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Added a hint system to allow configuration hints to be specified by t…

…he application.
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slouken committed Feb 5, 2011
1 parent 4b99677 commit 1b7df2723b21c1167352b33b810755b787ba09e8
Showing with 222 additions and 0 deletions.
  1. +1 −0 Makefile.in
  2. +1 −0 include/SDL.h
  3. +104 −0 include/SDL_hints.h
  4. +1 −0 src/SDL.c
  5. +115 −0 src/SDL_hints.c
@@ -53,6 +53,7 @@ HDRS = \
SDL_events.h \
SDL_gesture.h \
SDL_haptic.h \
SDL_hints.h \
SDL_input.h \
SDL_joystick.h \
SDL_keyboard.h \
@@ -79,6 +79,7 @@
#include "SDL_endian.h"
#include "SDL_error.h"
#include "SDL_events.h"
#include "SDL_hints.h"
#include "SDL_loadso.h"
#include "SDL_mutex.h"
#include "SDL_power.h"
@@ -0,0 +1,104 @@
/*
SDL - Simple DihintsMedia Layer
Copyright (C) 1997-2010 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
*/

/**
* \file SDL_hints.h
*
* Official documentation for SDL configuration variables
*
* This file contains functions to set and get configuration hints,
* as well as listing each of them alphabetically.
*
* The convention for naming hints is SDL_HINT_X, where "SDL_X" is
* the environment variable that can be used to override the default.
*
* In general these hints are just that - they may or may not be
* supported or applicable on any given platform, but they provide
* a way for an application or user to give the library a hint as
* to how they would like the library to work.
*/

#ifndef _SDL_hints_h
#define _SDL_hints_h

#include "SDL_stdinc.h"

#include "begin_code.h"
/* Set up for C function definitions, even when using C++ */
#ifdef __cplusplus
/* *INDENT-OFF* */
extern "C" {
/* *INDENT-ON* */
#endif



/**
* \brief An enumeration of hint priorities
*/
typedef enum
{
SDL_HINT_DEFAULT,
SDL_HINT_NORMAL,
SDL_HINT_OVERRIDE
} SDL_HintPriority;


/**
* \brief Set a hint
*
* The priority controls the behavior when setting a hint that already
* has a value. Hints will replace existing hints of their priority and
* lower. Environment variables are considered to have override priority.
*
* \return SDL_TRUE if the hint was set, SDL_FALSE otherwise
*/
extern DECLSPEC SDL_bool SDLCALL SDL_SetHint(const char *name,
const char *value,
SDL_HintPriority priority);

/**
* \brief Get a hint
*
* \return The string value of a hint variable.
*/
extern DECLSPEC const char * SDLCALL SDL_GetHint(const char *name);

/**
* \brief Clear all hints
*
* This function is called during SDL_Quit() to free stored hints.
*/
extern DECLSPEC void SDLCALL SDL_ClearHints();


/* Ends C function definitions when using C++ */
#ifdef __cplusplus
/* *INDENT-OFF* */
}
/* *INDENT-ON* */
#endif
#include "close_code.h"

#endif /* _SDL_hints_h */

/* vi: set ts=4 sw=4 expandtab: */
@@ -246,6 +246,7 @@ SDL_Quit(void)
/* Uninstall any parachute signal handlers */
SDL_UninstallParachute();

SDL_ClearHints();
SDL_AssertionsQuit();

#ifdef DEBUG_BUILD
@@ -0,0 +1,115 @@
/*
SDL - Simple DirectMedia Layer
Copyright (C) 1997-2010 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"

#include "SDL_hints.h"


/* Assuming there aren't many hints set and they aren't being queried in
critical performance paths, we'll just use a linked list here.
*/
typedef struct SDL_Hint {
char *name;
char *value;
SDL_HintPriority priority;
struct SDL_Hint *next;
} SDL_Hint;

static SDL_Hint *SDL_hints;


SDL_bool
SDL_SetHint(const char *name, const char *value, SDL_HintPriority priority)
{
const char *env;
SDL_Hint *prev, *hint;

if (!name || !value) {
return SDL_FALSE;
}

env = SDL_getenv(name);
if (env && priority < SDL_HINT_OVERRIDE) {
return SDL_FALSE;
}

prev = NULL;
for (hint = SDL_hints; hint; prev = hint, hint = hint->next) {
if (SDL_strcmp(name, hint->name) == 0) {
if (priority < hint->priority) {
return SDL_FALSE;
}
if (SDL_strcmp(hint->value, value) != 0) {
SDL_free(hint->value);
hint->value = SDL_strdup(value);
}
hint->priority = priority;
return SDL_TRUE;
}
}

/* Couldn't find the hint, add a new one */
hint = (SDL_Hint *)SDL_malloc(sizeof(*hint));
if (!hint) {
return SDL_FALSE;
}
hint->name = SDL_strdup(name);
hint->value = SDL_strdup(value);
hint->priority = priority;
hint->next = SDL_hints;
SDL_hints = hint;
return SDL_TRUE;
}

const char *
SDL_GetHint(const char *name)
{
const char *env;
SDL_Hint *hint;

env = SDL_getenv(name);
for (hint = SDL_hints; hint; hint = hint->next) {
if (SDL_strcmp(name, hint->name) == 0) {
if (!env || hint->priority == SDL_HINT_OVERRIDE) {
return hint->value;
}
break;
}
}
return env;
}

void SDL_ClearHints()
{
SDL_Hint *hint;

while (SDL_hints) {
hint = SDL_hints;
SDL_hints = hint->next;

SDL_free(hint->name);
SDL_free(hint->value);
SDL_free(hint);
}
}

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

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