0
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1 /*
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2 SDL - Simple DirectMedia Layer
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3 Copyright (C) 1997, 1998, 1999, 2000, 2001 Sam Lantinga
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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 Library General Public
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7 License as published by the Free Software Foundation; either
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8 version 2 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 Library 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 Library General Public
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16 License along with this library; if not, write to the Free
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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 Sam Lantinga
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20 slouken@devolution.com
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21 */
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22
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23 #ifdef SAVE_RCSID
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24 static char rcsid =
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25 "@(#) $Id$";
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26 #endif
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27
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28 /* Allow access to a raw mixing buffer */
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29
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30 #include <stdlib.h>
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31 #include <stdio.h>
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32 #include <string.h>
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33 #include <errno.h>
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34 #include <unistd.h>
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35 #include <fcntl.h>
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36 #include <signal.h>
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37 #include <sys/time.h>
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38 #include <sys/ioctl.h>
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39 #include <sys/stat.h>
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40 #ifdef linux
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41 #include <linux/soundcard.h>
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42 #endif
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43 #ifdef __bsdi__
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44 #include <sys/soundcard.h>
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45 #endif
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46 #ifdef __FreeBSD__
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47 #include <machine/soundcard.h>
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48 #endif
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49 #ifdef __USLC__
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50 #include <sys/soundcard.h>
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51 #endif
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52
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53 #include "SDL_audio.h"
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54 #include "SDL_error.h"
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55 #include "SDL_audiomem.h"
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56 #include "SDL_audio_c.h"
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57 #include "SDL_timer.h"
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58 #include "SDL_audiodev_c.h"
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59 #include "SDL_dspaudio.h"
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60
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61 /* The tag name used by DSP audio */
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62 #define DSP_DRIVER_NAME "dsp"
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63
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64 /* Open the audio device for playback, and don't block if busy */
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65 /*#define USE_BLOCKING_WRITES*/
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66 #ifdef USE_BLOCKING_WRITES
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67 #define OPEN_FLAGS O_WRONLY
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68 #else
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69 #define OPEN_FLAGS (O_WRONLY|O_NONBLOCK)
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70 #endif
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71
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72 /* Audio driver functions */
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73 static int DSP_OpenAudio(_THIS, SDL_AudioSpec *spec);
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74 static void DSP_WaitAudio(_THIS);
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75 static void DSP_PlayAudio(_THIS);
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76 static Uint8 *DSP_GetAudioBuf(_THIS);
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77 static void DSP_CloseAudio(_THIS);
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78
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79 /* Audio driver bootstrap functions */
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80
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81 static int Audio_Available(void)
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82 {
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83 int fd;
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84 int available;
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85
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86 available = 0;
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87 fd = SDL_OpenAudioPath(NULL, 0, OPEN_FLAGS, 0);
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88 if ( fd >= 0 ) {
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89 available = 1;
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90 close(fd);
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91 }
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92 return(available);
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93 }
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94
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95 static void Audio_DeleteDevice(SDL_AudioDevice *device)
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96 {
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97 free(device->hidden);
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98 free(device);
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99 }
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100
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101 static SDL_AudioDevice *Audio_CreateDevice(int devindex)
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102 {
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103 SDL_AudioDevice *this;
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104
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105 /* Initialize all variables that we clean on shutdown */
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106 this = (SDL_AudioDevice *)malloc(sizeof(SDL_AudioDevice));
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107 if ( this ) {
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108 memset(this, 0, (sizeof *this));
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109 this->hidden = (struct SDL_PrivateAudioData *)
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110 malloc((sizeof *this->hidden));
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111 }
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112 if ( (this == NULL) || (this->hidden == NULL) ) {
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113 SDL_OutOfMemory();
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114 if ( this ) {
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115 free(this);
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116 }
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117 return(0);
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118 }
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119 memset(this->hidden, 0, (sizeof *this->hidden));
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120 audio_fd = -1;
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121
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122 /* Set the function pointers */
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123 this->OpenAudio = DSP_OpenAudio;
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124 this->WaitAudio = DSP_WaitAudio;
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125 this->PlayAudio = DSP_PlayAudio;
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126 this->GetAudioBuf = DSP_GetAudioBuf;
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127 this->CloseAudio = DSP_CloseAudio;
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128
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129 this->free = Audio_DeleteDevice;
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130
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131 return this;
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132 }
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133
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134 AudioBootStrap DSP_bootstrap = {
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135 DSP_DRIVER_NAME, "OSS /dev/dsp standard audio",
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136 Audio_Available, Audio_CreateDevice
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137 };
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138
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139 /* This function waits until it is possible to write a full sound buffer */
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140 static void DSP_WaitAudio(_THIS)
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141 {
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142 #ifndef USE_BLOCKING_WRITES /* Not necessary because of blocking writes */
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143 fd_set fdset;
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144
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145 /* Check to see if the thread-parent process is still alive */
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146 { static int cnt = 0;
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147 /* Note that this only works with thread implementations
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148 that use a different process id for each thread.
