/*
 *  XMail by Davide Libenzi ( Intranet and Internet mail server )
 *  Copyright (C) 1999,..,2004  Davide Libenzi
 *
 *  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; either version 2 of the License, or
 *  (at your option) any later version.
 *
 *  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
 *
 *  Davide Libenzi <davidel@xmailserver.org>
 *
 */

#include "SysInclude.h"
#include "SysDep.h"
#include "SvrDefines.h"
#include "ShBlocks.h"

struct SharedBlock {
	unsigned int uSize;
	SYS_MUTEX hMutex;
	void *pData;
};

SHB_HANDLE ShbCreateBlock(unsigned int uSize)
{

	SharedBlock *pSHB = (SharedBlock *) SysAlloc(sizeof(SharedBlock));

	if (pSHB == NULL)
		return (SHB_INVALID_HANDLE);

	ZeroData(*pSHB);
	pSHB->uSize = uSize;

	if ((pSHB->hMutex = SysCreateMutex()) == SYS_INVALID_MUTEX) {
		SysFree(pSHB);
		return (SHB_INVALID_HANDLE);
	}

	if ((pSHB->pData = SysAlloc(uSize)) == NULL) {
		SysCloseMutex(pSHB->hMutex);
		SysFree(pSHB);
		return (SHB_INVALID_HANDLE);
	}

	memset(pSHB->pData, 0, uSize);

	return ((SHB_HANDLE) pSHB);

}

int ShbCloseBlock(SHB_HANDLE hBlock)
{

	SharedBlock *pSHB = (SharedBlock *) hBlock;

	SysCloseMutex(pSHB->hMutex);

	SysFree(pSHB->pData);

	SysFree(pSHB);

	return (0);

}

void *ShbLock(SHB_HANDLE hBlock)
{

	SharedBlock *pSHB = (SharedBlock *) hBlock;

	if (SysLockMutex(pSHB->hMutex, SYS_INFINITE_TIMEOUT) < 0)
		return (NULL);

	return (pSHB->pData);

}

int ShbUnlock(SHB_HANDLE hBlock)
{

	SharedBlock *pSHB = (SharedBlock *) hBlock;

	SysUnlockMutex(pSHB->hMutex);

	return (0);

}
