| 1 |
#ifndef lint |
| 2 |
static const char RCSid[] = "$Id: ra_gif.c,v 2.7 2003/02/22 02:07:27 greg Exp $"; |
| 3 |
#endif |
| 4 |
/* |
| 5 |
* Convert from Radiance picture file to Compuserve GIF. |
| 6 |
* Currently, we don't know how to get back. |
| 7 |
*/ |
| 8 |
|
| 9 |
#include <stdio.h> |
| 10 |
#include <time.h> |
| 11 |
#include <math.h> |
| 12 |
|
| 13 |
#include "platform.h" |
| 14 |
#include "color.h" |
| 15 |
#include "resolu.h" |
| 16 |
|
| 17 |
#define MAXCOLORS 256 |
| 18 |
|
| 19 |
int rmap[MAXCOLORS]; |
| 20 |
int gmap[MAXCOLORS]; |
| 21 |
int bmap[MAXCOLORS]; |
| 22 |
|
| 23 |
int currow; |
| 24 |
|
| 25 |
extern long ftell(); |
| 26 |
|
| 27 |
long picstart; |
| 28 |
|
| 29 |
BYTE clrtab[256][3]; |
| 30 |
|
| 31 |
extern int samplefac; |
| 32 |
|
| 33 |
extern int getgifpix(); |
| 34 |
|
| 35 |
COLR *scanln; |
| 36 |
BYTE *pixscan; |
| 37 |
|
| 38 |
int xmax, ymax; /* picture size */ |
| 39 |
|
| 40 |
double gamv = 2.2; /* gamma correction */ |
| 41 |
|
| 42 |
int greyscale = 0; /* convert to B&W? */ |
| 43 |
|
| 44 |
int dither = 1; /* dither colors? */ |
| 45 |
|
| 46 |
int bradj = 0; /* brightness adjustment */ |
| 47 |
|
| 48 |
int ncolors = 0; /* number of colors requested */ |
| 49 |
|
| 50 |
char *progname; |
| 51 |
|
| 52 |
|
| 53 |
main(argc, argv) |
| 54 |
int argc; |
| 55 |
char *argv[]; |
| 56 |
{ |
| 57 |
int bitsperpix; |
| 58 |
int i; |
| 59 |
SET_DEFAULT_BINARY(); |
| 60 |
SET_FILE_BINARY(stdin); |
| 61 |
SET_FILE_BINARY(stdout); |
| 62 |
progname = argv[0]; |
| 63 |
samplefac = 0; |
| 64 |
|
| 65 |
for (i = 1; i < argc; i++) |
| 66 |
if (argv[i][0] == '-') |
| 67 |
switch (argv[i][1]) { |
| 68 |
case 'g': |
| 69 |
gamv = atof(argv[++i]); |
| 70 |
break; |
| 71 |
case 'b': |
| 72 |
greyscale = 1; |
| 73 |
break; |
| 74 |
case 'd': |
| 75 |
dither = !dither; |
| 76 |
break; |
| 77 |
case 'c': |
| 78 |
ncolors = atoi(argv[++i]); |
| 79 |
break; |
| 80 |
case 'e': |
| 81 |
if (argv[i+1][0] != '+' && argv[i+1][0] != '-') |
| 82 |
goto userr; |
| 83 |
bradj = atoi(argv[++i]); |
| 84 |
break; |
| 85 |
case 'n': |
| 86 |
samplefac = atoi(argv[++i]); |
| 87 |
break; |
| 88 |
default: |
| 89 |
goto userr; |
| 90 |
} |
| 91 |
else |
| 92 |
break; |
| 93 |
|
| 94 |
if (i < argc-2) |
| 95 |
goto userr; |
| 96 |
if (i <= argc-1 && freopen(argv[i], "r", stdin) == NULL) { |
| 97 |
fprintf(stderr, "%s: cannot open input \"%s\"\n", |
| 98 |
progname, argv[i]); |
| 99 |
exit(1); |
| 100 |
} |
| 101 |
if (i == argc-2 && freopen(argv[i+1], "w", stdout) == NULL) { |
| 102 |
fprintf(stderr, "%s: cannot open output \"%s\"\n", |
| 103 |
progname, argv[i+1]); |
| 104 |
exit(1); |
| 105 |
} |
| 106 |
if (checkheader(stdin, COLRFMT, NULL) < 0 || |
| 107 |
fgetresolu(&xmax, &ymax, stdin) < 0) { |
| 108 |
fprintf(stderr, "%s: bad picture format\n", progname); |
