1 /* PSPP - a program for statistical analysis.
2 Copyright (C) 1997-9, 2000, 2006, 2009, 2010, 2011, 2012, 2013 Free Software Foundation, Inc.
3
4 This program is free software: you can redistribute it and/or modify
5 it under the terms of the GNU General Public License as published by
6 the Free Software Foundation, either version 3 of the License, or
7 (at your option) any later version.
8
9 This program is distributed in the hope that it will be useful,
10 but WITHOUT ANY WARRANTY; without even the implied warranty of
11 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
12 GNU General Public License for more details.
13
14 You should have received a copy of the GNU General Public License
15 along with this program. If not, see <http://www.gnu.org/licenses/>. */
16
17 #include <config.h>
18
19 #include "data/por-file-writer.h"
20
21 #include <ctype.h>
22 #include <errno.h>
23 #include <float.h>
24 #include <math.h>
25 #include <stdio.h>
26 #include <stdlib.h>
27 #include <sys/stat.h>
28 #include <time.h>
29
30 #include "data/case.h"
31 #include "data/casewriter-provider.h"
32 #include "data/casewriter.h"
33 #include "data/dictionary.h"
34 #include "data/file-handle-def.h"
35 #include "data/format.h"
36 #include "data/make-file.h"
37 #include "data/missing-values.h"
38 #include "data/short-names.h"
39 #include "data/value-labels.h"
40 #include "data/variable.h"
41 #include "libpspp/message.h"
42 #include "libpspp/misc.h"
43 #include "libpspp/str.h"
44 #include "libpspp/version.h"
45
46 #include "gl/minmax.h"
47 #include "gl/xalloc.h"
48
49 #include "gettext.h"
50 #define _(msgid) gettext (msgid)
51 #define N_(msgid) (msgid)
52
53 /* Maximum width of a variable in a portable file. */
54 #define MAX_POR_WIDTH 255
55
56 /* Portable file writer. */
57 struct pfm_writer
58 {
59 struct file_handle *fh; /* File handle. */
60 struct fh_lock *lock; /* Lock on file handle. */
61 FILE *file; /* File stream. */
62 struct replace_file *rf; /* Ticket for replacing output file. */
63
64 int lc; /* Number of characters on this line so far. */
65
66 size_t var_cnt; /* Number of variables. */
67 struct pfm_var *vars; /* Variables. */
68
69 int digits; /* Digits of precision. */
70 };
71
72 /* A variable to write to the portable file. */
73 struct pfm_var
74 {
75 int width; /* 0=numeric, otherwise string var width. */
76 int case_index; /* Index in case. */
77 };
78
79 static const struct casewriter_class por_file_casewriter_class;
80
81 static bool close_writer (struct pfm_writer *);
82 static void buf_write (struct pfm_writer *, const void *, size_t);
83 static void write_header (struct pfm_writer *);
84 static void write_version_data (struct pfm_writer *);
85 static void write_variables (struct pfm_writer *, struct dictionary *);
86 static void write_value_labels (struct pfm_writer *,
87 const struct dictionary *);
88 static void write_documents (struct pfm_writer *,
89 const struct dictionary *);
90
91 static void format_trig_double (long double, int base_10_precision, char[]);
92 static char *format_trig_int (int, bool force_sign, char[]);
93
94 /* Returns default options for writing a portable file. */
95 struct pfm_write_options
pfm_writer_default_options(void)96 pfm_writer_default_options (void)
97 {
98 struct pfm_write_options opts;
99 opts.create_writeable = true;
100 opts.type = PFM_COMM;
101 opts.digits = DBL_DIG;
102 return opts;
103 }
104
105 /* Writes the dictionary DICT to portable file HANDLE according
106 to the given OPTS. Returns nonzero only if successful. DICT
107 will not be modified, except to assign short names. */
108 struct casewriter *
pfm_open_writer(struct file_handle * fh,struct dictionary * dict,struct pfm_write_options opts)109 pfm_open_writer (struct file_handle *fh, struct dictionary *dict,
110 struct pfm_write_options opts)
