ref: 3a77c01f43821dcc4f7cae54aff89bb20f2d95a5
dir: /sys/src/cmd/audio/libogg/bitwise.c/
/********************************************************************
* *
* 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: bitwise.c,v 1.13 2002/07/11 09:09:08 xiphmont Exp $
********************************************************************/
/* We're 'LSb' endian; if we write a word but read individual bits,
then we'll read the lsb first */
#include <string.h>
#include <stdlib.h>
#include <ogg/ogg.h>
#define BUFFER_INCREMENT 256
static 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 oggpack_writeinit(oggpack_buffer *b){
memset(b,0,sizeof(*b));
b->ptr=b->buffer=_ogg_malloc(BUFFER_INCREMENT);
b->buffer[0]='\0';
b->storage=BUFFER_INCREMENT;
}
void oggpack_writetrunc(oggpack_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];
}
void oggpack_writealign(oggpack_buffer *b){
int bits=8-b->endbit;
if(bits<8)
oggpack_write(b,0,bits);
}
void oggpack_writecopy(oggpack_buffer *b,void *source,long bits){
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++)
oggpack_write(b,(long)(ptr[i]),8);
}else{
/* aligned block copy */
if(b->endbyte+bytes+1>=b->storage){
b->storage=b->endbyte+bytes+BUFFER_INCREMENT;
b->buffer=_ogg_realloc(b->buffer,b->storage);
b->ptr=b->buffer+b->endbyte;
}
memmove(b->ptr,source,bytes);
b->ptr+=bytes;
b->buffer+=bytes;
*b->ptr=0;
}
if(bits)
oggpack_write(b,(long)(ptr[bytes]),bits);
}
void oggpack_reset(oggpack_buffer *b){
b->ptr=b->buffer;
b->buffer[0]=0;
b->endbit=b->endbyte=0;
}
void oggpack_writeclear(oggpack_buffer *b){
_ogg_free(b->buffer);
memset(b,0,sizeof(*b));
}
void oggpack_readinit(oggpack_buffer *b,unsigned char *buf,int bytes){
memset(b,0,sizeof(*b));
b->buffer=b->ptr=buf;
b->storage=bytes;
}
/* Takes only up to 32 bits. */
void oggpack_write(oggpack_buffer *b,unsigned long value,int bits){
if(b->endbyte+4>=b->storage){
b->buffer=_ogg_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]=value>>(8-b->endbit);
if(bits>=16){
b->ptr[2]=value>>(16-b->endbit);
if(bits>=24){
b->ptr[3]=value>>(24-b->endbit);
if(bits>=32){
if(b->endbit)
b->ptr[4]=value>>(32-b->endbit);
else
b->ptr[4]=0;
}
}
}
}
b->endbyte+=bits/8;
b->ptr+=bits/8;
b->endbit=bits&7;
}
/* Read in bits without advancing the bitptr; bits <= 32 */
long oggpack_look(oggpack_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 oggpack_look1(oggpack_buffer *b){
if(b->endbyte>=b->storage)return(-1);
return((b->ptr[0]>>b->endbit)&1);
}
void oggpack_adv(oggpack_buffer *b,int bits){
bits+=b->endbit;
b->ptr+=bits/8;
b->endbyte+=bits/8;
b->endbit=bits&7;
}
void oggpack_adv1(oggpack_buffer *b){
if(++(b->endbit)>7){
b->endbit=0;
b->ptr++;
b->endbyte++;
}
}
/* bits <= 32 */
long oggpack_read(oggpack_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 */
ret=-1UL;
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 oggpack_read1(oggpack_buffer *b){
