Garbo/Garbo.cdr/mac/source/macgif.shr/macgif.shar

Text File | 1989-05-21 | 33.9 KB | 1,227 lines

#! /bin/sh
# This is a shell archive, meaning:
# 1. Remove everything above the #! /bin/sh line.
# 2. Save the resulting text in a file.
# 3. Execute the file with /bin/sh (not csh) to create the files:
#
#    gif2ras.c
#
# This archive created: Fri May 12 20:22:24 1989
# By:    Roger L. Long ([e-mail])
export PATH; PATH=/bin:$PATH
echo shar: extracting "'gif2ras.c'" '(14611 characters)'
if test -f 'gif2ras.c'
then
    echo shar: will not over-write existing file "'gif2ras.c'"
else
sed 's/^X//' << \SHAR_EOF > 'gif2ras.c'
X/*
X * gif2ras.c - Converts from a Compuserve GIF (tm) image to a Sun Raster image.
X *
X * Copyright (c) 1988 by Patrick J. Naughton
X *
X * Author: Patrick J. Naughton
X * [e-mail]
X *
X * Permission to use, copy, modify, and distribute this software and its
X * documentation for any purpose and without fee is hereby granted,
X * provided that the above copyright notice appear in all copies and that
X * both that copyright notice and this permission notice appear in
X * supporting documentation.
X *
X * This file is provided AS IS with no warranties of any kind.  The author
X * shall have no liability with respect to the infringement of copyrights,
X * trade secrets or any patents by this file or any part thereof.  In no
X * event will the author be liable for any lost revenue or profits or
X * other special, indirect and consequential damages.
X *
X * Comments and additions should be sent to the author:
X *
X *                     Patrick J. Naughton
X *                     Sun Microsystems, Inc.
X *                     2550 Garcia Ave, MS 14-40
X *                     Mountain View, CA 94043
X *                     [phone]
X *
X * Revision History:
X * 28-Aug-88: Modified by Jef Poskanzer to output PBM instead of Sun raster.
X * 27-Jul-88: Updated to use libpixrect to fix 386i byteswapping problems.
X * 11-Apr-88: Converted to C and changed to write Sun rasterfiles.
X * 19-Jan-88: GIFSLOW.PAS posted to comp.graphics by Jim Briebel,
X *            a Turbo Pascal 4.0 program to painfully slowly display
X *            GIF images on an EGA equipped IBM-PC.
X *
X * Description:
X *   This program takes a Compuserve "Graphics Interchange Format" or "GIF"
X * file as input and writes a file known as a Sun rasterfile.  This datafile
X * can be loaded by the NeWS "readcanvas" operator and is of the same format
X * as the files in /usr/NeWS/smi/*.  Under X11R2 there is a program called
X * xraster to display these files.
X *
X * Portability:
X *   To make this program convert to some image format other than PBM
X * format simply seach for the tag "PBMS:" in the source and
X * replace these simple mechanisms with the appropriate ones for the
X * other output format.  I have marked all (six) PBM Specific pieces
X * of code with this comment.
X *
X * SS: compile with "cc -o gif2ras -O gif2ras.c -lpixrect"
X * PBMS: compile with "cc -o giftopbm -O giftopbm.c libpbm.a
X */
X
X#include <stdio.h>
X#ifdef notdefSS
X#include <pixrect/pixrect_hs.h> /* SS: main Pixrect header file */
X#endif notdefSS
X#include <sys/types.h>
X#include "pbm.h"                /* PBMS: main PBM header file */
X
Xtypedef int boolean;
X#define True (1)
X#define False (0)
X
X#define NEXTSHORT (*ptr++ + (0x100 * *ptr++))
X#define NEXTBYTE (*ptr++)
X#define IMAGESEP 0x2c
X#define INTERLACEMASK 0x40
X#define COLORMAPMASK 0x80
X
Xint BitOffset = 0,              /* Bit Offset of next code */
X    XC = 0, YC = 0,             /* Output X and Y coords of current pixel */
X    Pass = 0,                   /* Used by output routine if interlaced pic */
X    OutCount = 0,               /* Decompressor output 'stack count' */
X    RWidth, RHeight,            /* screen dimensions */
X    Width, Height,              /* image dimensions */
X    LeftOfs, TopOfs,            /* image offset */
X    BitsPerPixel,               /* Bits per pixel, read from GIF header */
X    ColorMapSize,               /* number of colors */
X    CodeSize,                   /* Code size, read from GIF header */
X    InitCodeSize,               /* Starting code size, used during Clear */
X    Code,                       /* Value returned by ReadCode */
X    MaxCode,                    /* limiting value for current code size */
