ref: af257fcf44a4bb60b8ecb593fae7fcb16290c525
dir: /src/trim.c/
/* * July 5, 1991 * Copyright 1991 Lance Norskog And Sundry Contributors * This source code is freely redistributable and may be used for * any purpose. This copyright notice must be maintained. * Lance Norskog And Sundry Contributors are not responsible for * the consequences of using this software. */ /* * Sound Tools skeleton effect file. */ #include "st_i.h" #include <string.h> /* Time resolutin one millisecond */ #define TIMERES 1000 #define TRIM_USAGE "Trim usage: trim start [length]" typedef struct { /* options here */ char *start_str; char *length_str; /* options converted to values */ st_size_t start; st_size_t length; /* internal stuff */ st_size_t index; st_size_t trimmed; } * trim_t; /* * Process options */ int st_trim_getopts(eff_t effp, int n, char **argv) { trim_t trim = (trim_t) effp->priv; /* Do not know sample rate yet so hold off on completely parsing * time related strings. */ switch (n) { case 2: trim->length_str = malloc(strlen(argv[1])+1); if (!trim->length_str) { st_fail("Could not allocate memory"); return(ST_EOF); } strcpy(trim->length_str,argv[1]); /* Do a dummy parse to see if it will fail */ if (st_parsesamples(0, trim->length_str, &trim->length, 't') != ST_SUCCESS) { st_fail(TRIM_USAGE); return(ST_EOF); } case 1: trim->start_str = malloc(strlen(argv[0])+1); if (!trim->start_str) { st_fail("Could not allocate memory"); return(ST_EOF); } strcpy(trim->start_str,argv[0]); /* Do a dummy parse to see if it will fail */ if (st_parsesamples(0, trim->start_str, &trim->start, 't') != ST_SUCCESS) { st_fail(TRIM_USAGE); return(ST_EOF); } break; default: st_fail(TRIM_USAGE); return ST_EOF; break; } return (ST_SUCCESS); } /* * Start processing */ int st_trim_start(eff_t effp) { trim_t trim = (trim_t) effp->priv; if (st_parsesamples(effp->ininfo.rate, trim->start_str, &trim->start, 't') != ST_SUCCESS) { st_fail(TRIM_USAGE); return(ST_EOF); } /* Account for # of channels */ trim->start *= effp->ininfo.channels; if (trim->length_str) { if (st_parsesamples(effp->ininfo.rate, trim->length_str, &trim->length, 't') != ST_SUCCESS) { st_fail(TRIM_USAGE); return(ST_EOF); } } else trim->length = 0; /* Account for # of channels */ trim->length *= effp->ininfo.channels; trim->index = 0; trim->trimmed = 0; return (ST_SUCCESS); } /* * Read up to len samples from file. * Convert to signed longs. * Place in buf[]. * Return number of samples read. */ int st_trim_flow(eff_t effp, st_sample_t *ibuf, st_sample_t *obuf, st_size_t *isamp, st_size_t *osamp) { int finished = 0; int start_trim = 0; int offset = 0; int done; trim_t trim = (trim_t) effp->priv; /* Compute the most samples we can process this time */ done = ((*isamp < *osamp) ? *isamp : *osamp); /* Quick check to see if we are trimming off the back side yet. * If so then we can skip trimming from the front side. */ if (!trim->trimmed) { if ((trim->index+done) <= trim->start) { /* If we haven't read more then "start" samples, return that * we've read all this buffer without outputing anything */ *osamp = 0; *isamp = done; trim->index += done; return (ST_SUCCESS); } else { start_trim = 1; /* We've read at least "start" samples. Now find * out where our target data begins and subtract that * from the total to be copied this round. */ offset = trim->start - trim->index; done -= offset; } } /* !trimmed */ if (trim->trimmed || start_trim) { if (trim->length && ((trim->trimmed+done) >= trim->length)) { /* Since we know the end is in this block, we set done * to the desired length less the amount already read. */ done = trim->length - trim->trimmed; finished = 1; } trim->trimmed += done; } memcpy(obuf, ibuf+offset, done * sizeof(st_sample_t)); *osamp = done; *isamp = offset + done; trim->index += done; if (finished) return (ST_EOF); else return (ST_SUCCESS); } /* * Do anything required when you stop reading samples. * Don't close input file! */ int st_trim_stop(eff_t effp) { trim_t trim = (trim_t) effp->priv; if (trim->start_str) free(trim->start_str); if (trim->length_str) free(trim->length_str); return (ST_SUCCESS); }