/* June 1, 1992 * Copyright 1992 Guido van Rossum And Sundry Contributors * This source code is freely redistributable and may be used for * any purpose.  This copyright notice must be maintained. * Guido van Rossum And Sundry Contributors are not responsible for * the consequences of using this software. */ /* * "reverse" effect, uses a temporary file created by lsx_tmpfile(). */ #include "sox_i.h"#include <string.h> typedef struct {  off_t         pos;  FILE          * tmp_file;} priv_t; static int start(sox_effect_t * effp){  priv_t * p = (priv_t *)effp->priv;  p->pos = 0;  p->tmp_file = lsx_tmpfile();  if (p->tmp_file == NULL) {    lsx_fail("can't create temporary file: %s", strerror(errno));    return SOX_EOF;  }  return SOX_SUCCESS;} static int flow(sox_effect_t * effp, const sox_sample_t * ibuf,    sox_sample_t * obuf, size_t * isamp, size_t * osamp){  priv_t * p = (priv_t *)effp->priv;  if (fwrite(ibuf, sizeof(*ibuf), *isamp, p->tmp_file) != *isamp) {    lsx_fail("error writing temporary file: %s", strerror(errno));    return SOX_EOF;  }  (void)obuf, *osamp = 0; /* samples not output until drain */  return SOX_SUCCESS;} static int drain(sox_effect_t * effp, sox_sample_t *obuf, size_t *osamp){  priv_t * p = (priv_t *)effp->priv;  int i, j;   if (p->pos == 0) {    fflush(p->tmp_file);    p->pos = ftello(p->tmp_file);    if (p->pos % sizeof(sox_sample_t) != 0) {      lsx_fail("temporary file has incorrect size");      return SOX_EOF;    }    p->pos /= sizeof(sox_sample_t);  }  p->pos -= *osamp = min((off_t)*osamp, p->pos);  fseeko(p->tmp_file, (off_t)(p->pos * sizeof(sox_sample_t)), SEEK_SET);  if (fread(obuf, sizeof(sox_sample_t), *osamp, p->tmp_file) != *osamp) {    lsx_fail("error reading temporary file: %s", strerror(errno));    return SOX_EOF;  }  for (i = 0, j = *osamp - 1; i < j; ++i, --j) { /* reverse the samples */    sox_sample_t temp = obuf[i];    obuf[i] = obuf[j];    obuf[j] = temp;  }  return p->pos? SOX_SUCCESS : SOX_EOF;} static int stop(sox_effect_t * effp){  priv_t * p = (priv_t *)effp->priv;  fclose(p->tmp_file); /* auto-deleted by lsx_tmpfile */  return SOX_SUCCESS;} sox_effect_handler_t const * lsx_reverse_effect_fn(void){  static sox_effect_handler_t handler = {    "reverse", NULL, SOX_EFF_MODIFY, NULL, start, flow, drain, stop, NULL, sizeof(priv_t)  };  return &handler;}