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149 */
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150 if (parent && (((++cnt)%10) == 0)) { /* Check every 10 loops */
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151 if ( kill(parent, 0) < 0 ) {
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152 this->enabled = 0;
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153 }
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154 }
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155 }
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156
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157 /* See if we need to use timed audio synchronization */
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158 if ( frame_ticks ) {
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159 /* Use timer for general audio synchronization */
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160 Sint32 ticks;
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161
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162 ticks = ((Sint32)(next_frame - SDL_GetTicks()))-FUDGE_TICKS;
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163 if ( ticks > 0 ) {
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164 SDL_Delay(ticks);
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165 }
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166 } else {
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167 /* Use select() for audio synchronization */
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168 struct timeval timeout;
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169 FD_ZERO(&fdset);
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170 FD_SET(audio_fd, &fdset);
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171 timeout.tv_sec = 10;
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172 timeout.tv_usec = 0;
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173 #ifdef DEBUG_AUDIO
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174 fprintf(stderr, "Waiting for audio to get ready\n");
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175 #endif
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176 if ( select(audio_fd+1, NULL, &fdset, NULL, &timeout) <= 0 ) {
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177 const char *message =
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178 "Audio timeout - buggy audio driver? (disabled)";
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179 /* In general we should never print to the screen,
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180 but in this case we have no other way of letting
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181 the user know what happened.
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182 */
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183 fprintf(stderr, "SDL: %s\n", message);
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184 this->enabled = 0;
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185 /* Don't try to close - may hang */
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186 audio_fd = -1;
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187 #ifdef DEBUG_AUDIO
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188 fprintf(stderr, "Done disabling audio\n");
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189 #endif
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190 }
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191 #ifdef DEBUG_AUDIO
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192 fprintf(stderr, "Ready!\n");
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193 #endif
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194 }
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195 #endif /* !USE_BLOCKING_WRITES */
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196 }
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197
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198 static void DSP_PlayAudio(_THIS)
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199 {
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200 int written;
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201
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202 /* Write the audio data, checking for EAGAIN on broken audio drivers */
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203 do {
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204 written = write(audio_fd, mixbuf, mixlen);
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205 if ( (written < 0) && ((errno == 0) || (errno == EAGAIN)) ) {
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206 SDL_Delay(1); /* Let a little CPU time go by */
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207 }
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208 } while ( (written < 0) &&
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209 ((errno == 0) || (errno == EAGAIN) || (errno == EINTR)) );
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210
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211 /* If timer synchronization is enabled, set the next write frame */
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212 if ( frame_ticks ) {
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213 next_frame += frame_ticks;
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214 }
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215
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216 /* If we couldn't write, assume fatal error for now */
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217 if ( written < 0 ) {
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218 this->enabled = 0;
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219 }
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220 #ifdef DEBUG_AUDIO
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221 fprintf(stderr, "Wrote %d bytes of audio data\n", written);
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222 #endif
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223 }
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224
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225 static Uint8 *DSP_GetAudioBuf(_THIS)
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226 {
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227 return(mixbuf);
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228 }
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229
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230 static void DSP_CloseAudio(_THIS)
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231 {
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232 if ( mixbuf != NULL ) {
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233 SDL_FreeAudioMem(mixbuf);
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234 mixbuf = NULL;
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235 }
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236 if ( audio_fd >= 0 ) {
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237 close(audio_fd);
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238 audio_fd = -1;
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239 }
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240 }
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241
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242 static int DSP_ReopenAudio(_THIS, const char *audiodev, int format,
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243 SDL_AudioSpec *spec)
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244 {
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245 int frag_spec;
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246 int value;
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247
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248 /* Close and then reopen the audio device */
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249 close(audio_fd);
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250 audio_fd = open(audiodev, O_WRONLY, 0);
