cpl_path.cpp

用于读取TAB、MIF、SHP文件的类

/**
 * Replace the extension with the provided one.
 *
 * @param pszPath the input path, this string is not altered.
 * @param pszExt the new extension to apply to the given path.
 *
 * @return an altered filename with the new extension.    Do not
 * modify or free the returned string.  The string may be destroyed by the
 * next CPL call.
 */

const char *CPLResetExtension( const char *pszPath, const char *pszExt )

{
    char    *pszStaticResult = CPLGetStaticResult();
    size_t  i;

/* -------------------------------------------------------------------- */
/*      First, try and strip off any existing extension.                */
/* -------------------------------------------------------------------- */
    strncpy( pszStaticResult, pszPath, CPL_PATH_BUF_SIZE );
    pszStaticResult[CPL_PATH_BUF_SIZE - 1] = '\0';
    for( i = strlen(pszStaticResult) - 1; i > 0; i-- )
    {
        if( pszStaticResult[i] == '.' )
        {
            pszStaticResult[i] = '\0';
            break;
        }

        if( pszStaticResult[i] == '/' || pszStaticResult[i] == '\\' 
            || pszStaticResult[i] == ':' )
            break;
    }

/* -------------------------------------------------------------------- */
/*      Append the new extension.                                       */
/* -------------------------------------------------------------------- */
    CPLAssert( strlen(pszExt) + 2 < CPL_PATH_BUF_SIZE );
    
    strcat( pszStaticResult, "." );
    strcat( pszStaticResult, pszExt );

    return pszStaticResult;
}

/************************************************************************/
/*                          CPLFormFilename()                           */
/************************************************************************/

/**
 * Build a full file path from a passed path, file basename and extension.
 *
 * The path, and extension are optional.  The basename may in fact contain
 * an extension if desired.
 *
 * <pre>
 * CPLFormFilename("abc/xyz","def", ".dat" ) == "abc/xyz/def.dat"
 * CPLFormFilename(NULL,"def", NULL ) == "def"
 * CPLFormFilename(NULL,"abc/def.dat", NULL ) == "abc/def.dat"
 * CPLFormFilename("/abc/xyz/","def.dat", NULL ) == "/abc/xyz/def.dat"
 * </pre>
 *
 * @param pszPath directory path to the directory containing the file.  This
 * may be relative or absolute, and may have a trailing path separator or
 * not.  May be NULL.
 *
 * @param pszBasename file basename.  May optionally have path and/or
 * extension.  May not be NULL. 
 *
 * @param pszExtension file extension, optionally including the period.  May
 * be NULL.
 *
 * @return a fully formed filename in an internal static string.  Do not
 * modify or free the returned string.  The string may be destroyed by the
 * next CPL call.
 */

const char *CPLFormFilename( const char * pszPath,
                             const char * pszBasename,
                             const char * pszExtension )

{
    char *pszStaticResult = CPLGetStaticResult();
    const char  *pszAddedPathSep = "";
    const char  *pszAddedExtSep = "";

    if( pszPath == NULL )
        pszPath = "";
    else if( strlen(pszPath) > 0
             && pszPath[strlen(pszPath)-1] != '/'
             && pszPath[strlen(pszPath)-1] != '\\' )
        pszAddedPathSep = SEP_STRING;

    if( pszExtension == NULL )
        pszExtension = "";
    else if( pszExtension[0] != '.' && strlen(pszExtension) > 0 )
        pszAddedExtSep = ".";

    CPLAssert( strlen(pszPath) + strlen(pszAddedPathSep) +
               strlen(pszBasename) + strlen(pszAddedExtSep) +
               strlen(pszExtension) + 1 < CPL_PATH_BUF_SIZE );

    strncpy( pszStaticResult, pszPath, CPL_PATH_BUF_SIZE );
    strncat( pszStaticResult, pszAddedPathSep, CPL_PATH_BUF_SIZE);
    strncat( pszStaticResult, pszBasename, CPL_PATH_BUF_SIZE);
    strncat( pszStaticResult, pszAddedExtSep, CPL_PATH_BUF_SIZE);
    strncat( pszStaticResult, pszExtension, CPL_PATH_BUF_SIZE);
    pszStaticResult[CPL_PATH_BUF_SIZE - 1] = '\0';

    return pszStaticResult;
}

/************************************************************************/
/*                          CPLFormCIFilename()                         */
/************************************************************************/

/**
 * Case insensitive file searching, returing full path.
 *
 * This function tries to return the path to a file regardless of
 * whether the file exactly matches the basename, and extension case, or
 * is all upper case, or all lower case.  The path is treated as case 
 * sensitive.  This function is equivelent to CPLFormFilename() on 
 * case insensitive file systems (like Windows).
 *
 * @param pszPath directory path to the directory containing the file.  This
 * may be relative or absolute, and may have a trailing path separator or
 * not.  May be NULL.
 *
 * @param pszBasename file basename.  May optionally have path and/or
 * extension.  May not be NULL. 
 *
 * @param pszExtension file extension, optionally including the period.  May
 * be NULL.
 *
 * @return a fully formed filename in an internal static string.  Do not
 * modify or free the returned string.  The string may be destroyed by the
 * next CPL call.
 */

const char *CPLFormCIFilename( const char * pszPath,
                               const char * pszBasename,
                               const char * pszExtension )