X    ClearCode,                  /* GIF clear code */
X    EOFCode,                    /* GIF end-of-information code */
X    CurCode, OldCode, InCode,   /* Decompressor variables */
X    FirstFree,                  /* First free code, generated per GIF spec */
X    FreeCode,                   /* Decompressor, next free slot in hash table */
X    FinChar,                    /* Decompressor variable */
X    BitMask,                    /* AND mask for data size */
X    ReadMask;                   /* Code AND mask for current code size */
X
Xboolean Interlace, HasColormap;
X
X#ifdef notdefSS
X/* SS: defined in pixrect/pixrect_hs.h */
XPixrect *Output;                /* The Sun Pixrect */
Xcolormap_t Colormap;            /* The Pixrect Colormap */
Xu_char *Image;                  /* The result array */
X#endif notdefSS
X/* PBMS: defined in pbm.h */
Xbit **bits;                     /* The PBM bit array */
X
Xu_char *RawGIF;                 /* The heap array to hold it, raw */
Xu_char *Raster;                 /* The raster data stream, unblocked */
X
X    /* The hash table used by the decompressor */
Xint Prefix[4096];
Xint Suffix[4096];
X
X    /* An output array used by the decompressor */
Xint OutCode[1025];
X
X    /* The color map, read from the GIF header */
Xu_char Red[256], Green[256], Blue[256];
X
Xchar *id = "GIF87a";
X
Xchar *pname;                    /* program name (used for error messages) */
X
Xvoid
Xerror(s1, s2)
Xchar *s1, *s2;
X{
X    fprintf(stderr, s1, pname, s2);
X    exit(1);
X}
X
X
Xmain(argc, argv)
Xint argc;
Xchar *argv[];
X{
XFILE *fp;
Xchar *infname = argv[1];
Xchar *outfname = argv[2];
Xint filesize;
Xregister u_char ch, ch1;
Xregister u_char *ptr, *ptr1;
Xregister int i;
X
X    setbuf(stderr, NULL);
X    pname = argv[0];
X
X    if (argc < 3)
X        error("usage: %s GIFfile rasterfile\n", NULL);
X
X    if (!(fp = fopen(infname, "r")))
X        error("%s: %s not found.\n", infname);
X
X    /* find the size of the file */
X
X    fseek(fp, 0L, 2);
X    filesize = ftell(fp);
X    fseek(fp, 0L, 0);
X
X    if (!(ptr = RawGIF = (u_char *) malloc(filesize)))
X        error("%s: not enough memory to read gif file.\n", NULL);
X
X    if (!(Raster = (u_char *) malloc(filesize)))
X        error("%s: not enough memory to read gif file.\n", NULL);
X
X    fread(ptr, filesize, 1, fp);
X
X    if (strncmp(ptr, id, 6))
X        error("%s: %s is not a GIF file.\n", infname);
X    ptr += 6;
X
X/* Get variables from the GIF screen descriptor */
X
X    RWidth = NEXTSHORT;         /* screen dimensions... not used. */
X    RHeight = NEXTSHORT;
X
X    ch = NEXTBYTE;
X    HasColormap = ((ch & COLORMAPMASK) ? True : False);
X
X    BitsPerPixel = (ch & 7) + 1;
X    ColorMapSize = 1 << BitsPerPixel;
X    BitMask = ColorMapSize - 1;
X
X    ch = NEXTBYTE;              /* background color... not used. */
X
X    if (NEXTBYTE)               /* supposed to be NULL */
X        error("%s: %s is a corrupt GIF file.\n", infname);
X
X/* Read in global colormap. */
X
X    if (HasColormap) {
X        fprintf(stderr, "%s is %d bits per pixel, (%d colors).\n",
X                infname, BitsPerPixel, ColorMapSize);
X        for (i = 0; i < ColorMapSize; i++) {
X            Red[i] = NEXTBYTE;
X            Green[i] = NEXTBYTE;
X            Blue[i] = NEXTBYTE;
X        }
X
X#ifdef notdefSS
X/* SS: Fill in the Pixrect colormap struct */
X        Colormap.type = RMT_EQUAL_RGB;
X        Colormap.length = ColorMapSize;
X        Colormap.map[0] = Red;
X        Colormap.map[1] = Green;
X        Colormap.map[2] = Blue;
X#endif notdefSS
X        /* PBMS: PBM only handles bitmaps.  Reject any pixmaps here. */
X        if (BitsPerPixel != 1)
X            error("%s: %s has more than one bit per pixel - it's not a bitmap.\n
X", infname);
X    }
X    else error("%s: %s does not have a colormap.\n", infname);
X
X
X/* Check for image seperator */
X
X    if (NEXTBYTE != IMAGESEP)
X        error("%s: %s is a corrupt GIF file.\n", infname);
X
X/* Now read in values from the image descriptor */
X
X    LeftOfs = NEXTSHORT;
X    TopOfs = NEXTSHORT;
X    Width = NEXTSHORT;
X    Height = NEXTSHORT;
X    Interlace = ((NEXTBYTE & INTERLACEMASK) ? True : False);
X
X    fprintf(stderr, "Reading a %d by %d %sinterlaced image...",
X        Width, Height, (Interlace) ? "" : "non-");
X
X
X/* Note that I ignore the possible existence of a local color map.
