Club Amiga de Montreal - CAM/CAM_CD_1.iso/files/309.lha/PBM_PLUS/pbm/gemtopbm.c

C/C++ Source or Header | 1980-12-04 | 5KB | 213 lines

/*
 * Convert a GEM .img file to a portable bitmap file.
 *
 * Author: Diomidis D. Spinellis
 * (C) Copyright 1988 Diomidis D. Spinellis.
 *
 * Permission to use, copy, modify, and distribute this software and its
 * documentation for any purpose and without fee is hereby granted,
 * provided that the above copyright notice appear in all copies and that
 * both that copyright notice and this permission notice appear in
 * supporting documentation.
 *
 * This file is provided AS IS with no warranties of any kind.  The author
 * shall have no liability with respect to the infringement of copyrights,
 * trade secrets or any patents by this file or any part thereof.  In no
 * event will the author be liable for any lost revenue or profits or
 * other special, indirect and consequential damages.
 *
 * Comments and additions should be sent to the author:
 *
 *                     Diomidis D. Spinellis
 *                     1 Myrsinis Str.
 *                     GR-145 62 Kifissia
 *                     GREECE
 *
 */

#include <stdio.h>
#ifdef    SYSV
#include <string.h>
#else    SYSV
#include <strings.h>
#endif    SYSV
#include <assert.h>
#include "pbm.h"
#include "libpbm.h"

/*
 * Handle systems that do CR-LF translation on reading / writing and
 * little endians (some guesswork is involved).
 */
#ifdef MSDOS
#define LITTLE_ENDIAN
#endif
#ifdef xenix
#define LITTLE_ENDIAN
#endif
#ifdef sun386
#define LITTLE_ENDIAN
#endif


/* Seek from current position */
#ifndef SEEK_CUR
#define SEEK_CUR 1
#endif

/*
 * File header structure
 */
struct header {
    short           version;/* Image file version */
    unsigned short  hlen;    /* Header length in bytes */
    unsigned short  planes;    /* Number of planes */
    unsigned short  patlen;    /* Pattern definition length (bytes) */
    unsigned short  pxlen;    /* Pixel height (microns) */
    unsigned short  pxht;    /* Pixel height (microns) */
    unsigned short  linewid;/* Scan line width (bytes) */
    unsigned short  nitems;    /* Number of scan line items */
};

/*
 * Scan item header
 */
struct line {
    char            d1, d2;    /* Should be 0 */
    char            d3;    /* Should be 0xff */
    char            count;    /* Repetition count */
};

char            pattern[256];


static void byteswap();
static void pbmout();
extern int      errno;
extern char    *sys_errlist[];
#define strerror(x) (sys_errlist[x])

void
main(argc, argv)
    int             argc;
    char           *argv[];
{
    int             debug = 0;
    FILE           *f;
    struct header   hd;
    int             x;
    int             i, j, k, l;
    int             c, cc;
    int        rows, cols;
    bit        *bitrow;

    pm_progname = argv[0];

    /* Check if the compiler alligns structures the way we want */
    assert( sizeof( struct header ) == 16 ) ;

    if (argc > 1 && !strcmp(argv[1], "-d")) {
        argc--;
        argv[1] = argv[0];
        argv++;
        debug++;
    }

    if (argc != 2)
        pm_usage("[-d] <gemfile>");

    f = pm_openr( argv[1] );

    if (fread(&hd, sizeof hd, 1, f) != 1)
        pm_error( "read %s", strerror(errno), 0,0,0,0 );

#ifdef LITTLE_ENDIAN
    byteswap((unsigned short *) &hd, sizeof hd / 2);
#endif

    if( fseek(f, (long) hd.hlen * 2 - sizeof(struct header), SEEK_CUR) == -1 )
        pm_error( "fseek %s", strerror(errno), 0,0,0,0 );

    if (debug)
        fprintf(stderr,
            " version\t\t%d\n hlen\t\t%d\n planes\t\t%d\n patlen\t\t%d\n pxlen\t\t%d\n pxht\t\t%d\n linewid\t\t%d\n nitems\t\t%d\n",
                hd.version, hd.hlen, hd.planes, hd.patlen, hd.pxlen,
                hd.pxht, hd.linewid, hd.nitems);

    cols = hd.linewid % 8 == 0 ? hd.linewid : hd.linewid + 8 - hd.linewid % 8;
    rows = hd.nitems;
    pbm_writepbminit( stdout, cols, rows );
    bitrow = pbm_allocrow( cols );

    for (i = 0; i < hd.nitems; i++) {
        x = 0;
        while (x < hd.linewid) {
            switch (c = getc(f)) {
            case 0x80:    /* Bit String */
                c = getc(f);    /* Byte count */
                if (debug)
                    fprintf(stderr,
                        "Bit string of %d bytes\n", c);
                for (j = 0; j < c; j++) {
                    cc = getc(f);
                    for (k = 0x80; k; k >>= 1) {
                        bitrow[x] = (k & cc) ? PBM_BLACK : PBM_WHITE;
                        x++;
                }
                }
                break;
            case 0:        /* Pattern run */
                c = getc(f);    /* Repeat count */
                if (debug)
                    fprintf(stderr,
                        "Pattern run of %d repetitions\n",
                        c);
                fread(pattern, 1, hd.patlen, f);
                for (j = 0; j < c; j++)
                    for (l = 0; l < hd.patlen; l++)
                        for (k = 0x80; k; k >>= 1) {
                            bitrow[x] = (k & pattern[l]) ? PBM_BLACK : PBM_WHITE;
                            x++;
                        }
                break;

            default:    /* Solid run */
                if (debug)
                    fprintf(stderr,
                        "Solid run of %d bytes %s\n",
                        c & 0x7f,
                        c & 0x80 ? "on" : "off");
                for (i = 0; i < c & 0x7f; i++) {
                    bitrow[x] = (c & 0x80) ? PBM_BLACK : PBM_WHITE;
                    x++;
                }
                break;

            case EOF:    /* End of file */
                pm_error( "end of file reached", 0,0,0,0,0 );

            }
        }
        pbm_writepbmrow( stdout, bitrow, cols );
    }
    pm_close( f );
    exit(0);
}

#ifdef LITTLE_ENDIAN
static void
byteswap(data, n)
    unsigned short *data;
    int             n;
{
    register        i;
    char           *p, c;

    for (i = 0, p = (char *) data; i < n; i++, p++) {
        c = *p;
        *p = *(p + 1);
        *++p = c;
    }
}
#endif