From 1b7df2723b21c1167352b33b810755b787ba09e8 Mon Sep 17 00:00:00 2001 From: Sam Lantinga Date: Sat, 5 Feb 2011 10:02:39 -0800 Subject: [PATCH] Added a hint system to allow configuration hints to be specified by the application. --- Makefile.in | 1 + include/SDL.h | 1 + include/SDL_hints.h | 104 +++++++++++++++++++++++++++++++++++++++ src/SDL.c | 1 + src/SDL_hints.c | 115 ++++++++++++++++++++++++++++++++++++++++++++ 5 files changed, 222 insertions(+) create mode 100644 include/SDL_hints.h create mode 100644 src/SDL_hints.c diff --git a/Makefile.in b/Makefile.in index 82644d96d..569b64b3e 100644 --- a/Makefile.in +++ b/Makefile.in @@ -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 \ diff --git a/include/SDL.h b/include/SDL.h index 079b7d570..483064f2e 100644 --- a/include/SDL.h +++ b/include/SDL.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" diff --git a/include/SDL_hints.h b/include/SDL_hints.h new file mode 100644 index 000000000..ed6401a52 --- /dev/null +++ b/include/SDL_hints.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: */ diff --git a/src/SDL.c b/src/SDL.c index 53a1b8a1d..e6109bc34 100644 --- a/src/SDL.c +++ b/src/SDL.c @@ -246,6 +246,7 @@ SDL_Quit(void) /* Uninstall any parachute signal handlers */ SDL_UninstallParachute(); + SDL_ClearHints(); SDL_AssertionsQuit(); #ifdef DEBUG_BUILD diff --git a/src/SDL_hints.c b/src/SDL_hints.c new file mode 100644 index 000000000..b96c4e4bd --- /dev/null +++ b/src/SDL_hints.c @@ -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: */