/*
 * Copyright (c) 1990-1997 Sam Leffler
 * Copyright (c) 1991-1997 Silicon Graphics, Inc.
 *
 * Permission to use, copy, modify, distribute, and sell this software and
 * its documentation for any purpose is hereby granted without fee, provided
 * that (i) the above copyright notices and this permission notice appear in
 * all copies of the software and related documentation, and (ii) the names of
 * Sam Leffler and Silicon Graphics may not be used in any advertising or
 * publicity relating to the software without the specific, prior written
 * permission of Sam Leffler and Silicon Graphics.
 *
 * THE SOFTWARE IS PROVIDED "AS-IS" AND WITHOUT WARRANTY OF ANY KIND,
 * EXPRESS, IMPLIED OR OTHERWISE, INCLUDING WITHOUT LIMITATION, ANY
 * WARRANTY OF MERCHANTABILITY OR FITNESS FOR A PARTICULAR PURPOSE.
 *
 * IN NO EVENT SHALL SAM LEFFLER OR SILICON GRAPHICS BE LIABLE FOR
 * ANY SPECIAL, INCIDENTAL, INDIRECT OR CONSEQUENTIAL DAMAGES OF ANY KIND,
 * OR ANY DAMAGES WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS,
 * WHETHER OR NOT ADVISED OF THE POSSIBILITY OF DAMAGE, AND ON ANY THEORY OF
 * LIABILITY, ARISING OUT OF OR IN CONNECTION WITH THE USE OR PERFORMANCE
 * OF THIS SOFTWARE.
 */

/*
 *	convert a GIF file into a TIFF file.
 *	based on Paul Haeberli's fromgif program which in turn is
 *	based on a GIF file reader by Marcel J.E. Mol March 23 1989
 *
 *	if input is 320 by 200 pixel aspect is probably 1.2
 *	if input is 640 350 pixel aspect is probably 1.37
 *
 */
#include "tif_config.h"

#include <errno.h>
#include <math.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>

#ifdef HAVE_UNISTD_H
#include <unistd.h>
#endif

#ifdef NEED_LIBPORT
#include "libport.h"
#endif

#include "tiffio.h"

#define GIFGAMMA (1.5) /* smaller makes output img brighter */
#define IMAX 0xffff    /* max intensity value */
#define EXTRAFUDGE 128 /* some people write BAD .gif files */

#define streq(a, b) (strcmp(a, b) == 0)
#define strneq(a, b, n) (strncmp(a, b, n) == 0)

unsigned short gamtab[256];

void makegamtab(float gam)
{
    int i;

    for (i = 0; i < 256; i++)
        gamtab[i] = (unsigned short)(IMAX * pow(i / 255.0, gam) + 0.5);
}

char *stuff[] = {
    "usage: gif2tiff [options] input.gif output.tif",
    "where options are:",
    " -r #		make each strip have no more than # rows",
    "",
    " -c lzw[:opts]	compress output with Lempel-Ziv & Welch encoding",
    " -c zip[:opts]	compress output with deflate encoding",
    " -c packbits	compress output with packbits encoding",
    " -c none	use no compression algorithm on output",
    "",
    "LZW and deflate options:",
    " #		set predictor value",
    "For example, -c lzw:2 to get LZW-encoded data with horizontal "
    "differencing",
    NULL};

static void usage(void)
{
    char buf[BUFSIZ];
    int i;

    setbuf(stderr, buf);
    fprintf(stderr, "%s\n\n", TIFFGetVersion());
    for (i = 0; stuff[i] != NULL; i++)
        fprintf(stderr, "%s\n", stuff[i]);
    exit(-1);
}

#define COLSIZE 256

unsigned char *stackp;
unsigned int prefix[4096];
unsigned char suffix[4096];
unsigned char stack[4096];
int datasize, codesize, codemask; /* Decoder working variables */
int clear, eoi;                   /* Special code values */
int avail, oldcode;

