diff options
Diffstat (limited to 'bitwise.c')
-rw-r--r-- | bitwise.c | 675 |
1 files changed, 675 insertions, 0 deletions
diff --git a/bitwise.c b/bitwise.c new file mode 100644 index 0000000..e193957 --- /dev/null +++ b/bitwise.c @@ -0,0 +1,675 @@ +/******************************************************************** + * * + * THIS FILE IS PART OF THE OggVorbis 'TREMOR' 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 'TREMOR' SOURCE CODE IS (C) COPYRIGHT 1994-2003 * + * BY THE Xiph.Org FOUNDATION http://www.xiph.org/ * + * * + ******************************************************************** + + function: packing variable sized words into an octet stream + + ********************************************************************/ + +/* 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 "misc.h" +#include "ogg.h" + +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 }; + +/* spans forward, skipping as many bytes as headend is negative; if + headend is zero, simply finds next byte. If we're up to the end + of the buffer, leaves headend at zero. If we've read past the end, + halt the decode process. */ + +static void _span(oggpack_buffer *b){ + while(b->headend-(b->headbit>>3)<1){ + b->headend-=b->headbit>>3; + b->headbit&=0x7; + + if(b->head->next){ + b->count+=b->head->length; + b->head=b->head->next; + + if(b->headend+b->head->length>0) + b->headptr=b->head->buffer->data+b->head->begin-b->headend; + + b->headend+=b->head->length; + }else{ + /* we've either met the end of decode, or gone past it. halt + only if we're past */ + if(b->headend*8<b->headbit) + /* read has fallen off the end */ + b->headend=-1; + break; + } + } +} + +void oggpack_readinit(oggpack_buffer *b,ogg_reference *r){ + memset(b,0,sizeof(*b)); + + b->tail=b->head=r; + b->count=0; + b->headptr=b->head->buffer->data+b->head->begin; + b->headend=b->head->length; + _span(b); +} + +#define _lookspan() while(!end){\ + head=head->next;\ + if(!head) return -1;\ + ptr=head->buffer->data + head->begin;\ + end=head->length;\ + } + +/* Read in bits without advancing the bitptr; bits <= 32 */ +long oggpack_look(oggpack_buffer *b,int bits){ + unsigned long m=mask[bits]; + unsigned long ret; + + bits+=b->headbit; + + if(bits >= b->headend<<3){ + int end=b->headend; + unsigned char *ptr=b->headptr; + ogg_reference *head=b->head; + + if(end<0)return -1; + + if(bits){ + _lookspan(); + ret=*ptr++>>b->headbit; + if(bits>8){ + --end; + _lookspan(); + ret|=*ptr++<<(8-b->headbit); + if(bits>16){ + --end; + _lookspan(); + ret|=*ptr++<<(16-b->headbit); + if(bits>24){ + --end; + _lookspan(); + ret|=*ptr++<<(24-b->headbit); + if(bits>32 && b->headbit){ + --end; + _lookspan(); + ret|=*ptr<<(32-b->headbit); + } + } + } + } + } + + }else{ + + /* make this a switch jump-table */ + ret=b->headptr[0]>>b->headbit; + if(bits>8){ + ret|=b->headptr[1]<<(8-b->headbit); + if(bits>16){ + ret|=b->headptr[2]<<(16-b->headbit); + if(bits>24){ + ret|=b->headptr[3]<<(24-b->headbit); + if(bits>32 && b->headbit) + ret|=b->headptr[4]<<(32-b->headbit); + } + } + } + } + + ret&=m; + return ret; +} + +/* limited to 32 at a time */ +void oggpack_adv(oggpack_buffer *b,int bits){ + bits+=b->headbit; + b->headbit=bits&7; + b->headend-=(bits>>3); + b->headptr+=(bits>>3); + if(b->headend<1)_span(b); +} + +int oggpack_eop(oggpack_buffer *b){ + if(b->headend<0)return -1; + return 0; +} + +/* bits <= 32 */ +long oggpack_read(oggpack_buffer *b,int bits){ + long ret=oggpack_look(b,bits); + oggpack_adv(b,bits); + return(ret); +} + +long oggpack_bytes(oggpack_buffer *b){ + if(b->headend<0)return b->count+b->head->length; + return b->count + b->head->length-b->headend + + (b->headbit+7)/8; +} + +long oggpack_bits(oggpack_buffer *b){ + if(b->headend<0)return (b->count+b->head->length)*8; + return (b->count + b->head->length-b->headend)*8 + + b->headbit; +} + +/* Self test of the bitwise routines; everything else is based