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https://github.com/libsdl-org/SDL.git
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388 lines
11 KiB
C
388 lines
11 KiB
C
/*
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Simple DirectMedia Layer
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Copyright (C) 1997-2024 Sam Lantinga <slouken@libsdl.org>
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This software is provided 'as-is', without any express or implied
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warranty. In no event will the authors be held liable for any damages
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arising from the use of this software.
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Permission is granted to anyone to use this software for any purpose,
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including commercial applications, and to alter it and redistribute it
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freely, subject to the following restrictions:
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1. The origin of this software must not be misrepresented; you must not
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claim that you wrote the original software. If you use this software
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in a product, an acknowledgment in the product documentation would be
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appreciated but is not required.
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2. Altered source versions must be plainly marked as such, and must not be
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misrepresented as being the original software.
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3. This notice may not be removed or altered from any source distribution.
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*/
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#include "SDL_internal.h"
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#if defined(HAVE_GETHOSTNAME) && !defined(SDL_PLATFORM_WINDOWS)
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#include <unistd.h>
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#endif
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// Common utility functions that aren't in the public API
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int SDL_powerof2(int x)
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{
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int value;
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if (x <= 0) {
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// Return some sane value - we shouldn't hit this in our use cases
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return 1;
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}
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// This trick works for 32-bit values
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{
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SDL_COMPILE_TIME_ASSERT(SDL_powerof2, sizeof(x) == sizeof(Uint32));
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}
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value = x;
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value -= 1;
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value |= value >> 1;
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value |= value >> 2;
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value |= value >> 4;
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value |= value >> 8;
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value |= value >> 16;
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value += 1;
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return value;
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}
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Uint32 SDL_CalculateGCD(Uint32 a, Uint32 b)
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{
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if (b == 0) {
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return a;
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}
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return SDL_CalculateGCD(b, (a % b));
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}
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// Algorithm adapted with thanks from John Cook's blog post:
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// http://www.johndcook.com/blog/2010/10/20/best-rational-approximation
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void SDL_CalculateFraction(float x, int *numerator, int *denominator)
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{
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const int N = 1000;
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int a = 0, b = 1;
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int c = 1, d = 0;
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while (b <= N && d <= N) {
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float mediant = (float)(a + c) / (b + d);
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if (x == mediant) {
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if (b + d <= N) {
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*numerator = a + c;
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*denominator = b + d;
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} else if (d > b) {
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*numerator = c;
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*denominator = d;
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} else {
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*numerator = a;
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*denominator = b;
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}
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return;
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} else if (x > mediant) {
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a = a + c;
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b = b + d;
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} else {
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c = a + c;
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d = b + d;
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}
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}
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if (b > N) {
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*numerator = c;
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*denominator = d;
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} else {
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*numerator = a;
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*denominator = b;
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}
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}
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bool SDL_startswith(const char *string, const char *prefix)
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{
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if (SDL_strncmp(string, prefix, SDL_strlen(prefix)) == 0) {
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return true;
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}
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return false;
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}
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bool SDL_endswith(const char *string, const char *suffix)
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{
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size_t string_length = string ? SDL_strlen(string) : 0;
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size_t suffix_length = suffix ? SDL_strlen(suffix) : 0;
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if (suffix_length > 0 && suffix_length <= string_length) {
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if (SDL_memcmp(string + string_length - suffix_length, suffix, suffix_length) == 0) {
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return true;
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}
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}
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return false;
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}
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SDL_COMPILE_TIME_ASSERT(sizeof_object_id, sizeof(int) == sizeof(Uint32));
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Uint32 SDL_GetNextObjectID(void)
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{
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static SDL_AtomicInt last_id;
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Uint32 id = (Uint32)SDL_AtomicIncRef(&last_id) + 1;
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if (id == 0) {
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id = (Uint32)SDL_AtomicIncRef(&last_id) + 1;
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}
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return id;
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}
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static SDL_InitState SDL_objects_init;
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static SDL_HashTable *SDL_objects;
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static Uint32 SDL_HashObject(const void *key, void *unused)
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{
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return (Uint32)(uintptr_t)key;
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}
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static bool SDL_KeyMatchObject(const void *a, const void *b, void *unused)
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{
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return (a == b);
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}
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void SDL_SetObjectValid(void *object, SDL_ObjectType type, bool valid)
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{
