BESUncompress3BZ2.cc

// BESUncompress3BZ2.cc
 
// This file is part of bes, A C++ back-end server implementation framework
// for the OPeNDAP Data Access Protocol.
 
// Copyright (c) 2004-2009 University Corporation for Atmospheric Research
// Author: Patrick West <pwest@ucar.edu> and Jose Garcia <jgarcia@ucar.edu>
//
// This library is free software; you can redistribute it and/or
// modify it under the terms of the GNU Lesser General Public
// License as published by the Free Software Foundation; either
// version 2.1 of the License, or (at your option) any later version.
// 
// This library is distributed in the hope that it will be useful,
// but WITHOUT ANY WARRANTY; without even the implied warranty of
// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
// Lesser General Public License for more details.
// 
// You should have received a copy of the GNU Lesser General Public
// License along with this library; if not, write to the Free Software
// Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301  USA
//
// You can contact University Corporation for Atmospheric Research at
// 3080 Center Green Drive, Boulder, CO 80301
 
// (c) COPYRIGHT University Corporation for Atmospheric Research 2004-2005
// Please read the full copyright statement in the file COPYRIGHT_UCAR.
//
// Authors:
//      pwest       Patrick West <pwest@ucar.edu>
//      jgarcia     Jose Garcia <jgarcia@ucar.edu>
 
 
#include "config.h"
 
#ifdef HAVE_BZLIB_H
#include <bzlib.h>
#endif
 
#include <cstring>
#include <cerrno>
#include <sstream>
#include <unistd.h>
 
using std::ostringstream;
using std::string;
 
#include "BESUncompress3BZ2.h"
#include "BESInternalError.h"
#include "BESDebug.h"
 
#define CHUNK 4096
 
#if 0
static void bz_internal_error(int errcode)
{
    ostringstream strm;
    strm << "internal error in bz2 library occurred: " << errcode;
    throw BESInternalError(strm.str(), __FILE__, __LINE__);
}
#endif

void
BESUncompress3BZ2::uncompress( const string &src_name, int fd )
{
#ifndef HAVE_BZLIB_H
    string err = "Unable to uncompress bz2 files, feature not built. Check config.h in bes directory for HAVE_BZLIB_H flag set to 1";
    throw BESInternalError( err, __FILE__, __LINE__ );
#else
    FILE *src = fopen( src_name.c_str(), "rb" );
    if( !src )
    {
        char *serr = strerror( errno );
        string err = "Unable to open the compressed file "
        + src_name + ": ";
        if( serr )
        {
            err.append( serr );
        }
        else
        {
            err.append( "unknown error occurred" );
        }
        throw BESInternalError( err, __FILE__, __LINE__ );
    }
 
    int bzerror = 0; // any error flags will be stored here
    int verbosity = 0; // 0 is silent up to 4 which is very verbose
    int small = 0; // if non zero then memory management is different
    // unused void *unused = NULL; // any unused bytes would be stored in here
    // unused int nunused = 0; // the size of the unused buffer
    char in[CHUNK]; // input buffer used to read uncompressed data in bzRead
 
    BZFILE *bsrc = NULL;
 
    bsrc = BZ2_bzReadOpen( &bzerror, src, verbosity, small, NULL, 0 );
    if( bsrc == NULL )
    {
        const char *berr = BZ2_bzerror( bsrc, &bzerror );
        string err = "bzReadOpen failed on " + src_name + ": ";
        if( berr )
        {
            err.append( berr );
        }
        else
        {
            err.append( "Unknown error" );
        }
        fclose( src );
 
        throw BESInternalError( err, __FILE__, __LINE__ );
    }
 
    bool done = false;
    while( !done )
    {
        int bytes_read = BZ2_bzRead( &bzerror, bsrc, in, CHUNK );
        if( bzerror != BZ_OK && bzerror != BZ_STREAM_END )
        {
            const char *berr = BZ2_bzerror( bsrc, &bzerror );
            string err = "bzRead failed on " + src_name + ": ";
            if( berr )
            {
                err.append( berr );
            }
            else
            {
                err.append( "Unknown error" );
            }
 
            BZ2_bzReadClose( &bzerror, bsrc );
            fclose( src );
 
            throw BESInternalError( err, __FILE__, __LINE__ );
        }
        //if( bytes_read == 0 || bzerror == BZ_STREAM_END )
        if( bzerror == BZ_STREAM_END )
        {
            done = true;
        }
        int bytes_written = write(fd, in, bytes_read);
        if( bytes_written < bytes_read )
        {
            ostringstream strm;
            strm << "Error writing uncompressed data: "
            << "wrote " << bytes_written
            << " instead of " << bytes_read;
 
            BZ2_bzReadClose( &bzerror, bsrc );
            fclose( src );
 
            throw BESInternalError( strm.str(), __FILE__, __LINE__ );
        }
    }
 
    BZ2_bzReadClose( &bzerror, bsrc );
    fclose( src );
#endif
}