main.c

Microsoft Visual C++ 6.0环境下的无损压缩测试工程

/* Name : main.c
 *
 * Notes: This is the main driver code for the xpkCRSH command-line utility.
 *        It supports all features of xpkCRSH, even those that are not
 *        accessable using xpkmaster.library.
 */

#include <stdio.h>
#include <stdlib.h>
#include <assert.h>

#include "stdtypes.h"

#include "lz77.h"
#include "getopt.h"

#ifdef UNIX
#include <sys/types.h>
#include <sys/stat.h>
#endif


static void ShowUsage( STRPTR );
ULONG FileLength( FILE * file );
#define SEEK_END 2

int action      = 1;

struct option opts[] =
{
    { "compress",     0, &action,       1       },
    { "decompress",   0, &action,       0       },
    { "mode",         1, NULL,          'm'     },
    { NULL, }
};

/******************************************************************************/
/* Name : main()
 *
 * Notes:
 *
 */

int main( int argc, char ** argv )
{
    FILE            * input;
    FILE            * output;
    struct LZ77Info   info;
    int               opt;
    int               ch;


    info.Mode   = 0;
    info.Number = 0;
    info.buffer = NULL;
    memset( &info, 0, sizeof( info ) );

    /* Parse the command line and determine what the user wants us to do and
     * how they want us to do it.
     */

    optind = 0;
    while ( (ch = getopt_long_only( argc, argv, opts, &opt )) != EOF )
    {
        switch( ch )
        {
            case 'm' :
            {
                info.Mode = atoi( optarg );
                printf( "info.Mode = %ld\n", info.Mode );
                break;
            }

            case '?' :
            {
                ShowUsage( argv[0] );
                exit( 5 );
            }

            default:
                break;
        }
    }



    /* Once we've parsed the initial arguments, we need to get the names
     * of the files that the user wants us to work on.
     */

    if ( (argc - optind) < 2 )
    {
        ShowUsage( argv[0] );
        exit( 5 );
    }


    input  = fopen( argv[ optind ], "rb" );
    if ( input == NULL )
    {
        perror( argv[ optind ] );
        exit( 5 );
    }

    output = fopen( argv[ optind + 1 ], "wb" );
    if ( output == NULL )
    {
        fclose( input );
        perror( argv[ optind + 1 ] );
        exit( 5 );
    }


    info.length = FileLength( input );
    info.input  = malloc( info.length );

    printf( "info.length = %ld\n", info.length );

    /* Now we need to decide what the user wants us to do.  There's only
     * two choices, so it's not too rough.  To compress, or to decompress,
     * that is the question.
     */

    if ( action == 0 )
    {
        ULONG temp;


        fread( &temp, 4L, 1L, input );
        printf( __FILE__ ",%ld: temp = %ld\n", (long)__LINE__, temp );
        fflush( stdout );

        info.outBufSize = temp + 32;
        info.output = malloc( temp + 32 );

        info.length -= 4;
        fread( info.input, 1L, info.length, input );
        fclose( input );

        info.length = DecompressLZ77( &info );

        if ( temp != info.length )
        {
            printf( __FILE__ ",%ld: THPT! %ld != %ld\n", (long)__LINE__,
	            info.length, temp );
        }
    }
    else
    {
        fread( info.input, 1L, info.length, input );
        fclose( input );
        info.outBufSize = ((info.length * 17) / 16) + 1;
        info.output = malloc( info.outBufSize );


        fwrite( &info.length, 4L, 1L, output );
        info.length = CompressLZ77( &info );

        printf( __FILE__ ",%ld: Done compressing the data.\n", (long)__LINE__ );
    }


    fwrite( info.output, 1L, info.length, output );
    fclose( output );


    PackFreeLZ77( &info );

    free( info.input );
    free( info.output );

    return( 0 );
}




/******************************************************************************/
/* Name : FileLength()
 *
 * Notes: This function is used to determine the length of the file
 *        associated file handle in bytes.  This is a very generic ANSI
 *        implementation of this function.  It is advised that versions
 *        of this routine for other operating systems (i.e., Unix, AmigaDOS)
 *        use more specified OS functions (i.e., fstat(), Examine()).
 */

ULONG FileLength( FILE * file )
{
#ifndef UNIX
    ULONG   length;

    length = 0L;
    if ( fseek( file, 0L, SEEK_END ) == 0 )
    {
        length = ftell( file );
        rewind( file );
    }
    return( length );

#else

    struct stat buf;
    fstat( file->_file, &buf );

    return( buf.st_size );

#endif
}




/******************************************************************************/
/* Name : ShowUsage()
 *
 * Notes: This tiny routine simply shows the user how to run our neat little
 *        compression program.
 */

static void ShowUsage( STRPTR name )
{
    printf( "Usage: %s [options] infile outfile\n", name );
    printf( "Options:\n"
            "    --compress    Compress the input file\n"
            "    --decompress  Decompress the input file\n"
            "    --mode n      Use compression mode ``n''\n"
          );
}