CU Amiga Super CD-ROM 2/CU Amiga Magazine's Super CD-ROM 02 (1996)(EMAP Images)(GB)[!][issue 1996-04].iso/17_bit_pd/17bitgif/utility/amiga/giftrans.lha/GIFTRANS_Original.C

C/C++ Source or Header | 1995-05-05 | 28KB | 963 lines

/*
** GIFtrans v1.12
**
** Convert any GIF file into a GIF89a
** Allows for setting the transparent or background color, changing colors,
** adding or removing comments. Also code to analyze GIF contents.
**
** Copyright (c) 24.2.94 by Andreas Ley <[e-mail]>
**
** Permission to use, copy, modify, and distribute this software for any
** purpose and without fee is hereby granted, provided that the above
** copyright notice appears in all copies. This software is provided "as is"
** and without any express or implied warranties.
**
** This program has been tested on a HP9000/715 with HP-UX A.09.05
** In this environment, neither lint -u nor gcc -Wall produce any messages.
** It has also been compiled on AIX 3.2 and Solaris 2.3.
** If you encounter any errors or need to make any changes to port it
** to another platform, please contact me.
**
** Known bugs:
**    -B flag won't work if there's an Extension between the Global Color
**    Table and the Image Descriptor (or Graphic Control Extension). If -V
**    has been specified, a Warning Message will be displayed.
**    Will be fixed in 2.0 (if ever)
**    -D option may output changed data instead of original data, use
**    with caution, best only with then -L option.
**
** Version history
**
** Version 1.12 - 17.2.95
**    Incorporated dumpcomment by [e-mail] (Thomas Omerzu)
**    Outputs original version if newer than GIF89a.
**
** Version 1.11.2 - 14.12.94
**    Incorporated OS/2 port by [e-mail] (Klaus Johannes Rusch)
**    Different rgb.txt file for OS/2, setmode replaced by freopen for
**    OS/2 (SAA C)
**
** Version 1.11.1 - 11.8.94
**    Allows for use of the -g option without the -B option.
**
** Version 1.11 - 21.7.94
**    Moved Plain Text Extension to the Extensions section where it belongs.
**    Accept Unknown Extension Labels.
**    Incorporated MS-DOS port by [e-mail] (Enzo Michelangeli).
**    Added -o and -e options to redirect stdout and stderr.
**    Added -D debug flag.
**
** Version 1.10.2 - 22.6.94
**    Support for -DRGBTXT flag.
**
** Version 1.10.1 - 21.6.94
**    Different rgb.txt file FreeBSD/386BSD.
**
** Version 1.10 - 19.6.94
**    Added -g option to change a color in the global color table.
**    Added -B option to change the color for the transparent color index.
**
** Version 1.9.1 - 7.6.94
**    Different rgb.txt files for X11 and Open Windows.
**
** Version 1.9 - 1.6.94
**    Fixed a bug which caused color names to be rejected.
**
** Version 1.8 - 30.5.94
**    Accept #rrggbb style arguments.
**    Do nothing if rgb-color not found in GIF.
**
** Version 1.7 - 16.5.94
**    Added -l option to only list the color table.
**    Added -L option for verbose output without creating a gif.
**    Added -b option to change the background color index.
**    Display all matching color names for color table entries.
**    Fixed a bug which caused bad color names if rgb.txt starts with
**        whitespace.
**    Doesn't use strdup anymore.
**    Fixed =& bug on dec machines.
**
** Version 1.6 - 5.4.94
**    Added color names recognition.
**
** Version 1.5 - 15.3.94
**    Added basic verbose output to analyze GIFs.
**
** Version 1.4 - 8.3.94
**    Fixed off-by-one bug in Local Color table code.
**    Added -c and -C options to add or remove a comment.
**    Transparency is no longer the default.
**
** Thanx for bug reports, ideas and fixes to
**    [e-mail] (Patrick Atoon)
**    [e-mail] (Wes Barris)
**    [e-mail] (Patrick M. Fitzgerald)
**    [e-mail] (Frans van Hoesel)
**    [e-mail] (Dan Boardman)
**    [e-mail] (Ken Weiss)
**    [e-mail] (Chuck Musciano)
**    [e-mail] (Torsten Heycke)
**    [e-mail] (Colin Law)
**    [e-mail] (Joseph C. Walker)
**    [e-mail] (Bjorn Borud)
**    [e-mail] (CJS Vance)
**    [e-mail] (Peder Langlo)
**    [e-mail] (Ian Rutson)
**    [e-mail] (Nicolas Pioch)
**    [e-mail] (John Kilburg)
**    [e-mail] (Enzo Michelangeli)
**    [e-mail] (Terry von Gease)
**    [e-mail] (Klaus Johannes Rusch)
**    [e-mail] (Thomas Omerzu)
**
** Original distribution site is
**    ftp://ftp.rz.uni-karlsruhe.de/pub/net/www/tools/giftrans.c
** A man-page by [e-mail] (Kai Nordlund) is at
**    ftp://ftp.rz.uni-karlsruhe.de/pub/net/www/tools/giftrans.1
** To compile for MS-DOS or OS/2, you need getopt:
**    ftp://ftp.rz.uni-karlsruhe.de/pub/net/www/tools/getopt.c
** MS-DOS executable can be found at
**    ftp://ftp.rz.uni-karlsruhe.de/pub/net/www/tools/giftrans.exe
** OS/2 executable can be found at
**    ftp://ftp.rz.uni-karlsruhe.de/pub/net/www/tools/giftrans.os2.exe
** A template rgb.txt for use with the MS-DOS version can be found at
**    ftp://ftp.rz.uni-karlsruhe.de/pub/net/www/tools/rgb.txt
** Additional info can be found on
**    http://melmac.corp.harris.com/transparent_images.html
** The GIF file format is documented in
**    ftp://ftp.uu.net/doc/literary/obi/Standards/Graphics/Formats/gif89a.doc.Z
*/

