view src/audio/baudio/SDL_beaudio.cc @ 3162:dc1eb82ffdaa

Von: Thomas Zimmermann Betreff: [SDL] [PATCH] Make static variables const Datum: Tue, 19 May 2009 19:45:37 +0200 Hi, this is a set of simple changes which make some of SDL's internal static arrays constant. The purpose is to shrink the number of write-able static bytes and thus increase the number of memory pages shared between SDL applications. The patch set is against trunk@4513. Each of the attached patch files is specific to a sub-system. The set is completed by a second mail, because of the list's 40 KiB limit. The files readelf-r4513.txt and readelf-const-patch.txt where made by calling 'readelf -S libSDL.so'. They show the difference in ELF sections without and with the patch. Some numbers measured on my x86-64: Before [13] .rodata PROGBITS 00000000000eaaa0 000eaaa0 0000000000008170 0000000000000000 A 0 0 32 [19] .data.rel.ro PROGBITS 00000000003045e0 001045e0 00000000000023d0 0000000000000000 WA 0 0 32 [23] .data PROGBITS 00000000003076e0 001076e0 0000000000004988 0000000000000000 WA 0 0 32 After [13] .rodata PROGBITS 00000000000eaaa0 000eaaa0 0000000000009a50 0000000000000000 A 0 0 32 [19] .data.rel.ro PROGBITS 0000000000306040 00106040 0000000000002608 0000000000000000 WA 0 0 32 [23] .data PROGBITS 0000000000309360 00109360 0000000000002e88 0000000000000000 WA 0 0 32 The size of the write-able data section decreased considerably. Some entries became const-after-relocation, while most of its content went straight into the read-only data section. Best regards, Thomas
author Sam Lantinga <slouken@libsdl.org>
date Wed, 03 Jun 2009 04:37:27 +0000
parents 99210400e8b9
children 4160ba33b597
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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 Lesser General Public
    License as published by the Free Software Foundation; either
    version 2.1 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
    Lesser General Public License for more details.

    You should have received a copy of the GNU Lesser General Public
    License along with this library; if not, write to the Free Software
    Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA

    Sam Lantinga
    slouken@libsdl.org
*/
#include "SDL_config.h"

/* Allow access to the audio stream on BeOS */

#include <SoundPlayer.h>

#include "../../main/beos/SDL_BeApp.h"

extern "C"
{

#include "SDL_audio.h"
#include "../SDL_audio_c.h"
#include "../SDL_sysaudio.h"
#include "../../thread/beos/SDL_systhread_c.h"
#include "SDL_beaudio.h"

}


/* !!! FIXME: have the callback call the higher level to avoid code dupe. */
/* The BeOS callback for handling the audio buffer */
static void
FillSound(void *device, void *stream, size_t len,
          const media_raw_audio_format & format)
{
    SDL_AudioDevice *audio = (SDL_AudioDevice *) device;

    /* Silence the buffer, since it's ours */
    SDL_memset(stream, audio->spec.silence, len);

    /* Only do soemthing if audio is enabled */
    if (!audio->enabled)
        return;

    if (!audio->paused) {
        if (audio->convert.needed) {
            SDL_mutexP(audio->mixer_lock);
            (*audio->spec.callback) (audio->spec.userdata,
                                     (Uint8 *) audio->convert.buf,
                                     audio->convert.len);
            SDL_mutexV(audio->mixer_lock);
            SDL_ConvertAudio(&audio->convert);
            SDL_memcpy(stream, audio->convert.buf, audio->convert.len_cvt);
        } else {
            SDL_mutexP(audio->mixer_lock);
            (*audio->spec.callback) (audio->spec.userdata,
                                     (Uint8 *) stream, len);
            SDL_mutexV(audio->mixer_lock);
        }
    }
}

static void
BEOSAUDIO_CloseDevice(_THIS)
{
    if (_this->hidden != NULL) {
        if (_this->hidden->audio_obj) {
            _this->hidden->audio_obj->Stop();
            delete _this->hidden->audio_obj;
            _this->hidden->audio_obj = NULL;
        }

        delete _this->hidden;
        _this->hidden = NULL;
    }
}

static int
BEOSAUDIO_OpenDevice(_THIS, const char *devname, int iscapture)
{
    int valid_datatype = 0;
    media_raw_audio_format format;
    SDL_AudioFormat test_format = SDL_FirstAudioFormat(_this->spec.format);

