src/SDL_hints.c
author Ozkan Sezer
Thu, 21 Nov 2019 11:50:50 +0300
changeset 13267 a8e016c00f2e
parent 13246 6cdf7579575f
child 13422 fd6a12de91c7
permissions -rw-r--r--
ran gendynapi.pl after newly added SDL_string.c functions.
     1 /*
     2   Simple DirectMedia Layer
     3   Copyright (C) 1997-2019 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 #include "SDL_hints_c.h"
    26 
    27 
    28 /* Assuming there aren't many hints set and they aren't being queried in
    29    critical performance paths, we'll just use linked lists here.
    30  */
    31 typedef struct SDL_HintWatch {
    32     SDL_HintCallback callback;
    33     void *userdata;
    34     struct SDL_HintWatch *next;
    35 } SDL_HintWatch;
    36 
    37 typedef struct SDL_Hint {
    38     char *name;
    39     char *value;
    40     SDL_HintPriority priority;
    41     SDL_HintWatch *callbacks;
    42     struct SDL_Hint *next;
    43 } SDL_Hint;
    44 
    45 static SDL_Hint *SDL_hints;
    46 
    47 SDL_bool
    48 SDL_SetHintWithPriority(const char *name, const char *value,
    49                         SDL_HintPriority priority)
    50 {
    51     const char *env;
    52     SDL_Hint *hint;
    53     SDL_HintWatch *entry;
    54 
    55     if (!name || !value) {
    56         return SDL_FALSE;
    57     }
    58 
    59     env = SDL_getenv(name);
    60     if (env && priority < SDL_HINT_OVERRIDE) {
    61         return SDL_FALSE;
    62     }
    63 
    64     for (hint = SDL_hints; hint; hint = hint->next) {
    65         if (SDL_strcmp(name, hint->name) == 0) {
    66             if (priority < hint->priority) {
    67                 return SDL_FALSE;
    68             }
    69             if (!hint->value || !value || SDL_strcmp(hint->value, value) != 0) {
    70                 for (entry = hint->callbacks; entry; ) {
    71                     /* Save the next entry in case this one is deleted */
    72                     SDL_HintWatch *next = entry->next;
    73                     entry->callback(entry->userdata, name, hint->value, value);
    74                     entry = next;
    75                 }
    76                 SDL_free(hint->value);
    77                 hint->value = value ? SDL_strdup(value) : NULL;
    78             }
    79             hint->priority = priority;
    80             return SDL_TRUE;
    81         }
    82     }
    83 
    84     /* Couldn't find the hint, add a new one */
    85     hint = (SDL_Hint *)SDL_malloc(sizeof(*hint));
    86     if (!hint) {
    87         return SDL_FALSE;
    88     }
    89     hint->name = SDL_strdup(name);
    90     hint->value = value ? SDL_strdup(value) : NULL;
    91     hint->priority = priority;
    92     hint->callbacks = NULL;
    93     hint->next = SDL_hints;
    94     SDL_hints = hint;
    95     return SDL_TRUE;
    96 }
    97 
    98 SDL_bool
    99 SDL_SetHint(const char *name, const char *value)
   100 {
   101     return SDL_SetHintWithPriority(name, value, SDL_HINT_NORMAL);
   102 }
   103 
   104 const char *
   105 SDL_GetHint(const char *name)
   106 {
   107     const char *env;
   108     SDL_Hint *hint;
   109 
   110     env = SDL_getenv(name);
   111     for (hint = SDL_hints; hint; hint = hint->next) {
   112         if (SDL_strcmp(name, hint->name) == 0) {
   113             if (!env || hint->priority == SDL_HINT_OVERRIDE) {
   114                 return hint->value;
   115             }
   116             break;
   117         }
   118     }
   119     return env;
   120 }
   121 
   122 SDL_bool
   123 SDL_GetStringBoolean(const char *value, SDL_bool default_value)
   124 {
   125     if (!value || !*value) {
   126         return default_value;