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SDL_assert(object != NULL);
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if (valid && SDL_ShouldInit(&SDL_objects_init)) {
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SDL_objects = SDL_CreateHashTable(NULL, 32, SDL_HashObject, SDL_KeyMatchObject, NULL, true, false);
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if (!SDL_objects) {
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SDL_SetInitialized(&SDL_objects_init, false);
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}
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SDL_SetInitialized(&SDL_objects_init, true);
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}
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if (valid) {
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SDL_InsertIntoHashTable(SDL_objects, object, (void *)(uintptr_t)type);
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} else {
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SDL_RemoveFromHashTable(SDL_objects, object);
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}
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}
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bool SDL_ObjectValid(void *object, SDL_ObjectType type)
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{
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if (!object) {
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return false;
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}
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const void *object_type;
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if (!SDL_FindInHashTable(SDL_objects, object, &object_type)) {
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return false;
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}
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return (((SDL_ObjectType)(uintptr_t)object_type) == type);
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}
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void SDL_SetObjectsInvalid(void)
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{
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if (SDL_ShouldQuit(&SDL_objects_init)) {
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// Log any leaked objects
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const void *object, *object_type;
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void *iter = NULL;
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while (SDL_IterateHashTable(SDL_objects, &object, &object_type, &iter)) {
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const char *type;
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switch ((SDL_ObjectType)(uintptr_t)object_type) {
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case SDL_OBJECT_TYPE_WINDOW:
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type = "SDL_Window";
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break;
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case SDL_OBJECT_TYPE_RENDERER:
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type = "SDL_Renderer";
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break;
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case SDL_OBJECT_TYPE_TEXTURE:
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type = "SDL_Texture";
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break;
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case SDL_OBJECT_TYPE_JOYSTICK:
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type = "SDL_Joystick";
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break;
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case SDL_OBJECT_TYPE_GAMEPAD:
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type = "SDL_Gamepad";
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break;
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case SDL_OBJECT_TYPE_HAPTIC:
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type = "SDL_Haptic";
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break;
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case SDL_OBJECT_TYPE_SENSOR:
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type = "SDL_Sensor";
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break;
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case SDL_OBJECT_TYPE_HIDAPI_DEVICE:
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type = "hidapi device";
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break;
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case SDL_OBJECT_TYPE_HIDAPI_JOYSTICK:
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type = "hidapi joystick";
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break;
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case SDL_OBJECT_TYPE_THREAD:
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type = "thread";
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break;
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default:
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type = "unknown object";
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break;
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}
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SDL_Log("Leaked %s (%p)\n", type, object);
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}
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SDL_assert(SDL_HashTableEmpty(SDL_objects));
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SDL_DestroyHashTable(SDL_objects);
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SDL_objects = NULL;
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SDL_SetInitialized(&SDL_objects_init, false);
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}
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}
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static int SDL_URIDecode(const char *src, char *dst, int len)
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{
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int ri, wi, di;
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char decode = '\0';
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if (!src || !dst || len < 0) {
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return -1;
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}
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if (len == 0) {
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len = (int)SDL_strlen(src);
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}
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for (ri = 0, wi = 0, di = 0; ri < len && wi < len; ri += 1) {
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if (di == 0) {
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// start decoding
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if (src[ri] == '%') {
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decode = '\0';
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di += 1;
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continue;
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}
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// normal write
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dst[wi] = src[ri];
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wi += 1;
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} else if (di == 1 || di == 2) {
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char off = '\0';
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char isa = src[ri] >= 'a' && src[ri] <= 'f';
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char isA = src[ri] >= 'A' && src[ri] <= 'F';
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char isn = src[ri] >= '0' && src[ri] <= '9';
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if (!(isa || isA || isn)) {
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// not a hexadecimal
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int sri;
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for (sri = ri - di; sri <= ri; sri += 1) {
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dst[wi] = src[sri];
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wi += 1;
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}
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di = 0;
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continue;
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}
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// itsy bitsy magicsy
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if (isn) {
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off = 0 - '0';
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} else if (isa) {
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off = 10 - 'a';
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} else if (isA) {
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off = 10 - 'A';
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}
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decode |= (src[ri] + off) << (2 - di) * 4;
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if (di == 2) {
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dst[wi] = decode;
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wi += 1;
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di = 0;
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} else {
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di += 1;
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}
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}
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}
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dst[wi] = '\0';
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return wi;
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}
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int SDL_URIToLocal(const char *src, char *dst)
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{
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if (SDL_memcmp(src, "file:/", 6) == 0) {
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src += 6; // local file?