{
#if defined(WIN32) || defined(WIN32CE)
    return CPLFormFilename( pszPath, pszBasename, pszExtension );
#else
    const char  *pszAddedExtSep = "";
    char        *pszFilename;
    const char  *pszFullPath;
    int         nLen = strlen(pszBasename)+2, i;
    FILE        *fp;

    if( pszExtension != NULL )
        nLen += strlen(pszExtension);

    pszFilename = (char *) CPLMalloc(nLen);

    if( pszExtension == NULL )
        pszExtension = "";
    else if( pszExtension[0] != '.' && strlen(pszExtension) > 0 )
        pszAddedExtSep = ".";

    sprintf( pszFilename, "%s%s%s", 
             pszBasename, pszAddedExtSep, pszExtension );

    pszFullPath = CPLFormFilename( pszPath, pszFilename, NULL );
    fp = VSIFOpen( pszFullPath, "r" );
    if( fp == NULL )
    {
        for( i = 0; pszFilename[i] != '\0'; i++ )
        {
            if( islower(pszFilename[i]) )
                pszFilename[i] = toupper(pszFilename[i]);
        }

        pszFullPath = CPLFormFilename( pszPath, pszFilename, NULL );
        fp = VSIFOpen( pszFullPath, "r" );
    }

    if( fp == NULL )
    {
        for( i = 0; pszFilename[i] != '\0'; i++ )
        {
            if( isupper(pszFilename[i]) )
                pszFilename[i] = tolower(pszFilename[i]);
        }

        pszFullPath = CPLFormFilename( pszPath, pszFilename, NULL );
        fp = VSIFOpen( pszFullPath, "r" );
    }

    if( fp != NULL )
        VSIFClose( fp );
    else
        pszFullPath = CPLFormFilename( pszPath, pszBasename, pszExtension );

    CPLFree( pszFilename );

    return pszFullPath;
#endif
}

/************************************************************************/
/*                     CPLProjectRelativeFilename()                     */
/************************************************************************/

/**
 * Find a file relative to a project file. 
 *
 * Given the path to a "project" directory, and a path to a secondary file
 * referenced from that project, build a path to the secondary file
 * that the current application can use.  If the secondary path is already
 * absolute, rather than relative, then it will be returned unaltered. 
 * 
 * Examples:
 * <pre>
 * CPLProjectRelativeFilename("abc/def","tmp/abc.gif") == "abc/def/tmp/abc.gif"
 * CPLProjectRelativeFilename("abc/def","/tmp/abc.gif") == "/tmp/abc.gif"
 * CPLProjectRelativeFilename("/xy", "abc.gif") == "/xy/abc.gif"
 * CPLProjectRelativeFilename("/abc/def","../abc.gif") == "/abc/def/../abc.gif"
 * CPLProjectRelativeFilename("C:\WIN","abc.gif") == "C:\WIN\abc.gif"
 * </pre>
 *
 * @param pszProjectDir the directory relative to which the secondary files 
 * path should be interpreted.
 * @param pszSecondaryFilename the filename (potentially with path) that
 * is to be interpreted relative to the project directory.
 *
 * @return a composed path to the secondary file.  The returned string is
 * internal and should not be altered, freed, or depending on past the next
 * CPL call. 
 */

const char *CPLProjectRelativeFilename( const char *pszProjectDir, 
                                        const char *pszSecondaryFilename )

{
    char *pszStaticResult = CPLGetStaticResult();

    if( !CPLIsFilenameRelative( pszSecondaryFilename ) )
        return pszSecondaryFilename;

    if( pszProjectDir == NULL || strlen(pszProjectDir) == 0 )
        return pszSecondaryFilename;

    strncpy( pszStaticResult, pszProjectDir, CPL_PATH_BUF_SIZE );
    pszStaticResult[CPL_PATH_BUF_SIZE - 1] = '\0';

    if( pszProjectDir[strlen(pszProjectDir)-1] != '/' 
        && pszProjectDir[strlen(pszProjectDir)-1] != '\\' )
    {
        CPLAssert( strlen(SEP_STRING) + 1 < CPL_PATH_BUF_SIZE );

        strcat( pszStaticResult, SEP_STRING );
    }

    CPLAssert( strlen(pszSecondaryFilename) + 1 < CPL_PATH_BUF_SIZE );

    strcat( pszStaticResult, pszSecondaryFilename );
        
    return pszStaticResult;
}

/************************************************************************/
/*                       CPLIsFilenameRelative()                        */
/************************************************************************/

/**
 * Is filename relative or absolute?
 *
 * The test is filesystem convention agnostic.  That is it will test for
 * Unix style and windows style path conventions regardless of the actual
 * system in use.  
 *
 * @param pszFilename the filename with path to test.
 *
 * @return TRUE if the filename is relative or FALSE if it is absolute. 
 */

int CPLIsFilenameRelative( const char *pszFilename )