111 {
112 struct pfm_writer *w = NULL;
113 mode_t mode;
114 size_t i;
115
116 /* Initialize data structures. */
117 w = xmalloc (sizeof *w);
118 w->fh = fh_ref (fh);
119 w->lock = NULL;
120 w->file = NULL;
121 w->rf = NULL;
122 w->lc = 0;
123 w->var_cnt = 0;
124 w->vars = NULL;
125
126 w->var_cnt = dict_get_var_cnt (dict);
127 w->vars = xnmalloc (w->var_cnt, sizeof *w->vars);
128 for (i = 0; i < w->var_cnt; i++)
129 {
130 const struct variable *dv = dict_get_var (dict, i);
131 struct pfm_var *pv = &w->vars[i];
132 pv->width = MIN (var_get_width (dv), MAX_POR_WIDTH);
133 pv->case_index = var_get_case_index (dv);
134 }
135
136 w->digits = opts.digits;
137 if (w->digits < 1)
138 {
139 msg (ME, _("Invalid decimal digits count %d. Treating as %d."),
140 w->digits, DBL_DIG);
141 w->digits = DBL_DIG;
142 }
143
144 /* Lock file. */
145 /* TRANSLATORS: this fragment will be interpolated into
146 messages in fh_lock() that identify types of files. */
147 w->lock = fh_lock (fh, FH_REF_FILE, N_("portable file"), FH_ACC_WRITE, true);
148 if (w->lock == NULL)
149 goto error;
150
151 /* Create file. */
152 mode = 0444;
153 if (opts.create_writeable)
154 mode |= 0222;
155 w->rf = replace_file_start (fh, "w", mode,
156 &w->file);
157 if (w->rf == NULL)
158 {
159 msg (ME, _("Error opening `%s' for writing as a portable file: %s."),
160 fh_get_file_name (fh), strerror (errno));
161 goto error;
162 }
163
164 /* Write file header. */
165 write_header (w);
166 write_version_data (w);
167 write_variables (w, dict);
168 write_value_labels (w, dict);
169 if (dict_get_document_line_cnt (dict) > 0)
170 write_documents (w, dict);
171 buf_write (w, "F", 1);
172 if (ferror (w->file))
173 goto error;
174 return casewriter_create (dict_get_proto (dict),
175 &por_file_casewriter_class, w);
176
177 error:
178 close_writer (w);
179 return NULL;
180 }
181
182 /* Write NBYTES starting at BUF to the portable file represented by
183 H. Break lines properly every 80 characters. */
184 static void
buf_write(struct pfm_writer * w,const void * buf_,size_t nbytes)185 buf_write (struct pfm_writer *w, const void *buf_, size_t nbytes)
186 {
187 const char *buf = buf_;
188
189 if (ferror (w->file))
190 return;
191
192 assert (buf != NULL);
193 while (nbytes + w->lc >= 80)
194 {
195 size_t n = 80 - w->lc;
196
197 if (n)
198 fwrite (buf, n, 1, w->file);
199 fwrite ("\r\n", 2, 1, w->file);
200
201 nbytes -= n;
202 buf += n;
203 w->lc = 0;
204 }
205 fwrite (buf, nbytes, 1, w->file);
206
207 w->lc += nbytes;
208 }
209
210 /* Write D to the portable file as a floating-point field. */
211 static void
write_float(struct pfm_writer * w,double d)212 write_float (struct pfm_writer *w, double d)
213 {
214 char buffer[64];
215 format_trig_double (d, floor (d) == d ? DBL_DIG : w->digits, buffer);
216 buf_write (w, buffer, strlen (buffer));
217 if (d != SYSMIS)
218 buf_write (w, "/", 1);
219 }
220
221 /* Write N to the portable file as an integer field. */
222 static void
write_int(struct pfm_writer * w,int n)223 write_int (struct pfm_writer *w, int n)
224 {
225 char buffer[64];
226 format_trig_int (n, false, buffer);
227 buf_write (w, buffer, strlen (buffer));
228 buf_write (w, "/", 1);
229 }
230
231 /* Write S to the portable file as a string field. */
232 static void
write_string(struct pfm_writer * w,const char * s)233 write_string (struct pfm_writer *w, const char *s)
234 {
235 size_t n = strlen (s);
236 write_int (w, (int) n);
237 buf_write (w, s, n);
238 }
239
240 /* Write file header. */
241 static void
write_header(struct pfm_writer * w)242 write_header (struct pfm_writer *w)
243 {
244 static const char spss2ascii[256] =
245 {
246 "0000000000000000000000000000000000000000000000000000000000000000"
247 "0123456789ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz ."