#define    X11        /* When using X Window System */
#undef    OPENWIN        /* When using Open Windows */
#undef    X386        /* When using XFree86 with FreeBSD/386BSD */
#undef    OS2        /* When using IBM C/C++ 2.0 */
#ifndef    MSDOS    /* required for TurboC 1.0 */
#undef    MSDOS        /* When using Borland C (maybe MSC too) */
#endif

#ifndef OS2_OR_MSDOS
#ifdef OS2
#define OS2_OR_MSDOS
#endif /* OS2 */
#ifdef MSDOS
#define OS2_OR_MSDOS
#endif /* MSDOS */
#endif /* OS2_OR_MSDOS */

char copyright[] = "@(#)(c) Copyright 1994 by Andreas Ley ([e-mail])";
char sccsid[] = "@(#)GIFtrans v1.12 - Transpose GIF files";

#ifndef RGBTXT
#ifdef X11
#define    RGBTXT    "/usr/lib/X11/rgb.txt"
#else /* X11 */
#ifdef OPENWIN
#define    RGBTXT    "/usr/openwin/lib/rgb.txt"
#else /* OPENWIN */
#ifdef X386
#define    RGBTXT    "/usr/X386/lib/X11/rgb.txt"
#else /* X386 */
#ifdef OS2_OR_MSDOS
#define    RGBTXT    "rgb.txt"
#else /* OS2_OR_MSDOS */
#define    RGBTXT    "";
#endif /* OS2_OR_MSDOS */
#endif /* X386 */
#endif /* OPENWIN */
#endif /* X11 */
#endif /* RGBTXT */

#include <stdlib.h>
#include <stdio.h>
#include <string.h>
#include <errno.h>
#ifndef OS2_OR_MSDOS
#include <unistd.h>
#include <ctype.h>
#include <sys/param.h>
#else /* OS2_OR_MSDOS */
#include <fcntl.h>
#ifdef OS2
#include <io.h>
#endif /* OS2 */
#include "getopt.c"
#endif /* OS2_OR_MSDOS */

#ifndef MAXPATHLEN
#define MAXPATHLEN 256
#endif /* MAXPATHLEN */

#ifndef FALSE
#define    FALSE    (0)        /* This is the naked Truth */
#define    TRUE    (1)        /* and this is the Light */
#endif

#define    SUCCESS    (0)
#define    FAILURE    (1)

struct entry {
    struct entry    *next;
    char        *name;
    int        red;
    int        green;
    int        blue;
    } *root;

#define    NONE    (-1)
#define    OTHER    (-2)
#define    RGB    (-3)

struct color {
    int        index;
    int        red;
    int        green;
    int        blue;
    } bc,tc,tn,go,gn;

static char    *image,*comment;
static int    skipcomment,list,verbose,output,debug;
static long int    pos;

static char    rgbtxt[] = RGBTXT, *rgb = rgbtxt;
static char    true[] = "True";
static char    false[] = "False";

