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/* +-------------------------------------------------------------------+ */
/* | Copyright 1990, 1991, 1993, David Koblas. (koblas@netcom.com) | */
/* | 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 software is | */
/* | provided "as is" without express or implied warranty. | */
/* +-------------------------------------------------------------------+ */
#include "pnm.h"
#define MAXCOLORMAPSIZE 256
#define TRUE 1
#define FALSE 0
#define CM_RED 0
#define CM_GREEN 1
#define CM_BLUE 2
#define MAX_LWZ_BITS 12
#define INTERLACE 0x40
#define LOCALCOLORMAP 0x80
#define BitSet(byte, bit) (((byte) & (bit)) == (bit))
#define ReadOK(file,buffer,len) (fread(buffer, len, 1, file) != 0)
#define LM_to_uint(a,b) (((b)<<8)|(a))
static struct {
unsigned int Width;
unsigned int Height;
unsigned char ColorMap[3][MAXCOLORMAPSIZE];
unsigned int BitPixel;
unsigned int ColorResolution;
unsigned int Background;
unsigned int AspectRatio;
/*
**
*/
int GrayScale;
} GifScreen;
static struct {
int transparent;
int delayTime;
int inputFlag;
int disposal;
} Gif89 = { -1, -1, -1, 0 };
pixel *Image = NULL;
int verbose;
int showComment;
static char usage[] = "[-verbose] [-comments] [-image N] [GIFfile]";
static void ReadGIF ARGS(( FILE *fd, int imageNumber ));
static int ReadColorMap ARGS(( FILE *fd, int number, unsigned char buffer[3][MAXCOLORMAPSIZE], int *flag ));
static int DoExtension ARGS(( FILE *fd, int label ));
static int GetDataBlock ARGS(( FILE *fd, unsigned char *buf ));
static int GetCode ARGS(( FILE *fd, int code_size, int flag ));
static int LWZReadByte ARGS(( FILE *fd, int flag, int input_code_size ));
static void ReadImage ARGS(( FILE *fd, int len, int height, unsigned char cmap[3][MAXCOLORMAPSIZE], int gray, int interlace, int ignore ));
int
main(argc,argv)
int argc;
char **argv;
{
int argn;
FILE *in;
int imageNumber;
pnm_init(&argc, argv);
argn = 1;
imageNumber = 1;
verbose = FALSE;
showComment = FALSE;
while (argn < argc && argv[argn][0] == '-' && argv[argn][1] != '\0') {
if (pm_keymatch(argv[argn], "-verbose", 2)) {
verbose = TRUE;
showComment = TRUE;
} else if (pm_keymatch(argv[argn], "-comments", 2)) {
showComment = TRUE;
} else if (pm_keymatch(argv[argn], "-image", 2)) {
++argn;
if (argn == argc || sscanf(argv[argn], "%d", &imageNumber) != 1)
pm_usage(usage);
} else {
pm_usage(usage);
}
++argn;
}
if (argn != argc) {
in = pm_openr(argv[argn]);
++argn;
} else {
in = stdin;
}
if (argn != argc)
pm_usage(usage);
ReadGIF(in, imageNumber);
pm_close(in);
pm_close(stdout);
exit(0);
}
static void
ReadGIF(fd, imageNumber)
FILE *fd;
int imageNumber;
{
unsigned char buf[16];
unsigned char c;
unsigned char localColorMap[3][MAXCOLORMAPSIZE];
int grayScale;
int useGlobalColormap;
int bitPixel;
int imageCount = 0;
char version[4];
if (! ReadOK(fd,buf,6))
pm_error("error reading magic number" );
if (strncmp((char *)buf,"GIF",3) != 0)
pm_error("not a GIF file" );
strncpy(version, (char *)buf + 3, 3);
