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Diffstat (limited to 'lib/codebook.c')
| -rw-r--r-- | lib/codebook.c | 461 |
1 files changed, 461 insertions, 0 deletions
diff --git a/lib/codebook.c b/lib/codebook.c new file mode 100644 index 0000000..78672e2 --- /dev/null +++ b/lib/codebook.c @@ -0,0 +1,461 @@ +/******************************************************************** + * * + * 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 1994-2015 * + * by the Xiph.Org Foundation http://www.xiph.org/ * + * * + ******************************************************************** + + function: basic codebook pack/unpack/code/decode operations + + ********************************************************************/ + +#include <stdlib.h> +#include <string.h> +#include <math.h> +#include <ogg/ogg.h> +#include "vorbis/codec.h" +#include "codebook.h" +#include "scales.h" +#include "misc.h" +#include "os.h" + +/* packs the given codebook into the bitstream **************************/ + +int vorbis_staticbook_pack(const static_codebook *c,oggpack_buffer *opb){ + long i,j; + int ordered=0; + + /* first the basic parameters */ + oggpack_write(opb,0x564342,24); + oggpack_write(opb,c->dim,16); + oggpack_write(opb,c->entries,24); + + /* pack the codewords. There are two packings; length ordered and + length random. Decide between the two now. */ + + for(i=1;i<c->entries;i++) + if(c->lengthlist[i-1]==0 || c->lengthlist[i]<c->lengthlist[i-1])break; + if(i==c->entries)ordered=1; + + if(ordered){ + /* length ordered. We only need to say how many codewords of + each length. The actual codewords are generated + deterministically */ + + long count=0; + oggpack_write(opb,1,1); /* ordered */ + oggpack_write(opb,c->lengthlist[0]-1,5); /* 1 to 32 */ + + for(i=1;i<c->entries;i++){ + char this=c->lengthlist[i]; + char last=c->lengthlist[i-1]; + if(this>last){ + for(j=last;j<this;j++){ + oggpack_write(opb,i-count,ov_ilog(c->entries-count)); + count=i; + } + } + } + oggpack_write(opb,i-count,ov_ilog(c->entries-count)); + + }else{ + /* length random. Again, we don't code the codeword itself, just + the length. This time, though, we have to encode each length */ + oggpack_write(opb,0,1); /* unordered */ + + /* algortihmic mapping has use for 'unused entries', which we tag + here. The algorithmic mapping happens as usual, but the unused + entry has no codeword. */ + for(i=0;i<c->entries;i++) + if(c->lengthlist[i]==0)break; + + if(i==c->entries){ + oggpack_write(opb,0,1); /* no unused entries */ + for(i=0;i<c->entries;i++) + oggpack_write(opb,c->lengthlist[i]-1,5); + }else{ + oggpack_write(opb,1,1); /* we have unused entries; thus we tag */ + for(i=0;i<c->entries;i++){ + if(c->lengthlist[i]==0){ + oggpack_write(opb,0,1); + }else{ + oggpack_write(opb,1,1); + oggpack_write(opb,c->lengthlist[i]-1,5); + } + } + } + } + + /* is the entry number the desired return value, or do we have a + mapping? If we have a mapping, what type? */ + oggpack_write(opb,c->maptype,4); + switch(c->maptype){ + case 0: + /* no mapping */ + break; + case 1:case 2: + /* implicitly populated value mapping */ + /* explicitly populated value mapping */ + + if(!c->quantlist){ + /* no quantlist? error */ + return(-1); + } + + /* values that define the dequantization */ + oggpack_write(opb,c->q_min,32); + oggpack_write(opb,c->q_delta,32); + oggpack_write(opb,c->q_quant-1,4); + oggpack_write(opb,c->q_sequencep,1); + + { + int quantvals; + switch(c->maptype){ + case 1: + /* a single column of (c->entries/c->dim) quantized values for + building a full value list algorithmically (square lattice) */ + quantvals=_book_maptype1_quantvals(c); + break; + case 2: + /* every value (c->entries*c->dim total) specified explicitly */ + quantvals=c->entries*c->dim; + break; + default: /* NOT_REACHABLE */ + quantvals=-1; + } + + /* quantized values */ + for(i=0;i<quantvals;i++) + oggpack_write(opb,labs(c->quantlist[i]),c->q_quant); + + } + break; + default: + /* error case; we don't have any other map types now */ + return(-1); + } + + return(0); +} + +/* unpacks a codebook from the packet buffer into the codebook struct, + readies the codebook auxiliary structures for decode *************/ +static_codebook *vorbis_staticbook_unpack(oggpack_buffer *opb){ + long i,j; + static_codebook *s=_ogg_calloc(1,sizeof(*s)); + s->allocedp=1; + + /* make sure alignment is correct */ + if(oggpack_read(opb,24)!