#define    readword(buffer)    ((buffer)[0]+256*(buffer)[1])
#define    readflag(buffer)    ((buffer)?true:false)
#define    hex(c)            ('a'<=(c)&&(c)<='z'?(c)-'a'+10:'A'<=(c)&&(c)<='Z'?(c)-'A'+10:(c)-'0')


void dump(adr,data,len)
long int    adr;
unsigned char    *data;
size_t        len;
{
    int    i;

    while (len>0) {
        (void)fprintf(stderr,"%08lx:%*s",adr,(int)((adr%16)*3+(adr%16>8?1:0)),"");
        for (i=adr%16;i<16&&len>0;i++,adr++,data++,len--)
            (void)fprintf(stderr,"%s%02x",i==8?"  ":" ",*data);
        (void)fprintf(stderr,"\n");
    }
}



void writedata(dest,data,len)
FILE        *dest;
unsigned char    *data;
size_t        len;
{
    unsigned char    size;

    while (len) {
        size=len<256?len:255;
        (void)fwrite((void *)&size,1,1,dest);
        (void)fwrite((void *)data,(size_t)size,1,dest);
        data+=size;
        len-=size;
    }
    size=0;
    (void)fwrite((void *)&size,1,1,dest);
}


void skipdata(src)
FILE    *src;
{
    unsigned char    size,buffer[256];

    do {
        pos=ftell(src);
        (void)fread((void *)&size,1,1,src);
        if (debug)
            dump(pos,&size,1);
        if (debug) {
            pos=ftell(src);
            (void)fread((void *)buffer,(size_t)size,1,src);
            dump(pos,buffer,(size_t)size);
        }
        else
            (void)fseek(src,(long int)size,SEEK_CUR);
    } while (!feof(src)&&size>0);
}


void transblock(src,dest)
FILE    *src;
FILE    *dest;
{
    unsigned char    size,buffer[256];

    pos=ftell(src);
    (void)fread((void *)&size,1,1,src);
    if (debug)
        dump(pos,&size,1);
    if (output)
        (void)fwrite((void *)&size,1,1,dest);
    pos=ftell(src);
    (void)fread((void *)buffer,(size_t)size,1,src);
    if (debug)
        dump(pos,buffer,(size_t)size);
    if (output)
        (void)fwrite((void *)buffer,(size_t)size,1,dest);
}


void dumpcomment(src)
FILE    *src;
{
    unsigned char    size,buffer[256];
    size_t i;

    pos=ftell(src);
    (void)fread((void *)&size,1,1,src);
    if (debug)
        dump(pos,&size,1);
    (void)fread((void *)buffer,(size_t)size,1,src);
    if (debug)
        dump(pos+1,buffer,(size_t)size);
    for (i=0; i<(size_t)size; i++)
    {
        if (i%60==0)
            (void)putc('\t',stderr);
        if (isprint(buffer[i]))
            (void)putc(buffer[i],stderr);
        else
            (void)fprintf(stderr,"\\%03o",buffer[i]);
        if (i%60==59)
            (void)putc('\n',stderr);
    }
    if (i%60)
        (void)putc('\n',stderr);
    (void)fseek(src,(long int)pos,SEEK_SET);
}


void transdata(src,dest)
FILE    *src;
FILE    *dest;
{
    unsigned char    size,buffer[256];

    do {
        pos=ftell(src);
        (void)fread((void *)&size,1,1,src);
        if (debug)
            dump(pos,&size,1);
        if (output)
            (void)fwrite((void *)&size,1,1,dest);
        pos=ftell(src);
        (void)fread((void *)buffer,(size_t)size,1,src);
        if (debug)
            dump(pos,buffer,(size_t)size);
        if (output)
            (void)fwrite((void *)buffer,(size_t)size,1,dest);
    } while (!feof(src)&&size>0);
}


int giftrans(src,dest)
FILE    *src;
FILE    *dest;
{
    unsigned char    buffer[3*256],lsd[7],gct[3*256],gce[5];
    unsigned int    cnt,cols,size,gct_size,gct_delay,gce_present;
    struct entry    *rgbptr;


    /* Header */
    pos=ftell(src);
    (void)fread((void *)buffer,6,1,src);
    if (strncmp((char *)buffer,"GIF",3)) {
        (void)fprintf(stderr,"No GIF file!\n");
        return(1);
    }
    if (verbose) {
        buffer[6]='\0';
        (void)fprintf(stderr,"Header: \"%s\"\n",buffer);
    }
    if (debug)
        dump(pos,buffer,6);
    if (output) {
        if (!strncmp((char *)buffer,"GIF87a",6))
            buffer[4]='9';
        (void)fwrite((void *)buffer,6,1,dest);
    }

