ref: 9bddfb82cc8aa239fe499dcfa3ed32edc72f2ed6
dir: /split.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. */ /* * "split" effect by Lauren Weinstein (lauren@vortex.com); 2/94 * Splits 1 channel file to 2 channels (stereo), or 4 channels (quad); * or splits a 2 channel file to 4 channels. */ #include <math.h> #include "st.h" /* Private data for split */ typedef struct splitstuff { int rest; /* bytes remaining in current block */ } *split_t; /* * Process options */ void split_getopts(effp, n, argv) eff_t effp; int n; char **argv; { if (n) fail("Split effect takes no options."); } /* * Prepare processing. */ void split_start(effp) eff_t effp; { switch (effp->ininfo.channels) { case 1: /* 1 channel must split to 2 or 4 */ switch(effp->outinfo.channels) { case 2: case 4: return; } break; case 2: /* 2 channels must split to 4 */ switch(effp->outinfo.channels) { case 4: return; } break; } fail("Can't split %d channels into %d channels", effp->ininfo.channels, effp->outinfo.channels); } /* * Process signed long samples from ibuf to obuf, * isamp or osamp samples, whichever is smaller, * while splitting into appropriate channels. */ void split_flow(effp, ibuf, obuf, isamp, osamp) eff_t effp; LONG *ibuf, *obuf; int *isamp, *osamp; { int len, done; switch(effp->ininfo.channels) { case 1: /* 1 input channel */ switch(effp->outinfo.channels) { case 2: /* split to 2 channels */ len = ((*isamp > *osamp/2) ? *osamp/2 : *isamp); for(done = 0; done < len; done++) { obuf[0] = obuf[1] = *ibuf++; obuf += 2; } *isamp = len; *osamp = len * 2; break; case 4: /* split to 4 channels */ len = ((*isamp > *osamp/4) ? *osamp/4 : *isamp); for(done = 0; done < len; done++) { obuf[0] = obuf[1] = obuf[2] = obuf[3] = *ibuf++; obuf += 4; } *isamp = len; *osamp = len * 4; break; } break; case 2: /* 2 input channels; split to 4 channels */ /* We're using the same channel ordering */ /* as in "avg.c"--sure hope it's correct! */ len = ((*isamp/2 > *osamp/4) ? *osamp/4 : *isamp/2); for(done = 0; done < len; done++) { obuf[0] = obuf[2] = ibuf[0]; obuf[1] = obuf[3] = ibuf[1]; ibuf += 2; obuf += 4; } *isamp = len; *osamp = len * 2; break; } } /* * Do anything required when you stop reading samples. * Don't close input file! */ void split_stop(effp) eff_t effp; { /* nothing to do */ }