Repo created

3party/libtess2/Source/bucketalloc.c

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+/*
+** SGI FREE SOFTWARE LICENSE B (Version 2.0, Sept. 18, 2008)
+** Copyright (C) [dates of first publication] Silicon Graphics, Inc.
+** All Rights Reserved.
+**
+** Permission is hereby granted, free of charge, to any person obtaining a copy
+** of this software and associated documentation files (the "Software"), to deal
+** in the Software without restriction, including without limitation the rights
+** to use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies
+** of the Software, and to permit persons to whom the Software is furnished to do so,
+** subject to the following conditions:
+**
+** The above copyright notice including the dates of first publication and either this
+** permission notice or a reference to http://oss.sgi.com/projects/FreeB/ shall be
+** included in all copies or substantial portions of the Software.
+**
+** THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR IMPLIED,
+** INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS FOR A
+** PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL SILICON GRAPHICS, INC.
+** BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT,
+** TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE
+** OR OTHER DEALINGS IN THE SOFTWARE.
+**
+** Except as contained in this notice, the name of Silicon Graphics, Inc. shall not
+** be used in advertising or otherwise to promote the sale, use or other dealings in
+** this Software without prior written authorization from Silicon Graphics, Inc.
+*/
+/*
+** Author: Mikko Mononen, July 2009.
+*/
+
+#include <stdio.h>
+#include <stdlib.h>
+#include "../Include/tesselator.h"
+
+//#define CHECK_BOUNDS
+
+typedef struct BucketAlloc BucketAlloc;
+typedef struct Bucket Bucket;
+
+struct Bucket
+{
+	Bucket *next;
+};
+
+struct BucketAlloc
+{
+	void *freelist;
+	Bucket *buckets;
+	unsigned int itemSize;
+	unsigned int bucketSize;
+	const char *name;
+	TESSalloc* alloc;
+};
+
+static int CreateBucket( struct BucketAlloc* ba )
+{
+	size_t size;
+	Bucket* bucket;
+	void* freelist;
+	unsigned char* head;
+	unsigned char* it;
+
+	// Allocate memory for the bucket
+	size = sizeof(Bucket) + ba->itemSize * ba->bucketSize;
+	bucket = (Bucket*)ba->alloc->memalloc( ba->alloc->userData, size );
+	if ( !bucket )
+		return 0;
+	bucket->next = 0;
+
+	// Add the bucket into the list of buckets.
+	bucket->next = ba->buckets;
+	ba->buckets = bucket;
+
+	// Add new items to the free list.
+	freelist = ba->freelist;
+	head = (unsigned char*)bucket + sizeof(Bucket);
+	it = head + ba->itemSize * ba->bucketSize;
+	do
+	{
+		it -= ba->itemSize;
+		// Store pointer to next free item.
+		*((void**)it) = freelist;
+		// Pointer to next location containing a free item.
+		freelist = (void*)it;
+	}
+	while ( it != head );
+	// Update pointer to next location containing a free item.
+	ba->freelist = (void*)it;
+
+	return 1;
+}
+
+static void *NextFreeItem( struct BucketAlloc *ba )
+{
+	return *(void**)ba->freelist;
+}
+
+struct BucketAlloc* createBucketAlloc( TESSalloc* alloc, const char* name,
+									  unsigned int itemSize, unsigned int bucketSize )
+{
+	BucketAlloc* ba = (BucketAlloc*)alloc->memalloc( alloc->userData, sizeof(BucketAlloc) );
+
+	ba->alloc = alloc;
+	ba->name = name;
+	ba->itemSize = itemSize;
+	if ( ba->itemSize < sizeof(void*) )
+		ba->itemSize = sizeof(void*);
+	ba->bucketSize = bucketSize;
+	ba->freelist = 0;
+	ba->buckets = 0;
+
+	if ( !CreateBucket( ba ) )
+	{
+		alloc->memfree( alloc->userData, ba );
+		return 0;
+	}
+
+	return ba;
+}
+
+void* bucketAlloc( struct BucketAlloc *ba )
+{
+	void *it;
+
+	// If running out of memory, allocate new bucket and update the freelist.
+	if ( !ba->freelist || !NextFreeItem( ba ) )
+	{
+		if ( !CreateBucket( ba ) )
+			return 0;
+	}
+
+	// Pop item from in front of the free list.
+	it = ba->freelist;
+	ba->freelist = NextFreeItem( ba );
+
+	return it;
+}
+
+void bucketFree( struct BucketAlloc *ba, void *ptr )
+{
+#ifdef CHECK_BOUNDS
+	int inBounds = 0;
+	Bucket *bucket;
+
+	// Check that the pointer is allocated with this allocator.
+	bucket = ba->buckets;
+	while ( bucket )
+	{
+		void *bucketMin = (void*)((unsigned char*)bucket + sizeof(Bucket));
+		void *bucketMax = (void*)((unsigned char*)bucket + sizeof(Bucket) + ba->itemSize * ba->bucketSize);
+		if ( ptr >= bucketMin && ptr < bucketMax )
+		{
+			inBounds = 1;
+			break;
+		}
+		bucket = bucket->next;
+	}
+
+	if ( inBounds )
+	{
+		// Add the node in front of the free list.
+		*(void**)ptr = ba->freelist;
+		ba->freelist = ptr;
+	}
+	else
+	{
+		printf("ERROR! pointer 0x%p does not belong to allocator '%s'\n", ba->name);
+	}
+#else
+	// Add the node in front of the free list.
+	*(void**)ptr = ba->freelist;
+	ba->freelist = ptr;
+#endif
+}
+
+void deleteBucketAlloc( struct BucketAlloc *ba )
+{
+	TESSalloc* alloc = ba->alloc;
+	Bucket *bucket = ba->buckets;
+	Bucket *next;
+	while ( bucket )
+	{
+		next = bucket->next;
+		alloc->memfree( alloc->userData, bucket );
+		bucket = next;
+	}
+	ba->freelist = 0;
+	ba->buckets = 0;
+	alloc->memfree( alloc->userData, ba );
+}