    /* Logical Screen Descriptor */
    pos=ftell(src);
    (void)fread((void *)lsd,7,1,src);
    if (verbose) {
        (void)fprintf(stderr,"Logical Screen Descriptor:\n");
        (void)fprintf(stderr,"\tLogical Screen Width: %d pixels\n",readword(lsd));
        (void)fprintf(stderr,"\tLogical Screen Height: %d pixels\n",readword(lsd+2));
        (void)fprintf(stderr,"\tGlobal Color Table Flag: %s\n",readflag(lsd[4]&0x80));
        (void)fprintf(stderr,"\tColor Resolution: %d bits\n",(lsd[4]&0x70>>4)+1);
        if (lsd[4]&0x80) {
            (void)fprintf(stderr,"\tSort Flag: %s\n",readflag(lsd[4]&0x8));
            (void)fprintf(stderr,"\tSize of Global Color Table: %d colors\n",2<<(lsd[4]&0x7));
            (void)fprintf(stderr,"\tBackground Color Index: %d\n",lsd[5]);
        }
        if (lsd[6])
            (void)fprintf(stderr,"\tPixel Aspect Ratio: %d (Aspect Ratio %f)\n",lsd[6],((double)lsd[6]+15)/64);
    }
    if (debug)
        dump(pos,lsd,7);

    /* Global Color Table */
    gct_delay=FALSE;
    if (lsd[4]&0x80) {
        gct_size=2<<(lsd[4]&0x7);
        pos=ftell(src);
        (void)fread((void *)gct,gct_size,3,src);
        if (go.index==RGB)
            for(cnt=0;cnt<gct_size&&go.index==RGB;cnt++)
                if (gct[3*cnt]==go.red&&gct[3*cnt+1]==go.green&&gct[3*cnt+2]==go.blue)
                    go.index=cnt;
        if (go.index>=0) {
            if (gn.index>=0) {
                gn.red=gct[3*gn.index];
                gn.green=gct[3*gn.index+1];
                gn.blue=gct[3*gn.index+2];
            }
            gct[3*go.index]=gn.red;
            gct[3*go.index+1]=gn.green;
            gct[3*go.index+2]=gn.blue;
        }
        if (bc.index==RGB)
            for(cnt=0;cnt<gct_size&&bc.index==RGB;cnt++)
                if (gct[3*cnt]==bc.red&&gct[3*cnt+1]==bc.green&&gct[3*cnt+2]==bc.blue)
                    bc.index=cnt;
        if (bc.index>=0)
            lsd[5]=bc.index;
        if (tc.index==RGB)
            for(cnt=0;cnt<gct_size&&tc.index==RGB;cnt++)
                if (gct[3*cnt]==tc.red&&gct[3*cnt+1]==tc.green&&gct[3*cnt+2]==tc.blue)
                    tc.index=cnt;
        if (tc.index==OTHER)
            tc.index=lsd[5];
        if (tn.index>=0) {
            tn.red=gct[3*tn.index];
            tn.green=gct[3*tn.index+1];
            tn.blue=gct[3*tn.index+2];
        }
        if (tn.index!=NONE)
            gct_delay=TRUE;
    }
    if (output)
        (void)fwrite((void *)lsd,7,1,dest);
    if (lsd[4]&0x80) {
        if (list||verbose) {
            (void)fprintf(stderr,"Global Color Table:\n");
            for(cnt=0;cnt<gct_size;cnt++) {
                (void)fprintf(stderr,"\tColor %d: Red %d, Green %d, Blue %d",cnt,gct[3*cnt],gct[3*cnt+1],gct[3*cnt+2]);
                (void)fprintf(stderr,", #%02x%02x%02x",gct[3*cnt],gct[3*cnt+1],gct[3*cnt+2]);
                for (rgbptr=root,cols=0;rgbptr;rgbptr=rgbptr->next)
                    if (rgbptr->red==gct[3*cnt]&&rgbptr->green==gct[3*cnt+1]&&rgbptr->blue==gct[3*cnt+2])
                        (void)fprintf(stderr,"%s%s",cols++?", ":" (",rgbptr->name);
                (void)fprintf(stderr,"%s\n",cols?")":"");
            }
        }
        if (debug)
            dump(pos,gct,gct_size*3);
        if (output&&(!gct_delay))
            (void)fwrite((void *)gct,gct_size,3,dest);
    }

