/*
 * Copyright (c) 1993-1995 Argonaut Technologies Limited. All rights reserved.
 *
 * $Id: scratch.c 1.7 1995/08/31 16:29:46 sam Exp $
 * $Locker:  $
 *
 * Manage a temporary scratchpad for the rest of the system
 *
 * Will only allow 1 buffer to be allocated at any time
 */
#include "fw.h"
#include "brassert.h"

/*
 * Allocate a scratch buffer of the given size
 */
void *BR_PUBLIC_ENTRY BrScratchAllocate(br_size_t size)
{
	if(fw.scratch_inuse)
		BR_ERROR0("Scratchpad not available");

	fw.scratch_last = size;

	if(size > fw.scratch_size) {
		if(fw.scratch_ptr)
			BrResFree(fw.scratch_ptr);

		fw.scratch_ptr = BrResAllocate(fw.res,size,BR_MEMORY_SCRATCH);
#if 0
		fw.scratch_size = BrResSize(fw.scratch_ptr);
#else
		fw.scratch_size = size;
#endif
	}
	
	fw.scratch_inuse = 1;	

	return fw.scratch_ptr;
}

/*
 * Release a scratch buffer
 */
void BR_PUBLIC_ENTRY BrScratchFree(void *scratch)
{
	UASSERT(fw.scratch_ptr == scratch);

	fw.scratch_inuse = 0;	

#if 0 /* Churn memory allocator */
	BrResFree(fw.scratch_ptr);
	fw.scratch_ptr = NULL;
	fw.scratch_size = 0;
#endif
}

/*
 * Free any allocated scratch buffer
 */
void BR_PUBLIC_ENTRY BrScratchFlush(void)
{
	if(fw.scratch_inuse)
		BR_ERROR0("Scratchpad cannot be flushed while in use");

	if(fw.scratch_ptr)
		BrResFree(fw.scratch_ptr);

	fw.scratch_ptr = NULL;
	fw.scratch_size = 0;
}

/*
 * Find out how much scratch space is 'easily' available
 */
br_size_t BR_PUBLIC_ENTRY BrScratchInquire(void)
{
	return fw.scratch_size;
}