/* $Id$
 * reactos memory pools emulation of libcaptive
 * Copyright (C) 2002 Jan Kratochvil <project-captive@jankratochvil.net>
 * 
 * This program 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; exactly version 2 of June 1991 is required
 * 
 * This program 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 this program; if not, write to the Free Software
 * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
 */


#include "config.h"

#include "captive/mm.h"	/* self */
#include "reactos/internal/mm.h"	/* self */
#include "reactos/ntos/types.h"	/* for PVOID etc. */
#include <glib/gmessages.h>
#include <glib/gmem.h>
#include <glib/ghash.h>


/* map PVOID->GUINT_TO_POINTER(ULONG Tag) */
static GHashTable *memory_Tag_hash;

static void memory_Tag_hash_init(void)
{
	if (memory_Tag_hash)
		return;
	memory_Tag_hash=g_hash_table_new(g_direct_hash,g_direct_equal);
}


/**
 * ExAllocatePoolWithTag:
 * @PoolType: Type of memory to allocate. Safely ignored by libcaptive as it is
 * too low level for it.
 * @NumberOfBytes: Size of the requested allocation. Value 0 permitted (returns %NULL).
 * @Tag: 4-bytes of block identification for debugging purposes and/or ExFreePoolWithTag().
 * Bit 7 (==%0x80 ) of each byte must be cleared.
 * %PROTECTED_POOL with @Tag bit 31 set is not yet implemented.
 *
 * Allocates the specified memory block. libcaptive passes the allocation to
 * g_malloc() and @Tag is marked to this allocation.
 *
 * Returns: Memory block base if successfuly allocated. %NULL otherwise.
 * The allocated memory block is not cleared.
 */
PVOID ExAllocatePoolWithTag(ULONG PoolType,ULONG NumberOfBytes,ULONG Tag)
{
PVOID r;

	g_return_val_if_fail((Tag&0x80808080)==0,NULL);

	memory_Tag_hash_init();

	if (!NumberOfBytes)
		return NULL;
	/* FIXME: >=PAGE_SIZE allocations should be PAGE_SIZE aligned */
	r=g_malloc(NumberOfBytes);

	g_assert(FALSE==g_hash_table_lookup_extended(memory_Tag_hash,
						r,	/* lookup_key */
						NULL,	/* orig_key */
						NULL));	/* value */
	g_hash_table_insert(memory_Tag_hash,
			(gpointer)r,	/* key */
			GUINT_TO_POINTER(Tag));	/* value */

	return r;
}

/**
 * ExAllocatePool:
 * @PoolType: Type of memory to allocate. Safely ignored by libcaptive as it is
 * too low level for it.
 * @NumberOfBytes: Size of the requested allocation. Value 0 permitted (returns %NULL).
 *
 * Allocates the specified memory block. Calls ExAllocatePoolWithTag() with
 * @Tag value %0x00000000. At least this value seems to be assumed by WXP <ntddk.h>
 * although it is not officially documented for W32.
 *
 * Returns: Memory block base if successfuly allocated. %NULL otherwise.
 * The allocated memory block is not cleared.
 */
PVOID ExAllocatePool(POOL_TYPE PoolType,ULONG NumberOfBytes)
{
	/* FIXME: It would be better to mark such block as 'unTagged' but we would have
	 * to maintain some structure for 'memory_Tag_hash' values instead of just GUINT_TO_POINTER().
	 */
	return ExAllocatePoolWithTag(PoolType,NumberOfBytes,
			0x00000000); /* Tag; reactos uses TAG_NONE ('None') but it W32 uses %0x00000000 */
}

/**
 * ExFreePool:
 * @Block: Base address of the memory block. %NULL value is forbidden.
 *
 * Deallocate the given memory block. Block must be already successfuly
 * allocated by a previous ExAllocatePool() or ExAllocatePoolWithTag() call.
 * You can no longer assume anything about this base address / memory block.
 */
VOID ExFreePool(IN PVOID Block)
{
gboolean errbool;

	g_return_if_fail(Block!=NULL);

	memory_Tag_hash_init();

	errbool=g_hash_table_remove(memory_Tag_hash,Block);
	g_assert(errbool==TRUE);

	g_free(Block);
}


/**
 * ExFreePoolWithTag:
 * @Block: Base address of the memory block. %NULL value is forbidden.
 * @Tag: 4-bytes of required block identification.
 * Bit 7 (==%0x80 ) of each byte must be cleared.
 * %PROTECTED_POOL with @Tag bit 31 set is not yet implemented.
 * Value %0x0000000 is permitted for blocks marked with any Tag.
 *
 * Deallocate the given memory block. Block must be already successfuly
 * allocated by a previous ExAllocatePoolWithTag() call.
 * Block may be allocated by ExAllocatePool() if @Tag is passed %0x00000000.
 * Please see more about @Tag in ExAllocatePool().
 * It is forbidden to pass invalid @Tag for @Block.
 *
 * You can no longer assume anything about this base address / memory block.
 */
VOID ExFreePoolWithTag(IN PVOID Block,IN ULONG Tag)
{
gpointer memory_Tag_gpointer;
gboolean errbool;

	g_return_if_fail(Block!=NULL);
	g_return_if_fail((Tag&0x80808080)==0);

	memory_Tag_hash_init();

	errbool=g_hash_table_lookup_extended(memory_Tag_hash,
						Block,	/* lookup_key */
						NULL,	/* orig_key */
						&memory_Tag_gpointer);	/* value */
	g_return_if_fail(errbool==TRUE);
	g_return_if_fail(!Tag || GPOINTER_TO_UINT(memory_Tag_gpointer)==Tag);

	ExFreePool(Block);
}