summaryrefslogtreecommitdiffstats
path: root/hl/tools/gif2h5/hdfgifwr.c
blob: 7be68dcebd13a3eca51e23df03583b7319af27e8 (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
/* * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * *
 * Copyright by The HDF Group.                                               *
 * Copyright by the Board of Trustees of the University of Illinois.         *
 * All rights reserved.                                                      *
 *                                                                           *
 * This file is part of HDF5.  The full HDF5 copyright notice, including     *
 * terms governing use, modification, and redistribution, is contained in    *
 * the COPYING file, which can be found at the root of the source code       *
 * distribution tree, or in https://support.hdfgroup.org/ftp/HDF5/releases.  *
 * If you do not have access to either file, you may request a copy from     *
 * help@hdfgroup.org.                                                        *
 * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * * */

/*
 * hdfgifwr.c  - handles writing of GIF files.
 *
 * Contains:
 *   hdfWriteGIF(fp, pic, ptype, w, h, rmap, gmap, bmap, numcols, colorstyle,
 *               comment)
 *
 * Note: slightly brain-damaged, in that it'll only write non-interlaced
 *       GIF files (in the interests of speed, or something)
 */

/*****************************************************************
 * Portions of this code Copyright (C) 1989 by Michael Mauldin.
 * Permission is granted to use this file in whole or in
 * part for any purpose, educational, recreational or commercial,
 * provided that this copyright notice is retained unchanged.
 * This software is available to all free of charge by anonymous
 * FTP and in the UUNET archives.
 *
 *
 * Authors:  Michael Mauldin (mlm@cs.cmu.edu)
 *           David Rowley (mgardi@watdcsu.waterloo.edu)
 *
 * Based on: compress.c - File compression ala IEEE Computer, June 1984.
 *
 * Spencer W. Thomas       (decvax!harpo!utah-cs!utah-gr!thomas)
 * Jim McKie               (decvax!mcvax!jim)
 * Steve Davies            (decvax!vax135!petsd!peora!srd)
 * Ken Turkowski           (decvax!decwrl!turtlevax!ken)
 * James A. Woods          (decvax!ihnp4!ames!jaw)
 * Joe Orost               (decvax!vax135!petsd!joe)
 *****************************************************************/

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

#include "gif.h"

typedef GIFBYTE  byte;
typedef long int count_int;

#ifdef __STDC__
static void compress(int, FILE *, byte *, int);
static void output(int);
static void cl_block(void);
static void cl_hash(count_int);
static void char_init(void);
static void char_out(int);
static void flush_char(void);
#else
static void compress(), output(), cl_block(), cl_hash();
static void char_init(), char_out(), flush_char();
#endif /* __STDC__ */

static byte pc2nc[256];

/***********************************************************************/
static unsigned long cur_accum = 0;
static int           cur_bits  = 0;

#define MAXCODE(n_bits) ((1 << (n_bits)) - 1)
#define XV_BITS         12   /* BITS was already defined on some systems */
#define HSIZE           5003 /* 80% occupancy */

typedef unsigned char char_type;

static int n_bits;                    /* number of bits/code */
static int maxbits = XV_BITS;         /* user settable max # bits/code */
static int maxcode;                   /* maximum code, given n_bits */
static int maxmaxcode = 1 << XV_BITS; /* NEVER generate this */

static count_int *     htab;
static unsigned short *codetab;

#define HashTabOf(i) htab[i]
#define CodeTabOf(i) codetab[i]

static int hsize = HSIZE; /* for dynamic table sizing */

/*
 * To save much memory, we overlay the table used by compress() with those
 * used by decompress().  The tab_prefix table is the same size and type as
 * the codetab.  The tab_suffix table needs 2**BITS characters.  We get this
 * from the beginning of htab.  The output stack uses the rest of htab, and
 * contains characters.  There is plenty of room for any possible stack (stack
 * used to be 8000 characters).
 */

static int free_ent = 0; /* first unused entry */

/*
 * block compression parameters -- after all codes are used up,
 * and compression rate changes, start over.
 */
static int clear_flg = 0;

static long int in_count  = 1; /* length of input */
static long int out_count = 0; /* # of codes output (for debugging) */