on + them, so they damned well better be solid. */ + +#ifdef _V_BIT_TEST +#include <string.h> +#include <stdlib.h> +#include <stdio.h> +#include "framing.c" + +static int ilog(unsigned long v){ + int ret=0; + while(v){ + ret++; + v>>=1; + } + return(ret); +} + +oggpack_buffer r; +oggpack_buffer o; +ogg_buffer_state *bs; +ogg_reference *or; +#define TESTWORDS 256 + +void report(char *in){ + fprintf(stderr,"%s",in); + exit(1); +} + +int getbyte(ogg_reference *or,int position){ + while(or && position>=or->length){ + position-=or->length; + or=or->next; + if(or==NULL){ + fprintf(stderr,"\n\tERROR: getbyte ran off end of buffer.\n"); + exit(1); + } + } + + if((position+or->begin)&1) + return (or->buffer->data[(position+or->begin)>>1])&0xff; + else + return (or->buffer->data[(position+or->begin)>>1]>>8)&0xff; +} + +void cliptest(unsigned long *b,int vals,int bits,int *comp,int compsize){ + long i,bitcount=0; + ogg_reference *or=ogg_buffer_alloc(bs,64); + for(i=0;i<compsize;i++) + or->buffer->data[i]= comp[i]; + or->length=i; + + oggpack_readinit(&r,or); + for(i=0;i<vals;i++){ + unsigned long test; + int tbit=bits?bits:ilog(b[i]); + if((test=oggpack_look(&r,tbit))==0xffffffff) + report("out of data!\n"); + if(test!=(b[i]&mask[tbit])){ + fprintf(stderr,"%ld) %lx %lx\n",i,(b[i]&mask[tbit]),test); + report("looked at incorrect value!\n"); + } + if((test=oggpack_read(&r,tbit))==0xffffffff){ + report("premature end of data when reading!\n"); + } + if(test!=(b[i]&mask[tbit])){ + fprintf(stderr,"%ld) %lx %lx\n",i,(b[i]&mask[tbit]),test); + report("read incorrect value!\n"); + } + bitcount+=tbit; + + if(bitcount!=oggpack_bits(&r)) + report("wrong number of bits while reading!\n"); + if((bitcount+7)/8!=oggpack_bytes(&r)) + report("wrong number of bytes while reading!\n"); + + } + if(oggpack_bytes(&r)!=(bitcount+7)/8)report("leftover bytes after read!\n"); + ogg_buffer_release(or); +} + +void _end_verify(int count){ + int i; + + /* are the proper number of bits left over? */ + int leftover=count*8-oggpack_bits(&o); + if(leftover>7) + report("\nERROR: too many bits reported left over.\n"); + + /* does reading to exactly byte alignment *not* trip EOF? */ + if(oggpack_read(&o,leftover)==-1) + report("\nERROR: read to but not past exact end tripped EOF.\n"); + if(oggpack_bits(&o)!=count*8) + report("\nERROR: read to but not past exact end reported bad bitcount.\n"); + + /* does EOF trip properly after a single additional bit? */ + if(oggpack_read(&o,1)!=-1) + report("\nERROR: read past exact end did not trip EOF.\n"); + if(oggpack_bits(&o)!=count*8) + report("\nERROR: read past exact end reported bad bitcount.\n"); + + /* does EOF stay set over additional bit reads? */ + for(i=0;i<=32;i++){ + if(oggpack_read(&o,i)!=-1) + report("\nERROR: EOF did not stay set on stream.\n"); + if(oggpack_bits(&o)!=count*8) + report("\nERROR: read past exact end reported bad bitcount.\n"); + } +} + +void _end_verify2(int count){ + int i; + + /* are the proper number of bits left over? */ + int leftover=count*8-oggpack_bits(&o); + if(leftover>7) + report("\nERROR: too many bits reported left over.\n"); + + /* does reading to exactly byte alignment *not* trip EOF? */ + oggpack_adv(&o,leftover); + if(o.headend!=0) + report("\nERROR: read to but not past exact end tripped EOF.\n"); + if(oggpack_bits(&o)!=count*8) + report("\nERROR: read to but not past exact end reported bad bitcount.\n"); + + /* does EOF trip properly after a single additional bit? */ + oggpack_adv(&o,1); + if(o.headend>=0) + report("\nERROR: read past exact end did not trip EOF.\n"); + if(oggpack_bits(&o)!=count*8) + report("\nERROR: read past exact end reported bad bitcount.\n"); + + /* does EOF stay set over additional bit reads? */ + for(i=0;i<=32;i++){ + oggpack_adv(&o,i); + if(o.headend>=0) + report("\nERROR: EOF did not stay set on stream.\n"); + if(oggpack_bits(&o)!=count*8) + report("\nERROR: read past exact end reported bad bitcount.