/*
 *	PROGRAM:	Misc. Function for Server and Tools
 *	MODULE:		chop.cpp
 *	DESCRIPTION:	Function to nicely truncate a long path/file name
 *			to a specified length.
 *
 * The contents of this file are subject to the Interbase Public
 * License Version 1.0 (the "License"); you may not use this file
 * except in compliance with the License. You may obtain a copy
 * of the License at http://www.Inprise.com/IPL.html
 *
 * Software distributed under the License is distributed on an
 * "AS IS" basis, WITHOUT WARRANTY OF ANY KIND, either express
 * or implied. See the License for the specific language governing
 * rights and limitations under the License.
 *
 * The Original Code was created by Inprise Corporation
 * and its predecessors. Portions created by Inprise Corporation are
 * Copyright (C) Inprise Corporation.
 *
 * All Rights Reserved.
 * Contributor(s): ______________________________________.
 */

#include "firebird.h"
#include "ibase.h"


#define PATHSEP(c) ((c) == '\\' || (c) == '/')

char* ChopFileName(const char* szName, char* szShortName, ULONG dwLen)
{
/**************************************
 *
 *	C h o p F i l e N a m e
 *
 **************************************
 *
 * Functional description
 *	Try to shorten a given file name to a specified length.  Put
 *	in '...' where anything was taken out.
 *
 *	Both szName and szShort name can be the same pointer.
 *
 *  Inputs:
 *           szName - Null terminated input path/filename.
 *           szShortName - Output buffer for truncated path/filename.
 *           dwLen - Length to truncate to.
 *
 *  Outputs:
 *				 pointer to a buffer (szShortname).
 *
 **************************************/

	// Set pointers to the beginning and the end
	const char *pchLeft, *pchEnd;
	pchLeft = pchEnd = szName;
	while (*pchEnd)
		pchEnd++;

	// Check that the path is already short enough
	if (((ULONG) (pchEnd - pchLeft)) <= dwLen)
	{
		memcpy(szShortName, szName, pchEnd - pchLeft + 1);
		return szShortName;
	}

	// Subtract the room needed for the three dots
	dwLen -= 3;

	const char* pchRight = pchEnd;

	const char* pchLastLeft = pchLeft;
	const char* pchLastRight = pchRight;

	bool bLeft = true;
	bool bLeftFull = false;
	bool bRightFull = false;

	while (!bLeftFull || !bRightFull)
	{
		if (bLeft)
		{
			while (!bLeftFull && pchLeft++ && !PATHSEP(*pchLeft) && pchLeft < pchRight)
				;
			if ((pchLeft - szName) + ((ULONG) (pchEnd - pchRight)) > dwLen)
			{
				bLeftFull = true;
				pchLeft = pchLastLeft;
			}
			else
				pchLastLeft = pchLeft;
		}
		else
		{
			while (!bRightFull && pchRight-- && !PATHSEP(*pchRight) && pchLeft < pchRight)
				;
			if ((pchLeft - szName) + ((ULONG) (pchEnd - pchRight)) > dwLen)
			{
				bRightFull = true;
				pchRight = pchLastRight;
			}
			else
				pchLastRight = pchRight;
		}
		bLeft = !bLeft;
	}

	char* pchTmp = szShortName;
	pchLeft = szName;
	while (pchLeft <= pchLastLeft)
		*pchTmp++ = *pchLeft++;

	*pchTmp++ = '.';
	*pchTmp++ = '.';
	*pchTmp++ = '.';
	while (pchLastRight < pchEnd)
		*pchTmp++ = *pchLastRight++;

	*pchTmp++ = '\0';

	return szShortName;
}


