cpl_vsil.cpp

用于读取TAB、MIF、SHP文件的类

/******************************************************************************
 * $Id: cpl_vsil.cpp,v 1.8 2006/09/21 07:55:22 dron Exp $
 *
 * Project:  VSI Virtual File System
 * Purpose:  Implementation VSI*L File API and other file system access
 *           methods going through file virtualization.
 * Author:   Frank Warmerdam, [e-mail]
 *
 ******************************************************************************
 * Copyright (c) 2005, Frank Warmerdam <[e-mail]>
 *
 * Permission is hereby granted, free of charge, to any person obtaining a
 * copy of this software and associated documentation files (the "Software"),
 * to deal in the Software without restriction, including without limitation
 * the rights to use, copy, modify, merge, publish, distribute, sublicense,
 * and/or sell copies of the Software, and to permit persons to whom the
 * Software is furnished to do so, subject to the following conditions:
 *
 * The above copyright notice and this permission notice shall be included
 * in all copies or substantial portions of the Software.
 *
 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS
 * OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL
 * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
 * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
 * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER
 * DEALINGS IN THE SOFTWARE.
 ******************************************************************************
 *
 * $Log: cpl_vsil.cpp,v $
 * Revision 1.8  2006/09/21 07:55:22  dron
 * Fixed typo in documentation.
 *
 * Revision 1.7  2006/03/27 18:36:17  fwarmerdam
 * VSIFWriteL has const buffer now
 *
 * Revision 1.6  2006/01/11 00:29:54  fwarmerdam
 * added brief not on multithreading
 *
 * Revision 1.5  2006/01/10 17:03:56  fwarmerdam
 * added VSI Rename support
 *
 * Revision 1.4  2005/10/07 00:26:27  fwarmerdam
 * add documentation
 *
 * Revision 1.3  2005/09/15 18:39:00  fwarmerdam
 * fixedup filemanager cleanup
 *
 * Revision 1.2  2005/09/15 18:32:35  fwarmerdam
 * added VSICleanupFileManager
 *
 * Revision 1.1  2005/09/11 18:00:55  fwarmerdam
 * New
 *
 */

#include "cpl_vsi_private.h"

CPL_CVSID("$Id: cpl_vsil.cpp,v 1.8 2006/09/21 07:55:22 dron Exp $");

/************************************************************************/
/*                              VSIMkdir()                              */
/************************************************************************/

/**
 * \brief Create a directory. 
 * 
 * Create a new directory with the indicated mode.  The mode is ignored
 * on some platforms.  A reasonable default mode value would be 0666.
 * This method goes through the VSIFileHandler virtualization and may
 * work on unusual filesystems such as in memory.
 *
 * Analog of the POSIX mkdir() function.
 *
 * @param pszPathname the path to the directory to create. 
 * @param mode the permissions mode.
 *
 * @return 0 on success or -1 on an error.
 */

int VSIMkdir( const char *pszPathname, long mode )

{
    VSIFilesystemHandler *poFSHandler = 
        VSIFileManager::GetHandler( pszPathname );

    return poFSHandler->Mkdir( pszPathname, mode );
}

/************************************************************************/
/*                             VSIUnlink()                              */
/*************************a***********************************************/

/**
 * \brief Delete a file.
 * 
 * Deletes a file object from the file system. 
 * 
 * This method goes through the VSIFileHandler virtualization and may
 * work on unusual filesystems such as in memory.
 *
 * Analog of the POSIX unlink() function.
 *
 * @param pszFilename the path of the file to be deleted.
 *
 * @return 0 on success or -1 on an error.
 */

int VSIUnlink( const char * pszFilename )

{
    VSIFilesystemHandler *poFSHandler = 
        VSIFileManager::GetHandler( pszFilename );

    return poFSHandler->Unlink( pszFilename );
}

/************************************************************************/
/*                             VSIRename()                              */
/************************************************************************/

/**
 * \brief Rename a file.
 * 
 * Renames a file object in the file system.  It should be possible
 * to rename a file onto a new filesystem, but it is safest if this 
 * function is only used to rename files that remain in the same directory.
 * 
 * This method goes through the VSIFileHandler virtualization and may
 * work on unusual filesystems such as in memory.
 *
 * Analog of the POSIX rename() function.
 *
 * @param oldpath the name of the file to be renamed.
 * @param newpath the name the file should be given. 
 *
 * @return 0 on success or -1 on an error.
 */

int VSIRename( const char * oldpath, const char * newpath )

