src/SDL_hints.c
author Philipp Wiesemann <philipp.wiesemann@arcor.de>
Wed, 20 Aug 2014 22:49:59 +0200
changeset 9104 8824a6a7ed69
parent 8149 681eb46b8ac4
child 9201 21d9f9babb30
permissions -rw-r--r--
Fixed not needed standard includes in test program.
     1 /*
     2   Simple DirectMedia Layer
     3   Copyright (C) 1997-2014 Sam Lantinga <slouken@libsdl.org>
     4 
     5   This software is provided 'as-is', without any express or implied
     6   warranty.  In no event will the authors be held liable for any damages
     7   arising from the use of this software.
     8 
     9   Permission is granted to anyone to use this software for any purpose,
    10   including commercial applications, and to alter it and redistribute it
    11   freely, subject to the following restrictions:
    12 
    13   1. The origin of this software must not be misrepresented; you must not
    14      claim that you wrote the original software. If you use this software
    15      in a product, an acknowledgment in the product documentation would be
    16      appreciated but is not required.
    17   2. Altered source versions must be plainly marked as such, and must not be
    18      misrepresented as being the original software.
    19   3. This notice may not be removed or altered from any source distribution.
    20 */
    21 #include "./SDL_internal.h"
    22 
    23 #include "SDL_hints.h"
    24 #include "SDL_error.h"
    25 
    26 
    27 /* Assuming there aren't many hints set and they aren't being queried in
    28    critical performance paths, we'll just use linked lists here.
    29  */
    30 typedef struct SDL_HintWatch {
    31     SDL_HintCallback callback;
    32     void *userdata;
    33     struct SDL_HintWatch *next;
    34 } SDL_HintWatch;
    35 
    36 typedef struct SDL_Hint {
    37     char *name;
    38     char *value;
    39     SDL_HintPriority priority;
    40     SDL_HintWatch *callbacks;
    41     struct SDL_Hint *next;
    42 } SDL_Hint;
    43 
    44 static SDL_Hint *SDL_hints;
    45 
    46 SDL_bool
    47 SDL_SetHintWithPriority(const char *name, const char *value,
    48                         SDL_HintPriority priority)
    49 {
    50     const char *env;
    51     SDL_Hint *hint;
    52     SDL_HintWatch *entry;
    53 
    54     if (!name || !value) {
    55         return SDL_FALSE;
    56     }
    57 
    58     env = SDL_getenv(name);
    59     if (env && priority < SDL_HINT_OVERRIDE) {
    60         return SDL_FALSE;
    61     }
    62 
    63     for (hint = SDL_hints; hint; hint = hint->next) {
    64         if (SDL_strcmp(name, hint->name) == 0) {
    65             if (priority < hint->priority) {
    66                 return SDL_FALSE;
    67             }
    68             if (!hint->value || !value || SDL_strcmp(hint->value, value) != 0) {
    69                 for (entry = hint->callbacks; entry; ) {
    70                     /* Save the next entry in case this one is deleted */
    71                     SDL_HintWatch *next = entry->next;
    72                     entry->callback(entry->userdata, name, hint->value, value);
    73                     entry = next;
    74                 }
    75                 SDL_free(hint->value);
    76                 hint->value = value ? SDL_strdup(value) : NULL;
    77             }
    78             hint->priority = priority;
    79             return SDL_TRUE;
    80         }
    81     }
    82 
    83     /* Couldn't find the hint, add a new one */
    84     hint = (SDL_Hint *)SDL_malloc(sizeof(*hint));
    85     if (!hint) {
    86         return SDL_FALSE;
    87     }
    88     hint->name = SDL_strdup(name);
    89     hint->value = value ? SDL_strdup(value) : NULL;
    90     hint->priority = priority;
    91     hint->callbacks = NULL;
    92     hint->next = SDL_hints;
    93     SDL_hints = hint;