X * I'm told there aren't many files around that use them, and the spec
X * says it's defined for future use.  This could lead to an error
X * reading some files.
X */
X
X/* Start reading the raster data. First we get the intial code size
X * and compute decompressor constant values, based on this code size.
X */
X
X    CodeSize = NEXTBYTE;
X    ClearCode = (1 << CodeSize);
X    EOFCode = ClearCode + 1;
X    FreeCode = FirstFree = ClearCode + 2;
X
X/* The GIF spec has it that the code size is the code size used to
X * compute the above values is the code size given in the file, but the
X * code size used in compression/decompression is the code size given in
X * the file plus one. (thus the ++).
X */
X
X    CodeSize++;
X    InitCodeSize = CodeSize;
X    MaxCode = (1 << CodeSize);
X    ReadMask = MaxCode - 1;
X
X/* Read the raster data.  Here we just transpose it from the GIF array
X * to the Raster array, turning it from a series of blocks into one long
X * data stream, which makes life much easier for ReadCode().
X */
X
X    ptr1 = Raster;
X    do {
X        ch = ch1 = NEXTBYTE;
X        while (ch--) *ptr1++ = NEXTBYTE;
X    } while(ch1);
X
X    free(RawGIF);               /* We're done with the raw data now... */
X
X    fprintf(stderr, "done.\n");
X    fprintf(stderr, "Decompressing...");
X
X
X#ifdef notdefSS
X/* SS: Allocate the Sun Pixrect and make "Image" point to the image data. */
X    Output = mem_create(Width, Height, 8);
X    if (Output == (Pixrect *) NULL)
X        error("%s: not enough memory for output data.\n", NULL);
X    Image = (u_char *) mpr_d(Output)->md_image;
X#endif notdefSS
X/* PBMS: Allocate the PBM bit array. */
X    bits = pbm_allocarray(Width, Height);
X
X
X/* Decompress the file, continuing until you see the GIF EOF code.
X * One obvious enhancement is to add checking for corrupt files here.
X */
X
X    Code = ReadCode();
X    while (Code != EOFCode) {
X
X/* Clear code sets everything back to its initial value, then reads the
X * immediately subsequent code as uncompressed data.
X */
X
X        if (Code == ClearCode) {
X            CodeSize = InitCodeSize;
X            MaxCode = (1 << CodeSize);
X            ReadMask = MaxCode - 1;
X            FreeCode = FirstFree;
X            CurCode = OldCode = Code = ReadCode();
X            FinChar = CurCode & BitMask;
X            AddToPixel(FinChar);
X        }
X        else {
X
X/* If not a clear code, then must be data: save same as CurCode and InCode */
X
X            CurCode = InCode = Code;
X
X/* If greater or equal to FreeCode, not in the hash table yet;
X * repeat the last character decoded
X */
X
X            if (CurCode >= FreeCode) {
X                CurCode = OldCode;
X                OutCode[OutCount++] = FinChar;
X            }
X
X/* Unless this code is raw data, pursue the chain pointed to by CurCode
X * through the hash table to its end; each code in the chain puts its
X * associated output code on the output queue.
X */
X
X            while (CurCode > BitMask) {
X                OutCode[OutCount++] = Suffix[CurCode];
X                CurCode = Prefix[CurCode];
X            }
X
X/* The last code in the chain is treated as raw data. */
X
X            FinChar = CurCode & BitMask;
X            OutCode[OutCount++] = FinChar;
X
X/* Now we put the data out to the Output routine.
X * It's been stacked LIFO, so deal with it that way...