   127     }
   128     if (*value == '0' || SDL_strcasecmp(value, "false") == 0) {
   129         return SDL_FALSE;
   130     }
   131     return SDL_TRUE;
   132 }
   133 
   134 SDL_bool
   135 SDL_GetHintBoolean(const char *name, SDL_bool default_value)
   136 {
   137     const char *hint = SDL_GetHint(name);
   138     return SDL_GetStringBoolean(hint, default_value);
   139 }
   140 
   141 void
   142 SDL_AddHintCallback(const char *name, SDL_HintCallback callback, void *userdata)
   143 {
   144     SDL_Hint *hint;
   145     SDL_HintWatch *entry;
   146     const char *value;
   147 
   148     if (!name || !*name) {
   149         SDL_InvalidParamError("name");
   150         return;
   151     }
   152     if (!callback) {
   153         SDL_InvalidParamError("callback");
   154         return;
   155     }
   156 
   157     SDL_DelHintCallback(name, callback, userdata);
   158 
   159     entry = (SDL_HintWatch *)SDL_malloc(sizeof(*entry));
   160     if (!entry) {
   161         SDL_OutOfMemory();
   162         return;
   163     }
   164     entry->callback = callback;
   165     entry->userdata = userdata;
   166 
   167     for (hint = SDL_hints; hint; hint = hint->next) {
   168         if (SDL_strcmp(name, hint->name) == 0) {
   169             break;
   170         }
   171     }
   172     if (!hint) {
   173         /* Need to add a hint entry for this watcher */
   174         hint = (SDL_Hint *)SDL_malloc(sizeof(*hint));
   175         if (!hint) {
   176             SDL_OutOfMemory();
   177             SDL_free(entry);
   178             return;
   179         }
   180         hint->name = SDL_strdup(name);
   181         hint->value = NULL;
   182         hint->priority = SDL_HINT_DEFAULT;
   183         hint->callbacks = NULL;
   184         hint->next = SDL_hints;
   185         SDL_hints = hint;
   186     }
   187 
   188     /* Add it to the callbacks for this hint */
   189     entry->next = hint->callbacks;
   190     hint->callbacks = entry;
   191 
   192     /* Now call it with the current value */
   193     value = SDL_GetHint(name);
   194     callback(userdata, name, value, value);
   195 }
   196 
   197 void
   198 SDL_DelHintCallback(const char *name, SDL_HintCallback callback, void *userdata)
   199 {
   200     SDL_Hint *hint;
   201     SDL_HintWatch *entry, *prev;
   202 
   203     for (hint = SDL_hints; hint; hint = hint->next) {
   204         if (SDL_strcmp(name, hint->name) == 0) {
   205             prev = NULL;
   206             for (entry = hint->callbacks; entry; entry = entry->next) {
   207                 if (callback == entry->callback && userdata == entry->userdata) {
   208                     if (prev) {
   209                         prev->next = entry->next;
   210                     } else {
   211                         hint->callbacks = entry->next;
   212                     }
   213                     SDL_free(entry);
   214                     break;
   215                 }
   216                 prev = entry;
   217             }
   218             return;
   219         }
   220     }
   221 }
   222 
   223 void SDL_ClearHints(void)
   224 {
   225     SDL_Hint *hint;
   226     SDL_HintWatch *entry;
   227 
   228     while (SDL_hints) {
   229         hint = SDL_hints;
   230         SDL_hints = hint->next;
   231 
   232         SDL_free(hint->name);
   233         SDL_free(hint->value);
   234         for (entry = hint->callbacks; entry; ) {
   235             SDL_HintWatch *freeable = entry;
   236             entry = entry->next;
   237             SDL_free(freeable);
   238         }
   239         SDL_free(hint);
   240     }
   241 }
   242 
   243 /* vi: set ts=4 sw=4 expandtab: */