| 109 |
exit(1); |
| 110 |
} |
| 111 |
picstart = ftell(stdin); |
| 112 |
currow = -1; |
| 113 |
scanln = (COLR *)malloc(xmax*sizeof(COLR)); |
| 114 |
if (scanln == NULL) { |
| 115 |
fprintf(stderr, "%s: out of memory\n", progname); |
| 116 |
exit(1); |
| 117 |
} |
| 118 |
/* set up gamma correction */ |
| 119 |
setcolrgam(gamv); |
| 120 |
/* figure out the bits per pixel */ |
| 121 |
if (ncolors < 2 | ncolors > MAXCOLORS) |
| 122 |
ncolors = MAXCOLORS; |
| 123 |
for (bitsperpix = 1; ncolors > 1<<bitsperpix; bitsperpix++) |
| 124 |
; |
| 125 |
/* compute color map */ |
| 126 |
if (greyscale) |
| 127 |
mkgrymap(ncolors); |
| 128 |
else |
| 129 |
mkclrmap(ncolors); |
| 130 |
/* convert image */ |
| 131 |
GIFEncode(stdout, xmax, ymax, 0, 0, bitsperpix, |
| 132 |
rmap, gmap, bmap, getgifpix); |
| 133 |
exit(0); |
| 134 |
userr: |
| 135 |
fprintf(stderr, |
| 136 |
"Usage: %s [-b][-d][-n samp][-c ncolors][-g gamv][-e +/-stops] input [output]\n", |
| 137 |
progname); |
| 138 |
exit(1); |
| 139 |
} |
| 140 |
|
| 141 |
|
| 142 |
getrow(y) /* get the specified row from our image */ |
| 143 |
int y; |
| 144 |
{ |
| 145 |
if (y == currow) |
| 146 |
return; |
| 147 |
if (y < currow) { |
| 148 |
fseek(stdin, picstart, 0); |
| 149 |
currow = -1; |
| 150 |
} |
| 151 |
do |
| 152 |
if (freadcolrs(scanln, xmax, stdin) < 0) { |
| 153 |
fprintf(stderr, "%s: error reading picture (y==%d)\n", |
| 154 |
progname, ymax-1-y); |
| 155 |
exit(1); |
| 156 |
} |
| 157 |
while (++currow < y); |
| 158 |
if (bradj) |
| 159 |
shiftcolrs(scanln, xmax, bradj); |
| 160 |
colrs_gambs(scanln, xmax); |
| 161 |
if (pixscan != NULL) |
| 162 |
if (samplefac) |
| 163 |
neu_dith_colrs(pixscan, scanln, xmax); |
| 164 |
else |
| 165 |
dith_colrs(pixscan, scanln, xmax); |
| 166 |
} |
| 167 |
|
| 168 |
|
| 169 |
mkclrmap(nc) /* make our color map */ |
| 170 |
int nc; |
| 171 |
{ |
| 172 |
register int i; |
| 173 |
|
| 174 |
if ((samplefac ? neu_init(xmax*ymax) : new_histo(xmax*ymax)) == -1) |
| 175 |
goto memerr; |
| 176 |
for (i = 0; i < ymax; i++) { |
| 177 |
getrow(i); |
| 178 |
if (samplefac) |
| 179 |
neu_colrs(scanln, xmax); |
| 180 |
else |
| 181 |
cnt_colrs(scanln, xmax); |
| 182 |
} |
| 183 |
if (samplefac) |
| 184 |
neu_clrtab(nc); |
| 185 |
else |
| 186 |
new_clrtab(nc); |
| 187 |
for (i = 0; i < nc; i++) { |
| 188 |
rmap[i] = clrtab[i][RED]; |
| 189 |
gmap[i] = clrtab[i][GRN]; |
| 190 |
bmap[i] = clrtab[i][BLU]; |
| 191 |
} |
| 192 |
if (dither && (pixscan = (BYTE *)malloc(xmax)) == NULL) |
| 193 |
goto memerr; |
| 194 |
return; |
| 195 |
memerr: |
| 196 |
fprintf(stderr, "%s: out of memory\n", progname); |
| 197 |
exit(1); |
| 198 |
} |
| 199 |
|
| 200 |
|
| 201 |
mkgrymap(nc) |
| 202 |
int nc; |
| 203 |
{ |
| 204 |
register int i; |
| 205 |
|
| 206 |
for (i = 0; i < nc; i++) { |
| 207 |