/*
 * compress stdin to stdout
 *
 * Algorithm:  use open addressing double hashing (no chaining) on the prefix
 * code / next character combination.  We do a variant of Knuth's algorithm D
 * (vol. 3, sec. 6.4) along with G. Knott's relatively-prime secondary probe.
 * Here, the modular division first probe is gives way to a faster
 * exclusive-or manipulation.  Also do block compression with an adaptive
 * reset, whereby the code table is cleared when the compression ratio
 * decreases, but after the table fills.  The variable-length output codes are
 * re-sized at this point, and a special CLEAR code is generated for the
 * decompressor.  Late addition:  construct the table according to file size
 * for noticeable speed improvement on small files.  Please direct questions
 * about this implementation to ames!jaw.
 */

static int   g_init_bits;
static FILE *g_outfile;

static int ClearCode;
static int EOFCode;

/*************************************************************/
int
hdfWriteGIF(FILE *fp, byte *pic, int ptype, int w, int h, byte *rmap, byte *gmap, byte *bmap, byte *pc2ncmap,
            int numcols, int colorstyle, int BitsPerPixel)
{
    int   InitCodeSize;
    int   i;
    byte *pic8 = pic;

    if (!(htab = calloc(HSIZE, sizeof(count_int)))) {
        fprintf(stderr, "Out of memory");
        return 1;
    }
    if (!(codetab = calloc(HSIZE, sizeof(unsigned short)))) {
        fprintf(stderr, "Out of memory");
        return 1;
    }

    /* Shut compiler up... */
    ptype      = ptype;
    rmap       = rmap;
    gmap       = gmap;
    bmap       = bmap;
    numcols    = numcols;
    colorstyle = colorstyle;

    for (i = 0; i < 256; i++) {
        pc2nc[i] = pc2ncmap[i];
    }

    if (BitsPerPixel <= 1)
        InitCodeSize = 2;
    else
        InitCodeSize = BitsPerPixel;

    if (!fp) {
        fprintf(stderr, "WriteGIF: file not open for writing\n");
        return 1;
    }

    compress(InitCodeSize + 1, fp, pic8, w * h);

    free(htab);
    free(codetab);

    if (ferror(fp))
        return -1;

    return 0;
}

/********************************************************/
static void
compress(int init_bits, FILE *outfile, byte *data, int len)
{
    register long fcode;
    register int  i = 0;
    register int  c;
    register int  ent;
    register int  disp;
    register int  hsize_reg;
    register int  hshift;

    /*
     * Set up the globals:  g_init_bits - initial number of bits g_outfile -
     * pointer to output file
     */
    g_init_bits = init_bits;
    g_outfile   = outfile;

    /* initialize 'compress' globals */
    maxbits    = XV_BITS;
    maxmaxcode = 1 << XV_BITS;
    hsize      = HSIZE;
    free_ent   = 0;
    clear_flg  = 0;
    in_count   = 1;
    out_count  = 0;
    cur_accum  = 0;
    cur_bits   = 0;

    /* Set up the necessary values */
    out_count = 0;
    clear_flg = 0;
    in_count  = 1;
    maxcode   = MAXCODE(n_bits = g_init_bits);

    ClearCode = (1 << (init_bits - 1));
    EOFCode   = ClearCode + 1;
    free_ent  = ClearCode + 2;

    char_init();
    ent = pc2nc[*data++];
    len--;

    hshift = 0;
    for (fcode = (long)hsize; fcode < 65536L; fcode *= 2L)
        hshift++;

    hshift = 8 - hshift; /* set hash code range bound */

    hsize_reg = hsize;
    cl_hash((count_int)hsize_reg); /* clear hash table */

    output(ClearCode);

    while (len) {
        c = pc2nc[*data++];
        len--;
        in_count++;

        fcode = (long)(((long)c << maxbits) + ent);
        i     = (((int)c << hshift) ^ ent); /* xor hashing */

        if (HashTabOf(i) == fcode) {
            ent = CodeTabOf(i);
            continue;
        }
        else if ((long)HashTabOf(i) < 0) {
            /* empty slot */
            goto nomatch;
        }

        disp = hsize_reg - i; /* secondary hash (after G. Knott) */

        if (i == 0)
            disp = 1;

probe:
        if ((i -= disp) < 0)
            i += hsize_reg;

        if (HashTabOf(i) == fcode) {
            ent = CodeTabOf(i);
            continue;
        }

        if ((long)HashTabOf(i) >= 0)
            goto probe;

nomatch:
        output(ent);
        out_count++;
        ent = c;

        if (free_ent < maxmaxcode) {
            CodeTabOf(i) = (unsigned short)free_ent++; /* code -> hashtable */
            HashTabOf(i) = fcode;
        }
        else {
            cl_block();
        }
    }

