/*
Copyright (C) 1999-2007 id Software, Inc. and contributors.
For a list of contributors, see the accompanying CONTRIBUTORS file.

This file is part of GtkRadiant.

GtkRadiant is free software; you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
the Free Software Foundation; either version 2 of the License, or
(at your option) any later version.

GtkRadiant is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
GNU General Public License for more details.

You should have received a copy of the GNU General Public License
along with GtkRadiant; if not, write to the Free Software
Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA
*/


//
// ResourceManager.c
//

#include <stdio.h>
#include "resourcemanager.h"
#include <assert.h>

typedef struct ResMngr_Block_s
{
	char *start;
	unsigned int size;
	struct ResMngr_Block_s *next;
} ResMngr_Block_t;

static void ResMngr_CreateBlock(ResourceManager_t *resource)
{
	unsigned int _blockSize;
	char *block;
	char **current;
	ResMngr_Block_t *temp;
	unsigned int i;

	_blockSize = resource->nodeSize * resource->resPerBlock;

	block = malloc(_blockSize);

	assert(block);

	temp = malloc(sizeof(*temp));

	temp->start = block;
	temp->size = _blockSize;
	temp->next = resource->blockList;

	resource->blockList = temp; 

	resource->free = (char **)(block);

	current = resource->free;

	for(i = 1; i < resource->resPerBlock; ++i)
	{
		// set current->next to point to next node
		*current = (char *)(current) + resource->nodeSize;

		// set current node to current->next
		current = (char **)(*current);
	}

	*current = NULL;
}

H2COMMON_API void ResMngr_Con(ResourceManager_t *resource, size_t init_resSize, unsigned int init_resPerBlock, char *resman_name)
{
	resource->resSize = init_resSize;

	resource->resPerBlock = init_resPerBlock;

	resource->nodeSize = resource->resSize + sizeof(*resource->free);

	resource->blockList = NULL;

	resource->numResourcesAllocated = 0;

	ResMngr_CreateBlock(resource);
}

H2COMMON_API void ResMngr_Des(ResourceManager_t *resource)
{
	ResMngr_Block_t *toDelete;

#if 0
	if (resource->numResourcesAllocated)
	{
		char mess[100];
		sprintf(mess,"Potential memory leak %d bytes unfreed\n",resource->resSize*resource->numResourcesAllocated);
		OutputDebugString(mess);
	}
#endif

	while(resource->blockList)
	{
		toDelete = resource->blockList;
		resource->blockList = resource->blockList->next;
		free(toDelete->start);
		free(toDelete);
	}
}

H2COMMON_API void *ResMngr_AllocateResource(ResourceManager_t *resource, size_t size)
{
	char **toPop;

	assert(size == resource->resSize);

	++resource->numResourcesAllocated;

	assert(resource->free);	// constructor not called; possibly due to a static object
								// containing a static ResourceManagerFastLarge member being
								// constructed before its own static members

	toPop = resource->free;

	// set unallocated to the next node and check for NULL (end of list)
	if(!(resource->free = (char **)(*resource->free)))
	{	// if at end create new block
		ResMngr_CreateBlock(resource);
	}

	// set next to NULL
	*toPop = NULL;

	// return the resource for the node
	return (void *)(toPop + 1);
}

H2COMMON_API void ResMngr_DeallocateResource(ResourceManager_t *resource, void *toDeallocate, size_t size)
{
	char **toPush;

	assert(size == resource->resSize);

	--resource->numResourcesAllocated;

	toPush = (char **)(toDeallocate) - 1;

	assert(resource->free);	// see same assert at top of AllocateResource

	// set toPop->next to current unallocated front
	*toPush = (char *)(resource->free);

	// set unallocated to the node removed from allocated
	resource->free = toPush;
}

// end