Implemented an API for thread-local storage: SDL_TLSCreate(), SDL_TLSSet(), SDL_TLSGet()

src/thread/pthread/SDL_systls.c

@@ -0,0 +1,101 @@
+/*
+  Simple DirectMedia Layer
+  Copyright (C) 1997-2013 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_config.h"
+#include "SDL_thread.h"
+
+#include <pthread.h>
+
+
+#define TLS_ALLOC_CHUNKSIZE 8
+
+typedef struct {
+    int limit;
+    void *data[1];
+} SDL_TLSData;
+
+static SDL_SpinLock tls_lock;
+static pthread_key_t thread_local_storage;
+static SDL_atomic_t tls_id;
+
+
+SDL_TLSID
+SDL_TLSCreate()
+{
+    if (!thread_local_storage) {
+        SDL_AtomicLock(&tls_lock);
+        if (!thread_local_storage) {
+            if (pthread_key_create(&thread_local_storage, NULL) != 0) {
+                SDL_SetError("pthread_key_create() failed");
+                SDL_AtomicUnlock(&tls_lock);
+                return 0;
+            }
+        }
+        SDL_AtomicUnlock(&tls_lock);
+    }
+    return SDL_AtomicIncRef(&tls_id)+1;
+}
+
+void *
+SDL_TLSGet(SDL_TLSID id)
+{
+    SDL_TLSData *data;
+
+    data = (SDL_TLSData *)pthread_getspecific(thread_local_storage);
+    if (!data || id <= 0 || id > data->limit) {
+        return NULL;
+    }
+    return data->data[id-1];
+}
+
+int
+SDL_TLSSet(SDL_TLSID id, const void *value)
+{
+    SDL_TLSData *data;
+
+    if (!thread_local_storage || id <= 0) {
+        return SDL_InvalidParamError(id);
+    }
+
+    data = (SDL_TLSData *)pthread_getspecific(thread_local_storage);
+    if (!data || id > data->limit) {
+        int i, oldlimit, newlimit;
+
+        oldlimit = data ? data->limit : 0;
+        newlimit = (id + TLS_ALLOC_CHUNKSIZE);
+        data = (SDL_TLSData *)SDL_realloc(data, sizeof(*data)+(newlimit-1)*sizeof(void*));
+        if (!data) {
+            return SDL_OutOfMemory();
+        }
+        data->limit = newlimit;
+        for (i = oldlimit; i < newlimit; ++i) {
+            data->data[i] = NULL;
+        }
+        if (pthread_setspecific(thread_local_storage, data) != 0) {
+            return SDL_SetError("pthread_setspecific() failed");
+        }
+    }
+
+    data->data[id-1] = SDL_const_cast(void*, value);
+    return 0;
+}
+
+/* vi: set ts=4 sw=4 expandtab: */