248 "<(+|&[]!$*);^-/|,%_>?`:$@'=\"000000~-0000123456789000-()0{}\\00000"
249 "0000000000000000000000000000000000000000000000000000000000000000"
250 };
251 int i;
252
253 for (i = 0; i < 5; i++)
254 buf_write (w, "ASCII SPSS PORT FILE ", 40);
255
256 buf_write (w, spss2ascii, 256);
257 buf_write (w, "SPSSPORT", 8);
258 }
259
260 /* Writes version, date, and identification records. */
261 static void
write_version_data(struct pfm_writer * w)262 write_version_data (struct pfm_writer *w)
263 {
264 time_t t;
265 struct tm tm;
266 struct tm *tmp;
267
268 if ((time_t) -1 == time (&t))
269 {
270 tm.tm_sec = tm.tm_min = tm.tm_hour = tm.tm_mon = tm.tm_year = 0;
271 tm.tm_mday = 1;
272 tmp = &tm;
273 }
274 else
275 tmp = localtime (&t);
276
277 char *date_str = xasprintf ("%04d%02d%02d", tmp->tm_year + 1900,
278 tmp->tm_mon + 1, tmp->tm_mday);
279 char *time_str = xasprintf ("%02d%02d%02d",
280 tmp->tm_hour, tmp->tm_min, tmp->tm_sec);
281 buf_write (w, "A", 1);
282 write_string (w, date_str);
283 write_string (w, time_str);
284 free (date_str);
285 free (time_str);
286
287 /* Product identification. */
288 buf_write (w, "1", 1);
289 write_string (w, version);
290
291 /* Subproduct identification. */
292 buf_write (w, "3", 1);
293 write_string (w, host_system);
294 }
295
296 /* Write format F to file H. The format is first resized to fit
297 a value of the given WIDTH, which is handy in case F
298 represents a string longer than 255 bytes and thus WIDTH is
299 truncated to 255 bytes. */
300 static void
write_format(struct pfm_writer * w,struct fmt_spec f,int width)301 write_format (struct pfm_writer *w, struct fmt_spec f, int width)
302 {
303 fmt_resize (&f, width);
304 write_int (w, fmt_to_io (f.type));
305 write_int (w, f.w);
306 write_int (w, f.d);
307 }
308
309 /* Write value V with width WIDTH to file H. */
310 static void
write_value(struct pfm_writer * w,const union value * v,int width)311 write_value (struct pfm_writer *w, const union value *v, int width)
312 {
313 if (width == 0)
314 write_float (w, v->f);
315 else
316 {
317 width = MIN (width, MAX_POR_WIDTH);
318 write_int (w, width);
319 buf_write (w, v->s, width);
320 }
321 }
322
323 /* Write variable records. */
324 static void
write_variables(struct pfm_writer * w,struct dictionary * dict)325 write_variables (struct pfm_writer *w, struct dictionary *dict)
326 {
327 int i;
328
329 short_names_assign (dict);
330
331 if (dict_get_weight (dict) != NULL)
332 {
333 buf_write (w, "6", 1);
334 write_string (w, var_get_short_name (dict_get_weight (dict), 0));
335 }
336
337 buf_write (w, "4", 1);
338 write_int (w, dict_get_var_cnt (dict));
339
340 buf_write (w, "5", 1);
341 write_int (w, ceil (w->digits * (log (10) / log (30))));
342
343 for (i = 0; i < dict_get_var_cnt (dict); i++)
344 {
345 struct variable *v = dict_get_var (dict, i);
346 struct missing_values mv;
347 int width = MIN (var_get_width (v), MAX_POR_WIDTH);
348 int j;
349
350 buf_write (w, "7", 1);
351 write_int (w, width);
352 write_string (w, var_get_short_name (v, 0));
353 write_format (w, *var_get_print_format (v), width);
354 write_format (w, *var_get_write_format (v), width);
355
356 /* Write missing values. */
357 mv_copy (&mv, var_get_missing_values (v));
358 if (var_get_width (v) > 8)
359 mv_resize (&mv, 8);