    /* Initialize all variables that we clean on shutdown */
    _this->hidden = new SDL_PrivateAudioData;
    if (_this->hidden == NULL) {
        SDL_OutOfMemory();
        return 0;
    }
    SDL_memset(_this->hidden, 0, (sizeof *_this->hidden));

    /* Parse the audio format and fill the Be raw audio format */
    SDL_memset(&format, '\0', sizeof(media_raw_audio_format));
    format.byte_order = B_MEDIA_LITTLE_ENDIAN;
    format.frame_rate = (float) _this->spec.freq;
    format.channel_count = _this->spec.channels;        /* !!! FIXME: support > 2? */
    while ((!valid_datatype) && (test_format)) {
        valid_datatype = 1;
        _this->spec.format = test_format;
        switch (test_format) {
        case AUDIO_S8:
            format.format = media_raw_audio_format::B_AUDIO_CHAR;
            break;

        case AUDIO_U8:
            format.format = media_raw_audio_format::B_AUDIO_UCHAR;
            break;

        case AUDIO_S16LSB:
            format.format = media_raw_audio_format::B_AUDIO_SHORT;
            break;

        case AUDIO_S16MSB:
            format.format = media_raw_audio_format::B_AUDIO_SHORT;
            format.byte_order = B_MEDIA_BIG_ENDIAN;
            break;

        case AUDIO_S32LSB:
            format.format = media_raw_audio_format::B_AUDIO_INT;
            break;

        case AUDIO_S32MSB:
            format.format = media_raw_audio_format::B_AUDIO_INT;
            format.byte_order = B_MEDIA_BIG_ENDIAN;
            break;

        case AUDIO_F32LSB:
            format.format = media_raw_audio_format::B_AUDIO_FLOAT;
            break;

        case AUDIO_F32MSB:
            format.format = media_raw_audio_format::B_AUDIO_FLOAT;
            format.byte_order = B_MEDIA_BIG_ENDIAN;
            break;

        default:
            valid_datatype = 0;
            test_format = SDL_NextAudioFormat();
            break;
        }
    }

    format.buffer_size = _this->spec.samples;

    if (!valid_datatype) {      /* shouldn't happen, but just in case... */
        BEOSAUDIO_CloseDevice(_this);
        SDL_SetError("Unsupported audio format");
        return 0;
    }

    /* Calculate the final parameters for this audio specification */
    SDL_CalculateAudioSpec(&_this->spec);

    /* Subscribe to the audio stream (creates a new thread) */
    sigset_t omask;
    SDL_MaskSignals(&omask);
    _this->hidden->audio_obj = new BSoundPlayer(&format, "SDL Audio",
                                                FillSound, NULL, _this);
    SDL_UnmaskSignals(&omask);

    if (_this->hidden->audio_obj->Start() == B_NO_ERROR) {
        _this->hidden->audio_obj->SetHasData(true);
    } else {
        BEOSAUDIO_CloseDevice(_this);
        SDL_SetError("Unable to start Be audio");
        return 0;
    }

    /* We're running! */
    return 1;
}

static void
BEOSAUDIO_Deinitialize(void)
{
    SDL_QuitBeApp();
}

static int
BEOSAUDIO_Init(SDL_AudioDriverImpl * impl)
{
    /* Initialize the Be Application, if it's not already started */
    if (SDL_InitBeApp() < 0) {
        return 0;
    }

    /* Set the function pointers */
    impl->OpenDevice = BEOSAUDIO_OpenDevice;
    impl->CloseDevice = BEOSAUDIO_CloseDevice;
    impl->Deinitialize = BEOSAUDIO_Deinitialize;
    impl->ProvidesOwnCallbackThread = 1;
    impl->OnlyHasDefaultOutputDevice = 1;

    return 1;
}

extern "C"
{
    extern AudioBootStrap BEOSAUDIO_bootstrap;
}
AudioBootStrap BEOSAUDIO_bootstrap = {
    "baudio", "BeOS BSoundPlayer", BEOSAUDIO_Init, 0
};

/* vi: set ts=4 sw=4 expandtab: */