FILE *infile;
int global;                          /* Is there a global color map? */
int globalbits;                      /* Number of bits of global colors */
unsigned char globalmap[COLSIZE][3]; /* RGB values for global color map */
unsigned char *raster;               /* Decoded image data */
unsigned long width, height;
unsigned short red[COLSIZE];
unsigned short green[COLSIZE];
unsigned short blue[COLSIZE];
char *filename, *imagename;

static uint16_t compression = COMPRESSION_PACKBITS;
static uint16_t predictor = 0;
static uint32_t rowsperstrip = (uint32_t)-1;
static int processCompressOptions(char *);

int convert(void);
int checksignature(void);
int readscreen(void);
int readgifimage(char *);
int readextension(void);
int readraster(void);
int process(int, unsigned char **);
void initcolors(unsigned char[COLSIZE][3], int);
void rasterize(int, char *);

int main(int argc, char *argv[])
{
#if !HAVE_DECL_OPTARG
    extern int optind;
    extern char *optarg;
#endif

    int c, status;

    while ((c = getopt(argc, argv, "c:r:")) != -1)
        switch (c)
        {
            case 'c': /* compression scheme */
                if (!processCompressOptions(optarg))
                    usage();
                break;
            case 'r': /* rows/strip */
                rowsperstrip = atoi(optarg);
                break;
            case '?':
                usage();
                /*NOTREACHED*/
        }
    if (argc - optind != 2)
        usage();

    makegamtab(GIFGAMMA);
    filename = argv[optind];
    imagename = argv[optind + 1];
    if ((infile = fopen(imagename, "rb")) != NULL)
    {
        int c;
        fclose(infile);
        printf("overwrite %s? ", imagename);
        fflush(stdout);
        c = getc(stdin);
        if (c != 'y' && c != 'Y')
            return (1);
    }
    if ((infile = fopen(filename, "rb")) == NULL)
    {
        perror(filename);
        return (1);
    }
    status = convert();
    fclose(infile);
    return (status);
}

static int processCompressOptions(char *opt)
{
    if (streq(opt, "none"))
        compression = COMPRESSION_NONE;
    else if (streq(opt, "packbits"))
        compression = COMPRESSION_PACKBITS;
    else if (strneq(opt, "lzw", 3))
    {
        char *cp = strchr(opt, ':');
        if (cp)
            predictor = atoi(cp + 1);
        compression = COMPRESSION_LZW;
    }
    else if (strneq(opt, "zip", 3))
    {
        char *cp = strchr(opt, ':');
        if (cp)
            predictor = atoi(cp + 1);
        compression = COMPRESSION_ADOBE_DEFLATE;
    }
    else
        return (0);
    return (1);
}

int convert(void)
{
    int ch;
    char *mode = "w";

    if (!checksignature())
        return (-1);
    if (!readscreen())
        return (-1);
    while ((ch = getc(infile)) != ';' && ch != EOF)
    {
        switch (ch)
        {
            case '\0':
                break; /* this kludge for non-standard files */
            case ',':
                if (!readgifimage(mode))
                    return (-1);
                mode = "a"; /* subsequent images append */
                break;
            case '!':
                if (!readextension())
                    return (-1);
                break;
            default:
                fprintf(stderr, "illegal GIF block type\n");
                return (-1);
        }
    }
    return (0);
}

int checksignature(void)
{
    char buf[6];

    if (fread(buf, 1, 6, infile) != 6)
    {
        fprintf(stderr, "short read from file %s (%s)\n", filename,
                strerror(errno));
        return 0;
    }
    if (strncmp(buf, "GIF", 3))
    {
        fprintf(stderr, "file is not a GIF file\n");
        return 0;
    }
    if (strncmp(&buf[3], "87a", 3))
    {
        fprintf(stderr, "unknown GIF version number\n");
        return 0;
    }
    return 1;
}

/*
 * 	readscreen -
 *		Get information which is global to all the images stored
 *	in the file
 */
int readscreen(void)
{
    unsigned char buf[7];

    if (fread(buf, 1, 7, infile) != 7)
    {
        fprintf(stderr, "short read from file %s (%s)\n", filename,
                strerror(errno));
        return 0;
    }
    global = buf[4] & 0x80;
    if (global)
    {
        globalbits = (buf[4] & 0x07) + 1;
        if (fread(globalmap, 3, ((size_t)1) << globalbits, infile) !=
            ((size_t)1) << globalbits)
        {
            fprintf(stderr, "short read from file %s (%s)\n", filename,
                    strerror(errno));
            return 0;
        }
    }
    return 1;
}

int readgifimage(char *mode)
{
    unsigned char buf[9];
    int local, interleaved;
    unsigned char localmap[256][3];
    int localbits;
    int status;
    size_t raster_size;

