Line data    Source code

       1             : /******************************************************************************
       2             :  *
       3             :  * Purpose:  Implementation of the Open() function.
       4             :  *
       5             :  ******************************************************************************
       6             :  * Copyright (c) 2009
       7             :  * PCI Geomatics, 90 Allstate Parkway, Markham, Ontario, Canada.
       8             :  *
       9             :  * SPDX-License-Identifier: MIT
      10             :  ****************************************************************************/
      11             : #include "pcidsk.h"
      12             : #include "pcidsk_config.h"
      13             : #include "pcidsk_types.h"
      14             : #include "pcidsk_file.h"
      15             : #include "pcidsk_interfaces.h"
      16             : #include "core/cpcidskfile.h"
      17             : #include <string>
      18             : #include <cstring>
      19             : #include <cassert>
      20             : 
      21             : using namespace PCIDSK;
      22             : 
      23             : /************************************************************************/
      24             : /*                                Open()                                */
      25             : /************************************************************************/
      26             : 
      27             : /**
      28             :  * Open a PCIDSK (.pix) file.
      29             :  *
      30             :  * This function attempts to open the named file, with the indicated
      31             :  * access and the provided set of system interface methods.
      32             :  *
      33             :  * @param filename the name of the PCIDSK file to access.
      34             :  * @param access either "r" for read-only, or "r+" for read-write access.
      35             :  * @param interfaces Either NULL to use default interfaces, or a pointer
      36             :  * to a populated interfaces object.
      37             :  *
      38             :  * @return a pointer to a file object for accessing the PCIDSK file.
      39             :  */
      40             : 
      41         256 : PCIDSKFile *PCIDSK::Open( const std::string& filename, const std::string& access,
      42             :                           const PCIDSKInterfaces *interfaces,
      43             :                           int max_channel_count )
      44             : 
      45             : {
      46             : /* -------------------------------------------------------------------- */
      47             : /*      Use default interfaces if none are passed in.                   */
      48             : /* -------------------------------------------------------------------- */
      49         256 :     PCIDSKInterfaces default_interfaces;
      50         256 :     if( interfaces == nullptr )
      51           0 :         interfaces = &default_interfaces;
      52             : 
      53             : /* -------------------------------------------------------------------- */
      54             : /*      First open the file, and confirm that it is PCIDSK before       */
      55             : /*      going further.                                                  */
      56             : /* -------------------------------------------------------------------- */
      57         256 :     void *io_handle = interfaces->io->Open( filename, access );
      58             : 
      59         256 :     assert( io_handle != nullptr );
      60             : 
      61             :     char header_check[6];
      62             : 
      63         256 :     if( interfaces->io->Read( header_check, 1, 6, io_handle ) != 6
      64         256 :         || memcmp(header_check,"PCIDSK",6) != 0 )
      65             :     {
      66           1 :         interfaces->io->Close( io_handle );
      67           1 :         return (PCIDSKFile*)ThrowPCIDSKExceptionPtr( "File %s does not appear to be PCIDSK format.",
      68           0 :                               filename.c_str() );
      69             :     }
      70             : 
      71             : /* -------------------------------------------------------------------- */
      72             : /*      Create the PCIDSKFile object.                                   */
      73             : /* -------------------------------------------------------------------- */
      74             : 
      75         255 :     CPCIDSKFile *file = new CPCIDSKFile( filename );
      76             : 
      77         255 :     file->interfaces = *interfaces;
      78         255 :     file->io_handle = io_handle;
      79         255 :     file->io_mutex = interfaces->CreateMutex();
      80             : 
      81         255 :     if( strstr(access.c_str(),"+") != nullptr )
      82         124 :         file->updatable = true;
      83             : 
      84             : /* -------------------------------------------------------------------- */
      85             : /*      Initialize it from the header.                                  */
      86             : /* -------------------------------------------------------------------- */
      87             :     try
      88             :     {
      89         255 :         file->InitializeFromHeader(max_channel_count);
      90             :     }
      91           2 :     catch(...)
      92             :     {
      93           1 :         delete file;
      94           1 :         throw;
      95             :     }
      96             : 
      97         254 :     return file;
      98             : }