rmap[i] = |
| 208 |
gmap[i] = |
| 209 |
bmap[i] = ((unsigned)i<<8)/nc; |
| 210 |
} |
| 211 |
} |
| 212 |
|
| 213 |
|
| 214 |
int |
| 215 |
getgifpix(x, y) /* get a single pixel from our picture */ |
| 216 |
int x, y; |
| 217 |
{ |
| 218 |
int pix; |
| 219 |
|
| 220 |
getrow(y); |
| 221 |
if (greyscale) |
| 222 |
return((normbright(scanln[x])*ncolors)>>8); |
| 223 |
if (pixscan != NULL) |
| 224 |
return(pixscan[x]); |
| 225 |
return(samplefac ? neu_map_pixel(scanln[x]) : map_pixel(scanln[x])); |
| 226 |
} |
| 227 |
|
| 228 |
|
| 229 |
/* |
| 230 |
* SCARY GIF code follows . . . . sorry. |
| 231 |
* |
| 232 |
* Based on GIFENCOD by David Rowley <[email protected]>.A |
| 233 |
* Lempel-Zim compression based on "compress". |
| 234 |
* |
| 235 |
*/ |
| 236 |
|
| 237 |
/***************************************************************************** |
| 238 |
* |
| 239 |
* GIFENCODE.C - GIF Image compression interface |
| 240 |
* |
| 241 |
* GIFEncode( FName, GHeight, GWidth, GInterlace, Background, |
| 242 |
* BitsPerPixel, Red, Green, Blue, GetPixel ) |
| 243 |
* |
| 244 |
*****************************************************************************/ |
| 245 |
typedef int (* ifunptr)(); |
| 246 |
|
| 247 |
#define TRUE 1 |
| 248 |
#define FALSE 0 |
| 249 |
|
| 250 |
int Width, Height; |
| 251 |
int curx, cury; |
| 252 |
long CountDown; |
| 253 |
int Pass; |
| 254 |
int Interlace; |
| 255 |
unsigned long cur_accum = 0; |
| 256 |
int cur_bits = 0; |
| 257 |
|
| 258 |
/* |
| 259 |
* Bump the 'curx' and 'cury' to point to the next pixel |
| 260 |
*/ |
| 261 |
BumpPixel() |
| 262 |
{ |
| 263 |
curx++; |
| 264 |
if( curx == Width ) { |
| 265 |
curx = 0; |
| 266 |
if( !Interlace ) { |
| 267 |
cury++; |
| 268 |
} else { |
| 269 |
switch( Pass ) { |
| 270 |
case 0: |
| 271 |
cury += 8; |
| 272 |
if( cury >= Height ) { |
| 273 |
Pass++; |
| 274 |
cury = 4; |
| 275 |
} |
| 276 |
break; |
| 277 |
case 1: |
| 278 |
cury += 8; |
| 279 |
if( cury >= Height ) { |
| 280 |
Pass++; |
| 281 |
cury = 2; |
| 282 |
} |
| 283 |
break; |
| 284 |
case 2: |
| 285 |
cury += 4; |
| 286 |
if( cury >= Height ) { |
| 287 |
Pass++; |
| 288 |
cury = 1; |
| 289 |
} |
| 290 |
break; |
| 291 |
case 3: |
| 292 |
cury += 2; |
| 293 |
break; |
| 294 |
} |
| 295 |
} |
| 296 |
} |
| 297 |
} |
| 298 |
|
| 299 |
/* |
| 300 |
* Return the next pixel from the image |
| 301 |
*/ |
| 302 |
GIFNextPixel( getpixel ) |
| 303 |
ifunptr getpixel; |
| 304 |
{ |
| 305 |
int r; |
| 306 |
|
| 307 |
if( CountDown == 0 ) |
| 308 |
return EOF; |
| 309 |
CountDown--; |
| 310 |
r = (*getpixel)( curx, cury ); |
| 311 |
BumpPixel(); |
| 312 |
return r; |
| 313 |
} |
| 314 |
|
| 315 |
/* |
| 316 |
* public GIFEncode |
| 317 |
*/ |
| 318 |
GIFEncode( fp, GWidth, GHeight, GInterlace, Background, |
| 319 |
BitsPerPixel, Red, Green, Blue, GetPixel ) |
