annotate src/loadso/os2/SDL_sysloadso.c @ 4216:5b99971a27b4 SDL-1.2

Fixed bug #698 Hans de Goede 2009-02-13 01:10:52 PST Since the new "glitch free" version of pulseaudio (used in Fedora 10 amongst others), the sound of SDL using apps (like a simple playmus call) has been crackling. While looking in to fixing this I noticed that the current pulseaudio code in SDL uses pa_simple. However pa_simple uses a thread to pump pulseaudio events and ipc, given that SDL already has its own thread for audio handling this is clearly suboptimal, leading to unnecessary context switching IPC, etc. Also pa_simple does not allow one to implement the WaitAudio() callback for SDL audiodrivers properly. Given that my work is mostly a rewrite (although some original pieces remain) I'm attaching the new .c and .h file, as that is easier to review then the huge diff. Let me know if you also want the diff. This new version has the following features: -no longer use an additional thread next to the SDL sound thread -do not crackle with glitch free audio -when used with a newer pulse, which does glitch free audio, the total latency is the same as with the alsa driver -proper WaitAudio() implementation, saving another mixlen worth of latency -adds a WaitDone() implementation This patch has been written in consultancy with Lennart Poetering (the pulseaudio author) and has been reviewed by him for correct use of the pa API.
author Sam Lantinga <slouken@libsdl.org>
date Mon, 21 Sep 2009 09:27:08 +0000
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1 /*
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2 SDL - Simple DirectMedia Layer
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3 Copyright (C) 1997-2009 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 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., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA
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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 #include "SDL_config.h"
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23
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24 #ifdef SDL_LOADSO_OS2
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25
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26 /* * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * */
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27 /* System dependent library loading routines */
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28
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29 #include <stdio.h>
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30 #define INCL_DOSERRORS
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31 #define INCL_DOSMODULEMGR
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32 #include <os2.h>
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33
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34 #include "SDL_loadso.h"
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35
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36 void *SDL_LoadObject(const char *sofile)
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37 {
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38 HMODULE handle = NULL;
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39 char buf[512];
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40 APIRET ulrc = DosLoadModule(buf, sizeof (buf), (char *) sofile, &handle);
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41
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42 /* Generate an error message if all loads failed */
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43 if ((ulrc != NO_ERROR) || (handle == NULL))
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44 SDL_SetError("Failed loading %s: %s", sofile, buf);
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46 return((void *) handle);
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47 }
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48
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49 void *SDL_LoadFunction(void *handle, const char *name)
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50 {
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51 const char *loaderror = "Unknown error";
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52 void *symbol = NULL;
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53 APIRET ulrc = DosQueryProcAddr((HMODULE)handle, 0, (char *)name, &symbol);
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54 if (ulrc == ERROR_INVALID_HANDLE)
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55 loaderror = "Invalid module handle";
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56 else if (ulrc == ERROR_INVALID_NAME)
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57 loaderror = "Symbol not found";
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58
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59 if (symbol == NULL)
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60 SDL_SetError("Failed loading %s: %s", name, loaderror);
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61
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62 return(symbol);
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63 }
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64
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65 void SDL_UnloadObject(void *handle)
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66 {
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67 if ( handle != NULL )
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68 DosFreeModule((HMODULE) handle);
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69 }
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70
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71 #endif /* SDL_LOADSO_OS2 */