version[3] = '\0';
if ((strcmp(version, "87a") != 0) && (strcmp(version, "89a") != 0))
pm_error("bad version number, not '87a' or '89a'" );
if (! ReadOK(fd,buf,7))
pm_error("failed to read screen descriptor" );
GifScreen.Width = LM_to_uint(buf[0],buf[1]);
GifScreen.Height = LM_to_uint(buf[2],buf[3]);
GifScreen.BitPixel = 2<<(buf[4]&0x07);
GifScreen.ColorResolution = (((buf[4]&0x70)>>3)+1);
GifScreen.Background = buf[5];
GifScreen.AspectRatio = buf[6];
if (BitSet(buf[4], LOCALCOLORMAP)) { /* Global Colormap */
if (ReadColorMap(fd,GifScreen.BitPixel,GifScreen.ColorMap,
&GifScreen.GrayScale))
pm_error("error reading global colormap" );
}
if (GifScreen.AspectRatio != 0 && GifScreen.AspectRatio != 49) {
float r;
r = ( (float) GifScreen.AspectRatio + 15.0 ) / 64.0;
pm_message("warning - non-square pixels; to fix do a 'pnmscale -%cscale %g'",
r < 1.0 ? 'x' : 'y',
r < 1.0 ? 1.0 / r : r );
}
for (;;) {
if (! ReadOK(fd,&c,1))
pm_error("EOF / read error on image data" );
if (c == ';') { /* GIF terminator */
if (imageCount < imageNumber)
pm_error("only %d image%s found in file",
imageCount, imageCount>1?"s":"" );
return;
}
if (c == '!') { /* Extension */
if (! ReadOK(fd,&c,1))
pm_error("OF / read error on extention function code");
DoExtension(fd, c);
continue;
}
if (c != ',') { /* Not a valid start character */
pm_message("bogus character 0x%02x, ignoring", (int) c );
continue;
}
++imageCount;
if (! ReadOK(fd,buf,9))
pm_error("couldn't read left/top/width/height");
useGlobalColormap = ! BitSet(buf[8], LOCALCOLORMAP);
bitPixel = 1<<((buf[8]&0x07)+1);
if (! useGlobalColormap) {
if (ReadColorMap(fd, bitPixel, localColorMap, &grayScale))
pm_error("error reading local colormap" );
ReadImage(fd, LM_to_uint(buf[4],buf[5]),
LM_to_uint(buf[6],buf[7]),
localColorMap, grayScale,
BitSet(buf[8], INTERLACE), imageCount != imageNumber);
} else {
ReadImage(fd, LM_to_uint(buf[4],buf[5]),
LM_to_uint(buf[6],buf[7]),
GifScreen.ColorMap, GifScreen.GrayScale,
BitSet(buf[8], INTERLACE), imageCount != imageNumber);
}
}
}
static int
ReadColorMap(fd,number,buffer,pbm_format)
FILE *fd;
int number;
unsigned char buffer[3][MAXCOLORMAPSIZE];
int *pbm_format;
{
int i;
unsigned char rgb[3];
int flag;
flag = TRUE;
for (i = 0; i < number; ++i) {
if (! ReadOK(fd, rgb, sizeof(rgb)))
pm_error("bad colormap" );
buffer[CM_RED][i] = rgb[0] ;
buffer[CM_GREEN][i] = rgb[1] ;
buffer[CM_BLUE][i] = rgb[2] ;
flag &= (rgb[0] == rgb[1] && rgb[1] == rgb[2]);
}
if (flag)
*pbm_format = (number == 2) ? PBM_TYPE : PGM_TYPE;
else
*pbm_format = PPM_TYPE;
return FALSE;
}
static int
DoExtension(fd, label)
FILE *fd;
int label;
{
static char buf[256];
char *str;
switch (label) {
case 0x01: /* Plain Text Extension */
str = "Plain Text Extension";
#ifdef notdef
if (GetDataBlock(fd, (unsigned char*) buf) == 0)
;
lpos = LM_to_uint(buf[0], buf[1]);
tpos = LM_to_uint(buf[2], buf[3]);
width = LM_to_uint(buf[4], buf[5]);
height = LM_to_uint(buf[6], buf[7]);
cellw = buf[8];
cellh = buf[9];