    gce_present=FALSE;
    do {
        pos=ftell(src);
        (void)fread((void *)buffer,1,1,src);
        switch (buffer[0]) {
        case 0x2c:    /* Image Descriptor */
            if (verbose)
                (void)fprintf(stderr,"Image Descriptor:\n");
            (void)fread((void *)(buffer+1),9,1,src);
            /* Write Graphic Control Extension */
            if (tc.index>=0||gce_present) {
                if (!gce_present) {
                    gce[0]=0;
                    gce[1]=0;
                    gce[2]=0;
                }
                if (tc.index>=0) {
                    gce[0]|=0x01;    /* Set Transparent Color Flag */
                    gce[3]=tc.index;    /* Set Transparent Color Index */
                }
                else if (gce[0]&0x01)
                    tc.index=gce[3];    /* Remember Transparent Color Index */
                gce[4]=0;
                if (tc.index>=0&&(!(buffer[8]&0x80))) { /* Transparent Color Flag set and no Local Color Table */
                    gct[3*tc.index]=tn.red;
                    gct[3*tc.index+1]=tn.green;
                    gct[3*tc.index+2]=tn.blue;
                }
                if (output&&gct_delay) {
                    (void)fwrite((void *)gct,gct_size,3,dest);
                    gct_delay=FALSE;
                }
                if (output) {
                    (void)fputs("\041\371\004",dest);
                    (void)fwrite((void *)gce,5,1,dest);
                }
            }
            if (output&&gct_delay) {
                if (verbose)
                    (void)fprintf(stderr,"Warning: Global Color Table has not been modified as no Transparent Color Index has been set\n");
                (void)fwrite((void *)gct,gct_size,3,dest);
                gct_delay=FALSE;
            }
            /* Write Image Descriptor */
            if (verbose) {
                (void)fprintf(stderr,"\tImage Left Position: %d pixels\n",readword(buffer+1));
                (void)fprintf(stderr,"\tImage Top Position: %d pixels\n",readword(buffer+3));
                (void)fprintf(stderr,"\tImage Width: %d pixels\n",readword(buffer+5));
                (void)fprintf(stderr,"\tImage Height: %d pixels\n",readword(buffer+7));
                (void)fprintf(stderr,"\tLocal Color Table Flag: %s\n",readflag(buffer[9]&0x80));
                (void)fprintf(stderr,"\tInterlace Flag: %s\n",readflag(buffer[9]&0x40));
                if (buffer[9]&0x80) {
                    (void)fprintf(stderr,"\tSort Flag: %s\n",readflag(buffer[9]&0x20));
                    (void)fprintf(stderr,"\tSize of Global Color Table: %d colors\n",2<<(buffer[9]&0x7));
                }
            }
            if (debug)
                dump(pos,buffer,10);
            if (output)
                (void)fwrite((void *)buffer,10,1,dest);
            /* Local Color Table */
            if (buffer[8]&0x80) {
                size=2<<(buffer[8]&0x7);
                pos=ftell(src);
                (void)fread((void *)buffer,size,3,src);
                if (verbose) {
                    (void)fprintf(stderr,"Local Color Table:\n");
                    for(cnt=0;cnt<size;cnt++)
                        (void)fprintf(stderr,"\tColor %d: Red %d, Green %d, Blue %d\n",cnt,buffer[3*cnt],buffer[3*cnt+1],buffer[3*cnt+2]);
                }
                if (tc.index>=0) { /* Transparent Color Flag set */
                    buffer[3*tc.index]=tn.red;
                    buffer[3*tc.index+1]=tn.green;
                    buffer[3*tc.index+2]=tn.blue;
                }
                if (debug)
                    dump(pos,buffer,size*3);
                if (output)
                    (void)fwrite((void *)buffer,size,3,dest);
            }
            /* Table Based Image Data */
            pos=ftell(src);
            (void)fread((void *)buffer,1,1,src);
            if (verbose) {
                (void)fprintf(stderr,"Table Based Image Data:\n");
                (void)fprintf(stderr,"\tLZW Minimum Code Size: 0x%02x\n",buffer[0]);
            }
            if (debug)
                dump(pos,buffer,1);
            if (output)
                (void)fwrite((void *)buffer,1,1,dest);
            transdata(src,dest);
            gce_present=FALSE;
            break;
        case 0x3b:    /* Trailer */
            if (verbose)
                (void)fprintf(stderr,"Trailer\n");
            if (debug)
                dump(pos,buffer,1);
            if (comment&&*comment&&output) {
                (void)fputs("\041\376",dest);
                writedata(dest,(unsigned char *)comment,strlen(comment));
            }
            if (output)
                (void)fwrite((void *)buffer,1,1,dest);
            break;
        case 0x21:    /* Extension */
            (void)fread((void *)(buffer+1),1,1,src);
            switch (buffer[1]) {
            case 0x01:    /* Plain Text Extension */
                if (output&&gct_delay) {
                    if (verbose)
                        (void)fprintf(stderr,"Warning: Global Color Table has not been modified due to a Plain Text Extension\n");