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251 if ( audio_fd < 0 ) {
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252 SDL_SetError("Couldn't open %s: %s", audiodev, strerror(errno));
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253 return(-1);
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254 }
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255
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256 /* Calculate the final parameters for this audio specification */
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257 SDL_CalculateAudioSpec(spec);
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258
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259 /* Determine the power of two of the fragment size */
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260 for ( frag_spec = 0; (0x01<<frag_spec) < spec->size; ++frag_spec );
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261 if ( (0x01<<frag_spec) != spec->size ) {
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262 SDL_SetError("Fragment size must be a power of two");
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263 return(-1);
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264 }
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265 frag_spec |= 0x00020000; /* two fragments, for low latency */
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266
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267 /* Set the audio buffering parameters */
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268 #ifdef DEBUG_AUDIO
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269 fprintf(stderr, "Requesting %d fragments of size %d\n",
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270 (frag_spec >> 16), 1<<(frag_spec&0xFFFF));
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271 #endif
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272 if ( ioctl(audio_fd, SNDCTL_DSP_SETFRAGMENT, &frag_spec) < 0 ) {
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273 fprintf(stderr, "Warning: Couldn't set audio fragment size\n");
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274 }
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275 #ifdef DEBUG_AUDIO
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276 { audio_buf_info info;
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277 ioctl(audio_fd, SNDCTL_DSP_GETOSPACE, &info);
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278 fprintf(stderr, "fragments = %d\n", info.fragments);
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279 fprintf(stderr, "fragstotal = %d\n", info.fragstotal);
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280 fprintf(stderr, "fragsize = %d\n", info.fragsize);
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281 fprintf(stderr, "bytes = %d\n", info.bytes);
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282 }
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283 #endif
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284
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285 /* Set the audio format */
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286 value = format;
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287 if ( (ioctl(audio_fd, SNDCTL_DSP_SETFMT, &value) < 0) ||
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288 (value != format) ) {
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289 SDL_SetError("Couldn't set audio format");
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290 return(-1);
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291 }
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292
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293 /* Set the number of channels of output */
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294 value = spec->channels;
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295 #ifdef SNDCTL_DSP_CHANNELS
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296 if ( ioctl(audio_fd, SNDCTL_DSP_CHANNELS, &value) < 0 ) {
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297 #endif
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298 value = (spec->channels > 1);
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299 ioctl(audio_fd, SNDCTL_DSP_STEREO, &value);
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300 value = (value ? 2 : 1);
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301 #ifdef SNDCTL_DSP_CHANNELS
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302 }
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303 #endif
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304 if ( value != spec->channels ) {
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305 SDL_SetError("Couldn't set audio channels");
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306 return(-1);
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307 }
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308
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309 /* Set the DSP frequency */
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310 value = spec->freq;
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311 if ( ioctl(audio_fd, SOUND_PCM_WRITE_RATE, &value) < 0 ) {
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312 SDL_SetError("Couldn't set audio frequency");
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313 return(-1);
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314 }
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315 spec->freq = value;
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316
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317 /* We successfully re-opened the audio */
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318 return(0);
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319 }
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320
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321 static int DSP_OpenAudio(_THIS, SDL_AudioSpec *spec)
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322 {
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323 char audiodev[1024];
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324 int format;
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325 int value;
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326 Uint16 test_format;
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327
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328 /* Reset the timer synchronization flag */
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329 frame_ticks = 0.0;
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330
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331 /* Open the audio device */
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332 audio_fd = SDL_OpenAudioPath(audiodev, sizeof(audiodev), OPEN_FLAGS, 0);
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333 if ( audio_fd < 0 ) {
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334 SDL_SetError("Couldn't open %s: %s", audiodev, strerror(errno));
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335 return(-1);
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336 }
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337 mixbuf = NULL;
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338
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339 /* Get a list of supported hardware formats */
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340 if ( ioctl(audio_fd, SNDCTL_DSP_GETFMTS, &value) < 0 ) {
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341 SDL_SetError("Couldn't get audio format list");
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342 return(-1);
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343 }
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344
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345 /* Try for a closest match on audio format */
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346 format = 0;
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347 for ( test_format = SDL_FirstAudioFormat(spec->format);
