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comparison decoders/raw.c @ 4:341cea3e13c6

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Initial add.
author Ryan C. Gordon <icculus@icculus.org>
date Mon, 17 Sep 2001 18:12:03 +0000
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children 29313c20963d
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3:fd6cd0e04e6f 4:341cea3e13c6
1 /*
2 * SDL_sound -- An abstract sound format decoding API.
3 * Copyright (C) 2001 Ryan C. Gordon.
4 *
5 * This library is free software; you can redistribute it and/or
6 * modify it under the terms of the GNU Lesser General Public
7 * License as published by the Free Software Foundation; either
8 * version 2.1 of the License, or (at your option) any later version.
9 *
10 * This library is distributed in the hope that it will be useful,
11 * but WITHOUT ANY WARRANTY; without even the implied warranty of
12 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
13 * Lesser General Public License for more details.
14 *
15 * You should have received a copy of the GNU Lesser General Public
16 * License along with this library; if not, write to the Free Software
17 * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
18 */
19
20 /*
21 * RAW decoder for SDL_sound. This is as simple as it gets.
22 *
23 * This driver handles raw audio data. You must, regardless of where the
24 * data is actually coming from, specify the string "RAW" in the extension
25 * parameter of Sound_NewSample() (or, alternately, open a file with the
26 * extension ".raw" in Sound_NewSampleFromFile()). The string is checked
27 * case-insensitive. We need this check, because raw data, being raw, has
28 * no headers or magic number we can use to determine if we should handle a
29 * given file, so we needed some way to have this "decoder" discriminate.
30 *
31 * When calling Sound_NewSample*(), you must also specify a "desired"
32 * audio format. The "actual" format will always match what you specify, so
33 * there will be no conversion overhead, but these routines need to know how
34 * to treat the bits, since it's all random garbage otherwise.
35 *
36 * Please see the file LICENSE in the source's root directory.
37 *
38 * This file written by Ryan C. Gordon. (icculus@clutteredmind.org)
39 */
40
41 #include <stdio.h>
42 #include <stdlib.h>
43 #include <string.h>
44 #include <assert.h>
45 #include "SDL_sound.h"
46
47 #define __SDL_SOUND_INTERNAL__
48 #include "SDL_sound_internal.h"
49
50 #if (!defined SOUND_SUPPORTS_RAW)
51 #error SOUND_SUPPORTS_RAW must be defined.
52 #endif
53
54
55 static int RAW_open(Sound_Sample *sample, const char *ext);
56 static void RAW_close(Sound_Sample *sample);
57 static int RAW_read(Sound_Sample *sample);
58
59 const Sound_DecoderFunctions __Sound_DecoderFunctions_RAW =
60 {
61 {
62 "RAW",
63 "Raw audio",
64 "Ryan C. Gordon <icculus@clutteredmind.org>",
65 "http://www.icculus.org/SDL_sound/"
66 },
67
68 RAW_open, /* open() method */
69 RAW_close, /* close() method */
70 RAW_read /* read() method */
71 };
72
73
74 static int RAW_open(Sound_Sample *sample, const char *ext)
75 {
76 if (__Sound_strcasecmp(ext, "RAW") != 0)
77 return(0);
78
79 if ( (sample->desired.channels < 1) ||
80 (sample->desired.channels > 2) ||
81 (sample->desired.rate == 0) ||
82 (sample->desired.format == 0) )
83 {
84 return(0);
85 } /* if */
86
87 memcpy(&sample->actual, &sample->desired, sizeof (Sound_AudioInfo));
88 sample->flags = SOUND_SAMPLEFLAG_NONE;
89 return(1);
90 } /* RAW_open */
91
92
93 static void RAW_close(Sound_Sample *sample)
94 {
95 /* we don't allocate anything. That's easy, eh? */
96 } /* RAW_close */
97
98
99 static int RAW_read(Sound_Sample *sample)
100 {
101 int retval;
102 Sound_SampleInternal *internal = (Sound_SampleInternal *) sample->opaque;
103 retval = SDL_RWread(internal->rw, internal->buffer,
104 1, internal->buffer_size);
105
106 if (retval == 0)
107 sample->flags |= SOUND_SAMPLEFLAG_EOF;
108
109 else if (retval == -1)
110 sample->flags |= SOUND_SAMPLEFLAG_ERROR;
111
112 /* next call this may be a EOF or error... */
113 else if (retval < internal->buffer_size)
114 sample->flags |= SOUND_SAMPLEFLAG_EAGAIN;
115
116 return(retval);
117 } /* RAW_read */
118
119
120 /* end of raw.c ... */
121