=0x564342)goto _eofout; + + /* first the basic parameters */ + s->dim=oggpack_read(opb,16); + s->entries=oggpack_read(opb,24); + if(s->entries==-1)goto _eofout; + + if(ov_ilog(s->dim)+ov_ilog(s->entries)>24)goto _eofout; + + /* codeword ordering.... length ordered or unordered? */ + switch((int)oggpack_read(opb,1)){ + case 0:{ + long unused; + /* allocated but unused entries? */ + unused=oggpack_read(opb,1); + if((s->entries*(unused?1:5)+7)>>3>opb->storage-oggpack_bytes(opb)) + goto _eofout; + /* unordered */ + s->lengthlist=_ogg_malloc(sizeof(*s->lengthlist)*s->entries); + + /* allocated but unused entries? */ + if(unused){ + /* yes, unused entries */ + + for(i=0;i<s->entries;i++){ + if(oggpack_read(opb,1)){ + long num=oggpack_read(opb,5); + if(num==-1)goto _eofout; + s->lengthlist[i]=num+1; + }else + s->lengthlist[i]=0; + } + }else{ + /* all entries used; no tagging */ + for(i=0;i<s->entries;i++){ + long num=oggpack_read(opb,5); + if(num==-1)goto _eofout; + s->lengthlist[i]=num+1; + } + } + + break; + } + case 1: + /* ordered */ + { + long length=oggpack_read(opb,5)+1; + if(length==0)goto _eofout; + s->lengthlist=_ogg_malloc(sizeof(*s->lengthlist)*s->entries); + + for(i=0;i<s->entries;){ + long num=oggpack_read(opb,ov_ilog(s->entries-i)); + if(num==-1)goto _eofout; + if(length>32 || num>s->entries-i || + (num>0 && (num-1)>>(length-1)>1)){ + goto _errout; + } + if(length>32)goto _errout; + for(j=0;j<num;j++,i++) + s->lengthlist[i]=length; + length++; + } + } + break; + default: + /* EOF */ + goto _eofout; + } + + /* Do we have a mapping to unpack? */ + switch((s->maptype=oggpack_read(opb,4))){ + case 0: + /* no mapping */ + break; + case 1: case 2: + /* implicitly populated value mapping */ + /* explicitly populated value mapping */ + + s->q_min=oggpack_read(opb,32); + s->q_delta=oggpack_read(opb,32); + s->q_quant=oggpack_read(opb,4)+1; + s->q_sequencep=oggpack_read(opb,1); + if(s->q_sequencep==-1)goto _eofout; + + { + int quantvals=0; + switch(s->maptype){ + case 1: + quantvals=(s->dim==0?0:_book_maptype1_quantvals(s)); + break; + case 2: + quantvals=s->entries*s->dim; + break; + } + + /* quantized values */ + if(((quantvals*s->q_quant+7)>>3)>opb->storage-oggpack_bytes(opb)) + goto _eofout; + s->quantlist=_ogg_malloc(sizeof(*s->quantlist)*quantvals); + for(i=0;i<quantvals;i++) + s->quantlist[i]=oggpack_read(opb,s->q_quant); + + if(quantvals&&s->quantlist[quantvals-1]==-1)goto _eofout; + } + break; + default: + goto _errout; + } + + /* all set */ + return(s); + + _errout: + _eofout: + vorbis_staticbook_destroy(s); + return(NULL); +} + +/* returns the number of bits ************************************************/ +int vorbis_book_encode(codebook *book, int a, oggpack_buffer *b){ + if(a<0 || a>=book->c->entries)return(0); + oggpack_write(b,book->codelist[a],book->c->lengthlist[a]); + return(book->c->lengthlist[a]); +} + +/* the 'eliminate the decode tree' optimization actually requires the + codewords to be MSb first, not LSb. This is an annoying inelegancy + (and one of the first places where carefully thought out design + turned out to be wrong; Vorbis II and future Ogg codecs should go + to an MSb bitpacker), but not actually the huge hit it appears to + be. The first-stage decode table catches most words so that + bitreverse is not in the main execution path. */ + +static ogg_uint32_t bitreverse(ogg_uint32_t x){ + x= ((x>>16)&0x0000ffff) | ((x<<16)&0xffff0000); + x= ((x>> 8)&0x00ff00ff) | ((x<< 8)&0xff00ff00); + x= ((x>> 4)&0x0f0f0f0f) | ((x<< 4)&0xf0f0f0f0); + x= ((x>> 2)&0x33333333) | ((x<< 2)&0xcccccccc); + return((x>> 1)&0x55555555) | ((x<< 1)&0xaaaaaaaa); +} + +STIN long decode_packed_entry_number(codebook *book, oggpack_buffer *b){ + int read=book->dec_maxlength; + long lo,hi; + long lok = oggpack_look(b,book->dec_firsttablen); + + if (lok >= 0) { + long