diff options
Diffstat (limited to 'src/VBox/Runtime/common/path/RTPathCalcRelative.cpp')
| -rw-r--r-- | src/VBox/Runtime/common/path/RTPathCalcRelative.cpp | 238 |
1 files changed, 238 insertions, 0 deletions
diff --git a/src/VBox/Runtime/common/path/RTPathCalcRelative.cpp b/src/VBox/Runtime/common/path/RTPathCalcRelative.cpp new file mode 100644 index 00000000..5a9354a4 --- /dev/null +++ b/src/VBox/Runtime/common/path/RTPathCalcRelative.cpp @@ -0,0 +1,238 @@ +/* $Id: RTPathCalcRelative.cpp $ */ +/** @file + * IPRT - RTPathCreateRelative. + */ + +/* + * Copyright (C) 2013-2019 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/errcore.h> +#include <iprt/string.h> +#if RTPATH_STYLE == RTPATH_STR_F_STYLE_DOS +# include <iprt/uni.h> +#endif +#include "internal/path.h" + + +#if RTPATH_STYLE == RTPATH_STR_F_STYLE_DOS +/** Helper for doing case insensitive comparison of a mismatching codepoint. */ +DECLINLINE(bool) rtPathCalcRelativeEqualICaseCodepoint(const char *pszPathFromStart, const char *pszPathFrom, + const char *pszPathToStart, const char *pszPathTo) +{ + RTUNICP ucFrom = RTStrGetCp(RTStrPrevCp(pszPathFromStart, pszPathFrom)); + RTUNICP ucTo = RTStrGetCp(RTStrPrevCp(pszPathToStart, pszPathTo)); + return ucFrom == ucTo + || RTUniCpToLower(ucFrom) == RTUniCpToLower(ucTo) + || RTUniCpToUpper(ucFrom) == RTUniCpToUpper(ucTo); +} +#endif + + +RTDECL(int) RTPathCalcRelative(char *pszPathDst, size_t cbPathDst, + const char *pszPathFrom, bool fFromFile, + const char *pszPathTo) +{ + AssertPtrReturn(pszPathDst, VERR_INVALID_POINTER); + AssertReturn(cbPathDst, VERR_INVALID_PARAMETER); + AssertPtrReturn(pszPathFrom, VERR_INVALID_POINTER); + AssertPtrReturn(pszPathTo, VERR_INVALID_POINTER); +#if RTPATH_STYLE == RTPATH_STR_F_STYLE_DOS + const char * const pszPathFromStart = pszPathFrom; + const char * const pszPathToStart = pszPathTo; +#endif + + /* + * Check for different root specifiers (drive letters), creating a relative path doesn't work here. + */ + size_t offRootFrom = rtPathRootSpecLen(pszPathFrom); + AssertReturn(offRootFrom > 0, VERR_INVALID_PARAMETER); + + size_t offRootTo = rtPathRootSpecLen(pszPathTo); + AssertReturn(offRootTo > 0, VERR_INVALID_PARAMETER); + + + /** @todo correctly deal with extra root slashes! */ + if (offRootFrom != offRootTo) + return VERR_NOT_SUPPORTED; + +#if RTPATH_STYLE != RTPATH_STR_F_STYLE_DOS + if (RTStrNCmp(pszPathFrom, pszPathTo, offRootFrom)) + return VERR_NOT_SUPPORTED; +#else + if (RTStrNICmp(pszPathFrom, pszPathTo, offRootFrom)) + { + const char *pszFromCursor = pszPathFrom; + const char *pszToCursor = pszPathTo; + while ((size_t)(pszFromCursor - pszPathFrom) < offRootFrom) + { + RTUNICP ucFrom; + int rc = RTStrGetCpEx(&pszFromCursor, &ucFrom); + AssertRCReturn(rc, rc); + + RTUNICP ucTo; + rc = RTStrGetCpEx(&pszToCursor, &ucTo); + AssertRCReturn(rc, rc); + if ( ucFrom != ucTo + && RTUniCpToLower(ucFrom) != RTUniCpToLower(ucTo) + && RTUniCpToUpper(ucFrom) != RTUniCpToUpper(ucTo) + && (!RTPATH_IS_SLASH(ucFrom) || !RTPATH_IS_SLASH(ucTo)) ) + return