| 320 |
FILE *fp; |
| 321 |
int GWidth, GHeight; |
| 322 |
int GInterlace; |
| 323 |
int Background; |
| 324 |
int BitsPerPixel; |
| 325 |
int Red[], Green[], Blue[]; |
| 326 |
ifunptr GetPixel; |
| 327 |
{ |
| 328 |
int B; |
| 329 |
int RWidth, RHeight; |
| 330 |
int LeftOfs, TopOfs; |
| 331 |
int Resolution; |
| 332 |
int ColorMapSize; |
| 333 |
int InitCodeSize; |
| 334 |
int i; |
| 335 |
|
| 336 |
long cur_accum = 0; |
| 337 |
cur_bits = 0; |
| 338 |
|
| 339 |
Interlace = GInterlace; |
| 340 |
ColorMapSize = 1 << BitsPerPixel; |
| 341 |
RWidth = Width = GWidth; |
| 342 |
RHeight = Height = GHeight; |
| 343 |
LeftOfs = TopOfs = 0; |
| 344 |
Resolution = BitsPerPixel; |
| 345 |
|
| 346 |
CountDown = (long)Width * (long)Height; |
| 347 |
Pass = 0; |
| 348 |
if( BitsPerPixel <= 1 ) |
| 349 |
InitCodeSize = 2; |
| 350 |
else |
| 351 |
InitCodeSize = BitsPerPixel; |
| 352 |
curx = cury = 0; |
| 353 |
fwrite( "GIF87a", 1, 6, fp ); |
| 354 |
Putword( RWidth, fp ); |
| 355 |
Putword( RHeight, fp ); |
| 356 |
B = 0x80; /* Yes, there is a color map */ |
| 357 |
B |= (Resolution - 1) << 5; |
| 358 |
B |= (BitsPerPixel - 1); |
| 359 |
fputc( B, fp ); |
| 360 |
fputc( Background, fp ); |
| 361 |
fputc( 0, fp ); |
| 362 |
for( i=0; i<ColorMapSize; i++ ) { |
| 363 |
fputc( Red[i], fp ); |
| 364 |
fputc( Green[i], fp ); |
| 365 |
fputc( Blue[i], fp ); |
| 366 |
} |
| 367 |
fputc( ',', fp ); |
| 368 |
Putword( LeftOfs, fp ); |
| 369 |
Putword( TopOfs, fp ); |
| 370 |
Putword( Width, fp ); |
| 371 |
Putword( Height, fp ); |
| 372 |
if( Interlace ) |
| 373 |
fputc( 0x40, fp ); |
| 374 |
else |
| 375 |
fputc( 0x00, fp ); |
| 376 |
fputc( InitCodeSize, fp ); |
| 377 |
compress( InitCodeSize+1, fp, GetPixel ); |
| 378 |
fputc( 0, fp ); |
| 379 |
fputc( ';', fp ); |
| 380 |
fclose( fp ); |
| 381 |
} |
| 382 |
|
| 383 |
/* |
| 384 |
* Write out a word to the GIF file |
| 385 |
*/ |
| 386 |
Putword( w, fp ) |
| 387 |
int w; |
| 388 |
FILE *fp; |
| 389 |
{ |
| 390 |
fputc( w & 0xff, fp ); |
| 391 |
fputc( (w/256) & 0xff, fp ); |
| 392 |
} |
| 393 |
|
| 394 |
|
| 395 |
/*************************************************************************** |
| 396 |
* |
| 397 |
* GIFCOMPR.C - GIF Image compression routines |
| 398 |
* |
| 399 |
* Lempel-Ziv compression based on 'compress'. GIF modifications by |
| 400 |
* David Rowley ([email protected]) |
| 401 |
* |
| 402 |
***************************************************************************/ |
| 403 |
|
| 404 |
#define CBITS 12 |
| 405 |
#define HSIZE 5003 /* 80% occupancy */ |
| 406 |
|
| 407 |
/* |
| 408 |
* a code_int must be able to hold 2**CBITS values of type int, and also -1 |
| 409 |
*/ |
| 410 |
typedef int code_int; |
| 411 |
typedef long int count_int; |
| 412 |
typedef unsigned char char_type; |
| 413 |
|
| 414 |
/* |