unsigned long ret;
if(b->endbyte>=b->storage){
/* not the main path */
ret=-1UL;
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 oggpack_bytes(oggpack_buffer *b){
return(b->endbyte+(b->endbit+7)/8);
}
long oggpack_bits(oggpack_buffer *b){
return(b->endbyte*8+b->endbit);
}
unsigned char *oggpack_get_buffer(oggpack_buffer *b){
return(b->buffer);
}
/* Self test of the bitwise routines; everything else is based on
them, so they damned well better be solid. */
#ifdef _V_SELFTEST
#include <stdio.h>
static int ilog(unsigned int v){
int ret=0;
while(v){
ret++;
v>>=1;
}
return(ret);
}
oggpack_buffer o;
oggpack_buffer r;
void report(char *in){
fprintf(stderr,"%s",in);
exit(1);
}
void cliptest(unsigned long *b,int vals,int bits,int *comp,int compsize){
long bytes,i;
unsigned char *buffer;
oggpack_reset(&o);
for(i=0;i<vals;i++)
oggpack_write(&o,b[i],bits?bits:ilog(b[i]));
buffer=oggpack_get_buffer(&o);
bytes=oggpack_bytes(&o);
if(bytes!=compsize)report("wrong number of bytes!\n");
for(i=0;i<bytes;i++)if(buffer[i]!=comp[i]){
for(i=0;i<bytes;i++)fprintf(stderr,"%x %x\n",(int)buffer[i],(int)comp[i]);
report("wrote incorrect value!\n");
}
oggpack_readinit(&r,buffer,bytes);
for(i=0;i<vals;i++){
int tbit=bits?bits:ilog(b[i]);
if(oggpack_look(&r,tbit)==-1)
report("out of data!\n");
if(oggpack_look(&r,tbit)!=(b[i]&mask[tbit]))
report("looked at incorrect value!\n");
if(tbit==1)
if(oggpack_look1(&r)!=(b[i]&mask[tbit]))
report("looked at single bit incorrect value!\n");
if(tbit==1){
if(oggpack_read1(&r)!=(b[i]&mask[tbit]))
report("read incorrect single bit value!\n");
}else{
if(oggpack_read(&r,tbit)!=(b[i]&mask[tbit]))
report("read incorrect value!\n");
}
}
if(oggpack_bytes(&r)!=bytes)report("leftover bytes after read!\n");
}
int main(void){
unsigned char *buffer;
long bytes,i;
static unsigned long testbuffer1[]=
{18,12,103948,4325,543,76,432,52,3,65,4,56,32,42,34,21,1,23,32,546,456,7,
567,56,8,8,55,3,52,342,341,4,265,7,67,86,2199,21,7,1,5,1,4};
int test1size=43;
static unsigned long testbuffer2[]=
{216531625L,1237861823,56732452,131,3212421,12325343,34547562,12313212,
1233432,534,5,346435231,14436467,7869299,76326614,167548585,
85525151,0,12321,1,349528352};
int test2size=21;
static unsigned long large[]=
{2136531625L,2137861823,56732452,131,3212421,12325343,34547562,12313212,
1233432,534,5,2146435231,14436467,7869299,76326614,167548585,
85525151,0,12321,1,2146528352};
static unsigned long testbuffer3[]=
{1,0,14,0,1,0,12,0,1,0,0,0,1,1,0,1,0,1,0,1,0,1,0,1,0,1,0,0,1,1,1,1,1,0,0,1,
0,1,30,1,1,1,0,0,1,0,0,0,12,0,11,0,1,0,0,1};
int test3size=56;
int onesize=33;
static int one[]={146,25,44,151,195,15,153,176,233,131,196,65,85,172,47,40,
34,242,223,136,35,222,211,86,171,50,225,135,214,75,172,
223,4};
int twosize=6;
static int two[]={61,255,255,251,231,29};
int threesize=54;
static int three[]={169,2,232,252,91,132,156,36,89,13,123,176,144,32,254,