foreground = buf[10];
background = buf[11];
while (GetDataBlock(fd, (unsigned char*) buf) != 0) {
PPM_ASSIGN(image[ypos][xpos],
cmap[CM_RED][v],
cmap[CM_GREEN][v],
cmap[CM_BLUE][v]);
++index;
}
return FALSE;
#else
break;
#endif
case 0xff: /* Application Extension */
str = "Application Extension";
break;
case 0xfe: /* Comment Extension */
str = "Comment Extension";
while (GetDataBlock(fd, (unsigned char*) buf) != 0) {
if (showComment)
pm_message("gif comment: %s", buf );
}
return FALSE;
case 0xf9: /* Graphic Control Extension */
str = "Graphic Control Extension";
(void) GetDataBlock(fd, (unsigned char*) buf);
Gif89.disposal = (buf[0] >> 2) & 0x7;
Gif89.inputFlag = (buf[0] >> 1) & 0x1;
Gif89.delayTime = LM_to_uint(buf[1],buf[2]);
if ((buf[0] & 0x1) != 0)
Gif89.transparent = buf[3];
while (GetDataBlock(fd, (unsigned char*) buf) != 0)
;
return FALSE;
default:
str = buf;
sprintf(buf, "UNKNOWN (0x%02x)", label);
break;
}
pm_message("got a '%s' extension", str );
while (GetDataBlock(fd, (unsigned char*) buf) != 0)
;
return FALSE;
}
int ZeroDataBlock = FALSE;
static int
GetDataBlock(fd, buf)
FILE *fd;
unsigned char *buf;
{
unsigned char count;
if (! ReadOK(fd,&count,1)) {
pm_message("error in getting DataBlock size" );
return -1;
}
ZeroDataBlock = count == 0;
if ((count != 0) && (! ReadOK(fd, buf, count))) {
pm_message("error in reading DataBlock" );
return -1;
}
return count;
}
static int
GetCode(fd, code_size, flag)
FILE *fd;
int code_size;
int flag;
{
static unsigned char buf[280];
static int curbit, lastbit, done, last_byte;
int i, j, ret;
unsigned char count;
if (flag) {
curbit = 0;
lastbit = 0;
done = FALSE;
return 0;
}
if ( (curbit+code_size) >= lastbit) {
if (done) {
if (curbit >= lastbit)
pm_error("ran off the end of my bits" );
return -1;
}
buf[0] = buf[last_byte-2];
buf[1] = buf[last_byte-1];
if ((count = GetDataBlock(fd, &buf[2])) == 0)
done = TRUE;
last_byte = 2 + count;
curbit = (curbit - lastbit) + 16;
lastbit = (2+count)*8 ;
}
ret = 0;
for (i = curbit, j = 0; j < code_size; ++i, ++j)
ret |= ((buf[ i / 8 ] & (1 << (i % 8))) != 0) << j;
curbit += code_size;
return ret;
}
static int
LWZReadByte(fd, flag, input_code_size)
FILE *fd;
int flag;
int input_code_size;
{
static int fresh = FALSE;
int code, incode;
static int code_size, set_code_size;
static int max_code, max_code_size;
static int firstcode, oldcode;
static int clear_code, end_code;
static int table[2][(1<< MAX_LWZ_BITS)];
static int stack[(1<<(MAX_LWZ_BITS))*2], *sp;
register int i;
if (flag) {
set_code_size = input_code_size;
code_size = set_code_size+1;
clear_code = 1 << set_code_size ;
end_code = clear_code + 1;
max_code_size = 2*clear_code;
max_code = clear_code+2;
GetCode(fd, 0, TRUE);
fresh = TRUE;
for (i = 0; i < clear_code; ++i) {
table[0][i] = 0;
table[1][i] = i;
}
for (; i < (1<<MAX_LWZ_BITS); ++i)
table[0][i] = table[1][0] = 0;
sp = stack;
return 0;
} else if (fresh) {
fresh = FALSE;
do {
firstcode = oldcode =
GetCode(fd, code_size, FALSE);