| 415 |
* |
| 416 |
* GIF Image compression - modified 'compress' |
| 417 |
* |
| 418 |
* Based on: compress.c - File compression ala IEEE Computer, June 1984. |
| 419 |
* |
| 420 |
* By Authors: Spencer W. Thomas (decvax!harpo!utah-cs!utah-gr!thomas) |
| 421 |
* Jim McKie (decvax!mcvax!jim) |
| 422 |
* Steve Davies (decvax!vax135!petsd!peora!srd) |
| 423 |
* Ken Turkowski (decvax!decwrl!turtlevax!ken) |
| 424 |
* James A. Woods (decvax!ihnp4!ames!jaw) |
| 425 |
* Joe Orost (decvax!vax135!petsd!joe) |
| 426 |
* |
| 427 |
*/ |
| 428 |
#include <ctype.h> |
| 429 |
|
| 430 |
#define ARGVAL() (*++(*argv) || (--argc && *++argv)) |
| 431 |
|
| 432 |
int n_bits; /* number of bits/code */ |
| 433 |
int maxbits = CBITS; /* user settable max # bits/code */ |
| 434 |
code_int maxcode; /* maximum code, given n_bits */ |
| 435 |
code_int maxmaxcode = (code_int)1 << CBITS; /* should NEVER generate this code */ |
| 436 |
# define MAXCODE(n_bits) (((code_int) 1 << (n_bits)) - 1) |
| 437 |
|
| 438 |
count_int htab [HSIZE]; |
| 439 |
unsigned short codetab [HSIZE]; |
| 440 |
#define HashTabOf(i) htab[i] |
| 441 |
#define CodeTabOf(i) codetab[i] |
| 442 |
|
| 443 |
code_int hsize = HSIZE; /* for dynamic table sizing */ |
| 444 |
|
| 445 |
/* |
| 446 |
* To save much memory, we overlay the table used by compress() with those |
| 447 |
* used by decompress(). The tab_prefix table is the same size and type |
| 448 |
* as the codetab. The tab_suffix table needs 2**CBITS characters. We |
| 449 |
* get this from the beginning of htab. The output stack uses the rest |
| 450 |
* of htab, and contains characters. There is plenty of room for any |
| 451 |
* possible stack (stack used to be 8000 characters). |
| 452 |
*/ |
| 453 |
#define tab_prefixof(i) CodeTabOf(i) |
| 454 |
#define tab_suffixof(i) ((char_type *)(htab))[i] |
| 455 |
#define de_stack ((char_type *)&tab_suffixof((code_int)1<<CBITS)) |
| 456 |
|
| 457 |
code_int free_ent = 0; /* first unused entry */ |
| 458 |
|
| 459 |
/* |
| 460 |
* block compression parameters -- after all codes are used up, |
| 461 |
* and compression rate changes, start over. |
| 462 |
*/ |
| 463 |
int clear_flg = 0; |
| 464 |
int offset; |
| 465 |
long int in_count = 1; /* length of input */ |
| 466 |
long int out_count = 0; /* # of codes output (for debugging) */ |
| 467 |
|
| 468 |
/* |
| 469 |
* compress stdin to stdout |
| 470 |
* |
| 471 |
* Algorithm: use open addressing double hashing (no chaining) on the |
| 472 |
* prefix code / next character combination. We do a variant of Knuth's |
| 473 |
* algorithm D (vol. 3, sec. 6.4) along with G. Knott's relatively-prime |
| 474 |
* secondary probe. Here, the modular division first probe is gives way |
| 475 |
* to a faster exclusive-or manipulation. Also do block compression with |
| 476 |
