06390d082d
Remove the special case for 0 in EC_ILOG, as we never pass it 0 and this generates slightly better code. Update ec_enc_bits64 to split the encoded values along word boundaries... this should generate slightly better code, as well as fix a subtle bug (the proper bits were not being masked out of the low part). However, this will render previous streams that used this function undecodable (to my knowledge, no one is actually using it yet). git-svn-id: http://svn.xiph.org/trunk/ghost@14391 0101bb08-14d6-0310-b084-bc0e0c8e3800
130 lines
2.9 KiB
C
130 lines
2.9 KiB
C
#include <stdlib.h>
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#include <string.h>
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#include "entenc.h"
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#define EC_BUFFER_INCREMENT (256)
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void ec_byte_writeinit(ec_byte_buffer *_b){
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_b->ptr=_b->buf=malloc(EC_BUFFER_INCREMENT);
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_b->storage=EC_BUFFER_INCREMENT;
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}
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void ec_byte_writetrunc(ec_byte_buffer *_b,long _bytes){
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_b->ptr=_b->buf+_bytes;
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}
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void ec_byte_write1(ec_byte_buffer *_b,unsigned _value){
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ptrdiff_t endbyte;
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endbyte=_b->ptr-_b->buf;
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if(endbyte>=_b->storage){
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_b->buf=realloc(_b->buf,_b->storage+EC_BUFFER_INCREMENT);
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_b->storage+=EC_BUFFER_INCREMENT;
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_b->ptr=_b->buf+endbyte;
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}
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*(_b->ptr++)=(unsigned char)_value;
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}
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void ec_byte_write4(ec_byte_buffer *_b,ec_uint32 _value){
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ptrdiff_t endbyte;
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endbyte=_b->ptr-_b->buf;
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if(endbyte+4>_b->storage){
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_b->buf=realloc(_b->buf,_b->storage+EC_BUFFER_INCREMENT);
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_b->storage+=EC_BUFFER_INCREMENT;
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_b->ptr=_b->buf+endbyte;
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}
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*(_b->ptr++)=(unsigned char)_value;
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_value>>=8;
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*(_b->ptr++)=(unsigned char)_value;
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_value>>=8;
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*(_b->ptr++)=(unsigned char)_value;
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_value>>=8;
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*(_b->ptr++)=(unsigned char)_value;
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}
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void ec_byte_writecopy(ec_byte_buffer *_b,void *_source,long _bytes){
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ptrdiff_t endbyte;
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endbyte=_b->ptr-_b->buf;
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if(endbyte+_bytes>_b->storage){
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_b->storage=endbyte+_bytes+EC_BUFFER_INCREMENT;
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_b->buf=realloc(_b->buf,_b->storage);
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_b->ptr=_b->buf+endbyte;
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}
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memmove(_b->ptr,_source,_bytes);
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_b->ptr+=_bytes;
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}
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void ec_byte_writeclear(ec_byte_buffer *_b){
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free(_b->buf);
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}
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void ec_enc_bits(ec_enc *_this,ec_uint32 _fl,int _ftb){
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unsigned fl;
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unsigned ft;
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while(_ftb>EC_UNIT_BITS){
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_ftb-=EC_UNIT_BITS;
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fl=(unsigned)(_fl>>_ftb)&EC_UNIT_MASK;
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ec_encode(_this,fl,fl+1,EC_UNIT_MASK+1);
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}
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ft=1<<_ftb;
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fl=(unsigned)_fl&ft-1;
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ec_encode(_this,fl,fl+1,ft);
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}
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void ec_enc_bits64(ec_enc *_this,ec_uint64 _fl,int _ftb){
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if(_ftb>32){
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ec_enc_bits(_this,(ec_uint32)(_fl>>32),_ftb-32);
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_ftb=32;
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_fl&=0xFFFFFFFF;
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}
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ec_enc_bits(_this,(ec_uint32)_fl,_ftb);
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}
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void ec_enc_uint(ec_enc *_this,ec_uint32 _fl,ec_uint32 _ft){
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ec_uint32 mask;
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unsigned ft;
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unsigned fl;
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int ftb;
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_ft--;
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ftb=EC_ILOG(_ft)&-!!_ft;
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while(ftb>EC_UNIT_BITS){
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ftb-=EC_UNIT_BITS;
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ft=(_ft>>ftb)+1;
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fl=(unsigned)(_fl>>ftb);
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ec_encode(_this,fl,fl+1,ft);
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if(fl<ft-1){
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ec_enc_bits(_this,_fl,ftb);
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return;
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}
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mask=((ec_uint32)1<<ftb)-1;
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_fl=_fl&mask;
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_ft=_ft&mask;
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}
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ec_encode(_this,_fl,_fl+1,_ft+1);
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}
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void ec_enc_uint64(ec_enc *_this,ec_uint64 _fl,ec_uint64 _ft){
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ec_uint64 mask;
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unsigned ft;
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unsigned fl;
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int ftb;
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_ft--;
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ftb=EC_ILOG64(_ft)&-!!_ft;
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while(ftb>EC_UNIT_BITS){
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ftb-=EC_UNIT_BITS;
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ft=(unsigned)(_ft>>ftb)+1;
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fl=(unsigned)(_fl>>ftb);
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ec_encode(_this,fl,fl+1,ft);
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if(fl<ft-1){
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ec_enc_bits64(_this,_fl,ftb);
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return;
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}
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mask=((ec_uint64)1<<ftb)-1;
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_fl=_fl&mask;
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_ft=_ft&mask;
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}
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ec_encode(_this,_fl,_fl+1,_ft+1);
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}
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