360 if (mv_has_range (&mv))
361 {
362 double x, y;
363 mv_get_range (&mv, &x, &y);
364 if (x == LOWEST)
365 {
366 buf_write (w, "9", 1);
367 write_float (w, y);
368 }
369 else if (y == HIGHEST)
370 {
371 buf_write (w, "A", 1);
372 write_float (w, y);
373 }
374 else
375 {
376 buf_write (w, "B", 1);
377 write_float (w, x);
378 write_float (w, y);
379 }
380 }
381 for (j = 0; j < mv_n_values (&mv); j++)
382 {
383 buf_write (w, "8", 1);
384 write_value (w, mv_get_value (&mv, j), mv_get_width (&mv));
385 }
386 mv_destroy (&mv);
387
388 /* Write variable label. */
389 if (var_get_label (v) != NULL)
390 {
391 buf_write (w, "C", 1);
392 write_string (w, var_get_label (v));
393 }
394 }
395 }
396
397 /* Write value labels to disk. FIXME: Inefficient. */
398 static void
write_value_labels(struct pfm_writer * w,const struct dictionary * dict)399 write_value_labels (struct pfm_writer *w, const struct dictionary *dict)
400 {
401 int i;
402
403 for (i = 0; i < dict_get_var_cnt (dict); i++)
404 {
405 struct variable *v = dict_get_var (dict, i);
406 const struct val_labs *val_labs = var_get_value_labels (v);
407 size_t n_labels = val_labs_count (val_labs);
408 const struct val_lab **labels;
409 int j;
410
411 if (n_labels == 0)
412 continue;
413
414 buf_write (w, "D", 1);
415 write_int (w, 1);
416 write_string (w, var_get_short_name (v, 0));
417 write_int (w, val_labs_count (val_labs));
418
419 n_labels = val_labs_count (val_labs);
420 labels = val_labs_sorted (val_labs);
421 for (j = 0; j < n_labels; j++)
422 {
423 const struct val_lab *vl = labels[j];
424 write_value (w, val_lab_get_value (vl), var_get_width (v));
425 write_string (w, val_lab_get_escaped_label (vl));
426 }
427 free (labels);
428 }
429 }
430
431 /* Write documents in DICT to portable file W. */
432 static void
write_documents(struct pfm_writer * w,const struct dictionary * dict)433 write_documents (struct pfm_writer *w, const struct dictionary *dict)
434 {
435 size_t line_cnt = dict_get_document_line_cnt (dict);
436 struct string line = DS_EMPTY_INITIALIZER;
437 int i;
438
439 buf_write (w, "E", 1);
440 write_int (w, line_cnt);
441 for (i = 0; i < line_cnt; i++)
442 write_string (w, dict_get_document_line (dict, i));
443 ds_destroy (&line);
444 }
445
446 /* Writes case C to the portable file represented by WRITER. */
447 static void
por_file_casewriter_write(struct casewriter * writer,void * w_,struct ccase * c)448 por_file_casewriter_write (struct casewriter *writer, void *w_,
449 struct ccase *c)
450 {
451 struct pfm_writer *w = w_;
452 int i;
453
454 if (!ferror (w->file))
455 {
456 for (i = 0; i < w->var_cnt; i++)
457 {
458 struct pfm_var *v = &w->vars[i];
459
460 if (v->width == 0)
461 write_float (w, case_num_idx (c, v->case_index));
462 else
463 {
464 write_int (w, v->width);
465 buf_write (w, case_str_idx (c, v->case_index), v->width);
466 }
467 }
468 }
469 else
470 casewriter_force_error (writer);
471
472 case_unref (c);
473 }
474
475 static void
por_file_casewriter_destroy(struct casewriter * writer,void * w_)476 por_file_casewriter_destroy (struct casewriter *writer, void *w_)
477 {
478 struct pfm_writer *w = w_;
479 if (!close_writer (w))
480 casewriter_force_error (writer);
481 }
482
483 /* Closes a portable file after we're done with it.
