Add SDL2 sources

SDL2-2.0.12/src/SDL_hints.c

@@ -0,0 +1,243 @@
+/*
+  Simple DirectMedia Layer
+  Copyright (C) 1997-2020 Sam Lantinga <slouken@libsdl.org>
+
+  This software is provided 'as-is', without any express or implied
+  warranty.  In no event will the authors be held liable for any damages
+  arising from the use of this software.
+
+  Permission is granted to anyone to use this software for any purpose,
+  including commercial applications, and to alter it and redistribute it
+  freely, subject to the following restrictions:
+
+  1. The origin of this software must not be misrepresented; you must not
+     claim that you wrote the original software. If you use this software
+     in a product, an acknowledgment in the product documentation would be
+     appreciated but is not required.
+  2. Altered source versions must be plainly marked as such, and must not be
+     misrepresented as being the original software.
+  3. This notice may not be removed or altered from any source distribution.
+*/
+#include "./SDL_internal.h"
+
+#include "SDL_hints.h"
+#include "SDL_error.h"
+#include "SDL_hints_c.h"
+
+
+/* Assuming there aren't many hints set and they aren't being queried in
+   critical performance paths, we'll just use linked lists here.
+ */
+typedef struct SDL_HintWatch {
+    SDL_HintCallback callback;
+    void *userdata;
+    struct SDL_HintWatch *next;
+} SDL_HintWatch;
+
+typedef struct SDL_Hint {
+    char *name;
+    char *value;
+    SDL_HintPriority priority;
+    SDL_HintWatch *callbacks;
+    struct SDL_Hint *next;
+} SDL_Hint;
+
+static SDL_Hint *SDL_hints;
+
+SDL_bool
+SDL_SetHintWithPriority(const char *name, const char *value,
+                        SDL_HintPriority priority)
+{
+    const char *env;
+    SDL_Hint *hint;
+    SDL_HintWatch *entry;
+
+    if (!name || !value) {
+        return SDL_FALSE;
+    }
+
+    env = SDL_getenv(name);
+    if (env && priority < SDL_HINT_OVERRIDE) {
+        return SDL_FALSE;
+    }
+
+    for (hint = SDL_hints; hint; hint = hint->next) {
+        if (SDL_strcmp(name, hint->name) == 0) {
+            if (priority < hint->priority) {
+                return SDL_FALSE;
+            }
+            if (!hint->value || !value || SDL_strcmp(hint->value, value) != 0) {
+                for (entry = hint->callbacks; entry; ) {
+                    /* Save the next entry in case this one is deleted */
+                    SDL_HintWatch *next = entry->next;
+                    entry->callback(entry->userdata, name, hint->value, value);
+                    entry = next;
+                }
+                SDL_free(hint->value);
+                hint->value = value ? SDL_strdup(value) : NULL;
+            }
+            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 = value ? SDL_strdup(value) : NULL;
+    hint->priority = priority;
+    hint->callbacks = NULL;
+    hint->next = SDL_hints;
+    SDL_hints = hint;
+    return SDL_TRUE;
+}
+
+SDL_bool
+SDL_SetHint(const char *name, const char *value)
+{
+    return SDL_SetHintWithPriority(name, value, SDL_HINT_NORMAL);
+}
+
+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;
+}
+
+SDL_bool
+SDL_GetStringBoolean(const char *value, SDL_bool default_value)
+{
+    if (!value || !*value) {
+        return default_value;
+    }
+    if (*value == '0' || SDL_strcasecmp(value, "false") == 0) {
+        return SDL_FALSE;
+    }
+    return SDL_TRUE;
+}
+
+SDL_bool
+SDL_GetHintBoolean(const char *name, SDL_bool default_value)
+{
+    const char *hint = SDL_GetHint(name);
+    return SDL_GetStringBoolean(hint, default_value);
+}
+
+void
+SDL_AddHintCallback(const char *name, SDL_HintCallback callback, void *userdata)
+{
+    SDL_Hint *hint;
+    SDL_HintWatch *entry;
+    const char *value;
+
+    if (!name || !*name) {
+        SDL_InvalidParamError("name");
+        return;
+    }
+    if (!callback) {
+        SDL_InvalidParamError("callback");
+        return;
+    }
+
+    SDL_DelHintCallback(name, callback, userdata);
+
+    entry = (SDL_HintWatch *)SDL_malloc(sizeof(*entry));
+    if (!entry) {
+        SDL_OutOfMemory();
+        return;
+    }
+    entry->callback = callback;
+    entry->userdata = userdata;
+
+    for (hint = SDL_hints; hint; hint = hint->next) {
+        if (SDL_strcmp(name, hint->name) == 0) {
+            break;
+        }
+    }
+    if (!hint) {
+        /* Need to add a hint entry for this watcher */
+        hint = (SDL_Hint *)SDL_malloc(sizeof(*hint));
+        if (!hint) {
+            SDL_OutOfMemory();
+            SDL_free(entry);
+            return;
+        }
+        hint->name = SDL_strdup(name);
+        hint->value = NULL;
+        hint->priority = SDL_HINT_DEFAULT;
+        hint->callbacks = NULL;
+        hint->next = SDL_hints;
+        SDL_hints = hint;
+    }
+
+    /* Add it to the callbacks for this hint */
+    entry->next = hint->callbacks;
+    hint->callbacks = entry;
+
+    /* Now call it with the current value */
+    value = SDL_GetHint(name);
+    callback(userdata, name, value, value);
+}
+
+void
+SDL_DelHintCallback(const char *name, SDL_HintCallback callback, void *userdata)
+{
+    SDL_Hint *hint;
+    SDL_HintWatch *entry, *prev;
+
+    for (hint = SDL_hints; hint; hint = hint->next) {
+        if (SDL_strcmp(name, hint->name) == 0) {
+            prev = NULL;
+            for (entry = hint->callbacks; entry; entry = entry->next) {
+                if (callback == entry->callback && userdata == entry->userdata) {
+                    if (prev) {
+                        prev->next = entry->next;
+                    } else {
+                        hint->callbacks = entry->next;
+                    }
+                    SDL_free(entry);
+                    break;
+                }
+                prev = entry;
+            }
+            return;
+        }
+    }
+}
+
+void SDL_ClearHints(void)
+{
+    SDL_Hint *hint;
+    SDL_HintWatch *entry;
+
+    while (SDL_hints) {
+        hint = SDL_hints;
+        SDL_hints = hint->next;
+
+        SDL_free(hint->name);
+        SDL_free(hint->value);
+        for (entry = hint->callbacks; entry; ) {
+            SDL_HintWatch *freeable = entry;
+            entry = entry->next;
+            SDL_free(freeable);
+        }
+        SDL_free(hint);
+    }
+}
+
+/* vi: set ts=4 sw=4 expandtab: */