142,224,85,59,121,144,79,124,23,67,90,90,216,79,23,83,
58,135,196,61,55,129,183,54,101,100,170,37,127,126,10,
100,52,4,14,18,86,77,1};
int foursize=38;
static int four[]={18,6,163,252,97,194,104,131,32,1,7,82,137,42,129,11,72,
132,60,220,112,8,196,109,64,179,86,9,137,195,208,122,169,
28,2,133,0,1};
int fivesize=45;
static int five[]={169,2,126,139,144,172,30,4,80,72,240,59,130,218,73,62,
241,24,210,44,4,20,0,248,116,49,135,100,110,130,181,169,
84,75,159,2,1,0,132,192,8,0,0,18,22};
int sixsize=7;
static int six[]={17,177,170,242,169,19,148};
/* Test read/write together */
/* Later we test against pregenerated bitstreams */
oggpack_writeinit(&o);
fprintf(stderr,"\nSmall preclipped packing: ");
cliptest(testbuffer1,test1size,0,one,onesize);
fprintf(stderr,"ok.");
fprintf(stderr,"\nNull bit call: ");
cliptest(testbuffer3,test3size,0,two,twosize);
fprintf(stderr,"ok.");
fprintf(stderr,"\nLarge preclipped packing: ");
cliptest(testbuffer2,test2size,0,three,threesize);
fprintf(stderr,"ok.");
fprintf(stderr,"\n32 bit preclipped packing: ");
oggpack_reset(&o);
for(i=0;i<test2size;i++)
oggpack_write(&o,large[i],32);
buffer=oggpack_get_buffer(&o);
bytes=oggpack_bytes(&o);
oggpack_readinit(&r,buffer,bytes);
for(i=0;i<test2size;i++){
if(oggpack_look(&r,32)==-1)report("out of data. failed!");
if(oggpack_look(&r,32)!=large[i]){
fprintf(stderr,"%ld != %ld (%lx!=%lx):",oggpack_look(&r,32),large[i],
oggpack_look(&r,32),large[i]);
report("read incorrect value!\n");
}
oggpack_adv(&r,32);
}
if(oggpack_bytes(&r)!=bytes)report("leftover bytes after read!\n");
fprintf(stderr,"ok.");
fprintf(stderr,"\nSmall unclipped packing: ");
cliptest(testbuffer1,test1size,7,four,foursize);
fprintf(stderr,"ok.");
fprintf(stderr,"\nLarge unclipped packing: ");
cliptest(testbuffer2,test2size,17,five,fivesize);
fprintf(stderr,"ok.");
fprintf(stderr,"\nSingle bit unclipped packing: ");
cliptest(testbuffer3,test3size,1,six,sixsize);
fprintf(stderr,"ok.");
fprintf(stderr,"\nTesting read past end: ");
oggpack_readinit(&r,"\0\0\0\0\0\0\0\0",8);
for(i=0;i<64;i++){
if(oggpack_read(&r,1)!=0){
fprintf(stderr,"failed; got -1 prematurely.\n");
exit(1);
}
}
if(oggpack_look(&r,1)!=-1 ||
oggpack_read(&r,1)!=-1){
fprintf(stderr,"failed; read past end without -1.\n");
exit(1);
}
oggpack_readinit(&r,"\0\0\0\0\0\0\0\0",8);
if(oggpack_read(&r,30)!=0 || oggpack_read(&r,16)!=0){
fprintf(stderr,"failed 2; got -1 prematurely.\n");
exit(1);
}
if(oggpack_look(&r,18)!=0 ||
oggpack_look(&r,18)!=0){
fprintf(stderr,"failed 3; got -1 prematurely.\n");
exit(1);
}
if(oggpack_look(&r,19)!=-1 ||
oggpack_look(&r,19)!=-1){
fprintf(stderr,"failed; read past end without -1.\n");
exit(1);
}
if(oggpack_look(&r,32)!=-1 ||
oggpack_look(&r,32)!=-1){
fprintf(stderr,"failed; read past end without -1.\n");
exit(1);
}
fprintf(stderr,"ok.\n\n");
return(0);
}
#endif /* _V_SELFTEST */
#undef BUFFER_INCREMENT