view src/joystick/SDL_sysjoystick.h @ 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 f7b03b6838cb
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/*
    SDL - Simple DirectMedia Layer
    Copyright (C) 1997-2009 Sam Lantinga

    This library is SDL_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"

/* This is the system specific header for the SDL joystick API */

#include "SDL_joystick.h"

/* The SDL joystick structure */
struct _SDL_Joystick
{
    Uint8 index;                /* Device index */
    const char *name;           /* Joystick name - system dependent */

    int naxes;                  /* Number of axis controls on the joystick */
    Sint16 *axes;               /* Current axis states */

    int nhats;                  /* Number of hats on the joystick */
    Uint8 *hats;                /* Current hat states */

    int nballs;                 /* Number of trackballs on the joystick */
    struct balldelta
    {
        int dx;
        int dy;
    } *balls;                   /* Current ball motion deltas */

    int nbuttons;               /* Number of buttons on the joystick */
    Uint8 *buttons;             /* Current button states */

    struct joystick_hwdata *hwdata;     /* Driver dependent information */

    int ref_count;              /* Reference count for multiple opens */
};

/* Function to scan the system for joysticks.
 * Joystick 0 should be the system default joystick.
 * This function should return the number of available joysticks, or -1
 * on an unrecoverable fatal error.
 */
extern int SDL_SYS_JoystickInit(void);

/* Function to get the device-dependent name of a joystick */
extern const char *SDL_SYS_JoystickName(int index);

/* Function to open a joystick for use.
   The joystick to open is specified by the index field of the joystick.
   This should fill the nbuttons and naxes fields of the joystick structure.
   It returns 0, or -1 if there is an error.
 */
extern int SDL_SYS_JoystickOpen(SDL_Joystick * joystick);

/* Function to update the state of a joystick - called as a device poll.
 * This function shouldn't update the joystick structure directly,
 * but instead should call SDL_PrivateJoystick*() to deliver events
 * and update joystick device state.
 */
extern void SDL_SYS_JoystickUpdate(SDL_Joystick * joystick);

/* Function to close a joystick after use */
extern void SDL_SYS_JoystickClose(SDL_Joystick * joystick);

/* Function to perform any system-specific joystick related cleanup */
extern void SDL_SYS_JoystickQuit(void);

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