1 /*
2 Simple DirectMedia Layer
3 Copyright (C) 1997-2016 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
SDL_SetHintWithPriority(const char * name,const char * value,SDL_HintPriority priority)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
SDL_SetHint(const char * name,const char * value)98 SDL_SetHint(const char *name, const char *value)
99 {
100 return SDL_SetHintWithPriority(name, value, SDL_HINT_NORMAL);
101 }
102
103 const char *
SDL_GetHint(const char * name)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 SDL_bool
SDL_GetHintBoolean(const char * name,SDL_bool default_value)122 SDL_GetHintBoolean(const char *name, SDL_bool default_value)
123 {
124 const char *hint = SDL_GetHint(name);
125 if (!hint) {
126 return default_value;
127 }
128 if (*hint == '0' || SDL_strcasecmp(hint, "false") == 0) {
129 return SDL_FALSE;
130 }
131 return SDL_TRUE;
132 }
133
134 void
SDL_AddHintCallback(const char * name,SDL_HintCallback callback,void * userdata)135 SDL_AddHintCallback(const char *name, SDL_HintCallback callback, void *userdata)
136 {
137 SDL_Hint *hint;
138 SDL_HintWatch *entry;
139 const char *value;
140
141 if (!name || !*name) {
142 SDL_InvalidParamError("name");
143 return;
144 }
145 if (!callback) {
146 SDL_InvalidParamError("callback");
147 return;
148 }
149
150 SDL_DelHintCallback(name, callback, userdata);
151
152 entry = (SDL_HintWatch *)SDL_malloc(sizeof(*entry));
153 if (!entry) {
154 SDL_OutOfMemory();
155 return;
156 }
157 entry->callback = callback;
158 entry->userdata = userdata;
159
160 for (hint = SDL_hints; hint; hint = hint->next) {
161 if (SDL_strcmp(name, hint->name) == 0) {
162 break;
163 }
164 }
165 if (!hint) {
166 /* Need to add a hint entry for this watcher */
167 hint = (SDL_Hint *)SDL_malloc(sizeof(*hint));
168 if (!hint) {
169 SDL_OutOfMemory();
170 SDL_free(entry);
171 return;
172 }
173 hint->name = SDL_strdup(name);
174 hint->value = NULL;
175 hint->priority = SDL_HINT_DEFAULT;
176 hint->callbacks = NULL;
177 hint->next = SDL_hints;
178 SDL_hints = hint;
179 }
180
181 /* Add it to the callbacks for this hint */
182 entry->next = hint->callbacks;
183 hint->callbacks = entry;
184
185 /* Now call it with the current value */
186 value = SDL_GetHint(name);
187 callback(userdata, name, value, value);
188 }
189
190 void
SDL_DelHintCallback(const char * name,SDL_HintCallback callback,void * userdata)191 SDL_DelHintCallback(const char *name, SDL_HintCallback callback, void *userdata)
192 {
193 SDL_Hint *hint;
194 SDL_HintWatch *entry, *prev;
195
196 for (hint = SDL_hints; hint; hint = hint->next) {
197 if (SDL_strcmp(name, hint->name) == 0) {
198 prev = NULL;
199 for (entry = hint->callbacks; entry; entry = entry->next) {
200 if (callback == entry->callback && userdata == entry->userdata) {
201 if (prev) {
202 prev->next = entry->next;
203 } else {
204 hint->callbacks = entry->next;
205 }
206 SDL_free(entry);
207 break;
208 }
209 prev = entry;
210 }
211 return;
212 }
213 }
214 }
215
SDL_ClearHints(void)216 void SDL_ClearHints(void)
217 {
218 SDL_Hint *hint;
219 SDL_HintWatch *entry;
220
221 while (SDL_hints) {
222 hint = SDL_hints;
223 SDL_hints = hint->next;
224
225 SDL_free(hint->name);
226 SDL_free(hint->value);
227 for (entry = hint->callbacks; entry; ) {
228 SDL_HintWatch *freeable = entry;
229 entry = entry->next;
230 SDL_free(freeable);
231 }
232 SDL_free(hint);
233 }
234 }
235
236 /* vi: set ts=4 sw=4 expandtab: */
237