                    (void)fwrite((void *)gct,gct_size,3,dest);
                    gct_delay=FALSE;
                }
                if (verbose)
                    (void)fprintf(stderr,"Plain Text Extension\n");
                if (debug)
                    dump(pos,buffer,2);
                if (output)
                    (void)fwrite((void *)buffer,2,1,dest);
                transblock(src,dest);
                transdata(src,dest);
                break;
            case 0xf9:    /* Graphic Control Extension */
                if (verbose)
                    (void)fprintf(stderr,"Graphic Control Extension:\n");
                (void)fread((void *)(buffer+2),1,1,src);
                size=buffer[2];
                (void)fread((void *)gce,size,1,src);
                if (verbose) {
                    (void)fprintf(stderr,"\tDisposal Method: %d ",gce[0]&0x1c>>2);
                    switch (gce[0]&0x1c>>2) {
                    case 0:
                        (void)fprintf(stderr,"(no disposal specified)\n");
                        break;
                    case 1:
                        (void)fprintf(stderr,"(do not dispose)\n");
                        break;
                    case 2:
                        (void)fprintf(stderr,"(restore to background color)\n");
                        break;
                    case 3:
                        (void)fprintf(stderr,"(restore to previous)\n");
                        break;
                    default:
                        (void)fprintf(stderr,"(to be defined)\n");
                    }
                    (void)fprintf(stderr,"\tUser Input Flag: %s\n",readflag(gce[0]&0x2));
                    (void)fprintf(stderr,"\tTransparent Color Flag: %s\n",readflag(gce[0]&0x1));
                    (void)fprintf(stderr,"\tDelay Time: %d\n",readword(gce+1));
                    if (gce[0]&0x1)
                        (void)fprintf(stderr,"\tTransparent Color Index: %d\n",gce[3]);
                }
                if (debug) {
                    dump(pos,buffer,3);
                    dump(pos+3,gce,size);
                }
                pos=ftell(src);
                (void)fread((void *)buffer,1,1,src);
                if (debug)
                    dump(pos,buffer,1);
                gce_present=TRUE;
                break;
            case 0xfe:    /* Comment Extension */
                if (verbose)
                {
                    (void)fprintf(stderr,"Comment Extension\n");
                    dumpcomment(src);
                }
                if (debug)
                    dump(pos,buffer,2);
                if (skipcomment)
                    skipdata(src);
                else {
                    if (output&&gct_delay) {
                        if (verbose)
                            (void)fprintf(stderr,"Warning: Global Color Table has not been modified due to a Comment Extension\n");
                        (void)fwrite((void *)gct,gct_size,3,dest);
                        gct_delay=FALSE;
                    }
                    if (output)
                        (void)fwrite((void *)buffer,2,1,dest);
                    transdata(src,dest);
                }
                break;
            case 0xff:    /* Application Extension */
                if (output&&gct_delay) {
                    if (verbose)
                        (void)fprintf(stderr,"Warning: Global Color Table has not been modified due to a Application Extension\n");
                    (void)fwrite((void *)gct,gct_size,3,dest);
                    gct_delay=FALSE;
                }
                if (verbose)
                    (void)fprintf(stderr,"Application Extension\n");
                if (debug)
                    dump(pos,buffer,2);
                if (output)
                    (void)fwrite((void *)buffer,2,1,dest);
                transblock(src,dest);
                transdata(src,dest);
                break;
            default:
                if (output&&gct_delay) {
                    if (verbose)
                        (void)fprintf(stderr,"Warning: Global Color Table has not been modified due to an unknown Extension\n");
                    (void)fwrite((void *)gct,gct_size,3,dest);
                    gct_delay=FALSE;
                }
                if (verbose)
                    (void)fprintf(stderr,"Unknown label: 0x%02x\n",buffer[1]);
                if (debug)
                    dump(pos,buffer,2);
                if (output)
                    (void)fwrite((void *)buffer,2,1,dest);
                transblock(src,dest);
                transdata(src,dest);
                break;
            }
            break;
        default:
            (void)fprintf(stderr,"0x%08lx: Unknown extension 0x%02x!\n",ftell(src)-1,buffer[0]);
            if (debug)
                dump(pos,buffer,1);
            return(1);
        }
    } while (buffer[0]!=0x3b&&!feof(src));
    return(buffer[0]==0x3b?SUCCESS:FAILURE);
}



