src/SDL_hints.c
author Sam Lantinga <slouken@libsdl.org>
Sun, 14 Jul 2013 11:28:44 -0700
changeset 7776 d4a39491577f
parent 7719 31b5f9ff36ca
child 8093 b43765095a6f
permissions -rw-r--r--
Added the platform specific messagebox function to the video function list
slouken@5189
     1
/*
slouken@5535
     2
  Simple DirectMedia Layer
slouken@6885
     3
  Copyright (C) 1997-2013 Sam Lantinga <slouken@libsdl.org>
slouken@5189
     4
slouken@5535
     5
  This software is provided 'as-is', without any express or implied
slouken@5535
     6
  warranty.  In no event will the authors be held liable for any damages
slouken@5535
     7
  arising from the use of this software.
slouken@5189
     8
slouken@5535
     9
  Permission is granted to anyone to use this software for any purpose,
slouken@5535
    10
  including commercial applications, and to alter it and redistribute it
slouken@5535
    11
  freely, subject to the following restrictions:
slouken@5189
    12
slouken@5535
    13
  1. The origin of this software must not be misrepresented; you must not
slouken@5535
    14
     claim that you wrote the original software. If you use this software
slouken@5535
    15
     in a product, an acknowledgment in the product documentation would be
slouken@5535
    16
     appreciated but is not required.
slouken@5535
    17
  2. Altered source versions must be plainly marked as such, and must not be
slouken@5535
    18
     misrepresented as being the original software.
slouken@5535
    19
  3. This notice may not be removed or altered from any source distribution.
slouken@5189
    20
*/
slouken@5189
    21
#include "SDL_config.h"
slouken@5189
    22
slouken@5189
    23
#include "SDL_hints.h"
slouken@7432
    24
#include "SDL_error.h"
slouken@5189
    25
slouken@5189
    26
slouken@5189
    27
/* Assuming there aren't many hints set and they aren't being queried in
slouken@7432
    28
   critical performance paths, we'll just use linked lists here.
slouken@5189
    29
 */
slouken@7432
    30
typedef struct SDL_HintWatch {
slouken@7432
    31
    SDL_HintCallback callback;
slouken@7432
    32
    void *userdata;
slouken@7432
    33
    struct SDL_HintWatch *next;
slouken@7432
    34
} SDL_HintWatch;
slouken@7432
    35
slouken@5189
    36
typedef struct SDL_Hint {
slouken@5189
    37
    char *name;
slouken@5189
    38
    char *value;
slouken@5189
    39
    SDL_HintPriority priority;
slouken@7432
    40
    SDL_HintWatch *callbacks;
slouken@5189
    41
    struct SDL_Hint *next;
slouken@5189
    42
} SDL_Hint;
slouken@5189
    43
slouken@5189
    44
static SDL_Hint *SDL_hints;
slouken@5189
    45
tim@5555
    46
SDL_bool
slouken@5200
    47
SDL_SetHintWithPriority(const char *name, const char *value,
slouken@5200
    48
                        SDL_HintPriority priority)
slouken@5189
    49
{
slouken@5189
    50
    const char *env;
icculus@6389
    51
    SDL_Hint *hint;
slouken@7432
    52
    SDL_HintWatch *entry;
slouken@5189
    53
slouken@5189
    54
    if (!name || !value) {
slouken@5189
    55
        return SDL_FALSE;
slouken@5189
    56
    }
slouken@5189
    57
slouken@5189
    58
    env = SDL_getenv(name);
slouken@5189
    59
    if (env && priority < SDL_HINT_OVERRIDE) {
slouken@5189
    60
        return SDL_FALSE;
slouken@5189
    61
    }
slouken@5189
    62
icculus@6389
    63
    for (hint = SDL_hints; hint; hint = hint->next) {
slouken@5189
    64
        if (SDL_strcmp(name, hint->name) == 0) {
slouken@5189
    65
            if (priority < hint->priority) {
