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little easier to understand (hoepfully)

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This commit is contained in:
Mark Borgerding 2004-01-24 22:13:14 +00:00
parent e335546c3e
commit 49a6ad07e0
1 changed files with 37 additions and 24 deletions
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61
tools/kiss_fastfir.c
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@ -35,7 +35,7 @@ void * kiss_fastfir_alloc(const kffsamp_t * imp_resp,size_t n_imp_resp,
size_t * nfft,void * mem,size_t*lenmem);
/* see do_file_filter for usage */
size_t kiss_fastfir( void * cfg, kffsamp_t * inbuf, kffsamp_t * outbuf, size_t n, int do_flush, size_t *offset);
size_t kiss_fastfir( void * cfg, kffsamp_t * inbuf, kffsamp_t * outbuf, size_t n, size_t *offset);
@ -212,18 +212,18 @@ size_t kiss_fastfir(
void * vst,
kffsamp_t * inbuf,
kffsamp_t * outbuf,
size_t n,
int do_flush,
size_t n_new,
size_t *offset)
{
if (do_flush==0) {
size_t nwritten = kff_nocopy(vst,inbuf,outbuf,n);
*offset = n - nwritten;
size_t ntot = n_new + *offset;
if (n_new==0) {
return kff_flush(vst,inbuf,outbuf,ntot);
}else{
size_t nwritten = kff_nocopy(vst,inbuf,outbuf,ntot);
*offset = ntot - nwritten;
/*save the unused or underused samples at the front of the input buffer */
memcpy( inbuf , inbuf+nwritten , *offset * sizeof(kffsamp_t) );
return nwritten;
}else{
/*flush*/
return kff_flush(vst,inbuf,outbuf,n);
}
}
@ -239,31 +239,44 @@ void do_file_filter(
size_t n_imp_resp,
size_t nfft )
{
size_t memcfg,membuf;
size_t n_bytes_cfg;
size_t n_samps_buf;
void * cfg;
size_t max_samps;
kffsamp_t *inbuf,*outbuf;
size_t ninbuf,noutbuf;
size_t idx_inbuf=0;
size_t nread,nwrite;
size_t idx_inbuf;
kiss_fastfir_alloc(imp_resp,n_imp_resp,&nfft,0,&memcfg);
max_samps = 4*nfft;
membuf = max_samps*sizeof(kffsamp_t);
cfg = malloc(membuf*2+memcfg);
kiss_fastfir_alloc(imp_resp,n_imp_resp,&nfft,cfg,&memcfg);
inbuf = (kffsamp_t*)((char*)cfg+memcfg);
outbuf = (kffsamp_t*)((char*)cfg+memcfg+membuf);
/*Note this is probably more difficult than it needs to be since
I like to only have one malloc if possible. */
/*figure out how big cfg will be */
kiss_fastfir_alloc(imp_resp,n_imp_resp,&nfft,0,&n_bytes_cfg);
/* how much space for the input & output buffers */
n_samps_buf = 4*nfft;
/*allocate space and initialize pointers */
cfg = malloc( n_samps_buf * sizeof(kffsamp_t) *2 + n_bytes_cfg );
kiss_fastfir_alloc(imp_resp,n_imp_resp,&nfft,cfg,&n_bytes_cfg);
inbuf = (kffsamp_t*)((char*)cfg+n_bytes_cfg);
outbuf = inbuf + n_samps_buf;
idx_inbuf=0;
do{
ninbuf = fread( &inbuf[idx_inbuf], sizeof(inbuf[0]), max_samps-idx_inbuf , fin );
/* start reading at inbuf[idx_inbuf] */
nread = fread( inbuf + idx_inbuf, sizeof(kffsamp_t), n_samps_buf - idx_inbuf , fin );
noutbuf = kiss_fastfir(cfg, inbuf, outbuf,idx_inbuf+ninbuf,ninbuf==0,&idx_inbuf);
/* If nread==0, then this is a flush.
The total number of samples in input is idx_inbuf + nread . */
nwrite = kiss_fastfir(cfg, inbuf, outbuf,nread,&idx_inbuf);
/* kiss_fastfir moved any unused samples to the front of inbuf and updated idx_inbuf */
if ( fwrite( outbuf, sizeof(outbuf[0]), noutbuf, fout) != noutbuf ) {
if ( fwrite( outbuf, sizeof(outbuf[0]), nwrite, fout) != nwrite ) {
perror("short write");
exit(1);
}
}while ( ninbuf );
}while ( nread );
free(cfg);
}