{
    if( (strlen(pszFilename) > 2
         && (strncmp(pszFilename+1,":\\",2) == 0
             || strncmp(pszFilename+1,":/",2) == 0))
        || pszFilename[0] == '\\'
        || pszFilename[0] == '/' )
        return FALSE;
    else
        return TRUE;
}

/************************************************************************/
/*                       CPLExtractRelativePath()                       */
/************************************************************************/

/**
 * Get relative path from directory to target file.
 *
 * Computes a relative path for pszTarget relative to pszBaseDir. 
 * Currently this only works if they share a common base path.  The returned
 * path is normally into the pszTarget string.  It should only be considered
 * valid as long as pszTarget is valid or till the next call to 
 * this function, whichever comes first. 
 *
 * @param pszBaseDir the name of the directory relative to which the path 
 * should be computed.  pszBaseDir may be NULL in which case the original
 * target is returned without relitivizing.
 * 
 * @param pszTarget the filename to be changed to be relative to pszBaseDir.
 *
 * @param pbGotRelative Pointer to location in which a flag is placed 
 * indicating that the returned path is relative to the basename (TRUE) or
 * not (FALSE).  This pointer may be NULL if flag is not desired.
 *
 * @return an adjusted path or the original if it could not be made relative
 * to the pszBaseFile's path. 
 **/

const char *CPLExtractRelativePath( const char *pszBaseDir, 
                                    const char *pszTarget,
                                    int *pbGotRelative )

{
    size_t nBasePathLen;

/* -------------------------------------------------------------------- */
/*      If we don't have a basedir, then we can't relativize the path.  */
/* -------------------------------------------------------------------- */
    if( pszBaseDir == NULL )
    {
        if( pbGotRelative != NULL )
            *pbGotRelative = FALSE;

        return pszTarget;
    }

    nBasePathLen = strlen(pszBaseDir);

/* -------------------------------------------------------------------- */
/*      One simple case is where neither file has a path.  We return    */
/*      the original target filename and it is relative.                */
/* -------------------------------------------------------------------- */
    const char *pszTargetPath = CPLGetPath(pszTarget);

    if( (nBasePathLen == 0 || EQUAL(pszBaseDir,"."))
        && (strlen(pszTargetPath) == 0 || EQUAL(pszTargetPath,".")) )
    {
        if( pbGotRelative != NULL )
            *pbGotRelative = TRUE;

        return pszTarget;
    }

/* -------------------------------------------------------------------- */
/*      By this point, if we don't have a base path, we can't have a    */
/*      meaningful common prefix.                                       */
/* -------------------------------------------------------------------- */
    if( nBasePathLen == 0 )
    {
        if( pbGotRelative != NULL )
            *pbGotRelative = FALSE;

        return pszTarget;
    }

/* -------------------------------------------------------------------- */
/*      If we don't have a common path prefix, then we can't get a      */
/*      relative path.                                                  */
/* -------------------------------------------------------------------- */
    if( !EQUALN(pszBaseDir,pszTarget,nBasePathLen) 
        || (pszTarget[nBasePathLen] != '\\' 
            && pszTarget[nBasePathLen] != '/') )
    {
        if( pbGotRelative != NULL )
            *pbGotRelative = FALSE;

        return pszTarget;
    }

/* -------------------------------------------------------------------- */
/*      We have a relative path.  Strip it off to get a string to       */
/*      return.                                                         */
/* -------------------------------------------------------------------- */
    if( pbGotRelative != NULL )
        *pbGotRelative = TRUE;

    return pszTarget + nBasePathLen + 1;
}

/************************************************************************/
/*                            CPLCleanTrailingSlash()                   */
/************************************************************************/

/**
 * Remove trailing forward/backward slash from the path for unix/windows resp.
 *
 * Returns a string containing the portion of the passed path string with 
 * trailing slash removed. If there is no path in the passed filename 
 * an empty string will be returned (not NULL).
 *
 * <pre>
 * CPLCleanTrailingSlash( "abc/def/" ) == "abc/def"
 * CPLCleanTrailingSlash( "abc/def" ) == "abc/def"
 * CPLCleanTrailingSlash( "c:\abc\def\" ) == "c:\abc\def"
 * CPLCleanTrailingSlash( "c:\abc\def" ) == "c:\abc\def"
 * CPLCleanTrailingSlash( "abc" ) == "abc"
 * </pre>
 *
 * @param pszPath the path to be cleaned up
 *
 *  @return Path in an internal string which must not be freed.  The string
 * may be destroyed by the next CPL filename handling call.  The returned
 * will generally not contain a trailing path separator.
 */

const char *CPLCleanTrailingSlash( const char *pszFilename )

{
    char       *pszStaticResult = CPLGetStaticResult();
    int        iPathLength = strlen(pszFilename);

    strncpy( pszStaticResult, pszFilename, iPathLength );
    pszStaticResult[iPathLength] = '\0';

    if( iPathLength > 0 
        && (pszStaticResult[iPathLength-1] == '\\' 
            || pszStaticResult[iPathLength-1] == '/'))
        pszStaticResult[iPathLength-1] = '\0';

    return pszStaticResult;
}