X */
X
X            for (i = OutCount - 1; i >= 0; i--)
X                AddToPixel(OutCode[i]);
X            OutCount = 0;
X
X/* Build the hash table on-the-fly. No table is stored in the file. */
X
X            Prefix[FreeCode] = OldCode;
X            Suffix[FreeCode] = FinChar;
X            OldCode = InCode;
X
X/* Point to the next slot in the table.  If we exceed the current
X * MaxCode value, increment the code size unless it's already 12.  If it
X * is, do nothing: the next code decompressed better be CLEAR
X */
X
X            FreeCode++;
X            if (FreeCode >= MaxCode) {
X                if (CodeSize < 12) {
X                    CodeSize++;
X                    MaxCode *= 2;
X                    ReadMask = (1 << CodeSize) - 1;
X                }
X            }
X        }
X        Code = ReadCode();
X    }
X
X    free(Raster);
X
X    fprintf(stderr, "done.\n");
X
X    if (!(fp = fopen(outfname, "w")))
X        error("%s: can't create %s.\n", outfname);
X
X#ifdef notdefSS
X/* SS: Pixrect Rasterfile output code. */
X    fprintf(stderr, "Writing Sun Rasterfile: %s...", outfname);
X    if (pr_dump(Output, fp, &Colormap, RT_STANDARD, 0) == PIX_ERR)
X        error("%s: error writing Sun Rasterfile: %s\n", outfname);
X#endif notdefSS
X/* PBMS: PBM output code. */
X    pbm_writepbm(stdout, bits, Width, Height);
X
X    fclose(fp);
X
X    fprintf(stderr, "done.\n");
X}
X
X
X/* Fetch the next code from the raster data stream.  The codes can be
X * any length from 3 to 12 bits, packed into 8-bit bytes, so we have to
X * maintain our location in the Raster array as a BIT Offset.  We compute
X * the byte Offset into the raster array by dividing this by 8, pick up
X * three bytes, compute the bit Offset into our 24-bit chunk, shift to
X * bring the desired code to the bottom, then mask it off and return it.
X */
XReadCode()
X{
Xint RawCode, ByteOffset;
X
X    ByteOffset = BitOffset / 8;
X    RawCode = Raster[ByteOffset] + (0x100 * Raster[ByteOffset + 1]);
X    if (CodeSize >= 8)
X        RawCode += (0x10000 * Raster[ByteOffset + 2]);
X    RawCode >>= (BitOffset % 8);
X    BitOffset += CodeSize;
X    return(RawCode & ReadMask);
X}
X
X
XAddToPixel(Index)
Xu_char Index;
X{
X#ifdef notdefSS
X    *(Image + YC * Width + XC) = Index;
X#endif notdefSS
X/* PBMS: Store a pixel. */
X    bits[YC][XC] = Index;
X
X/* Update the X-coordinate, and if it overflows, update the Y-coordinate */
X
X    if (++XC == Width) {
X
X/* If a non-interlaced picture, just increment YC to the next scan line.
X * If it's interlaced, deal with the interlace as described in the GIF
X * spec.  Put the decoded scan line out to the screen if we haven't gone
X * past the bottom of it
X */
X
X        XC = 0;
X        if (!Interlace) YC++;
X        else {
X            switch (Pass) {
X                case 0:
X                    YC += 8;
X                    if (YC >= Height) {
X                        Pass++;
X                        YC = 4;
X                    }
X                break;
X                case 1:
X                    YC += 8;
X                    if (YC >= Height) {
X                        Pass++;
X                        YC = 2;
X                    }
X                break;
X                case 2:
X                    YC += 4;
X                    if (YC >= Height) {
X                        Pass++;
X                        YC = 1;
X                    }
X                break;
X                case 3:
X                    YC += 2;
X                break;
X                default:
X                break;
X            }
X        }
X    }
X}
SHAR_EOF
if test 14611 -ne "`wc -c < 'gif2ras.c'`"
then
    echo shar: error transmitting "'gif2ras.c'" '(should have been 14611 characters)'
fi
fi # end of overwriting check
#    End of shell archive
exit 0
#! /bin/sh
# This is a shell archive, meaning:
# 1. Remove everything above the #! /bin/sh line.
# 2. Save the resulting text in a file.
# 3. Execute the file with /bin/sh (not csh) to create the files:
#
#    gifcompr.c
#    gifencod.c
#
# This archive created: Fri May 12 20:26:46 1989
# By:    Roger L. Long ([e-mail])
export PATH; PATH=/bin:$PATH
echo shar: extracting "'gifcompr.c'" '(11182 characters)'
if test -f 'gifcompr.c'
then
    echo shar: will not over-write existing file "'gifcompr.c'"
else
sed 's/^X//' << \SHAR_EOF > 'gifcompr.c'
X/***************************************************************************
X *
X *  GIFENCOD.C       - GIF Image compression routines
X *
X *  Lempel-Ziv compression based on 'compress'.  GIF modifications by
X *  David Rowley ([e-mail])
X *
X ***************************************************************************/
X
X/*
X * General DEFINEs
X */
X#define min(a,b)        ((a>b) ? b : a)
X
X#define BITS    12
X#define MSDOS   1
X
X#define HSIZE  5003            /* 80% occupancy */
X
X/*
X * Pointer to function returning an int
X */
Xtypedef int (* ifunptr)();
X
X/*
X * a code_int must be able to hold 2**BITS values of type int, and also -1
X */
Xtypedef int             code_int;
X
X#ifdef SIGNED_COMPARE_SLOW
Xtypedef unsigned long int count_int;
Xtypedef unsigned short int count_short;
X#else
Xtypedef long int          count_int;
X#endif
X
X#ifdef NO_UCHAR
X typedef char   char_type;
X#else
X typedef        unsigned char   char_type;
X#endif /* UCHAR */
X
X/*
X *
X * GIF Image compression - modified 'compress'
X *
X * Based on: compress.c - File compression ala IEEE Computer, June 1984.
