view include/begin_code.h @ 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
parents 430e6690c4cd
children 4c4113c2162c
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/*
    SDL - Simple DirectMedia Layer
    Copyright (C) 1997-2009 Sam Lantinga

    This library is free software; you can redistribute it and/or
    modify it under the terms of the GNU Library General Public
    License as published by the Free Software Foundation; either
    version 2 of the License, or (at your option) any later version.

    This library is distributed in the hope that it will be useful,
    but WITHOUT ANY WARRANTY; without even the implied warranty of
    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
    Library General Public License for more details.

    You should have received a copy of the GNU Library General Public
    License along with this library; if not, write to the Free
    Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA

    Sam Lantinga
    slouken@libsdl.org
*/

/* This file sets things up for C dynamic library function definitions,
   static inlined functions, and structures aligned at 4-byte alignment.
   If you don't like ugly C preprocessor code, don't look at this file. :)
*/

/* This shouldn't be nested -- included it around code only. */
#ifdef _begin_code_h
#error Nested inclusion of begin_code.h
#endif
#define _begin_code_h

/* Some compilers use a special export keyword */
#ifndef DECLSPEC
# if defined(__BEOS__) || defined(__HAIKU__)
#  if defined(__GNUC__)
#   define DECLSPEC	__declspec(dllexport)
#  else
#   define DECLSPEC	__declspec(export)
#  endif
# elif defined(__WIN32__)
#  ifdef __BORLANDC__
#   ifdef BUILD_SDL
#    define DECLSPEC 
#   else
#    define DECLSPEC	__declspec(dllimport)
#   endif
#  else
#   define DECLSPEC	__declspec(dllexport)
#  endif
# elif defined(__OS2__)
#  ifdef __WATCOMC__
#   ifdef BUILD_SDL
#    define DECLSPEC	__declspec(dllexport)
#   else
#    define DECLSPEC
#   endif
#  elif defined (__GNUC__) && __GNUC__ < 4
#   /* Added support for GCC-EMX <v4.x */
#   /* this is needed for XFree86/OS2 developement */
#   /* F. Ambacher(anakor@snafu.de) 05.2008 */
#   ifdef BUILD_SDL
#    define DECLSPEC    __declspec(dllexport)
#   else
#    define DECLSPEC
#   endif
#  else
#   define DECLSPEC
#  endif
# else
#  if defined(__GNUC__) && __GNUC__ >= 4
#   define DECLSPEC	__attribute__ ((visibility("default")))
#  else
#   define DECLSPEC
#  endif
# endif
#endif

/* By default SDL uses the C calling convention */
#ifndef SDLCALL
# if defined(__WIN32__) && !defined(__GNUC__)
#  define SDLCALL __cdecl
# elif defined(__OS2__)
#  if defined (__GNUC__) && __GNUC__ < 4
#   /* Added support for GCC-EMX <v4.x */
#   /* this is needed for XFree86/OS2 developement */
#   /* F. Ambacher(anakor@snafu.de) 05.2008 */
#   define SDLCALL _cdecl
#  else
#   /* On other compilers on OS/2, we use the _System calling convention */
#   /* to be compatible with every compiler */
#   define SDLCALL _System
#  endif
# else
#  define SDLCALL
# endif
#endif /* SDLCALL */

#ifdef __SYMBIAN32__ 
#ifndef EKA2 
#undef DECLSPEC
#define DECLSPEC
#elif !defined(__WINS__)
#undef DECLSPEC
#define DECLSPEC __declspec(dllexport)
#endif /* !EKA2 */
#endif /* __SYMBIAN32__ */

/* Force structure packing at 4 byte alignment.
   This is necessary if the header is included in code which has structure
   packing set to an alternate value, say for loading structures from disk.
   The packing is reset to the previous value in close_code.h
 */
#if defined(_MSC_VER) || defined(__MWERKS__) || defined(__BORLANDC__)
#ifdef _MSC_VER
#pragma warning(disable: 4103)
#endif
#ifdef __BORLANDC__
#pragma nopackwarning
#endif
#pragma pack(push,4)
#elif (defined(__MWERKS__) && defined(__MACOS__))
#pragma options align=mac68k4byte
#pragma enumsalwaysint on
#endif /* Compiler needs structure packing set */

/* Set up compiler-specific options for inlining functions */
#ifndef SDL_INLINE_OKAY
#ifdef __GNUC__
#define SDL_INLINE_OKAY
#else
/* Add any special compiler-specific cases here */
#if defined(_MSC_VER) || defined(__BORLANDC__) || \
    defined(__DMC__) || defined(__SC__) || \
    defined(__WATCOMC__) || defined(__LCC__) || \
    defined(__DECC) || defined(__EABI__)
#ifndef __inline__
#define __inline__	__inline
#endif
#define SDL_INLINE_OKAY
#else
#if !defined(__MRC__) && !defined(_SGI_SOURCE)
#ifndef __inline__
#define __inline__ inline
#endif
#define SDL_INLINE_OKAY
#endif /* Not a funky compiler */
#endif /* Visual C++ */
#endif /* GNU C */
#endif /* SDL_INLINE_OKAY */

/* If inlining isn't supported, remove "__inline__", turning static
   inlined functions into static functions (resulting in code bloat
   in all files which include the offending header files)
*/
#ifndef SDL_INLINE_OKAY
#define __inline__
#endif

/* Apparently this is needed by several Windows compilers */
#if !defined(__MACH__)
#ifndef NULL
#ifdef __cplusplus
#define NULL 0
#else
#define NULL ((void *)0)
#endif
#endif /* NULL */
#endif /* ! Mac OS X - breaks precompiled headers */