\n"); + } +} + +long ogg_buffer_length(ogg_reference *or){ + int count=0; + while(or){ + count+=or->length; + or=or->next; + } + return count; +} + +ogg_reference *ogg_buffer_extend(ogg_reference *or,long bytes){ + if(or){ + while(or->next){ + or=or->next; + } + or->next=ogg_buffer_alloc(or->buffer->ptr.owner,bytes); + return(or->next); + } + return 0; +} + +void ogg_buffer_posttruncate(ogg_reference *or,long pos){ + /* walk to the point where we want to begin truncate */ + while(or && pos>or->length){ + pos-=or->length; + or=or->next; + } + if(or){ + ogg_buffer_release(or->next); + or->next=0; + or->length=pos; + } +} + +int main(void){ + long 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 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; + + 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}; + + int onesize=33; + static int one[33]={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[6]={61,255,255,251,231,29}; + + int threesize=54; + static int three[54]={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[38]={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[45]={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[7]={17,177,170,242,169,19,148}; + + /* Test read/write together */ + /* Later we test against pregenerated bitstreams */ + bs=ogg_buffer_create(); + + fprintf(stderr,"\nSmall preclipped packing (LSb): "); + cliptest(testbuffer1,test1size,0,one,onesize); + fprintf(stderr,"ok."); + + fprintf(stderr,"\nNull bit call (LSb): "); + cliptest(testbuffer3,test3size,0,two,twosize); + fprintf(stderr,"ok."); + + fprintf(stderr,"\nLarge preclipped packing (LSb): "); + cliptest(testbuffer2,test2size,0,three,threesize); + fprintf(stderr,"ok."); + + fprintf(stderr,"\n32 bit preclipped packing (LSb): "); + + or=ogg_buffer_alloc(bs,128); + for(i=0;i<test2size;i++){ + or->buffer->data[i*4] = large[i]&0xff; + or->buffer->data[i*4+1] = (large[i]>>8)&0xff; + or->buffer->data[i*4+2] = (large[i]>>16)&0xff; + or->buffer->data[i*4+3] = (large[i]>>24)&0xff; + } + or->length=test2size*4; + oggpack_readinit(&r,or); + for(i=0;i<test2size;i++){ + unsigned long test; + if((test=oggpack_look(&r,32))==0xffffffffUL)report("out of data. failed!"); + if(test!=large[i]){ + fprintf(stderr,"%ld != %ld (%lx!=%lx):",test,large[i], + test,large[i]); + report("read incorrect value!\n"); + } + oggpack_adv(&r,32); + } + ogg_buffer_release(or); + if(oggpack_bytes(&r)!=test2size*4)report("leftover bytes after read!\n"); + fprintf(stderr,"ok."); + + fprintf(stderr,"\nSmall unclipped packing (LSb): "); + cliptest(testbuffer1,test1size,7,four,foursize); + fprintf(stderr,"ok."); + + fprintf(stderr,"\nLarge unclipped packing (LSb): "); + cliptest(testbuffer2,test2size,17,five,fivesize); + fprintf(stderr,"ok."); + + fprintf(stderr,"\nSingle bit unclipped packing (LSb): "); + cliptest(testbuffer3,test3size,1,six,sixsize); + fprintf(stderr,"ok."); + + fprintf(stderr,"\nTesting read past end (LSb): "); + { + unsigned char dda[]={0,0,0,0}; + ogg_buffer lob={dda,8,0,{0}}; + ogg_reference lor={&lob,0,8,0}; + + oggpack_readinit(&r,&lor); + 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); + } + } + { + unsigned char dda[]={0,0,0,0}; + ogg_buffer lob={dda,8,0,{0}}; + ogg_reference lor={&lob,0,8,0}; + unsigned long test; + + oggpack_readinit(&r,&lor); + if((test=oggpack_read(&r,30))==0xffffffffUL || + (test=oggpack_read(&r,16))==0xffffffffUL){ + fprintf(stderr,"failed 2; got -1 prematurely.\n"); + exit(1); + } + + if((test=oggpack_look(&r,18))==0xffffffffUL){ + fprintf(stderr,"failed 3; got -1 prematurely.\n"); + exit(1); + } + if((test=oggpack_look(&r,19))!=0xffffffffUL){ + fprintf(stderr,"failed; read past end without -1.\n"); + exit(1); + } + if((test=oggpack_look(&r,32))!=0xffffffffUL){ + fprintf(stderr,"failed; read past end without -1.\n"); + exit(1); + } + } + fprintf(stderr,"ok.