X *
X * By Authors:  Spencer W. Thomas       (decvax!harpo!utah-cs!utah-gr!thomas)
X *              Jim McKie               (decvax!mcvax!jim)
X *              Steve Davies            (decvax!vax135!petsd!peora!srd)
X *              Ken Turkowski           (decvax!decwrl!turtlevax!ken)
X *              James A. Woods          (decvax!ihnp4!ames!jaw)
X *              Joe Orost               (decvax!vax135!petsd!joe)
X *
X */
X#include <stdio.h>
X#include <ctype.h>
X#include <signal.h>
X
X#define ARGVAL() (*++(*argv) || (--argc && *++argv))
X
Xstatic int n_bits;                        /* number of bits/code */
Xstatic int maxbits = BITS;                /* user settable max # bits/code */
Xstatic code_int maxcode;                  /* maximum code, given n_bits */
Xstatic code_int maxmaxcode = (code_int)1 << BITS; /* should NEVER generate this
Xcode */
X#ifdef COMPATIBLE               /* But wrong! */
X# define MAXCODE(n_bits)        ((code_int) 1 << (n_bits) - 1)
X#else
X# define MAXCODE(n_bits)        (((code_int) 1 << (n_bits)) - 1)
X#endif /* COMPATIBLE */
X
Xstatic count_int htab [HSIZE];
Xstatic unsigned short codetab [HSIZE];
X#define HashTabOf(i)       htab[i]
X#define CodeTabOf(i)    codetab[i]
X
Xstatic code_int hsize = HSIZE;                 /* for dynamic table sizing */
Xstatic count_int fsize;
X
X/*
X * To save much memory, we overlay the table used by compress() with those
X * used by decompress().  The tab_prefix table is the same size and type
X * as the codetab.  The tab_suffix table needs 2**BITS characters.  We
X * get this from the beginning of htab.  The output stack uses the rest
X * of htab, and contains characters.  There is plenty of room for any
X * possible stack (stack used to be 8000 characters).
X */
X
X#define tab_prefixof(i) CodeTabOf(i)
X#define tab_suffixof(i)        ((char_type *)(htab))[i]
X#define de_stack               ((char_type *)&tab_suffixof((code_int)1<<BITS))
X
Xstatic code_int free_ent = 0;                  /* first unused entry */
Xstatic int exit_stat = 0;
X
X/*
X * block compression parameters -- after all codes are used up,
X * and compression rate changes, start over.
X */
Xstatic int clear_flg = 0;
X
Xstatic int offset;
Xstatic long int in_count = 1;            /* length of input */
Xstatic long int out_count = 0;           /* # of codes output (for debugging) */
X
X/*
X * compress stdin to stdout
X *
X * Algorithm:  use open addressing double hashing (no chaining) on the
X * prefix code / next character combination.  We do a variant of Knuth's
X * algorithm D (vol. 3, sec. 6.4) along with G. Knott's relatively-prime
X * secondary probe.  Here, the modular division first probe is gives way
X * to a faster exclusive-or manipulation.  Also do block compression with
X * an adaptive reset, whereby the code table is cleared when the compression
X * ratio decreases, but after the table fills.  The variable-length output
X * codes are re-sized at this point, and a special CLEAR code is generated
X * for the decompressor.  Late addition:  construct the table according to
X * file size for noticeable speed improvement on small files.  Please direct
X * questions about this implementation to ames!jaw.