{
    VSIFilesystemHandler *poFSHandler = 
        VSIFileManager::GetHandler( oldpath );

    return poFSHandler->Rename( oldpath, newpath );
}

/************************************************************************/
/*                              VSIRmdir()                              */
/************************************************************************/

/**
 * \brief Delete a directory.
 * 
 * Deletes a directory object from the file system.  On some systems
 * the directory must be empty before it can be deleted.
 * 
 * This method goes through the VSIFileHandler virtualization and may
 * work on unusual filesystems such as in memory.
 *
 * Analog of the POSIX rmdir() function.
 *
 * @param pszDirname the path of the directory to be deleted.
 *
 * @return 0 on success or -1 on an error.
 */

int VSIRmdir( const char * pszDirname )

{
    VSIFilesystemHandler *poFSHandler = 
        VSIFileManager::GetHandler( pszDirname );

    return poFSHandler->Rmdir( pszDirname );
}

/************************************************************************/
/*                              VSIStatL()                              */
/************************************************************************/

/**
 * \brief Get filesystem object info.
 * 
 * Fetches status information about a filesystem object (file, directory, etc).
 * The returned information is placed in the VSIStatBufL structure.   For
 * portability only the st_size (size in bytes), and st_mode (file type). 
 * This method is similar to VSIStat(), but will work on large files on 
 * systems where this requires special calls. 
 * 
 * This method goes through the VSIFileHandler virtualization and may
 * work on unusual filesystems such as in memory.
 *
 * Analog of the POSIX stat() function.
 *
 * @param pszFilename the path of the filesystem object to be queried.
 * @param psStatBuf the structure to load with information. 
 *
 * @return 0 on success or -1 on an error.
 */

int VSIStatL( const char * pszFilename, VSIStatBufL *psStatBuf )

{
    VSIFilesystemHandler *poFSHandler = 
        VSIFileManager::GetHandler( pszFilename );

    return poFSHandler->Stat( pszFilename, psStatBuf );
}

/************************************************************************/
/*                             VSIFOpenL()                              */
/************************************************************************/

/**
 * \brief Open file.
 *
 * This function opens a file with the desired access.  Large files (larger
 * than 2GB) should be supported.  Binary access is always implied and
 * the "b" does not need to be included in the pszAccess string.
 *
 * Note that the "FILE *" returned by this function is not really a 
 * standard C library FILE *, and cannot be used with any functions other
 * than the "VSI*L" family of functions.  They aren't "real" FILE objects.
 *
 * This method goes through the VSIFileHandler virtualization and may
 * work on unusual filesystems such as in memory.
 *
 * Analog of the POSIX fopen() function.
 *
 * @param pszFilename the file to open.
 * @param pszAccess access requested (ie. "r", "r+", "w".  
 *
 * @return NULL on failure, or the file handle.
 */

FILE *VSIFOpenL( const char * pszFilename, const char * pszAccess )

{
    VSIFilesystemHandler *poFSHandler = 
        VSIFileManager::GetHandler( pszFilename );

    return (FILE *) poFSHandler->Open( pszFilename, pszAccess );
}

/************************************************************************/
/*                             VSIFCloseL()                             */
/************************************************************************/

/**
 * \brief Close file.
 *
 * This function closes the indicated file.
 *
 * This method goes through the VSIFileHandler virtualization and may
 * work on unusual filesystems such as in memory.
 *
 * Analog of the POSIX fclose() function.
 *
 * @param fp file handle opened with VSIFOpenL().
 *
 * @return 0 on success or -1 on failure.
 */

int VSIFCloseL( FILE * fp )

{
    VSIVirtualHandle *poFileHandle = (VSIVirtualHandle *) fp;
    int nResult = poFileHandle->Close();
    
    delete poFileHandle;

    return nResult;
}

/************************************************************************/
/*                             VSIFSeekL()                              */
/************************************************************************/

/**
 * \brief Seek to requested offset.
 *
 * Seek to the desired offset (nOffset) in the indicated file. 
 *
 * This method goes through the VSIFileHandler virtualization and may
 * work on unusual filesystems such as in memory.
 *