* an adaptive reset, whereby the code table is cleared when the compression |
| 477 |
* ratio decreases, but after the table fills. The variable-length output |
| 478 |
* codes are re-sized at this point, and a special CLEAR code is generated |
| 479 |
* for the decompressor. Late addition: construct the table according to |
| 480 |
* file size for noticeable speed improvement on small files. Please direct |
| 481 |
* questions about this implementation to ames!jaw. |
| 482 |
*/ |
| 483 |
|
| 484 |
int g_init_bits; |
| 485 |
FILE *g_outfile; |
| 486 |
int ClearCode; |
| 487 |
int EOFCode; |
| 488 |
|
| 489 |
compress( init_bits, outfile, ReadValue ) |
| 490 |
int init_bits; |
| 491 |
FILE *outfile; |
| 492 |
ifunptr ReadValue; |
| 493 |
{ |
| 494 |
register long fcode; |
| 495 |
register code_int i = 0; |
| 496 |
register int c; |
| 497 |
register code_int ent; |
| 498 |
register code_int disp; |
| 499 |
register code_int hsize_reg; |
| 500 |
register int hshift; |
| 501 |
|
| 502 |
/* |
| 503 |
* Set up the globals: g_init_bits - initial number of bits |
| 504 |
* g_outfile - pointer to output file |
| 505 |
*/ |
| 506 |
g_init_bits = init_bits; |
| 507 |
g_outfile = outfile; |
| 508 |
/* |
| 509 |
* Set up the necessary values |
| 510 |
*/ |
| 511 |
offset = 0; |
| 512 |
out_count = 0; |
| 513 |
clear_flg = 0; |
| 514 |
in_count = 1; |
| 515 |
maxcode = MAXCODE(n_bits = g_init_bits); |
| 516 |
ClearCode = (1 << (init_bits - 1)); |
| 517 |
EOFCode = ClearCode + 1; |
| 518 |
free_ent = ClearCode + 2; |
| 519 |
char_init(); |
| 520 |
ent = GIFNextPixel( ReadValue ); |
| 521 |
hshift = 0; |
| 522 |
for ( fcode = (long) hsize; fcode < 65536L; fcode *= 2L ) |
| 523 |
hshift++; |
| 524 |
hshift = 8 - hshift; /* set hash code range bound */ |
| 525 |
hsize_reg = hsize; |
| 526 |
cl_hash( (count_int) hsize_reg); /* clear hash table */ |
| 527 |
output( (code_int)ClearCode ); |
| 528 |
while ( (c = GIFNextPixel( ReadValue )) != EOF ) { |
| 529 |
in_count++; |
| 530 |
fcode = (long) (((long) c << maxbits) + ent); |
| 531 |
/* i = (((code_int)c << hshift) ~ ent); /* xor hashing */ |
| 532 |
i = (((code_int)c << hshift) ^ ent); /* xor hashing */ |
| 533 |
if ( HashTabOf (i) == fcode ) { |
| 534 |
ent = CodeTabOf (i); |
| 535 |
continue; |
| 536 |
} else if ( (long)HashTabOf (i) < 0 ) /* empty slot */ |
| 537 |
goto nomatch; |
| 538 |
disp = hsize_reg - i; /* secondary hash (after G. Knott) */ |
| 539 |
if ( i == 0 ) |
| 540 |
disp = 1; |
| 541 |
probe: |
| 542 |
if ( (i -= disp) < 0 ) |
| 543 |
i += hsize_reg; |
| 544 |
if ( HashTabOf (i) == fcode ) { |
| 545 |
ent = CodeTabOf (i); |
| 546 |
continue; |
| 547 |
} |
| 548 |
if ( (long)HashTabOf (i) > 0 ) |
| 549 |
goto probe; |
| 550 |
nomatch: |
| 551 |
output ( (code_int) ent ); |
| 552 |
out_count++; |
| 553 |
ent = c; |
| 554 |