X */
X
Xstatic int g_init_bits;
Xstatic FILE *g_outfile;
X
Xstatic int ClearCode;
Xstatic int EOFCode;
X
Xcompress( init_bits, outfile, ReadValue )
Xint init_bits;
XFILE *outfile;
Xifunptr ReadValue;
X{
X    register long fcode;
X    register code_int i = 0;
X    register int c;
X    register code_int ent;
X    register code_int disp;
X    register code_int hsize_reg;
X    register int hshift;
X
X    /*
X     * Set up the globals:  g_init_bits - initial number of bits
X     *                      g_outfile   - pointer to output file
X     */
X    g_init_bits = init_bits;
X    g_outfile = outfile;
X
X    /*
X     * Set up the necessary values
X     */
X    offset = 0;
X    out_count = 0;
X    clear_flg = 0;
X    in_count = 1;
X    maxcode = MAXCODE(n_bits = g_init_bits);
X
X    ClearCode = (1 << (init_bits - 1));
X    EOFCode = ClearCode + 1;
X    free_ent = ClearCode + 2;
X
X    char_init();
X
X    ent = GIFNextPixel( ReadValue );
X
X    hshift = 0;
X    for ( fcode = (long) hsize;  fcode < 65536L; fcode *= 2L )
X        hshift++;
X    hshift = 8 - hshift;                /* set hash code range bound */
X
X    hsize_reg = hsize;
X    cl_hash( (count_int) hsize_reg);            /* clear hash table */
X
X    output( (code_int)ClearCode );
X
X#ifdef SIGNED_COMPARE_SLOW
X    while ( (c = GIFNextPixel( ReadValue )) != (unsigned) EOF ) {
X#else
X    while ( (c = GIFNextPixel( ReadValue )) != EOF ) {
X#endif
X
X        in_count++;
X
X        fcode = (long) (((long) c << maxbits) + ent);
X        i = (((code_int)c << hshift) ~ ent);    /* xor hashing */
X
X        if ( HashTabOf (i) == fcode ) {
X            ent = CodeTabOf (i);
X            continue;
X        } else if ( (long)HashTabOf (i) < 0 )      /* empty slot */
X            goto nomatch;
X        disp = hsize_reg - i;           /* secondary hash (after G. Knott) */
X        if ( i == 0 )
X            disp = 1;
Xprobe:
X        if ( (i -= disp) < 0 )
X            i += hsize_reg;
X
X        if ( HashTabOf (i) == fcode ) {
X            ent = CodeTabOf (i);
X            continue;
X        }
X        if ( (long)HashTabOf (i) > 0 )
X            goto probe;
Xnomatch:
X        output ( (code_int) ent );
X        out_count++;
X        ent = c;
X#ifdef SIGNED_COMPARE_SLOW
X        if ( (unsigned) free_ent < (unsigned) maxmaxcode) {
X#else
X        if ( free_ent < maxmaxcode ) {
X#endif
X            CodeTabOf (i) = free_ent++; /* code -> hashtable */
X            HashTabOf (i) = fcode;
X        } else
X                cl_block();
X    }
X    /*
X     * Put out the final code.
X     */
X    output( (code_int)ent );
X    out_count++;
X    output( (code_int) EOFCode );
X
X    return;
X}
X
X/*****************************************************************
X * TAG( output )
X *
X * Output the given code.
X * Inputs:
X *      code:   A n_bits-bit integer.  If == -1, then EOF.  This assumes
X *              that n_bits =< (long)wordsize - 1.
X * Outputs:
X *      Outputs code to the file.
X * Assumptions:
X *      Chars are 8 bits long.
X * Algorithm:
X *      Maintain a BITS character long buffer (so that 8 codes will
X * fit in it exactly).  Use the VAX insv instruction to insert each
X * code in turn.  When the buffer fills up empty it and start over.
X */
X
Xstatic unsigned long cur_accum = 0;
Xstatic int  cur_bits = 0;
X
Xstatic
Xunsigned long masks[] = { 0x0000, 0x0001, 0x0003, 0x0007, 0x000F,
X                                  0x001F, 0x003F, 0x007F, 0x00FF,
X                                  0x01FF, 0x03FF, 0x07FF, 0x0FFF,
X                                  0x1FFF, 0x3FFF, 0x7FFF, 0xFFFF };
X
Xstatic
Xoutput( code )
Xcode_int  code;
X{
X    cur_accum &= masks[ cur_bits ];
X
X    if( cur_bits > 0 )
X        cur_accum |= ((long)code << cur_bits);
X    else
X        cur_accum = code;
X
X    cur_bits += n_bits;
X
X    while( cur_bits >= 8 ) {
X        char_out( (unsigned int)(cur_accum & 0xff) );
X        cur_accum >>= 8;
X        cur_bits -= 8;
X    }
X
X    /*
X     * If the next entry is going to be too big for the code size,
X     * then increase it, if possible.
X     */
X   if ( free_ent > maxcode || clear_flg ) {
X
X            if( clear_flg ) {
X
X                maxcode = MAXCODE (n_bits = g_init_bits);
X                clear_flg = 0;
X
X            } else {
X
X                n_bits++;
X                if ( n_bits == maxbits )
X                    maxcode = maxmaxcode;
X                else
X                    maxcode = MAXCODE(n_bits);
X            }
X        }
X
X    if( code == EOFCode ) {
X        /*
X         * At EOF, write the rest of the buffer.