    if (fread(buf, 1, 9, infile) != 9)
    {
        fprintf(stderr, "short read from file %s (%s)\n", filename,
                strerror(errno));
        return (0);
    }
    width = (buf[4] + (buf[5] << 8)) & 0xffff;  /* 16 bit */
    height = (buf[6] + (buf[7] << 8)) & 0xffff; /* 16 bit */
    local = buf[8] & 0x80;
    interleaved = buf[8] & 0x40;
    if (width == 0UL || height == 0UL || (width > 2000000000UL / height))
    {
        fprintf(stderr, "Invalid value of width or height\n");
        return (0);
    }
    if (local == 0 && global == 0)
    {
        fprintf(stderr, "no colormap present for image\n");
        return (0);
    }
    raster_size = width * height;
    if ((raster_size / width) == height)
    {
        raster_size += EXTRAFUDGE; /* Add elbow room */
    }
    else
    {
        raster_size = 0;
    }
    if ((raster = (unsigned char *)_TIFFmalloc(raster_size)) == NULL)
    {
        fprintf(stderr, "not enough memory for image\n");
        return (0);
    }
    if (local)
    {
        localbits = (buf[8] & 0x7) + 1;

        fprintf(stderr, "   local colors: %d\n", 1 << localbits);

        if (fread(localmap, 3, ((size_t)1) << localbits, infile) !=
            ((size_t)1) << localbits)
        {
            fprintf(stderr, "short read from file %s (%s)\n", filename,
                    strerror(errno));
            return (0);
        }
        initcolors(localmap, 1 << localbits);
    }
    else if (global)
    {
        initcolors(globalmap, 1 << globalbits);
    }
    if ((status = readraster()))
        rasterize(interleaved, mode);
    _TIFFfree(raster);
    return status;
}

/*
 * 	readextension -
 *		Read a GIF extension block (and do nothing with it).
 *
 */
int readextension(void)
{
    int count;
    char buf[255];
    int status = 1;

    (void)getc(infile);
    while ((count = getc(infile)) && count <= 255)
        if (fread(buf, 1, count, infile) != (size_t)count)
        {
            fprintf(stderr, "short read from file %s (%s)\n", filename,
                    strerror(errno));
            status = 0;
            break;
        }
    return status;
}

/*
 * 	readraster -
 *		Decode a raster image
 *
 */
int readraster(void)
{
    unsigned char *fill = raster;
    unsigned char buf[255];
    register int bits = 0;
    register unsigned long datum = 0;
    register unsigned char *ch;
    register int count, code;
    int status = 1;

    datasize = getc(infile);
    if (datasize > 12)
        return 0;
    clear = 1 << datasize;
    eoi = clear + 1;
    avail = clear + 2;
    oldcode = -1;
    codesize = datasize + 1;
    codemask = (1 << codesize) - 1;
    for (code = 0; code < clear; code++)
    {
        prefix[code] = 0;
        suffix[code] = code;
    }
    stackp = stack;
    for (count = getc(infile); count > 0 && count <= 255; count = getc(infile))
    {
        if (fread(buf, 1, count, infile) != (size_t)count)
        {
            fprintf(stderr, "short read from file %s (%s)\n", filename,
                    strerror(errno));
            return 0;
        }
        for (ch = buf; count-- > 0; ch++)
        {
            datum += (unsigned long)*ch << bits;
            bits += 8;
            while (bits >= codesize)
            {
                code = datum & codemask;
                datum >>= codesize;
                bits -= codesize;
                if (code == eoi)
                {                  /* This kludge put in */
                    goto exitloop; /* because some GIF files*/
                }                  /* aren't standard */
                if (!process(code, &fill))
                {
                    status = 0;
                    goto exitloop;
                }
            }
        }
        if (fill >= raster + width * height)
        {
            fprintf(stderr, "raster full before eoi code\n");
            break;
        }
    }
exitloop:
    if (fill != raster + width * height)
    {
        fprintf(stderr, "warning: wrong rastersize: %ld bytes\n",
                (long)(fill - raster));
        fprintf(stderr, "         instead of %ld bytes\n",
                (long)width * height);
    }
    return status;
}

/*
 * 	process -
 *		Process a compression code.  "clear" resets the code table.
 *	Otherwise make a new code table entry, and output the bytes
 *	associated with the code.
 */
int process(register int code, unsigned char **fill)
{
    int incode;
    static unsigned char firstchar;

    if (code == clear)
    {
        codesize = datasize + 1;
        codemask = (1 << codesize) - 1;
        avail = clear + 2;
        oldcode = -1;
        return 1;
    }

    if (oldcode == -1)
    {
        if (code >= clear)
        {
            fprintf(stderr, "bad input: code=%d is larger than clear=%d\n",
                    code, clear);
            return 0;
        }
        if (*fill >= raster + width * height)
        {
            fprintf(stderr, "raster full before eoi code\n");
            return 0;
        }
        *(*fill)++ = suffix[code];
        firstchar = oldcode = code;
        return 1;
    }
    if (code > avail)
    {
        fprintf(stderr, "code %d too large for %d\n", code, avail);
        return 0;
    }

    incode = code;
    if (code == avail)
    { /* the first code is always < avail */
        *stackp++ = firstchar;
        code = oldcode;
    }
    while (code > clear)
    {
        *stackp++ = suffix[code];
        code = prefix[code];
    }