int getindex(c,arg)
struct color    *c;
char    *arg;
{
    struct entry    *ptr;

    if ('0'<=*arg&&*arg<='9')
        c->index=atoi(arg);
    else if (*arg=='#') {
        if (strlen(arg)==4) {
            c->index=RGB;
            c->red=hex(arg[1])<<4;
            c->green=hex(arg[2])<<4;
            c->blue=hex(arg[3])<<4;
        }
        else if (strlen(arg)==7) {
            c->index=RGB;
            c->red=(hex(arg[1])<<4)+hex(arg[2]);
            c->green=(hex(arg[3])<<4)+hex(arg[4]);
            c->blue=(hex(arg[5])<<4)+hex(arg[6]);
        }
        else {
            (void)fprintf(stderr,"%s: illegal color specification: %s\n",image,arg);
            return(FAILURE);
        }
    }
    else {
        for (ptr=root;ptr&&c->index!=RGB;ptr=ptr->next)
            if (!strcmp(ptr->name,arg)) {
                c->index=RGB;
                c->red=ptr->red;
                c->green=ptr->green;
                c->blue=ptr->blue;
            }
        if (c->index!=RGB) {
            (void)fprintf(stderr,"%s: no such color: %s\n",image,arg);
            return(FAILURE);
        }
    }
    return(SUCCESS);
}



void usage()
{
    (void)fprintf(stderr,"Usage: %s [-t color|-T] [-B color] [-b color] [-g oldcolor=newcolor] [-c comment|-C] [-l|-L|-V] [-o filename] [-e filename] [filename]\n",image);
    (void)fprintf(stderr,"Convert any GIF file into a GIF89a, with the folloing changes possible:\n");
    (void)fprintf(stderr,"-t Specify the transparent color\n");
    (void)fprintf(stderr,"-T Index of the transparent color is the background color index\n");
    (void)fprintf(stderr,"-B Specify the transparent color's new value\n");
    (void)fprintf(stderr,"-b Specify the background color\n");
    (void)fprintf(stderr,"-g Change a color in the global color table\n");
    (void)fprintf(stderr,"-c Add a comment\n");
    (void)fprintf(stderr,"-C Remove old comment\n");
    (void)fprintf(stderr,"-l Only list the color table\n");
    (void)fprintf(stderr,"-L Verbose output of GIFs contents\n");
    (void)fprintf(stderr,"-V Verbose output while converting\n");
    (void)fprintf(stderr,"-o Redirect stdout to a file\n");
    (void)fprintf(stderr,"-e Redirect stderr to a file\n");
    if (*rgb)
        (void)fprintf(stderr,"Colors may be specified as index, as rgb.txt entry or in the #rrggbb form.\n");
    else
        (void)fprintf(stderr,"Colors may be specified as index or in the #rrggbb form.\n");
    exit(1);
}


int main(argc,argv)
int    argc;
char    *argv[];
{
    int        c;
    extern char    *optarg;
    extern int    optind;
    char        error[2*MAXPATHLEN+14],line[BUFSIZ],*ptr,*nptr,*oname,*ename;
    struct entry    **next;
    FILE        *src;
    int        stat;

#ifdef OS2
    ptr=getenv("XFILES");
    if (ptr) {
        rgb=(char *)malloc(strlen(ptr)+strlen(rgbtxt)+2);
        (void)strcpy(rgb,ptr);
        (void)strcat(rgb,"\\");
        (void)strcat(rgb,rgbtxt);
    }
#endif /* OS2 */

    image=argv[0];
    root=NULL;
    if (*rgb)
        if ((src=fopen(rgb,"r"))!=NULL) {
            next= &root;
            while (fgets(line,sizeof(line),src)) {
                *next=(struct entry *)malloc(sizeof(struct entry));
                for (ptr=line;strchr(" \t",*ptr);ptr++);
                for (nptr=ptr;!strchr(" \t",*ptr);ptr++);
                *ptr++='\0';
                (*next)->red=atoi(nptr);
                for (;strchr(" \t",*ptr);ptr++);
                for (nptr=ptr;!strchr(" \t",*ptr);ptr++);
                *ptr++='\0';
                (*next)->green=atoi(nptr);
                for (;strchr(" \t",*ptr);ptr++);
                for (nptr=ptr;!strchr(" \t",*ptr);ptr++);
                *ptr++='\0';
                (*next)->blue=atoi(nptr);
                for (;strchr(" \t",*ptr);ptr++);
                for (nptr=ptr;!strchr(" \t\r\n",*ptr);ptr++);
                *ptr='\0';
                (void)strcpy((*next)->name=(char *)malloc(strlen(nptr)+1),nptr);
                (*next)->next=NULL;
                next= &(*next)->next;
            }
            (void)fclose(src);
        }
        else {
#ifndef OS2_OR_MSDOS
            (void)sprintf(error,"%s: cannot open %s",image,rgb);
            perror(error);
            return(FAILURE);
#else /* OS2_OR_MSDOS */
            *rgb='\0';
#endif
        }