slouken@5189
    66
                return SDL_FALSE;
slouken@5189
    67
            }
slouken@7432
    68
            if (!hint->value || !value || SDL_strcmp(hint->value, value) != 0) {
slouken@7432
    69
                for (entry = hint->callbacks; entry; ) {
slouken@7432
    70
                    /* Save the next entry in case this one is deleted */
slouken@7432
    71
                    SDL_HintWatch *next = entry->next;
slouken@7432
    72
                    entry->callback(entry->userdata, name, hint->value, value);
slouken@7432
    73
                    entry = next;
tim@5555
    74
                }
slouken@7719
    75
                SDL_free(hint->value);
slouken@7716
    76
                hint->value = value ? SDL_strdup(value) : NULL;
slouken@5189
    77
            }
slouken@5189
    78
            hint->priority = priority;
slouken@5189
    79
            return SDL_TRUE;
slouken@5189
    80
        }
slouken@5189
    81
    }
slouken@5189
    82
slouken@5189
    83
    /* Couldn't find the hint, add a new one */
slouken@5189
    84
    hint = (SDL_Hint *)SDL_malloc(sizeof(*hint));
slouken@5189
    85
    if (!hint) {
slouken@5189
    86
        return SDL_FALSE;
slouken@5189
    87
    }
slouken@5189
    88
    hint->name = SDL_strdup(name);
slouken@7432
    89
    hint->value = value ? SDL_strdup(value) : NULL;
slouken@5189
    90
    hint->priority = priority;
slouken@7432
    91
    hint->callbacks = NULL;
slouken@5189
    92
    hint->next = SDL_hints;
slouken@5189
    93
    SDL_hints = hint;
slouken@5189
    94
    return SDL_TRUE;
slouken@5189
    95
}
slouken@5189
    96
slouken@5200
    97
SDL_bool
slouken@5200
    98
SDL_SetHint(const char *name, const char *value)
slouken@5200
    99
{
slouken@5200
   100
    return SDL_SetHintWithPriority(name, value, SDL_HINT_NORMAL);
slouken@5200
   101
}
slouken@5200
   102
slouken@5189
   103
const char *
slouken@5189
   104
SDL_GetHint(const char *name)
slouken@5189
   105
{
slouken@5189
   106
    const char *env;
slouken@5189
   107
    SDL_Hint *hint;
slouken@5189
   108
slouken@5189
   109
    env = SDL_getenv(name);
slouken@5189
   110
    for (hint = SDL_hints; hint; hint = hint->next) {
slouken@5189
   111
        if (SDL_strcmp(name, hint->name) == 0) {
slouken@5189
   112
            if (!env || hint->priority == SDL_HINT_OVERRIDE) {
slouken@5189
   113
                return hint->value;
slouken@5189
   114
            }
slouken@5189
   115
            break;
slouken@5189
   116
        }
slouken@5189
   117
    }
slouken@5189
   118
    return env;
slouken@5189
   119
}
slouken@5189
   120
slouken@7432
   121
void
slouken@7432
   122
SDL_AddHintCallback(const char *name, SDL_HintCallback callback, void *userdata)
slouken@7432
   123
{
slouken@7432
   124
    SDL_Hint *hint;
slouken@7432
   125
    SDL_HintWatch *entry;
slouken@7432
   126
    const char *value;
slouken@7432
   127
slouken@7432
   128
    if (!name || !*name) {
slouken@7432
   129
        SDL_InvalidParamError("name");
slouken@7432
   130
        return;
slouken@7432
   131
    }
slouken@7432
   132
    if (!callback) {
slouken@7432
   133
        SDL_InvalidParamError("callback");
slouken@7432
   134
        return;
slouken@7432
   135
    }
slouken@7432
   136
slouken@7432
   137
    SDL_DelHintCallback(name, callback, userdata);
slouken@7432
   138
slouken@7432
   139
    entry = (SDL_HintWatch *)SDL_malloc(sizeof(*entry));
slouken@7432
   140
    entry->callback = callback;
slouken@7432
   141