    *stackp++ = firstchar = suffix[code];
    prefix[avail] = oldcode;
    suffix[avail] = firstchar;
    avail++;

    if (((avail & codemask) == 0) && (avail < 4096))
    {
        codesize++;
        codemask += avail;
    }
    oldcode = incode;
    do
    {
        if (*fill >= raster + width * height)
        {
            fprintf(stderr, "raster full before eoi code\n");
            return 0;
        }
        *(*fill)++ = *--stackp;
    } while (stackp > stack);
    return 1;
}

/*
 * 	initcolors -
 *		Convert a color map (local or global) to arrays with R, G and B
 * 	values.
 *
 */
void initcolors(unsigned char colormap[COLSIZE][3], int ncolors)
{
    register int i;

    for (i = 0; i < ncolors; i++)
    {
        red[i] = gamtab[colormap[i][0]];
        green[i] = gamtab[colormap[i][1]];
        blue[i] = gamtab[colormap[i][2]];
    }
}

void rasterize(int interleaved, char *mode)
{
    register unsigned long row;
    unsigned char *newras;
    unsigned char *ras;
    TIFF *tif;
    tstrip_t strip;
    tsize_t stripsize;

    if ((newras = (unsigned char *)_TIFFmalloc(width * height + EXTRAFUDGE)) ==
        NULL)
    {
        fprintf(stderr, "not enough memory for image\n");
        return;
    }
#define DRAWSEGMENT(offset, step)                                              \
    {                                                                          \
        for (row = offset; row < height; row += step)                          \
        {                                                                      \
            _TIFFmemcpy(newras + row * width, ras, width);                     \
            ras += width;                                                      \
        }                                                                      \
    }
    ras = raster;
    if (interleaved)
    {
        DRAWSEGMENT(0, 8);
        DRAWSEGMENT(4, 8);
        DRAWSEGMENT(2, 4);
        DRAWSEGMENT(1, 2);
    }
    else
        DRAWSEGMENT(0, 1);
#undef DRAWSEGMENT

    tif = TIFFOpen(imagename, mode);
    if (!tif)
    {
        TIFFError(imagename, "Can not open output image");
        exit(-1);
    }
    TIFFSetField(tif, TIFFTAG_IMAGEWIDTH, (uint32_t)width);
    TIFFSetField(tif, TIFFTAG_IMAGELENGTH, (uint32_t)height);
    TIFFSetField(tif, TIFFTAG_PHOTOMETRIC, PHOTOMETRIC_PALETTE);
    TIFFSetField(tif, TIFFTAG_PLANARCONFIG, PLANARCONFIG_CONTIG);
    TIFFSetField(tif, TIFFTAG_SAMPLESPERPIXEL, 1);
    TIFFSetField(tif, TIFFTAG_BITSPERSAMPLE, 8);
    TIFFSetField(tif, TIFFTAG_ROWSPERSTRIP,
                 rowsperstrip = TIFFDefaultStripSize(tif, rowsperstrip));
    TIFFSetField(tif, TIFFTAG_COMPRESSION, compression);
    switch (compression)
    {
        case COMPRESSION_LZW:
        case COMPRESSION_ADOBE_DEFLATE:
        case COMPRESSION_DEFLATE:
            if (predictor != 0)
                TIFFSetField(tif, TIFFTAG_PREDICTOR, predictor);
            break;
    }
    TIFFSetField(tif, TIFFTAG_COLORMAP, red, green, blue);
    TIFFSetField(tif, TIFFTAG_ORIENTATION, ORIENTATION_TOPLEFT);
    strip = 0;
    stripsize = TIFFStripSize(tif);
    for (row = 0; row < height; row += rowsperstrip)
    {
        if (rowsperstrip > height - row)
        {
            rowsperstrip = height - row;
            stripsize = TIFFVStripSize(tif, rowsperstrip);
        }
        if (TIFFWriteEncodedStrip(tif, strip, newras + row * width, stripsize) <
            0)
            break;
        strip++;
    }
    TIFFClose(tif);

    _TIFFfree(newras);
}