    bc.index=NONE;
    tc.index=NONE;
    tn.index=NONE;
    go.index=NONE;
    gn.index=NONE;
    comment=NULL;
    skipcomment=FALSE;
    verbose=FALSE;
    output=TRUE;
    debug=FALSE;
    oname=NULL;
    ename=NULL;
    while ((c=getopt(argc,argv,"t:TB:b:g:c:ClLVDo:e:vh?")) != EOF)
        switch ((char)c) {
        case 'b':
            if (getindex(&bc,optarg))
                return(FAILURE);
            break;
        case 't':
            if (getindex(&tc,optarg))
                return(FAILURE);
            break;
        case 'T':
            tc.index=OTHER;
            break;
        case 'B':
            if (getindex(&tn,optarg))
                return(FAILURE);
            break;
        case 'g':
            if ((ptr=strchr(optarg,'='))!=NULL) {
                *ptr++='\0';
                if (getindex(&go,optarg))
                    return(FAILURE);
                if (getindex(&gn,ptr))
                    return(FAILURE);
            }
            else
                usage();
            break;
        case 'c':
            comment=optarg;
            break;
        case 'C':
            skipcomment=TRUE;
            break;
        case 'l':
            list=TRUE;
            output=FALSE;
            break;
        case 'L':
            verbose=TRUE;
            output=FALSE;
            break;
        case 'V':
            verbose=TRUE;
            break;
        case 'D':
            debug=TRUE;
            break;
        case 'o':
            oname=optarg;
            break;
        case 'e':
            ename=optarg;
            break;
        case 'v':
            (void)fprintf(stderr,"%s\n",sccsid+4);
            (void)fprintf(stderr,"%s\n",copyright+4);
            return(0);
        case 'h':
            (void)fprintf(stderr,"%s\n",sccsid+4);
            (void)fprintf(stderr,"%s\n",copyright+4);
        case '?':
            usage();
        }
    if (optind+1<argc||(bc.index==NONE&&tc.index==NONE&&tn.index==NONE&&gn.index==NONE&&comment==NULL&&!skipcomment&&!list&&!verbose))
        usage();

    if (oname&&freopen(oname,"wb",stdout)==NULL) {
        (void)sprintf(error,"%s: cannot open %s",image,oname);
        perror(error);
        return(FAILURE);
    }

    if (ename&&freopen(ename,"wb",stderr)==NULL) {
        (void)sprintf(error,"%s: cannot open %s",image,ename);
        perror(error);
        return(FAILURE);
    }

#ifdef OS2_OR_MSDOS
#ifdef MSDOS
    if(oname==NULL&&(stdout->flags&_F_TERM)==0&&setmode(fileno(stdout),O_BINARY)!=0) {
#endif /* MSDOS */
#ifdef OS2
    if(oname==NULL&&!freopen("", "wb", stdout)) {
#endif /* OS2 */
        (void)fprintf(stderr,"%s: can't set stdout's mode to binary\n",image);
        exit(2);
    }
#ifdef MSDOS
    if(optind==argc&&(stdin->flags&_F_TERM)==0&&setmode(fileno(stdin),O_BINARY)) {
#endif /* MSDOS */
#ifdef OS2
    if(optind==argc&&!freopen("", "rb", stdin)) {
#endif /* OS2 */
        (void)fprintf(stderr,"%s: can't set stdin's mode to binary\n",image);
        exit(2);
    }
#endif /* OS2_OR_MSDOS */

    if (optind<argc)
        if (strcmp(argv[optind],"-"))
            if ((src=fopen(argv[optind],"rb"))!=NULL) {
                stat=giftrans(src,stdout);
                (void)fclose(src);
            }
            else {
                (void)sprintf(error,"%s: cannot open %s",image,argv[optind]);
                perror(error);
                return(FAILURE);
            }
        else
            stat=giftrans(stdin,stdout);
    else
        stat=giftrans(stdin,stdout);

    (void)fclose(stdout);
    (void)fclose(stderr);
    return(stat);
}