if ( free_ent < maxmaxcode ) { |
| 555 |
CodeTabOf (i) = free_ent++; /* code -> hashtable */ |
| 556 |
HashTabOf (i) = fcode; |
| 557 |
} else |
| 558 |
cl_block(); |
| 559 |
} |
| 560 |
/* |
| 561 |
* Put out the final code. |
| 562 |
*/ |
| 563 |
output( (code_int)ent ); |
| 564 |
out_count++; |
| 565 |
output( (code_int) EOFCode ); |
| 566 |
return; |
| 567 |
} |
| 568 |
|
| 569 |
/***************************************************************** |
| 570 |
* TAG( output ) |
| 571 |
* |
| 572 |
* Output the given code. |
| 573 |
* Inputs: |
| 574 |
* code: A n_bits-bit integer. If == -1, then EOF. This assumes |
| 575 |
* that n_bits =< (long)wordsize - 1. |
| 576 |
* Outputs: |
| 577 |
* Outputs code to the file. |
| 578 |
* Assumptions: |
| 579 |
* Chars are 8 bits long. |
| 580 |
* Algorithm: |
| 581 |
* Maintain a CBITS character long buffer (so that 8 codes will |
| 582 |
* fit in it exactly). Use the VAX insv instruction to insert each |
| 583 |
* code in turn. When the buffer fills up empty it and start over. |
| 584 |
*/ |
| 585 |
|
| 586 |
unsigned long masks[] = { 0x0000, 0x0001, 0x0003, 0x0007, 0x000F, |
| 587 |
0x001F, 0x003F, 0x007F, 0x00FF, |
| 588 |
0x01FF, 0x03FF, 0x07FF, 0x0FFF, |
| 589 |
0x1FFF, 0x3FFF, 0x7FFF, 0xFFFF }; |
| 590 |
|
| 591 |
output( code ) |
| 592 |
code_int code; |
| 593 |
{ |
| 594 |
cur_accum &= masks[ cur_bits ]; |
| 595 |
if( cur_bits > 0 ) |
| 596 |
cur_accum |= ((long)code << cur_bits); |
| 597 |
else |
| 598 |
cur_accum = code; |
| 599 |
cur_bits += n_bits; |
| 600 |
while( cur_bits >= 8 ) { |
| 601 |
char_out( (unsigned int)(cur_accum & 0xff) ); |
| 602 |
cur_accum >>= 8; |
| 603 |
cur_bits -= 8; |
| 604 |
} |
| 605 |
|
| 606 |
/* |
| 607 |
* If the next entry is going to be too big for the code size, |
| 608 |
* then increase it, if possible. |
| 609 |
*/ |
| 610 |
if ( free_ent > maxcode || clear_flg ) { |
| 611 |
if( clear_flg ) { |
| 612 |
maxcode = MAXCODE (n_bits = g_init_bits); |
| 613 |
clear_flg = 0; |
| 614 |
} else { |
| 615 |
n_bits++; |
| 616 |
if ( n_bits == maxbits ) |
| 617 |
maxcode = maxmaxcode; |
| 618 |
else |
| 619 |
maxcode = MAXCODE(n_bits); |
| 620 |
} |
| 621 |
} |
| 622 |
if( code == EOFCode ) { |
| 623 |
/* |
| 624 |
* At EOF, write the rest of the buffer. |
| 625 |
*/ |
| 626 |
while( cur_bits > 0 ) { |
| 627 |
char_out( (unsigned int)(cur_accum & 0xff) ); |
| 628 |
cur_accum >>= 8; |
| 629 |
cur_bits -= 8; |
| 630 |
} |
| 631 |
flush_char(); |
| 632 |
fflush( g_outfile ); |
| 633 |
if( ferror( g_outfile ) ) |
| 634 |
writeerr(); |
| 635 |
} |
| 636 |
} |
| 637 |
|
| 638 |
/* |
| 639 |
* Clear out the hash table |
| 640 |
*/ |
| 641 |
cl_block () /* table clear for block compress */ |
| 642 |
{ |
| 643 |
cl_hash ( (count_int) hsize ); |
| 644 |
free_ent = ClearCode + 2; |
| 645 |
clear_flg = 1; |
