rleskel.c

Go to the documentation of this file.

/*
 * This software is copyrighted as noted below.  It may be freely copied,
 * modified, and redistributed, provided that the copyright notice is 
 * preserved on all copies.
 * 
 * There is no warranty or other guarantee of fitness for this software,
 * it is provided solely "as is".  Bug reports or fixes may be sent
 * to the author, who may or may not act on them as he desires.
 *
 * You may not include this software in a program or other software product
 * without supplying the source, or without informing the end-user that the 
 * source is available for no extra charge.
 *
 * If you modify this software, you should include a notice giving the
 * name of the person performing the modification, the date of modification,
 * and the reason for such modification.
 */
/* 
 * rleskel.c - Skeleton RLE tool.
 * 
 * Author:  Spencer W. Thomas
 *      EECS Dept.
 *      University of Michigan
 * Date:    Tue Jun 12 1990
 * Copyright (c) 1990, University of Michigan
 */
#if 0
rleskel()           /* For tags. */
#endif

#include <stdio.h>
#include "rle.h"

/*****************************************************************
 * TAG( main )
 * 
 * A skeleton RLE tool.  Demonstrates argument parsing, opening,
 * reading, and writing RLE files.  Includes support for files
 * consisting of concatenated images.
 * Usage:
 *  rleskel [-o outfile] [infile]
 * Inputs:
 *  infile:     The input RLE file.  Default stdin.
 *          "-" means stdin.
 * Outputs:
 *  -o outfile: The output RLE file.  Default stdout.
 *          "-" means stdout.
 * Assumptions:
 *  [None]
 * Algorithm:
 *  Repeatedly read from the input until the file EOF or an
 *  error is encountered.
 */
main( argc, argv )
int argc;
char **argv;
{
    char       *infname = NULL,
               *outfname = NULL;
    int     oflag = 0;
    int     rle_cnt, rle_err, width, y;
    FILE       *outfile = 0;
    rle_hdr     in_hdr, out_hdr;
    rle_pixel **rows;       /* Will be used for scanline storage. */

    in_hdr = *rle_hdr_init( NULL );
    out_hdr = *rle_hdr_init( NULL );

    if ( scanargs( argc, argv, "% o%-outfile!s infile%s",
           &oflag, &outfname, &infname ) == 0 )
    exit( 1 );

    /* Open the input file.
     * The output file won't be opened until the first image header
     * has been read.  This avoids unnecessarily wiping out a
     * pre-existing file if the input is garbage.
     */
    in_hdr.rle_file = rle_open_f( cmd_name( argv ), infname, "r" );
    rle_names( &in_hdr, cmd_name( argv ), infname, 0 );
    rle_names( &out_hdr, in_hdr.cmd, outfname, 0 );

    /* Read images from the input file until the end of file is
     * encountered or an error occurs.
     */
    for ( rle_cnt = 0;
      (rle_err = rle_get_setup( &in_hdr )) == RLE_SUCCESS;
      rle_cnt++ )
    {
    /* Open the output file when the first header is successfully read. */
    if ( rle_cnt == 0 )
        outfile = rle_open_f( cmd_name( argv ), outfname, "w" );

    /* The output header is a copy of the input header.  The only
     * difference is the FILE pointer.
     */
    (void)rle_hdr_cp( &in_hdr, &out_hdr );
    out_hdr.rle_file = outfile;

    /* Add to the history comment. */
    rle_addhist( argv, &in_hdr, &out_hdr );

    /* Write the output image header. */
    rle_put_setup( &out_hdr );

    /* Since rle_getrow and rle_putrow use different array origins,
     * we will compensate by adjusting the xmin and xmax values in
     * the input header.  [rle_getrow assumes that the scanline
     * array starts at pixel 0, while rle_putrow assumes that the
     * scanline array starts at pixel xmin.  This is a botch, but
     * it's too late to change it now.]
     */
    in_hdr.xmax -= in_hdr.xmin;
    in_hdr.xmin = 0;
    width = in_hdr.xmax + 1;    /* Width of a scanline. */

    /* Allocate memory into which the image scanlines can be read.
     * This should happen after the above adjustment, to minimize
     * the amount of memory allocated.
     */
    if ( rle_row_alloc( &in_hdr, &rows ) < 0 )
        RLE_CHECK_ALLOC( in_hdr.cmd, 0, "image memory" );

    /* Read the input image and copy it to the output file. */
    for ( y = in_hdr.ymin; y <= in_hdr.ymax; y++ )
    {
        /* Read a scanline. */
        rle_getrow( &in_hdr, rows );

        /* Process the scanline as desired here. */

        /* Write the processed scanline. */
        rle_putrow( rows, width, &out_hdr );
    }

    /* Protect from bad input. */
    while ( rle_getskip( &in_hdr ) != 32768 )
        ;

    /* Free memory. */
    rle_row_free( &in_hdr, rows );

    /* Write an end-of-image code. */
    rle_puteof( &out_hdr );
    }

    /* Close the files. */
    rle_close_f( in_hdr.rle_file );
    rle_close_f( outfile ); /* Still safe if outfile == 0. */

    /* Check for an error.  EOF or EMPTY is ok if at least one image
     * has been read.  Otherwise, print an error message.
     */
    if ( rle_cnt == 0 || (rle_err != RLE_EOF && rle_err != RLE_EMPTY) )
    rle_get_error( rle_err, cmd_name( argv ), infname );

    exit( 0 );
}