    entry->userdata = userdata;
slouken@7432
   142
slouken@7432
   143
    for (hint = SDL_hints; hint; hint = hint->next) {
slouken@7432
   144
        if (SDL_strcmp(name, hint->name) == 0) {
slouken@7432
   145
            break;
slouken@7432
   146
        }
slouken@7432
   147
    }
slouken@7432
   148
    if (!hint) {
slouken@7432
   149
        /* Need to add a hint entry for this watcher */
slouken@7432
   150
        hint = (SDL_Hint *)SDL_malloc(sizeof(*hint));
slouken@7432
   151
        if (!hint) {
slouken@7432
   152
            return;
slouken@7432
   153
        }
slouken@7432
   154
        hint->name = SDL_strdup(name);
slouken@7432
   155
        hint->value = NULL;
slouken@7432
   156
        hint->priority = SDL_HINT_DEFAULT;
slouken@7432
   157
        hint->callbacks = NULL;
slouken@7432
   158
        hint->next = SDL_hints;
slouken@7432
   159
        SDL_hints = hint;
slouken@7432
   160
    }
slouken@7432
   161
slouken@7432
   162
    /* Add it to the callbacks for this hint */
slouken@7432
   163
    entry->next = hint->callbacks;
slouken@7432
   164
    hint->callbacks = entry;
slouken@7432
   165
slouken@7432
   166
    /* Now call it with the current value */
slouken@7432
   167
    value = SDL_GetHint(name);
slouken@7432
   168
    callback(userdata, name, value, value);
slouken@7432
   169
}
slouken@7432
   170
slouken@7432
   171
void
slouken@7432
   172
SDL_DelHintCallback(const char *name, SDL_HintCallback callback, void *userdata)
slouken@7432
   173
{
slouken@7432
   174
    SDL_Hint *hint;
slouken@7432
   175
    SDL_HintWatch *entry, *prev;
slouken@7432
   176
slouken@7432
   177
    for (hint = SDL_hints; hint; hint = hint->next) {
slouken@7432
   178
        if (SDL_strcmp(name, hint->name) == 0) {
slouken@7432
   179
            prev = NULL;
slouken@7432
   180
            for (entry = hint->callbacks; entry; entry = entry->next) {
slouken@7432
   181
                if (callback == entry->callback && userdata == entry->userdata) {
slouken@7432
   182
                    if (prev) {
slouken@7432
   183
                        prev->next = entry->next;
slouken@7432
   184
                    } else {
slouken@7432
   185
                        hint->callbacks = entry->next;
slouken@7432
   186
                    }
slouken@7432
   187
                    SDL_free(entry);
slouken@7432
   188
                    break;
slouken@7432
   189
                }
slouken@7432
   190
                prev = entry;
slouken@7432
   191
            }
slouken@7432
   192
            return;
slouken@7432
   193
        }
slouken@7432
   194
    }
slouken@7432
   195
}
slouken@7432
   196
slouken@5273
   197
void SDL_ClearHints(void)
slouken@5189
   198
{
slouken@5189
   199
    SDL_Hint *hint;
slouken@7432
   200
    SDL_HintWatch *entry;
slouken@5189
   201
slouken@5189
   202
    while (SDL_hints) {
slouken@5189
   203
        hint = SDL_hints;
slouken@5189
   204
        SDL_hints = hint->next;
slouken@5189
   205
slouken@5189
   206
        SDL_free(hint->name);
slouken@7719
   207
        SDL_free(hint->value);
slouken@7432
   208
        for (entry = hint->callbacks; entry; ) {
slouken@7432
   209
            SDL_HintWatch *freeable = entry;
slouken@7432
   210
            entry = entry->next;
slouken@7432
   211
            SDL_free(freeable);
slouken@7432
   212
        }
slouken@5189
   213
        SDL_free(hint);
slouken@5189
   214
    }
slouken@5189
   215
}
slouken@5189
   216
slouken@5189
   217
/* vi: set ts=4 sw=4 expandtab: */