/*
 * Copyright (c) 1998,1999,2000
 *	Traakan, Inc., Los Altos, CA
 *	All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 * 1. Redistributions of source code must retain the above copyright
 *    notice unmodified, this list of conditions, and the following
 *    disclaimer.
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in the
 *    documentation and/or other materials provided with the distribution.
 *
 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
 * ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
 * SUCH DAMAGE.
 */

/*
 * Project:  NDMJOB
 * Ident:    $Id: $
 *
 * Description:
 *	The heap is managed like this:
 *
 *			+----------------+
 *	table ------>	|     entry      |  <----- heap_top
 *			|    -------     |
 *			|     entry      |
 *			|    -------     |
 *			|     entry      |
 *			|    -------     |
 *	allo_ent --->	|     .....      |
 *		|	|                |
 *		V	|                |
 *			~                ~
 *			~                ~
 *		^	|                |
 *		|	|                |
 *	allo_item--->	|     ....       |
 *			|    -------     |
 *			|     item       |
 *			|    -------     |
 *			|     item       |
 *			|    -------     |
 *			|     item       |
 *			+----------------+  <----- heap_end
 *
 * n_entry = allo_ent - table;
 */


#include "ndmlib.h"




int
ndmfhh_initialize (struct ndmfhheap *fhh)
{
	NDMOS_MACRO_ZEROFILL (fhh);

	return NDMFHH_RET_OK;
}

int
ndmfhh_commission (struct ndmfhheap *fhh, void *heap, unsigned size)
{
	fhh->heap_base = heap;
	fhh->heap_size = size;
	fhh->heap_end = (char*)heap + size;

	/* Align everything */
	fhh->heap_top = (void*) (((long)heap + (NDMOS_CONST_ALIGN-1))
						&~ (NDMOS_CONST_ALIGN-1));
	fhh->heap_bot = (void*)
		((long)((char*)heap+size) &~ (NDMOS_CONST_ALIGN-1));

	ndmfhh_reset (fhh);

	return NDMFHH_RET_OK;
}

#define SLOP	32

int
ndmfhh_prepare (struct ndmfhheap *fhh,
  int fhtype, int entry_size,
  unsigned n_item, unsigned total_size_of_items)
{
	void *			pe;
	void *			pi;
	unsigned		items_need;

	if (fhh->heap_base == 0)
		return NDMFHH_RET_NO_HEAP;

	if (fhh->allo_entry == fhh->heap_top) {
		fhh->fhtype = fhtype;
		fhh->entry_size = entry_size;
	} else {
		if (fhh->fhtype != fhtype)
			return NDMFHH_RET_TYPE_CHANGE;

		if (fhh->entry_size != entry_size)
			return NDMFHH_RET_ENTRY_SIZE_MISMATCH;
	}

	items_need = total_size_of_items + n_item * NDMOS_CONST_ALIGN + SLOP;

	pe = (char*)fhh->allo_entry + fhh->entry_size;
	pi = (char*)fhh->allo_item - items_need;

	if (pe >= pi)
		return NDMFHH_RET_OVERFLOW;

	/* it'll fit! */
	return NDMFHH_RET_OK;
}

void *
ndmfhh_add_entry (struct ndmfhheap *fhh)
{
	void *		p;

	p = fhh->allo_entry;
	if ((char*)fhh->allo_entry + fhh->entry_size < (char*)fhh->allo_item) {
		fhh->allo_entry = (char *)p + fhh->entry_size;
		return p;
	} else {
		return 0;
	}

}

void *
ndmfhh_add_item (struct ndmfhheap *fhh, unsigned size)
{
	void *		p;

	size += (NDMOS_CONST_ALIGN-1);
	size &= ~(NDMOS_CONST_ALIGN-1);

	p = (char*)fhh->allo_item - size;
	if (p > fhh->allo_entry) {
		fhh->allo_item = p;
		return p;
	} else {
		return 0;
	}
}

void *
ndmfhh_save_item (struct ndmfhheap *fhh, void *item, unsigned size)
{
	void *		p;

	p = ndmfhh_add_item (fhh, size);
	if (p) {
		NDMOS_API_BCOPY (item, p, size);
	}
	return p;
}

int
ndmfhh_reset (struct ndmfhheap *fhh)
{
	fhh->allo_entry = fhh->heap_top;
	fhh->allo_item = fhh->heap_bot;

	return NDMFHH_RET_OK;
}

int
ndmfhh_get_table (struct ndmfhheap *fhh,
  int *fhtype_p, void **table_p, unsigned *n_entry_p)
{
	unsigned		n;

	*fhtype_p = fhh->fhtype;
	*table_p = fhh->heap_top;
	n = (char*)fhh->allo_entry - (char*)fhh->heap_top;
	if (n > 0)
		n /= fhh->entry_size;

	*n_entry_p = n;

	return NDMFHH_RET_OK;
}