| 646 |
output( (code_int)ClearCode ); |
| 647 |
} |
| 648 |
|
| 649 |
cl_hash(hsize) /* reset code table */ |
| 650 |
register count_int hsize; |
| 651 |
{ |
| 652 |
register count_int *htab_p = htab+hsize; |
| 653 |
register long i; |
| 654 |
register long m1 = -1; |
| 655 |
|
| 656 |
i = hsize - 16; |
| 657 |
do { /* might use Sys V memset(3) here */ |
| 658 |
*(htab_p-16) = m1; |
| 659 |
*(htab_p-15) = m1; |
| 660 |
*(htab_p-14) = m1; |
| 661 |
*(htab_p-13) = m1; |
| 662 |
*(htab_p-12) = m1; |
| 663 |
*(htab_p-11) = m1; |
| 664 |
*(htab_p-10) = m1; |
| 665 |
*(htab_p-9) = m1; |
| 666 |
*(htab_p-8) = m1; |
| 667 |
*(htab_p-7) = m1; |
| 668 |
*(htab_p-6) = m1; |
| 669 |
*(htab_p-5) = m1; |
| 670 |
*(htab_p-4) = m1; |
| 671 |
*(htab_p-3) = m1; |
| 672 |
*(htab_p-2) = m1; |
| 673 |
*(htab_p-1) = m1; |
| 674 |
htab_p -= 16; |
| 675 |
} while ((i -= 16) >= 0); |
| 676 |
for ( i += 16; i > 0; i-- ) |
| 677 |
*--htab_p = m1; |
| 678 |
} |
| 679 |
|
| 680 |
writeerr() |
| 681 |
{ |
| 682 |
printf( "error writing output file\n" ); |
| 683 |
exit(1); |
| 684 |
} |
| 685 |
|
| 686 |
/****************************************************************************** |
| 687 |
* |
| 688 |
* GIF Specific routines |
| 689 |
* |
| 690 |
******************************************************************************/ |
| 691 |
|
| 692 |
/* |
| 693 |
* Number of characters so far in this 'packet' |
| 694 |
*/ |
| 695 |
int a_count; |
| 696 |
|
| 697 |
/* |
| 698 |
* Set up the 'byte output' routine |
| 699 |
*/ |
| 700 |
char_init() |
| 701 |
{ |
| 702 |
a_count = 0; |
| 703 |
} |
| 704 |
|
| 705 |
/* |
| 706 |
* Define the storage for the packet accumulator |
| 707 |
*/ |
| 708 |
char accum[256]; |
| 709 |
|
| 710 |
/* |
| 711 |
* Add a character to the end of the current packet, and if it is 254 |
| 712 |
* characters, flush the packet to disk. |
| 713 |
*/ |
| 714 |
char_out( c ) |
| 715 |
int c; |
| 716 |
{ |
| 717 |
accum[ a_count++ ] = c; |
| 718 |
if( a_count >= 254 ) |
| 719 |
flush_char(); |
| 720 |
} |
| 721 |
|
| 722 |
/* |
| 723 |
* Flush the packet to disk, and reset the accumulator |
| 724 |
*/ |
| 725 |
flush_char() |
| 726 |
{ |
| 727 |
if( a_count > 0 ) { |
| 728 |
fputc( a_count, g_outfile ); |
| 729 |
fwrite( accum, 1, a_count, g_outfile ); |
| 730 |
a_count = 0; |
| 731 |
} |
| 732 |
} |
| 733 |
|
| 734 |
static float curgamma; |
| 735 |
static short gamtab[256]; |
| 736 |
|
| 737 |
gammawarp(sbuf,gam,n) |
| 738 |
short *sbuf; |
| 739 |
float gam; |
| 740 |
int n; |
| 741 |
{ |
| 742 |
int i; |
| 743 |
float f; |
| 744 |
|
| 745 |
if(gam!=curgamma) { |
| 746 |
for(i=0; i<256; i++) |
| 747 |
gamtab[i] = 255*pow(i/255.0,gam)+0.5; |
| 748 |
curgamma = gam; |
| 749 |
} |
| 750 |
while(n--) { |
| 751 |
*sbuf = gamtab[*sbuf]; |
| 752 |
sbuf++; |
| 753 |
} |
| 754 |
} |