    94     return SDL_TRUE;
    95 }
    96 
    97 SDL_bool
    98 SDL_SetHint(const char *name, const char *value)
    99 {
   100     return SDL_SetHintWithPriority(name, value, SDL_HINT_NORMAL);
   101 }
   102 
   103 const char *
   104 SDL_GetHint(const char *name)
   105 {
   106     const char *env;
   107     SDL_Hint *hint;
   108 
   109     env = SDL_getenv(name);
   110     for (hint = SDL_hints; hint; hint = hint->next) {
   111         if (SDL_strcmp(name, hint->name) == 0) {
   112             if (!env || hint->priority == SDL_HINT_OVERRIDE) {
   113                 return hint->value;
   114             }
   115             break;
   116         }
   117     }
   118     return env;
   119 }
   120 
   121 void
   122 SDL_AddHintCallback(const char *name, SDL_HintCallback callback, void *userdata)
   123 {
   124     SDL_Hint *hint;
   125     SDL_HintWatch *entry;
   126     const char *value;
   127 
   128     if (!name || !*name) {
   129         SDL_InvalidParamError("name");
   130         return;
   131     }
   132     if (!callback) {
   133         SDL_InvalidParamError("callback");
   134         return;
   135     }
   136 
   137     SDL_DelHintCallback(name, callback, userdata);
   138 
   139     entry = (SDL_HintWatch *)SDL_malloc(sizeof(*entry));
   140     entry->callback = callback;
   141     entry->userdata = userdata;
   142 
   143     for (hint = SDL_hints; hint; hint = hint->next) {
   144         if (SDL_strcmp(name, hint->name) == 0) {
   145             break;
   146         }
   147     }
   148     if (!hint) {
   149         /* Need to add a hint entry for this watcher */
   150         hint = (SDL_Hint *)SDL_malloc(sizeof(*hint));
   151         if (!hint) {
   152             return;
   153         }
   154         hint->name = SDL_strdup(name);
   155         hint->value = NULL;
   156         hint->priority = SDL_HINT_DEFAULT;
   157         hint->callbacks = NULL;
   158         hint->next = SDL_hints;
   159         SDL_hints = hint;
   160     }
   161 
   162     /* Add it to the callbacks for this hint */
   163     entry->next = hint->callbacks;
   164     hint->callbacks = entry;
   165 
   166     /* Now call it with the current value */
   167     value = SDL_GetHint(name);
   168     callback(userdata, name, value, value);
   169 }
   170 
   171 void
   172 SDL_DelHintCallback(const char *name, SDL_HintCallback callback, void *userdata)
   173 {
   174     SDL_Hint *hint;
   175     SDL_HintWatch *entry, *prev;
   176 
   177     for (hint = SDL_hints; hint; hint = hint->next) {
   178         if (SDL_strcmp(name, hint->name) == 0) {
   179             prev = NULL;
   180             for (entry = hint->callbacks; entry; entry = entry->next) {
   181                 if (callback == entry->callback && userdata == entry->userdata) {
   182                     if (prev) {
   183                         prev->next = entry->next;
   184                     } else {
   185                         hint->callbacks = entry->next;
   186                     }
   187                     SDL_free(entry);
   188                     break;
   189                 }
   190                 prev = entry;
   191             }
   192             return;
   193         }
   194     }
   195 }
   196 
   197 void SDL_ClearHints(void)
   198 {
   199     SDL_Hint *hint;
   200     SDL_HintWatch *entry;
   201 
   202     while (SDL_hints) {
   203         hint = SDL_hints;
   204         SDL_hints = hint->next;
   205 
   206         SDL_free(hint->name);
   207         SDL_free(hint->value);
   208         for (entry = hint->callbacks; entry; ) {
   209             SDL_HintWatch *freeable = entry;
   210             entry = entry->next;
   211             SDL_free(freeable);
   212         }
   213         SDL_free(hint);
   214     }
   215 }
   216 
   217 /* vi: set ts=4 sw=4 expandtab: */