/******************************************************************************
 * $Id: subfile_source.h 7e07230bbff24eb333608de4dbd460b7312839d0 2017-12-11 19:08:47Z Even Rouault $
 *
 * Project:  JPEG-2000
 * Purpose:  Implements read-only virtual io on a subregion of a file.
 * Author:   Frank Warmerdam, warmerdam@pobox.com
 *
 ******************************************************************************
 * Copyright (c) 2004, Frank Warmerdam <warmerdam@pobox.com>
 * Copyright (c) 2013, Even Rouault <even dot rouault at mines-paris dot org>
 *
 * 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.
 ****************************************************************************/

#ifndef JP2KAK_SUBFILE_SOURCE_H
#define JP2KAK_SUBFILE_SOURCE_H

#include "kdu_file_io.h"
#include "cpl_error.h"
#include "cpl_vsi_virtual.h"

#include <assert.h>

#if KDU_MAJOR_VERSION > 7 || (KDU_MAJOR_VERSION == 7 && KDU_MINOR_VERSION >= 5)
    using namespace kdu_core;
    using namespace kdu_supp;
#endif

static const long IO_CHUNK_SIZE = 65536L;
static const long IO_BUFFER_SIZE = 1048576L;

/************************************************************************/
/*                            subfile_source                            */
/************************************************************************/

class subfile_source : public kdu_compressed_source {
  public:
    subfile_source() :
        capabilities(0),
        subfile_offset(0),
        subfile_size(0),
        file(nullptr)
    {}

    ~subfile_source() override { close(); }

    bool exists() const { return (file != nullptr); }

    bool operator!() const { return (file == nullptr); }

    void open(const char *fname, int bSequential, int bCached )
      {
          close();

          const char *real_filename = nullptr;

          if( EQUALN( fname, "J2K_SUBFILE:",12) )
          {
              char** papszTokens = CSLTokenizeString2(fname + 12, ",", 0);
              if (CSLCount(papszTokens) >= 2)
              {
                  subfile_offset = static_cast<int>(
                      CPLScanUIntBig(papszTokens[0],
                                     static_cast<int>(strlen(papszTokens[0]))));
                  subfile_size = static_cast<int>(
                      CPLScanUIntBig(papszTokens[1],
                                     static_cast<int>(strlen(papszTokens[1]))));
              }
              else
              {
                  kdu_error e;

                  e << "Corrupt subfile definition:" << fname;
                  return;
              }
              CSLDestroy(papszTokens);

              real_filename = strstr(fname,",");
              if( real_filename != nullptr )
              {
                  real_filename = strstr(real_filename+1,",");
              }
              if( real_filename != nullptr )
              {
                  real_filename++;
              }
              else
              {
                  kdu_error e;

                  e << "Could not find filename in subfile definition."
                      << fname;
                  return;
              }
          }
          else
          {
              real_filename = fname;
              subfile_offset = 0;
              subfile_size = 0;
          }

          file = VSIFOpenL( real_filename, "r");
          if( file == nullptr )
          {
              kdu_error e;
              e << "Unable to open compressed data file, \"" <<
                  real_filename << "\"!";
              return;
          }

          if ( bCached )
          {
              file = reinterpret_cast<VSILFILE *>(
                  VSICreateCachedFile(
                      reinterpret_cast<VSIVirtualHandle *>(file),
                      IO_CHUNK_SIZE, IO_BUFFER_SIZE));
              if( file == nullptr )
              {
                  kdu_error e;
                  e << "Unable to open compressed data file, \"" <<
                      real_filename << "\"!";
                  return;
              }
          }

          if( bSequential )
              capabilities = KDU_SOURCE_CAP_SEQUENTIAL;
          else
              capabilities =
                  KDU_SOURCE_CAP_SEQUENTIAL | KDU_SOURCE_CAP_SEEKABLE;

          seek(0);
      }

    int get_capabilities() override { return capabilities; }

    bool seek(kdu_long offset) override
      {
          assert(file != nullptr);
          if( file == nullptr )
              return false;

          if (!(capabilities & KDU_SOURCE_CAP_SEEKABLE))
              return false;

          if( VSIFSeekL( file, subfile_offset+offset, SEEK_SET ) == 0 )
              return true;
          else
              return false;
      }

    kdu_long get_pos() override
      {
        if (file == nullptr) return -1;
        kdu_long result = VSIFTellL(file);
        result -= subfile_offset;
        return result;
      }

    int read(kdu_byte *buf, int num_bytes) override
      {
        assert(file != nullptr);

        num_bytes = static_cast<int>(
            VSIFReadL(buf, 1, static_cast<size_t>(num_bytes), file));
        return num_bytes;
      }

    bool close() override
      {
        if (file != nullptr)
            VSIFCloseL(file);
        file = nullptr;
        return true;
      }

  private: // Data
    int capabilities;

    int subfile_offset;
    int subfile_size;

    VSILFILE *file;
  };

#endif  // JP2KAK_SUBFILE_SOURCE_H