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} else if (SDL_strstr(src, ":/") != NULL) {
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return -1; // wrong scheme
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}
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bool local = src[0] != '/' || (src[0] != '\0' && src[1] == '/');
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// Check the hostname, if present. RFC 3986 states that the hostname component of a URI is not case-sensitive.
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if (!local && src[0] == '/' && src[2] != '/') {
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char *hostname_end = SDL_strchr(src + 1, '/');
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if (hostname_end) {
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const size_t src_len = hostname_end - (src + 1);
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size_t hostname_len;
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#if defined(HAVE_GETHOSTNAME) && !defined(SDL_PLATFORM_WINDOWS)
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char hostname[257];
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if (gethostname(hostname, 255) == 0) {
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hostname[256] = '\0';
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hostname_len = SDL_strlen(hostname);
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if (hostname_len == src_len && SDL_strncasecmp(src + 1, hostname, src_len) == 0) {
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src = hostname_end + 1;
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local = true;
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}
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}
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#endif
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if (!local) {
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static const char *localhost = "localhost";
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hostname_len = SDL_strlen(localhost);
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if (hostname_len == src_len && SDL_strncasecmp(src + 1, localhost, src_len) == 0) {
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src = hostname_end + 1;
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local = true;
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}
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}
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}
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}
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if (local) {
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// Convert URI escape sequences to real characters
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if (src[0] == '/') {
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src++;
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} else {
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src--;
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}
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return SDL_URIDecode(src, dst, 0);
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}
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return -1;
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}
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// This is a set of per-thread persistent strings that we can return from the SDL API.
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// This is used for short strings that might persist past the lifetime of the object
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// they are related to.
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static SDL_TLSID SDL_string_storage;
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static void SDL_FreePersistentStrings( void *value )
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{
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SDL_HashTable *strings = (SDL_HashTable *)value;
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SDL_DestroyHashTable(strings);
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}
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const char *SDL_GetPersistentString(const char *string)
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{
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if (!string) {
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return NULL;
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}
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if (!*string) {
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return "";
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}
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SDL_HashTable *strings = (SDL_HashTable *)SDL_GetTLS(&SDL_string_storage);
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if (!strings) {
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strings = SDL_CreateHashTable(NULL, 32, SDL_HashString, SDL_KeyMatchString, SDL_NukeFreeValue, false, false);
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if (!strings) {
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return NULL;
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}
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SDL_SetTLS(&SDL_string_storage, strings, SDL_FreePersistentStrings);
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}
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const char *result;
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if (!SDL_FindInHashTable(strings, string, (const void **)&result)) {
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char *new_string = SDL_strdup(string);
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if (!new_string) {
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return NULL;
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}
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// If the hash table insert fails, at least we can return the string we allocated
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SDL_InsertIntoHashTable(strings, new_string, new_string);
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result = new_string;
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}
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return result;
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}
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