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/* $Id: RTPathCalcRelative.cpp $ */
/** @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;
* you can redistribute it and/or modify it under the terms of the GNU
* 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 *
*******************************************************************************/
#include "internal/iprt.h"
#include <iprt/path.h>
#include <iprt/assert.h>
#include <iprt/err.h>
#include <iprt/string.h>
#include "internal/path.h"
RTDECL(int) RTPathCalcRelative(char *pszPathDst, size_t cbPathDst,
const char *pszPathFrom,
const char *pszPathTo)
{
int rc = VINF_SUCCESS;
AssertPtrReturn(pszPathDst, VERR_INVALID_POINTER);
AssertReturn(cbPathDst, VERR_INVALID_PARAMETER);
AssertPtrReturn(pszPathFrom, VERR_INVALID_POINTER);
AssertPtrReturn(pszPathTo, VERR_INVALID_POINTER);
AssertReturn(RTPathStartsWithRoot(pszPathFrom), VERR_INVALID_PARAMETER);
AssertReturn(RTPathStartsWithRoot(pszPathTo), VERR_INVALID_PARAMETER);
AssertReturn(RTStrCmp(pszPathFrom, pszPathTo), VERR_INVALID_PARAMETER);
/*
* Check for different root specifiers (drive letters), creating a relative path doesn't work here.
* @todo: How to handle case insensitive root specifiers correctly?
*/
size_t offRootFrom = rtPathRootSpecLen(pszPathFrom);
size_t offRootTo = rtPathRootSpecLen(pszPathTo);
if ( offRootFrom != offRootTo
|| RTStrNCmp(pszPathFrom, pszPathTo, offRootFrom))
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. */
char aszPathTmp[RTPATH_MAX + 1];
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))
{
if (offPathTmp + 3 >= sizeof(aszPathTmp) - 1)
return VERR_FILENAME_TOO_LONG;
aszPathTmp[offPathTmp++] = '.';
aszPathTmp[offPathTmp++] = '.';
aszPathTmp[offPathTmp++] = RTPATH_SLASH;
pszPathFrom++;
}
}
aszPathTmp[offPathTmp] = '\0';
/* Now append the rest of pszPathTo to the final path. */
char *pszPathTmp = &aszPathTmp[offPathTmp];
size_t cbPathTmp = sizeof(aszPathTmp) - offPathTmp - 1;
rc = RTStrCatP(&pszPathTmp, &cbPathTmp, pszPathTo);
if (RT_SUCCESS(rc))
{
*pszPathTmp = '\0';
size_t cchPathTmp = strlen(aszPathTmp);
if (cchPathTmp >= cbPathDst)
return VERR_BUFFER_OVERFLOW;
memcpy(pszPathDst, aszPathTmp, cchPathTmp + 1);
}
else
rc = VERR_FILENAME_TOO_LONG;
return rc;
}
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