src/fir.c

   1 /* Effect: fir filter from coefs   Copyright (c) 2009 robs@users.sourceforge.net
   2  *
   3  * This library is free software; you can redistribute it and/or modify it
   4  * under the terms of the GNU Lesser General Public License as published by
   5  * the Free Software Foundation; either version 2.1 of the License, or (at
   6  * your option) any later version.
   7  *
   8  * This library is distributed in the hope that it will be useful, but
   9  * WITHOUT ANY WARRANTY; without even the implied warranty of
  10  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU Lesser
  11  * General Public License for more details.
  12  *
  13  * You should have received a copy of the GNU Lesser General Public License
  14  * along with this library; if not, write to the Free Software Foundation,
  15  * Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301  USA
  16  */
  17
  18 #include "sox_i.h"
  19 #include "dft_filter.h"
  20
  21 typedef struct {
  22   dft_filter_priv_t  base;
  23   char const         * filename;
  24   double             * h;
  25   int                n;
  26 } priv_t;
  27
  28 static int create(sox_effect_t * effp, int argc, char * * argv)
  29 {
  30   priv_t             * p = (priv_t *)effp->priv;
  31   dft_filter_priv_t  * b = &p->base;
  32   double             d;
  33   char               c;
  34
  35   b->filter_ptr = &b->filter;
  36   --argc, ++argv;
  37   if (!argc)
  38     p->filename = "-"; /* default to stdin */
  39   else if (argc == 1)
  40     p->filename = argv[0], --argc;
  41   else for (; argc && sscanf(*argv, "%lf%c", &d, &c) == 1; --argc, ++argv) {
  42     p->n++;
  43     p->h = lsx_realloc(p->h, p->n * sizeof(*p->h));
  44     p->h[p->n - 1] = d;
  45   }
  46   return argc? lsx_usage(effp) : SOX_SUCCESS;
  47 }
  48
  49 static int start(sox_effect_t * effp)
  50 {
  51   priv_t        * p = (priv_t *)effp->priv;
  52   dft_filter_t  * f = p->base.filter_ptr;
  53   double        d;
  54   char          c;
  55   int           i;
  56
  57   if (!f->num_taps) {
  58     if (!p->n && p->filename) {
  59       FILE * file = lsx_open_input_file(effp, p->filename, sox_true);
  60       if (!file)
  61         return SOX_EOF;
  62       while ((i = fscanf(file, " #%*[^\n]%c", &c)) >= 0) {
  63         if (i >= 1) continue; /* found and skipped a comment */
  64         if ((i = fscanf(file, "%lf", &d)) > 0) {
  65           /* found a coefficient value */
  66           p->n++;
  67           p->h = lsx_realloc(p->h, p->n * sizeof(*p->h));
  68           p->h[p->n - 1] = d;
  69         } else break; /* either EOF, or something went wrong
  70                          (read or syntax error) */
  71       }
  72       if (!feof(file)) {
  73         lsx_fail("error reading coefficient file");
  74         if (file != stdin) fclose(file);
  75         return SOX_EOF;
  76       }
  77       if (file != stdin) fclose(file);
  78     }
  79     lsx_report("%i coefficients", p->n);
  80     if (!p->n)
  81       return SOX_EFF_NULL;
  82     if (effp->global_info->plot != sox_plot_off) {
  83       char title[100];
  84       sprintf(title, "SoX effect: fir (%d coefficients)", p->n);
  85       lsx_plot_fir(p->h, p->n, effp->in_signal.rate,
  86           effp->global_info->plot, title, -30., 30.);
  87       free(p->h);
  88       return SOX_EOF;
  89     }
  90     lsx_set_dft_filter(f, p->h, p->n, p->n >> 1);
  91   }
  92   return lsx_dft_filter_effect_fn()->start(effp);
  93 }
  94
  95 sox_effect_handler_t const * lsx_fir_effect_fn(void)
  96 {
  97   static sox_effect_handler_t handler;
  98   handler = *lsx_dft_filter_effect_fn();
  99   handler.name = "fir";
 100   handler.usage = "[coef-file|coefs]";
 101   handler.getopts = create;
 102   handler.start = start;
 103   handler.priv_size = sizeof(priv_t);
 104   return &handler;
 105 }