\n"); + + /* now the scary shit: randomized testing */ + + for(i=0;i<10000;i++){ + long j,count=0,count2=0,bitcount=0; + unsigned long values[TESTWORDS]; + int len[TESTWORDS]; + unsigned char flat[4*TESTWORDS]; /* max possible needed size */ + + memset(flat,0,sizeof(flat)); + fprintf(stderr,"\rRandomized testing (LSb)... (%ld) ",10000-i); + + /* generate a list of words and lengths */ + /* write the required number of bits out to packbuffer */ + { + long word=0; + long bit=0; + int k; + + for(j=0;j<TESTWORDS;j++){ + values[j]=rand(); + len[j]=(rand()%33); + + for(k=0;k<len[j];k++){ + flat[word] |= ((values[j]>>k)&0x1)<<bit; + bit++; + bitcount++; + if(bit>7){ + bit=0; + word++; + } + } + } + } + count2=(bitcount+7)>>3; + + /* construct random-length buffer chain from flat vector; random + byte starting offset within the length of the vector */ + { + ogg_reference *or=NULL,*orl=NULL; + long pos=0; + + /* build buffer chain */ + while(count2){ + int ilen=(rand()%32),k; + int ibegin=(rand()%32); + + + if(ilen>count2)ilen=count2; + + if(or) + orl=ogg_buffer_extend(orl,64); + else + or=orl=ogg_buffer_alloc(bs,64); + + orl->length=ilen; + orl->begin=ibegin; + + for(k=0;k<ilen;k++) + orl->buffer->data[ibegin++]= flat[pos++]; + + count2-=ilen; + } + + if(ogg_buffer_length(or)!=(bitcount+7)/8){ + fprintf(stderr,"\nERROR: buffer length incorrect after build.\n"); + exit(1); + } + + + { + int begin=0; //=(rand()%TESTWORDS); + int ilen=(rand()%(TESTWORDS-begin)); + int bitoffset,bitcount=0; + unsigned long temp; + + for(j=0;j<begin;j++) + bitcount+=len[j]; + or=ogg_buffer_pretruncate(or,bitcount/8); + bitoffset=bitcount%=8; + for(;j<begin+ilen;j++) + bitcount+=len[j]; + ogg_buffer_posttruncate(or,((bitcount+7)/8)); + + if((count=ogg_buffer_length(or))!=(bitcount+7)/8){ + fprintf(stderr,"\nERROR: buffer length incorrect after truncate.\n"); + exit(1); + } + + oggpack_readinit(&o,or); + + /* verify bit count */ + if(oggpack_bits(&o)!=0){ + fprintf(stderr,"\nERROR: Read bitcounter not zero!\n"); + exit(1); + } + if(oggpack_bytes(&o)!=0){ + fprintf(stderr,"\nERROR: Read bytecounter not zero!\n"); + exit(1); + } + + bitcount=bitoffset; + oggpack_read(&o,bitoffset); + + /* read and compare to original list */ + for(j=begin;j<begin+ilen;j++){ + temp=oggpack_read(&o,len[j]); + if(temp==0xffffffffUL){ + fprintf(stderr,"\nERROR: End of stream too soon! word: %ld,%d\n", + j-begin,ilen); + exit(1); + } + if(temp!=(values[j]&mask[len[j]])){ + fprintf(stderr,"\nERROR: Incorrect read %lx != %lx, word %ld, len %d\n" +, + values[j]&mask[len[j]],temp,j-begin,len[j]); + exit(1); + } + bitcount+=len[j]; + if(oggpack_bits(&o)!=bitcount){ + fprintf(stderr,"\nERROR: Read bitcounter %d != %ld!\n", + bitcount,oggpack_bits(&o)); + exit(1); + } + if(oggpack_bytes(&o)!=(bitcount+7)/8){ + fprintf(stderr,"\nERROR: Read bytecounter %d != %ld!\n", + (bitcount+7)/8,oggpack_bytes(&o)); + exit(1); + } + + } + _end_verify(count); + + /* look/adv version */ + oggpack_readinit(&o,or); + bitcount=bitoffset; + oggpack_adv(&o,bitoffset); + + /* read and compare to original list */ + for(j=begin;j<begin+ilen;j++){ + temp=oggpack_look(&o,len[j]); + + if(temp==0xffffffffUL){ + fprintf(stderr,"\nERROR: End of stream too soon! word: %ld\n", + j-begin); + exit(1); + } + if(temp!=(values[j]&mask[len[j]])){ + fprintf(stderr,"\nERROR: Incorrect look %lx != %lx, word %ld, len %d\n" +, + values[j]&mask[len[j]],temp,j-begin,len[j]); + exit(1); + } + oggpack_adv(&o,len[j]); + bitcount+=len[j]; + if(oggpack_bits(&o)!=bitcount){ + fprintf(stderr,"\nERROR: Look/Adv bitcounter %d != %ld!\n", + bitcount,oggpack_bits(&o)); + exit(1); + } + if(oggpack_bytes(&o)!=(bitcount+7)/8){ + fprintf(stderr,"\nERROR: Look/Adv bytecounter %d != %ld!\n", + (bitcount+7)/8,oggpack_bytes(&o)); + exit(1); + } + + } + _end_verify2(count); + + } + ogg_buffer_release(or); + } + } + fprintf(stderr,"\rRandomized testing (LSb)... ok. \n"); + + return(0); +} +#endif |