Mercurial > sdl-ios-xcode
annotate docs/html/guideaudioexamples.html @ 4355:9b464226e541 SDL-1.2
Fixed bug #855
Ludwig Nussel 2009-10-18 06:31:52 PDT
an mprotect call was added to fix bug 528. However that results in a buffer
that allows writing and code execution. Ie the no-execute security features of
modern operating systems are defeated this way. Two mprotect calls are needed.
One to make the buffer executable but not writeable when done and another one
to make the buffer writeable again if the content needs to be changed.
| author | Sam Lantinga <slouken@libsdl.org> |
|---|---|
| date | Sun, 18 Oct 2009 17:31:37 +0000 |
| parents | 355632dca928 |
| children |
| rev | line source |
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| 0 | 1 <HTML |
| 2 ><HEAD | |
| 3 ><TITLE | |
| 4 >Audio Examples</TITLE | |
| 5 ><META | |
| 6 NAME="GENERATOR" | |
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7 CONTENT="Modular DocBook HTML Stylesheet Version 1.76b+ |
| 0 | 8 "><LINK |
| 9 REL="HOME" | |
| 10 TITLE="SDL Library Documentation" | |
| 11 HREF="index.html"><LINK | |
| 12 REL="UP" | |
| 13 TITLE="Examples" | |
| 14 HREF="guideexamples.html"><LINK | |
| 15 REL="PREVIOUS" | |
| 16 TITLE="Event Examples" | |
| 17 HREF="guideeventexamples.html"><LINK | |
| 18 REL="NEXT" | |
| 19 TITLE="CDROM Examples" | |
| 20 HREF="guidecdromexamples.html"></HEAD | |
| 21 ><BODY | |
| 22 CLASS="SECT1" | |
| 23 BGCOLOR="#FFF8DC" | |
| 24 TEXT="#000000" | |
| 25 LINK="#0000ee" | |
| 26 VLINK="#551a8b" | |
| 27 ALINK="#ff0000" | |
| 28 ><DIV | |
| 29 CLASS="NAVHEADER" | |
| 30 ><TABLE | |
|
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31 SUMMARY="Header navigation table" |
| 0 | 32 WIDTH="100%" |
| 33 BORDER="0" | |
| 34 CELLPADDING="0" | |
| 35 CELLSPACING="0" | |
| 36 ><TR | |
| 37 ><TH | |
| 38 COLSPAN="3" | |
| 39 ALIGN="center" | |
| 40 >SDL Library Documentation</TH | |
| 41 ></TR | |
| 42 ><TR | |
| 43 ><TD | |
| 44 WIDTH="10%" | |
| 45 ALIGN="left" | |
| 46 VALIGN="bottom" | |
| 47 ><A | |
| 48 HREF="guideeventexamples.html" | |
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49 ACCESSKEY="P" |
| 0 | 50 >Prev</A |
| 51 ></TD | |
| 52 ><TD | |
| 53 WIDTH="80%" | |
| 54 ALIGN="center" | |
| 55 VALIGN="bottom" | |
| 56 >Chapter 4. Examples</TD | |
| 57 ><TD | |
| 58 WIDTH="10%" | |
| 59 ALIGN="right" | |
| 60 VALIGN="bottom" | |
| 61 ><A | |
| 62 HREF="guidecdromexamples.html" | |
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63 ACCESSKEY="N" |
| 0 | 64 >Next</A |
| 65 ></TD | |
| 66 ></TR | |
| 67 ></TABLE | |
| 68 ><HR | |
| 69 ALIGN="LEFT" | |
| 70 WIDTH="100%"></DIV | |
| 71 ><DIV | |
| 72 CLASS="SECT1" | |
| 73 ><H1 | |
| 74 CLASS="SECT1" | |
| 75 ><A | |
| 76 NAME="GUIDEAUDIOEXAMPLES" | |
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77 ></A |
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78 >Audio Examples</H1 |
| 0 | 79 ><P |
| 80 ></P | |
| 81 ><DIV | |
| 82 CLASS="SECT2" | |
| 83 ><H2 | |
| 84 CLASS="SECT2" | |
| 85 ><A | |
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86 NAME="AEN382" |
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87 ></A |
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88 >Opening the audio device</H2 |
| 0 | 89 ><P |
| 90 ><PRE | |
| 91 CLASS="PROGRAMLISTING" | |
| 92 > SDL_AudioSpec wanted; | |
| 93 extern void fill_audio(void *udata, Uint8 *stream, int len); | |
| 94 | |
| 95 /* Set the audio format */ | |
| 96 wanted.freq = 22050; | |
| 97 wanted.format = AUDIO_S16; | |
| 98 wanted.channels = 2; /* 1 = mono, 2 = stereo */ | |
| 99 wanted.samples = 1024; /* Good low-latency value for callback */ | |
| 100 wanted.callback = fill_audio; | |
| 101 wanted.userdata = NULL; | |
| 102 | |
| 103 /* Open the audio device, forcing the desired format */ | |
