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