Add documentation to struct rc4_context.
[paraslash.git] / 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
11 #include "para.h"
12 #include "amp_filter.cmdline.h"
13 #include "list.h"
14 #include "sched.h"
15 #include "ggo.h"
16 #include "filter.h"
17 #include "string.h"
18 #include "error.h"
19
20 /** The size of the output data buffer. */
21 #define AMP_CHUNK_SIZE 40960
22
23 extern char *stat_item_values[NUM_STAT_ITEMS];
24
25 /** Data specific to the amplify filter. */
26 struct private_amp_data {
27 /** Points to the configuration data for this instance of this filter. */
28 struct amp_filter_args_info *conf;
29 /** Amplification factor. */
30 unsigned amp;
31 };
32
33 static ssize_t amp_convert(char *inbuf, size_t inbuf_len, struct filter_node *fn)
34 {
35 size_t i, length = PARA_MIN((inbuf_len / 2) * 2,
36 (fn->bufsize - fn->loaded) / 2 * 2);
37 struct private_amp_data *pad = fn->private_data;
38 int16_t *ip = (int16_t *)inbuf, *op = (int16_t *)(fn->buf + fn->loaded);
39
40 if (!length)
41 return 0;
42 for (i = 0; i < length / 2; i++) {
43 int x = (PARA_ABS(*ip) * (64 + pad->amp)) >> 6;
44 *op++ = *ip++ > 0? PARA_MIN(x, 32767) : PARA_MAX(-x, -32768);
45 }
46 fn->loaded += length;
47 return length;
48 }
49
50 static void amp_close(struct filter_node *fn)
51 {
52 free(fn->private_data);
53 free(fn->buf);
54 }
55
56 static int amp_parse_config(int argc, char **argv, void **config)
57 {
58 struct amp_filter_args_info *amp_conf = para_calloc(sizeof(*amp_conf));
59 int ret = -E_AMP_SYNTAX;
60
61 if (amp_cmdline_parser(argc, argv, amp_conf))
62 goto err;
63 ret = -ERRNO_TO_PARA_ERROR(EINVAL);
64 if (amp_conf->amp_arg < 0)
65 goto err;
66 PARA_NOTICE_LOG("amplification: %u (scaling factor: %1.2f)\n",
67 amp_conf->amp_arg, amp_conf->amp_arg / 64.0 + 1.0);
68 *config = amp_conf;
69 return 1;
70 err:
71 free(amp_conf);
72 return ret;
73 }
74
75 static void amp_open(struct filter_node *fn)
76 {
77 struct private_amp_data *pad = para_calloc(sizeof(*pad));
78
79 pad->conf = fn->conf;
80 fn->private_data = pad;
81 if (!pad->conf->amp_given && stat_item_values[SI_AMPLIFICATION])
82 sscanf(stat_item_values[SI_AMPLIFICATION], "%u", &pad->amp);
83 else
84 pad->amp = pad->conf->amp_arg;
85 fn->bufsize = AMP_CHUNK_SIZE;
86 fn->buf = para_malloc(fn->bufsize);
87 }
88
89 /**
90 * The init function of the amplify filter.
91 *
92 * \param f Pointer to the struct to initialize.
93 */
94 void amp_filter_init(struct filter *f)
95 {
96 struct amp_filter_args_info dummy;
97
98 amp_cmdline_parser_init(&dummy);
99 f->open = amp_open;
100 f->close = amp_close;
101 f->convert = amp_convert;
102 f->parse_config = amp_parse_config;
103 f->help = (struct ggo_help) {
104 .short_help = amp_filter_args_info_help,
105 .detailed_help = amp_filter_args_info_detailed_help
106 };
107 }