endbit)&1;
overflow:
b->endbit++;
if(b->endbit>7){
b->endbit=0;
b->ptr++;
b->endbyte++;
}
return(ret);
}
long kate_pack_bytes(kate_pack_buffer *b){
return(b->endbyte+(b->endbit+7)/8);
}
long kate_pack_bits(kate_pack_buffer *b){
return(b->endbyte*8+b->endbit);
}
unsigned char *kate_pack_get_buffer(kate_pack_buffer *b){
return(b->buffer);
}
long kate_pack_readable_bits(kate_pack_buffer *b){
return b->storage*8-kate_pack_bits(b);
}
#undef BUFFER_INCREMENT
|