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348 ! format && test_format; ) {
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349 #ifdef DEBUG_AUDIO
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350 fprintf(stderr, "Trying format 0x%4.4x\n", test_format);
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351 #endif
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352 switch ( test_format ) {
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353 case AUDIO_U8:
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354 if ( value & AFMT_U8 ) {
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355 format = AFMT_U8;
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356 }
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357 break;
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358 case AUDIO_S8:
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359 if ( value & AFMT_S8 ) {
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360 format = AFMT_S8;
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361 }
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362 break;
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363 case AUDIO_S16LSB:
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364 if ( value & AFMT_S16_LE ) {
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365 format = AFMT_S16_LE;
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366 }
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367 break;
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368 case AUDIO_S16MSB:
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369 if ( value & AFMT_S16_BE ) {
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370 format = AFMT_S16_BE;
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371 }
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372 break;
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373 case AUDIO_U16LSB:
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374 if ( value & AFMT_U16_LE ) {
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375 format = AFMT_U16_LE;
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376 }
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377 break;
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378 case AUDIO_U16MSB:
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379 if ( value & AFMT_U16_BE ) {
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380 format = AFMT_U16_BE;
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381 }
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382 break;
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383 default:
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384 break;
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385 }
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386 if ( ! format ) {
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387 test_format = SDL_NextAudioFormat();
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388 }
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389 }
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390 if ( format == 0 ) {
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391 SDL_SetError("Couldn't find any hardware audio formats");
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392 return(-1);
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393 }
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394 spec->format = test_format;
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395
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396 /* Set the audio format */
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397 value = format;
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398 if ( (ioctl(audio_fd, SNDCTL_DSP_SETFMT, &value) < 0) ||
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399 (value != format) ) {
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400 SDL_SetError("Couldn't set audio format");
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401 return(-1);
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402 }
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403
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404 /* Set the number of channels of output */
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405 value = spec->channels;
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406 #ifdef SNDCTL_DSP_CHANNELS
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407 if ( ioctl(audio_fd, SNDCTL_DSP_CHANNELS, &value) < 0 ) {
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408 #endif
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409 value = (spec->channels > 1);
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410 ioctl(audio_fd, SNDCTL_DSP_STEREO, &value);
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411 value = (value ? 2 : 1);
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412 #ifdef SNDCTL_DSP_CHANNELS
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413 }
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414 #endif
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415 spec->channels = value;
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416
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417 /* Because some drivers don't allow setting the buffer size
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418 after setting the format, we must re-open the audio device
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419 once we know what format and channels are supported
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420 */
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421 if ( DSP_ReopenAudio(this, audiodev, format, spec) < 0 ) {
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422 /* Error is set by DSP_ReopenAudio() */
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423 return(-1);
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424 }
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425
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426 /* Allocate mixing buffer */
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427 mixlen = spec->size;
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428 mixbuf = (Uint8 *)SDL_AllocAudioMem(mixlen);
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429 if ( mixbuf == NULL ) {
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430 return(-1);
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431 }
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432 memset(mixbuf, spec->silence, spec->size);
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433
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434 #ifndef USE_BLOCKING_WRITES
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435 /* Check to see if we need to use select() workaround */
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436 { char *workaround;
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437 workaround = getenv("SDL_DSP_NOSELECT");
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438 if ( workaround ) {
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439 frame_ticks = (float)(spec->samples*1000)/spec->freq;
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440 next_frame = SDL_GetTicks()+frame_ticks;
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441 }
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442 }
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443 #endif /* !USE_BLOCKING_WRITES */
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444
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445 /* Get the parent process id (we're the parent of the audio thread) */
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446 parent = getpid();
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447
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448 /* We're ready to rock and roll. :-) */
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449 return(0);
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450 }
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