amp_filter.c

   1 /*
   2  * Copyright (C) 2009 Andre Noll <maan@systemlinux.org>
   3  *
   4  * Licensed under the GPL v2. For licencing details see COPYING.
   5  */
   6
   7 /** \file amp_filter.c Paraslash's amplify filter. */
   8
   9 #include <regex.h>
  10 #include <stdbool.h>
  11
  12 #include "para.h"
  13 #include "amp_filter.cmdline.h"
  14 #include "list.h"
  15 #include "sched.h"
  16 #include "ggo.h"
  17 #include "buffer_tree.h"
  18 #include "filter.h"
  19 #include "string.h"
  20 #include "error.h"
  21
  22 /** The size of the output data buffer. */
  23 #define AMP_CHUNK_SIZE 40960
  24
  25 extern char *stat_item_values[NUM_STAT_ITEMS];
  26
  27 /** Data specific to the amplify filter. */
  28 struct private_amp_data {
  29         /** Points to the configuration data for this instance of this filter. */
  30         struct amp_filter_args_info *conf;
  31         /** Amplification factor. */
  32         unsigned amp;
  33 };
  34
  35 static ssize_t amp_convert(char *inbuf, size_t inbuf_len, struct filter_node *fn)
  36 {
  37         size_t i, length = PARA_MIN((inbuf_len / 2),
  38                 (fn->bufsize - fn->loaded) / 2);
  39         struct private_amp_data *pad = fn->private_data;
  40         int16_t *ip = (int16_t *)inbuf, *op = (int16_t *)(fn->buf + fn->loaded);
  41         int factor = 64 + pad->amp;
  42
  43         if (!length)
  44                 return 0;
  45
  46         if (pad->amp == 0) {
  47                 memcpy(op, ip, length * 2);
  48                 goto out;
  49         }
  50         for (i = 0; i < length; i++) {
  51                 int x = (ip[i] * factor) >> 6;
  52
  53                 op[i] = x;
  54                 if (op[i] != x)
  55                         op[i] = (x >= 32768)? 32767 : -32768;
  56         }
  57 out:
  58         fn->loaded += length * 2;
  59         return length * 2;
  60 }
  61
  62 static void amp_close(struct filter_node *fn)
  63 {
  64         free(fn->private_data);
  65         free(fn->buf);
  66 }
  67
  68 static int amp_parse_config(int argc, char **argv, void **config)
  69 {
  70         struct amp_filter_args_info *amp_conf = para_calloc(sizeof(*amp_conf));
  71         int ret = -E_AMP_SYNTAX;
  72
  73         if (amp_cmdline_parser(argc, argv, amp_conf))
  74                 goto err;
  75         ret = -ERRNO_TO_PARA_ERROR(EINVAL);
  76         if (amp_conf->amp_arg < 0)
  77                 goto err;
  78         PARA_NOTICE_LOG("amplification: %u (scaling factor: %1.2f)\n",
  79                 amp_conf->amp_arg, amp_conf->amp_arg / 64.0 + 1.0);
  80         *config = amp_conf;
  81         return 1;
  82 err:
  83         free(amp_conf);
  84         return ret;
  85 }
  86
  87 static void amp_open(struct filter_node *fn)
  88 {
  89         struct private_amp_data *pad = para_calloc(sizeof(*pad));
  90
  91         pad->conf = fn->conf;
  92         fn->private_data = pad;
  93         if (!pad->conf->amp_given && stat_item_values[SI_AMPLIFICATION])
  94                 sscanf(stat_item_values[SI_AMPLIFICATION], "%u", &pad->amp);
  95         else
  96                 pad->amp = pad->conf->amp_arg;
  97         fn->bufsize = AMP_CHUNK_SIZE;
  98         fn->buf = para_malloc(fn->bufsize);
  99 }
 100
 101 /**
 102  * The init function of the amplify filter.
 103  *
 104  * \param f Pointer to the struct to initialize.
 105  */
 106 void amp_filter_init(struct filter *f)
 107 {
 108         struct amp_filter_args_info dummy;
 109
 110         amp_cmdline_parser_init(&dummy);
 111         f->open = amp_open;
 112         f->close = amp_close;
 113         f->convert = amp_convert;
 114         f->parse_config = amp_parse_config;
 115         f->help = (struct ggo_help) {
 116                 .short_help = amp_filter_args_info_help,
 117                 .detailed_help = amp_filter_args_info_detailed_help
 118         };
 119 }