X         */
X        while( cur_bits > 0 ) {
X                char_out( (unsigned int)(cur_accum & 0xff) );
X                cur_accum >>= 8;
X                cur_bits -= 8;
X        }
X
X        flush_char();
X
X        fflush( g_outfile );
X
X        if( ferror( g_outfile ) )
X                writeerr();
X    }
X}
X
X/*
X * Clear out the hash table
X */
Xstatic
Xcl_block ()             /* table clear for block compress */
X{
X
X        cl_hash ( (count_int) hsize );
X        free_ent = ClearCode + 2;
X        clear_flg = 1;
X
X        output( (code_int)ClearCode );
X}
X
Xstatic
Xcl_hash(hsize)          /* reset code table */
Xregister count_int hsize;
X{
X
X        register count_int *htab_p = htab+hsize;
X
X        register long i;
X        register long m1 = -1;
X
X        i = hsize - 16;
X        do {                            /* might use Sys V memset(3) here */
X                *(htab_p-16) = m1;
X                *(htab_p-15) = m1;
X                *(htab_p-14) = m1;
X                *(htab_p-13) = m1;
X                *(htab_p-12) = m1;
X                *(htab_p-11) = m1;
X                *(htab_p-10) = m1;
X                *(htab_p-9) = m1;
X                *(htab_p-8) = m1;
X                *(htab_p-7) = m1;
X                *(htab_p-6) = m1;
X                *(htab_p-5) = m1;
X                *(htab_p-4) = m1;
X                *(htab_p-3) = m1;
X                *(htab_p-2) = m1;
X                *(htab_p-1) = m1;
X                htab_p -= 16;
X        } while ((i -= 16) >= 0);
X
X        for ( i += 16; i > 0; i-- )
X                *--htab_p = m1;
X}
X
Xstatic
Xwriteerr()
X{
X        printf( "error writing output file\n" );
X        exit(1);
X}
X
X/******************************************************************************
X *
X * GIF Specific routines
X *
X ******************************************************************************/
X
X/*
X * Number of characters so far in this 'packet'
X */
Xstatic int a_count;
X
X/*
X * Set up the 'byte output' routine
X */
Xstatic
Xchar_init()
X{
X        a_count = 0;
X}
X
X/*
X * Define the storage for the packet accumulator
X */
Xstatic char accum[ 256 ];
X
X/*
X * Add a character to the end of the current packet, and if it is 254
X * characters, flush the packet to disk.
X */
Xstatic
Xchar_out( c )
Xint c;
X{
X        accum[ a_count++ ] = c;
X        if( a_count >= 254 )
X                flush_char();
X}
X
X/*
X * Flush the packet to disk, and reset the accumulator
X */
Xstatic
Xflush_char()
X{
X        if( a_count > 0 ) {
X                fputc( a_count, g_outfile );
X                fwrite( accum, 1, a_count, g_outfile );
X                a_count = 0;
X        }
X}
X
X/* The End */
SHAR_EOF
if test 11182 -ne "`wc -c < 'gifcompr.c'`"
then
    echo shar: error transmitting "'gifcompr.c'" '(should have been 11182 characters)'
fi
fi # end of overwriting check
echo shar: extracting "'gifencod.c'" '(5916 characters)'
if test -f 'gifencod.c'
then
    echo shar: will not over-write existing file "'gifencod.c'"
else
sed 's/^X//' << \SHAR_EOF > 'gifencod.c'
X
X/*****************************************************************************
X *
X * GIFENCODE.C    - GIF Image compression interface
X *
X * GIFEncode( FName, GHeight, GWidth, GInterlace, Background,
X *            BitsPerPixel, Red, Green, Blue, GetPixel )
X *
X *****************************************************************************/
X
X#include <stdio.h>
X
X/*
X * Pointer to function returning an int
X */
Xtypedef int (* ifunptr)();
X
X#define TRUE 1
X#define FALSE 0
X
Xstatic int Width, Height;
Xstatic int curx, cury;
Xstatic long CountDown;
Xstatic int Pass = 0;
Xstatic int Interlace;
X
X/*
X * Bump the 'curx' and 'cury' to point to the next pixel
X */
Xstatic
XBumpPixel()
X{
X        /*
X         * Bump the current X position
X         */
X        curx++;
X
X        /*
X         * If we are at the end of a scan line, set curx back to the beginning
X         * If we are interlaced, bump the cury to the appropriate spot,
X         * otherwise, just increment it.