entry = book->dec_firsttable[lok]; + if(entry&0x80000000UL){ + lo=(entry>>15)&0x7fff; + hi=book->used_entries-(entry&0x7fff); + }else{ + oggpack_adv(b, book->dec_codelengths[entry-1]); + return(entry-1); + } + }else{ + lo=0; + hi=book->used_entries; + } + + /* Single entry codebooks use a firsttablen of 1 and a + dec_maxlength of 1. If a single-entry codebook gets here (due to + failure to read one bit above), the next look attempt will also + fail and we'll correctly kick out instead of trying to walk the + underformed tree */ + + lok = oggpack_look(b, read); + + while(lok<0 && read>1) + lok = oggpack_look(b, --read); + if(lok<0)return -1; + + /* bisect search for the codeword in the ordered list */ + { + ogg_uint32_t testword=bitreverse((ogg_uint32_t)lok); + + while(hi-lo>1){ + long p=(hi-lo)>>1; + long test=book->codelist[lo+p]>testword; + lo+=p&(test-1); + hi-=p&(-test); + } + + if(book->dec_codelengths[lo]<=read){ + oggpack_adv(b, book->dec_codelengths[lo]); + return(lo); + } + } + + oggpack_adv(b, read); + + return(-1); +} + +/* Decode side is specced and easier, because we don't need to find + matches using different criteria; we simply read and map. There are + two things we need to do 'depending': + + We may need to support interleave. We don't really, but it's + convenient to do it here rather than rebuild the vector later. + + Cascades may be additive or multiplicitive; this is not inherent in + the codebook, but set in the code using the codebook. Like + interleaving, it's easiest to do it here. + addmul==0 -> declarative (set the value) + addmul==1 -> additive + addmul==2 -> multiplicitive */ + +/* returns the [original, not compacted] entry number or -1 on eof *********/ +long vorbis_book_decode(codebook *book, oggpack_buffer *b){ + if(book->used_entries>0){ + long packed_entry=decode_packed_entry_number(book,b); + if(packed_entry>=0) + return(book->dec_index[packed_entry]); + } + + /* if there's no dec_index, the codebook unpacking isn't collapsed */ + return(-1); +} + +/* returns 0 on OK or -1 on eof *************************************/ +/* decode vector / dim granularity gaurding is done in the upper layer */ +long vorbis_book_decodevs_add(codebook *book,float *a,oggpack_buffer *b,int n){ + if(book->used_entries>0){ + int step=n/book->dim; + long *entry = alloca(sizeof(*entry)*step); + float **t = alloca(sizeof(*t)*step); + int i,j,o; + + for (i = 0; i < step; i++) { + entry[i]=decode_packed_entry_number(book,b); + if(entry[i]==-1)return(-1); + t[i] = book->valuelist+entry[i]*book->dim; + } + for(i=0,o=0;i<book->dim;i++,o+=step) + for (j=0;o+j<n && j<step;j++) + a[o+j]+=t[j][i]; + } + return(0); +} + +/* decode vector / dim granularity gaurding is done in the upper layer */ +long vorbis_book_decodev_add(codebook *book,float *a,oggpack_buffer *b,int n){ + if(book->used_entries>0){ + int i,j,entry; + float *t; + + for(i=0;i<n;){ + entry = decode_packed_entry_number(book,b); + if(entry==-1)return(-1); + t = book->valuelist+entry*book->dim; + for(j=0;i<n && j<book->dim;) + a[i++]+=t[j++]; + } + } + return(0); +} + +/* unlike the others, we guard against n not being an integer number + of <dim> internally rather than in the upper layer (called only by + floor0) */ +long vorbis_book_decodev_set(codebook *book,float *a,oggpack_buffer *b,int n){ + if(book->used_entries>0){ + int i,j,entry; + float *t; + + for(i=0;i<n;){ + entry = decode_packed_entry_number(book,b); + if(entry==-1)return(-1); + t = book->valuelist+entry*book->dim; + for (j=0;i<n && j<book->dim;){ + a[i++]=t[j++]; + } + } + }else{ + int i; + + for(i=0;i<n;){ + a[i++]=0.f; + } + } + return(0); +} + +long vorbis_book_decodevv_add(codebook *book,float **a,long offset,int ch, + oggpack_buffer *b,int n){ + + long i,j,entry; + int chptr=0; + if(book->used_entries>0){ + int m=(offset+n)/ch; + for(i=offset/ch;i<m;){ + entry = decode_packed_entry_number(book,b); + if(entry==-1)return(-1); + { + const float *t = book->valuelist+entry*book->dim; + for (j=0;i<m && j<book->dim;j++){ + a[chptr++][i]+=t[j]; + if(chptr==ch){ + chptr=0; + i++; + } + } + } + } + } + return(0); +} |