RTPathCalcRelative.cpp revision 82913817d8868e08ec4af3c8aac24c034d4beccb
/* $Id$ */
/** @file
* IPRT - RTPathCreateRelative.
*/
/*
* Copyright (C) 2013 Oracle Corporation
*
* This file is part of VirtualBox Open Source Edition (OSE), as
* available from http://www.virtualbox.org. This file is free software;
* General Public License (GPL) as published by the Free Software
* Foundation, in version 2 as it comes in the "COPYING" file of the
* VirtualBox OSE distribution. VirtualBox OSE is distributed in the
* hope that it will be useful, but WITHOUT ANY WARRANTY of any kind.
*
* The contents of this file may alternatively be used under the terms
* of the Common Development and Distribution License Version 1.0
* (CDDL) only, as it comes in the "COPYING.CDDL" file of the
* VirtualBox OSE distribution, in which case the provisions of the
* CDDL are applicable instead of those of the GPL.
*
* You may elect to license modified versions of this file under the
* terms and conditions of either the GPL or the CDDL or both.
*/
/*******************************************************************************
* Header Files *
*******************************************************************************/
const char *pszPathFrom,
const char *pszPathTo)
{
int rc = VINF_SUCCESS;
/*
* Check for different root specifiers (drive letters), creating a relative path doesn't work here.
* @todo: How to handle case insensitive root specifiers correctly?
*/
if ( offRootFrom != offRootTo
return VERR_NOT_SUPPORTED;
/* Filter out the parent path which is equal to both paths. */
while ( *pszPathFrom == *pszPathTo
&& *pszPathFrom != '\0'
&& *pszPathTo != '\0')
{
pszPathFrom++;
pszPathTo++;
}
/*
* Because path components can start with an equal string but differ afterwards we
* need to go back to the beginning of the current component.
*/
while (!RTPATH_IS_SEP(*pszPathFrom))
pszPathFrom--;
pszPathFrom++; /* Skip path separator. */
while (!RTPATH_IS_SEP(*pszPathTo))
pszPathTo--;
pszPathTo++; /* Skip path separator. */
/* Paths point to the first non equal component now. */
unsigned offPathTmp = 0;
/* Create the part to go up from pszPathFrom. */
while (*pszPathFrom != '\0')
{
while ( !RTPATH_IS_SEP(*pszPathFrom)
&& *pszPathFrom != '\0')
pszPathFrom++;
if (RTPATH_IS_SEP(*pszPathFrom))
{
return VERR_FILENAME_TOO_LONG;
pszPathFrom++;
}
}
/* Now append the rest of pszPathTo to the final path. */
if (RT_SUCCESS(rc))
{
*pszPathTmp = '\0';
if (cchPathTmp >= cbPathDst)
return VERR_BUFFER_OVERFLOW;
}
else
return rc;
}