X         */
X        if( curx == Width ) {
X                curx = 0;
X
X                if( !Interlace )
X                        cury++;
X                else {
X                     switch( Pass ) {
X
X                       case 0:
X                          cury += 8;
X                          if( cury >= Height ) {
X                                Pass++;
X                                cury = 4;
X                          }
X                          break;
X
X                       case 1:
X                          cury += 8;
X                          if( cury >= Height ) {
X                                Pass++;
X                                cury = 2;
X                          }
X                          break;
X
X                       case 2:
X                          cury += 4;
X                          if( cury >= Height ) {
X                             Pass++;
X                             cury = 1;
X                          }
X                          break;
X
X                       case 3:
X                          cury += 2;
X                          break;
X                        }
X                }
X        }
X}
X
X/*
X * Return the next pixel from the image
X */
XGIFNextPixel( getpixel )
Xifunptr getpixel;
X{
X        int r;
X
X        if( CountDown == 0 )
X                return EOF;
X
X        CountDown--;
X
X        r = ( * getpixel )( curx, cury );
X
X        BumpPixel();
X
X        return r;
X}
X
X/* public */
X
XGIFEncode( FName, GWidth, GHeight, GInterlace, Background,
X           BitsPerPixel, Red, Green, Blue, GetPixel )
X
Xchar *FName;
Xint GWidth, GHeight;
Xint GInterlace;
Xint Background;
Xint BitsPerPixel;
Xint Red[], Green[], Blue[];
Xifunptr GetPixel;
X
X{
X        FILE *fp;
X        int B;
X        int RWidth, RHeight;
X        int LeftOfs, TopOfs;
X        int Resolution;
X        int ColorMapSize;
X        int InitCodeSize;
X        int i;
X
X        Interlace = GInterlace;
X
X        ColorMapSize = 1 << BitsPerPixel;
X
X        RWidth = Width = GWidth;
X        RHeight = Height = GHeight;
X        LeftOfs = TopOfs = 0;
X
X        Resolution = BitsPerPixel;
X
X        /*
X         * Calculate number of bits we are expecting
X         */
X        CountDown = (long)Width * (long)Height;
X
X        /*
X         * Indicate which pass we are on (if interlace)
X         */
X        Pass = 0;
X
X        /*
X         * The initial code size
X         */
X        if( BitsPerPixel <= 1 )
X                InitCodeSize = 2;
X        else
X                InitCodeSize = BitsPerPixel;
X
X        /*
X         * Set up the current x and y position
X         */
X        curx = cury = 0;
X
X        /*
X         * Open the GIF file for binary write
X         */
X        fp = fopen( FName, "wb" );
X
X        if( fp == (FILE *)0 ) {
X                printf( "error: could not open output file\n" );
X                exit(1);
X        }
X
X        /*
X         * Write the Magic header
X         */
X        fwrite( "GIF87a", 1, 6, fp );
X
X        /*
X         * Write out the screen width and height
X         */
X        Putword( RWidth, fp );
X        Putword( RHeight, fp );
X
X        /*
X         * Indicate that there is a global colour map
X         */
X        B = 0x80;       /* Yes, there is a color map */
X
X        /*
X         * OR in the resolution
X         */
X        B |= (Resolution - 1) << 5;
X
X        /*
X         * OR in the Bits per Pixel
X         */
X        B |= (BitsPerPixel - 1);
X
X        /*
X         * Write it out
X         */
X        fputc( B, fp );
X
X        /*
X         * Write out the Background colour
X         */
X        fputc( Background, fp );
X
X        /*
X         * Byte of 0's (future expansion)
X         */
X        fputc( 0, fp );
X
X        /*
X         * Write out the Global Colour Map
X         */
X        for( i=0; i<ColorMapSize; i++ ) {
X                fputc( Red[i], fp );
X                fputc( Green[i], fp );
X                fputc( Blue[i], fp );
X        }
X
X        /*
X         * Write an Image separator
X         */
X        fputc( ',', fp );
X
X        /*
X         * Write the Image header
X         */
X
X        Putword( LeftOfs, fp );
X        Putword( TopOfs, fp );
X        Putword( Width, fp );
X        Putword( Height, fp );
X
X        /*
X         * Write out whether or not the image is interlaced
X         */
X        if( Interlace )
X                fputc( 0x40, fp );
X        else
X                fputc( 0x00, fp );
X
X        /*
X         * Write out the initial code size
X         */
X        fputc( InitCodeSize, fp );
X
X        /*
X         * Go and actually compress the data
X         */
X        compress( InitCodeSize+1, fp, GetPixel );
X
X        /*
X         * Write out a Zero-length packet (to end the series)
X         */
X        fputc( 0, fp );
X
X        /*
X         * Write the GIF file terminator
X         */
X        fputc( ';', fp );
X
X        /*
X         * And close the file
X         */
X        fclose( fp );
X
X}
X
X/*
X * Write out a word to the GIF file
X */
Xstatic
XPutword( w, fp )
Xint w;
XFILE *fp;
X{
X        fputc( w & 0xff, fp );
X        fputc( (w / 256) & 0xff, fp );
X}
X
SHAR_EOF
if test 5916 -ne "`wc -c < 'gifencod.c'`"
then
    echo shar: error transmitting "'gifencod.c'" '(should have been 5916 characters)'
fi
fi # end of overwriting check
#    End of shell archive
exit 0
---