    /* Put out the final code */
    output(ent);
    out_count++;
    output(EOFCode);
}

/*****************************************************************
 * TAG( output )
 *
 * Output the given code.
 * Inputs:
 *      code:   A n_bits-bit integer.  If == -1, then EOF.  This assumes
 *              that n_bits =< (long)wordsize - 1.
 * Outputs:
 *      Outputs code to the file.
 * Assumptions:
 *      Chars are 8 bits long.
 * Algorithm:
 *      Maintain a BITS character long buffer (so that 8 codes will
 * fit in it exactly).  Use the VAX insv instruction to insert each
 * code in turn.  When the buffer fills up empty it and start over.
 */

static unsigned long masks[] = {0x0000, 0x0001, 0x0003, 0x0007, 0x000F, 0x001F, 0x003F, 0x007F, 0x00FF,
                                0x01FF, 0x03FF, 0x07FF, 0x0FFF, 0x1FFF, 0x3FFF, 0x7FFF, 0xFFFF};

static void
output(int code)
{
    cur_accum &= masks[cur_bits];

    if (cur_bits > 0)
        cur_accum |= (unsigned long)((long)code << cur_bits);
    else
        cur_accum = (unsigned long)code;

    cur_bits += n_bits;

    while (cur_bits >= 8) {
        char_out((int)((unsigned int)cur_accum & 0xff));
        cur_accum >>= 8;
        cur_bits -= 8;
    }

    /*
     * If the next entry is going to be too big for the code size, then
     * increase it, if possible.
     */
    if (free_ent > maxcode || clear_flg) {
        if (clear_flg) {
            maxcode   = MAXCODE(n_bits = g_init_bits);
            clear_flg = 0;
        }
        else {
            n_bits++;

            if (n_bits == maxbits)
                maxcode = maxmaxcode;
            else
                maxcode = MAXCODE(n_bits);
        }
    }

    if (code == EOFCode) {
        /* At EOF, write the rest of the buffer */
        while (cur_bits > 0) {
            char_out((int)((unsigned int)cur_accum & 0xff));
            cur_accum >>= 8;
            cur_bits -= 8;
        }

        flush_char();
        fflush(g_outfile);

#ifdef FOO
        if (ferror(g_outfile))
            FatalError("unable to write GIF file");
#endif
    }
}

/********************************/
static void
cl_block(void) /* table clear for block compress */
{
    /* Clear out the hash table */
    cl_hash((count_int)hsize);
    free_ent  = ClearCode + 2;
    clear_flg = 1;
    output(ClearCode);
}

/********************************/
static void
cl_hash(count_int hashsize) /* reset code table */
{
    count_int *htab_p = htab + hashsize;
    long       i, m1 = -1;

    i = hashsize - 16;

    do { /* might use Sys V memset(3) here */
        *(htab_p - 16) = m1;
        *(htab_p - 15) = m1;
        *(htab_p - 14) = m1;
        *(htab_p - 13) = m1;
        *(htab_p - 12) = m1;
        *(htab_p - 11) = m1;
        *(htab_p - 10) = m1;
        *(htab_p - 9)  = m1;
        *(htab_p - 8)  = m1;
        *(htab_p - 7)  = m1;
        *(htab_p - 6)  = m1;
        *(htab_p - 5)  = m1;
        *(htab_p - 4)  = m1;
        *(htab_p - 3)  = m1;
        *(htab_p - 2)  = m1;
        *(htab_p - 1)  = m1;
        htab_p -= 16;
    } while ((i -= 16) >= 0);

    for (i += 16; i > 0; i--)
        *--htab_p = m1;
}

/******************************************************************************
 *
 * GIF Specific routines
 *
 ******************************************************************************/

/*
 * Number of characters so far in this 'packet'
 */
static int a_count;

/*
 * Set up the 'byte output' routine
 */
static void
char_init(void)
{
    a_count = 0;
}

/*
 * Define the storage for the packet accumulator
 */
static char accum[256];

/*
 * Add a character to the end of the current packet, and if it is 254
 * characters, flush the packet to disk.
 */
static void
char_out(int c)
{
    accum[a_count++] = (char)c;

    if (a_count >= 254)
        flush_char();
}

/*
 * Flush the packet to disk, and reset the accumulator
 */
static void
flush_char(void)
{
    if (a_count > 0) {
        fputc(a_count, g_outfile);
        fwrite(accum, (size_t)1, (size_t)a_count, g_outfile);
        a_count = 0;
    }
}