void codeSilence (void *inb, void *outb)
/***********************************************************************
Silence encoding, takes care of "silence" pieces
************************************************************************
inb input buffer
outb output buffer
***********************************************************************/
{
memBUFF *inbuff = (memBUFF *) inb;
memBUFF *outbuff = (memBUFF *) outb;
int look_ahead[LOOKAHSZ];
int index, i, run_length, flag;
/* preload the look ahead buffer */
for(i=0; i<LOOKAHSZ; i++)
if(buffGetc(inbuff, look_ahead[i]) == MEM_EOB)
break;
/* if not enough samples, no RLE */
if(i < LOOKAHSZ){
buffMerge(outbuff, inbuff);
return;
}
index = 0;
for(;;){
if(look_ahead[index] == MEM_EOB) break;
if(silence_run(look_ahead, index)){
run_length = 0;
do{
flag = buffGetc(inbuff, look_ahead[index]);
if(flag == MEM_EOB) look_ahead[index] = MEM_EOB;
index ++;
index &= LOOKAHMASK;
if(++run_length == MAXLENGTH){
buffPutc(outbuff, SILENCECODE);
buffPutc(outbuff, MAXLENGTH);
run_length = 0;
}
} while(!end_of_silence(look_ahead, index));
if(run_length > 0){
buffPutc(outbuff, SILENCECODE);
buffPutc(outbuff, run_length);
}
}
if(look_ahead[index] == MEM_EOB) break;
/* the silence code in the input get changed */
if(look_ahead[index] == SILENCECODE) look_ahead[index]++;
buffPutc(outbuff, look_ahead[index]);
/* get a new code */
flag = buffGetc(inbuff, look_ahead[index]);
if(flag == MEM_EOB) look_ahead[index] = MEM_EOB;
index ++;
index &= LOOKAHMASK;
}
}
void codeSilence (void *inb, void *outb)
/***********************************************************************
Silence encoding, takes care of "silence" pieces
************************************************************************
inb input buffer
outb output buffer
************************************************************************
Note: To avoid the inefficiency in encoding isolated 0's, I start a run
only when there are CODESTARTTHRSHOLD consective 0's. Therefore,
a look ahead buffer is needed. The run is stopped as soon as there
is a non-0 symbol.
***********************************************************************/
{
wpcBUFF *inbuff = (wpcBUFF *) inb;
wpcBUFF *outbuff = (wpcBUFF *) outb;
int look_ahead[CODELOOKAHSZ];
int index, i, run_length, flag;
/* preload the look ahead buffer */
for(i=0; i<CODELOOKAHSZ; i++)
if(buffGetc(inbuff, look_ahead[i]) == WPC_EOB)
break;
/* if not enough samples, no RLE */
if(i < CODELOOKAHSZ){
buffMerge(outbuff, inbuff);
return;
}
index = 0;
for(;;){
if(look_ahead[index] == WPC_EOB) break;
if(silence_run(look_ahead, index)){
run_length = 0;
do{
flag = buffGetc(inbuff, look_ahead[index]);
if(flag == WPC_EOB) look_ahead[index] = WPC_EOB;
index ++;
index &= CODELOOKAHMASK;
if(++run_length == CODEMAXLENGTH){
buffPutc(outbuff, CODESILENCECODE);
buffPutc(outbuff, CODEMAXLENGTH);
run_length = 0;
}
} while(!end_of_silence(look_ahead, index));
if(run_length > 0){
buffPutc(outbuff, CODESILENCECODE);
buffPutc(outbuff, run_length);
}
}
if(look_ahead[index] == WPC_EOB) break;
/* the silence code in the input get changed */
if(look_ahead[index] == CODESILENCECODE) look_ahead[index]++;
buffPutc(outbuff, look_ahead[index]);
/* get a new code */
flag = buffGetc(inbuff, look_ahead[index]);
if(flag == WPC_EOB) look_ahead[index] = WPC_EOB;
index ++;
index &= CODELOOKAHMASK;
}
}