} while (firstcode == clear_code);
return firstcode;
}
if (sp > stack)
return *--sp;
while ((code = GetCode(fd, code_size, FALSE)) >= 0) {
if (code == clear_code) {
for (i = 0; i < clear_code; ++i) {
table[0][i] = 0;
table[1][i] = i;
}
for (; i < (1<<MAX_LWZ_BITS); ++i)
table[0][i] = table[1][i] = 0;
code_size = set_code_size+1;
max_code_size = 2*clear_code;
max_code = clear_code+2;
sp = stack;
firstcode = oldcode =
GetCode(fd, code_size, FALSE);
return firstcode;
} else if (code == end_code) {
int count;
unsigned char buf[260];
if (ZeroDataBlock)
return -2;
while ((count = GetDataBlock(fd, buf)) > 0)
;
if (count != 0)
pm_message("missing EOD in data stream (common occurence)");
return -2;
}
incode = code;
if (code >= max_code) {
*sp++ = firstcode;
code = oldcode;
}
while (code >= clear_code) {
*sp++ = table[1][code];
if (code == table[0][code])
pm_error("circular table entry BIG ERROR");
code = table[0][code];
}
*sp++ = firstcode = table[1][code];
if ((code = max_code) <(1<<MAX_LWZ_BITS)) {
table[0][code] = oldcode;
table[1][code] = firstcode;
++max_code;
if ((max_code >= max_code_size) &&
(max_code_size < (1<<MAX_LWZ_BITS))) {
max_code_size *= 2;
++code_size;
}
}
oldcode = incode;
if (sp > stack)
return *--sp;
}
return code;
}
static void
ReadImage(fd, len, height, cmap, pbm_format, interlace, ignore)
FILE *fd;
int len, height;
unsigned char cmap[3][MAXCOLORMAPSIZE];
int pbm_format, interlace, ignore;
{
unsigned char c;
int v;
int xpos = 0, ypos = 0, pass = 0;
pixel **image;
/*
** Initialize the Compression routines
*/
if (! ReadOK(fd,&c,1))
pm_error("EOF / read error on image data" );
if (LWZReadByte(fd, TRUE, c) < 0)
pm_error("error reading image" );
/*
** If this is an "uninteresting picture" ignore it.
*/
if (ignore) {
if (verbose)
pm_message("skipping image..." );
while (LWZReadByte(fd, FALSE, c) >= 0)
;
return;
}
if ((image = pnm_allocarray(len, height)) == NULL)
pm_error("couldn't alloc space for image" );
if (verbose)
pm_message("reading %d by %d%s GIF image",
len, height, interlace ? " interlaced" : "" );
while ((v = LWZReadByte(fd,FALSE,c)) >= 0 ) {
PPM_ASSIGN(image[ypos][xpos], cmap[CM_RED][v],
cmap[CM_GREEN][v], cmap[CM_BLUE][v]);
++xpos;
if (xpos == len) {
xpos = 0;
if (interlace) {
switch (pass) {
case 0:
case 1:
ypos += 8; break;
case 2:
ypos += 4; break;
case 3:
ypos += 2; break;
}
if (ypos >= height) {
++pass;
switch (pass) {
case 1:
ypos = 4; break;
case 2:
ypos = 2; break;
case 3:
ypos = 1; break;
default:
goto fini;
}
}
} else {
++ypos;
}
}
if (ypos >= height)
break;
}
fini:
if (LWZReadByte(fd,FALSE,c)>=0)
pm_message("too much input data, ignoring extra...");
if (verbose)
pm_message("writing a %s file",
pbm_format == PBM_TYPE ? "PBM" :
pbm_format == PGM_TYPE ? "PGM" :
pbm_format == PPM_TYPE ? "PPM" :
"UNKNOWN!");
pnm_writepnm(stdout, image, len, height, (pixval) 255, pbm_format, 0 );
}
These are the contents of the former NiCE NeXT User Group NeXTSTEP/OpenStep software archive, currently hosted by Netfuture.ch.