VERR_NOT_SUPPORTED; + } + } +#endif + + pszPathFrom += offRootFrom; + pszPathTo += offRootTo; + + /* + * Skip out the part of the path which is equal to both. + */ + const char *pszStartOfFromComp = pszPathFrom; + for (;;) + { + char const chFrom = *pszPathFrom; + char const chTo = *pszPathTo; + if (!RTPATH_IS_SLASH(chFrom)) + { + if (chFrom == chTo) + { + if (chFrom) + { /* likely */ } + else + { + /* Special case: The two paths are equal. */ + if (fFromFile) + { + size_t cchComp = pszPathFrom - pszStartOfFromComp; + if (cchComp < cbPathDst) + { + memcpy(pszPathDst, pszStartOfFromComp, cchComp); + pszPathDst[cchComp] = '\0'; + return VINF_SUCCESS; + } + } + else if (sizeof(".") <= cbPathDst) + { + memcpy(pszPathDst, ".", sizeof(".")); + return VINF_SUCCESS; + } + return VERR_BUFFER_OVERFLOW; + } + } +#if RTPATH_STYLE == RTPATH_STR_F_STYLE_DOS + else if (rtPathCalcRelativeEqualICaseCodepoint(pszPathFromStart, pszPathFrom + 1, pszPathToStart, pszPathTo + 1)) + { /* if not likely, then simpler code structure wise. */ } +#endif + else if (chFrom != '\0' || !RTPATH_IS_SLASH(chTo) || fFromFile) + break; + else + { + pszStartOfFromComp = pszPathFrom; + do + pszPathTo++; + while (RTPATH_IS_SLASH(*pszPathTo)); + break; + } + pszPathFrom++; + pszPathTo++; + } + else if (RTPATH_IS_SLASH(chTo)) + { + /* Both have slashes. Skip any additional ones before taking down + the start of the component for rewinding purposes. */ + do + pszPathTo++; + while (RTPATH_IS_SLASH(*pszPathTo)); + do + pszPathFrom++; + while (RTPATH_IS_SLASH(*pszPathFrom)); + pszStartOfFromComp = pszPathFrom; + } + else + break; + } + + /* Rewind to the start of the current component. */ + pszPathTo -= pszPathFrom - pszStartOfFromComp; + pszPathFrom = pszStartOfFromComp; + + /* Paths point to the first non equal component now. */ + + /* + * Constructure the relative path. + */ + + /* Create the part to go up from pszPathFrom. */ + unsigned offDst = 0; + + if (!fFromFile && *pszPathFrom != '\0') + { + if (offDst + 3 < cbPathDst) + { + pszPathDst[offDst++] = '.'; + pszPathDst[offDst++] = '.'; + pszPathDst[offDst++] = RTPATH_SLASH; + } + else + return VERR_BUFFER_OVERFLOW; + } + + while (*pszPathFrom != '\0') + { + char ch; + while ( (ch = *pszPathFrom) != '\0' + && !RTPATH_IS_SLASH(*pszPathFrom)) + pszPathFrom++; + while ( (ch = *pszPathFrom) != '\0' + && RTPATH_IS_SLASH(ch)) + pszPathFrom++; + if (!ch) + break; + + if (offDst + 3 < cbPathDst) + { + pszPathDst[offDst++] = '.'; + pszPathDst[offDst++] = '.'; + pszPathDst[offDst++] = RTPATH_SLASH; + } + else + return VERR_BUFFER_OVERFLOW; + } + + /* Now append the rest of pszPathTo to the final path. */ + size_t cchTo = strlen(pszPathTo); + if (offDst + cchTo <= cbPathDst) + { + memcpy(&pszPathDst[offDst], pszPathTo, cchTo); + pszPathDst[offDst + cchTo] = '\0'; + return VINF_SUCCESS; + } + return VERR_BUFFER_OVERFLOW; +} + |