annotate src/audio/SDL_audiomem.c @ 956:4263beff9e38

Date: Mon, 30 Aug 2004 18:20:25 +0200 From: Joost Baas Subject: why call arts artsc? I, and a few other people at the mplayer-docs-mailinglist were wondering why you decided to call arts artsc. I understand usually users have nothing to do with libsdl, just developers, but because you can choose the audio-driver being used by mplayer, one of which is sdl, and you can also choose the sdl subdriver, it is necessary to have a well-known or logical name. artsc is not the logical choice, and it's very hard to look up the right name if you don't know what you're looking for.
author Sam Lantinga <slouken@libsdl.org>
date Fri, 17 Sep 2004 13:25:06 +0000
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1 /*
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2 SDL - Simple DirectMedia Layer
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3 Copyright (C) 1997-2004 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@libsdl.org
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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 /* Functions to allocate audio buffer memory, shareable across threads
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29 (necessary because SDL audio emulates threads with fork()
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30 */
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31
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32 #include <stdlib.h>
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33 #ifdef FORK_HACK
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34 #include <sys/types.h>
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35 #include <sys/ipc.h>
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36 #include <sys/shm.h>
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37 #include <stddef.h>
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38 #endif
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39
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40 #include "SDL_audiomem.h"
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41
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42 /* Allocate memory that will be shared between threads (freed on exit) */
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43 void *SDL_AllocAudioMem(int size)
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44 {
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45 void *chunk;
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46
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47 #ifdef FORK_HACK
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48 int semid;
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49
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50 /* Create and get the address of a shared memory segment */
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51 semid = shmget(IPC_PRIVATE, size, (IPC_CREAT|0600));
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52 if ( semid < 0 ) {
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53 return(NULL);
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54 }
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55 chunk = shmat(semid, NULL, 0);
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56
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57 /* Set the segment for deletion when it is detatched */
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58 shmctl(semid, IPC_RMID, NULL); /* Delets semid if shmat() fails */
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59 #else
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60 chunk = malloc(size);
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61 #endif
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62 return((void *)chunk);
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63 }
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64
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65 void SDL_FreeAudioMem(void *chunk)
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66 {
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67 #ifdef FORK_HACK
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68 shmdt(chunk);
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69 #else
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70 free(chunk);
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71 #endif
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72 }