| 104 if ( SDL_OpenAudio(&wanted, NULL) < 0 ) { | |
| 105 fprintf(stderr, "Couldn't open audio: %s\n", SDL_GetError()); | |
| 106 return(-1); | |
| 107 } | |
| 108 return(0);</PRE | |
| 109 ></P | |
| 110 ></DIV | |
| 111 ><DIV | |
| 112 CLASS="SECT2" | |
| 113 ><H2 | |
| 114 CLASS="SECT2" | |
| 115 ><A | |
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116 NAME="AEN386" |
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117 ></A |
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118 >Playing audio</H2 |
| 0 | 119 ><P |
| 120 ><PRE | |
| 121 CLASS="PROGRAMLISTING" | |
| 122 > static Uint8 *audio_chunk; | |
| 123 static Uint32 audio_len; | |
| 124 static Uint8 *audio_pos; | |
| 125 | |
| 126 /* The audio function callback takes the following parameters: | |
| 127 stream: A pointer to the audio buffer to be filled | |
| 128 len: The length (in bytes) of the audio buffer | |
| 129 */ | |
| 130 void fill_audio(void *udata, Uint8 *stream, int len) | |
| 131 { | |
| 132 /* Only play if we have data left */ | |
| 133 if ( audio_len == 0 ) | |
| 134 return; | |
| 135 | |
| 136 /* Mix as much data as possible */ | |
| 137 len = ( len > audio_len ? audio_len : len ); | |
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138 SDL_MixAudio(stream, audio_pos, len, SDL_MIX_MAXVOLUME); |
| 0 | 139 audio_pos += len; |
| 140 audio_len -= len; | |
| 141 } | |
| 142 | |
| 143 /* Load the audio data ... */ | |
| 144 | |
| 145 ;;;;; | |
| 146 | |
| 147 audio_pos = audio_chunk; | |
| 148 | |
| 149 /* Let the callback function play the audio chunk */ | |
| 150 SDL_PauseAudio(0); | |
| 151 | |
| 152 /* Do some processing */ | |
| 153 | |
| 154 ;;;;; | |
| 155 | |
| 156 /* Wait for sound to complete */ | |
| 157 while ( audio_len > 0 ) { | |
| 158 SDL_Delay(100); /* Sleep 1/10 second */ | |
| 159 } | |
| 160 SDL_CloseAudio();</PRE | |
| 161 ></P | |
| 162 ></DIV | |
| 163 ></DIV | |
| 164 ><DIV | |
| 165 CLASS="NAVFOOTER" | |
| 166 ><HR | |
| 167 ALIGN="LEFT" | |
| 168 WIDTH="100%"><TABLE | |
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169 SUMMARY="Footer navigation table" |
| 0 | 170 WIDTH="100%" |
| 171 BORDER="0" | |
| 172 CELLPADDING="0" | |
| 173 CELLSPACING="0" | |
| 174 ><TR | |
| 175 ><TD | |
| 176 WIDTH="33%" | |
| 177 ALIGN="left" | |
| 178 VALIGN="top" | |
| 179 ><A | |
| 180 HREF="guideeventexamples.html" | |
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181 ACCESSKEY="P" |
| 0 | 182 >Prev</A |
| 183 ></TD | |
| 184 ><TD | |
| 185 WIDTH="34%" | |
| 186 ALIGN="center" | |
| 187 VALIGN="top" | |
| 188 ><A | |
| 189 HREF="index.html" | |
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355632dca928
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parents:
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190 ACCESSKEY="H" |
| 0 | 191 >Home</A |
| 192 ></TD | |
| 193 ><TD | |
| 194 WIDTH="33%" | |
| 195 ALIGN="right" | |
| 196 VALIGN="top" | |
| 197 ><A | |
| 198 HREF="guidecdromexamples.html" | |
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parents:
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199 ACCESSKEY="N" |
| 0 | 200 >Next</A |
| 201 ></TD | |
| 202 ></TR | |
| 203 ><TR | |
| 204 ><TD | |
| 205 WIDTH="33%" | |
| 206 ALIGN="left" | |
| 207 VALIGN="top" | |
| 208 >Event Examples</TD | |
| 209 ><TD | |
| 210 WIDTH="34%" | |
| 211 ALIGN="center" | |
| 212 VALIGN="top" | |
| 213 ><A | |
| 214 HREF="guideexamples.html" | |
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parents:
181
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215 ACCESSKEY="U" |
| 0 | 216 >Up</A |
| 217 ></TD | |
| 218 ><TD | |
| 219 WIDTH="33%" | |
| 220 ALIGN="right" | |
| 221 VALIGN="top" | |
| 222 >CDROM Examples</TD | |
| 223 ></TR | |
| 224 ></TABLE | |
| 225 ></DIV | |
| 226 ></BODY | |
| 227 ></HTML | |
| 228 > |