484 Returns true if successful, false if an I/O error occurred. */
485 static bool
close_writer(struct pfm_writer * w)486 close_writer (struct pfm_writer *w)
487 {
488 bool ok;
489
490 if (w == NULL)
491 return true;
492
493 ok = true;
494 if (w->file != NULL)
495 {
496 char buf[80];
497 memset (buf, 'Z', sizeof buf);
498 buf_write (w, buf, w->lc >= 80 ? 80 : 80 - w->lc);
499
500 ok = !ferror (w->file);
501 if (fclose (w->file) == EOF)
502 ok = false;
503
504 if (!ok)
505 msg (ME, _("An I/O error occurred writing portable file `%s'."),
506 fh_get_file_name (w->fh));
507
508 if (ok ? !replace_file_commit (w->rf) : !replace_file_abort (w->rf))
509 ok = false;
510 }
511
512 fh_unlock (w->lock);
513 fh_unref (w->fh);
514
515 free (w->vars);
516 free (w);
517
518 return ok;
519 }
520
521 /* Base-30 conversion.
522
523 Portable files represent numbers in base-30 format, so we need
524 to be able to convert real and integer number to that base.
525 Older versions of PSPP used libgmp to do so, but this added a
526 big library dependency to do just one thing. Now we do it
527 ourselves internally.
528
529 Important fact: base 30 is called "trigesimal". */
530
531 /* Conversion base. */
532 #define BASE 30 /* As an integer. */
533 #define LDBASE ((long double) BASE) /* As a long double. */
534
535 /* This is floor(log30(2**31)), the minimum number of trigesimal
536 digits that a `long int' can hold. */
537 #define CHUNK_SIZE 6
538
539 /* pow_tab[i] = pow (30, pow (2, i)) */
540 static long double pow_tab[16];
541
542 /* Initializes pow_tab[]. */
543 static void
init_pow_tab(void)544 init_pow_tab (void)
545 {
546 static bool did_init = false;
547 long double power;
548 size_t i;
549
550 /* Only initialize once. */
551 if (did_init)
552 return;
553 did_init = true;
554
555 /* Set each element of pow_tab[] until we run out of numerical
556 range. */
557 i = 0;
558 for (power = 30.0L; power < DBL_MAX; power *= power)
559 {
560 assert (i < sizeof pow_tab / sizeof *pow_tab);
561 pow_tab[i++] = power;
562 }
563 }
564
565 /* Returns 30**EXPONENT, for 0 <= EXPONENT <= log30(DBL_MAX). */
566 static long double
pow30_nonnegative(int exponent)567 pow30_nonnegative (int exponent)
568 {
569 long double power;
570 int i;
571
572 assert (exponent >= 0);
573 assert (exponent < 1L << (sizeof pow_tab / sizeof *pow_tab));
574
575 power = 1.L;
576 for (i = 0; exponent > 0; exponent >>= 1, i++)
577 if (exponent & 1)
578 power *= pow_tab[i];
579
580 return power;
581 }
582
583 /* Returns 30**EXPONENT, for log30(DBL_MIN) <= EXPONENT <=
584 log30(DBL_MAX). */
585 static long double
pow30(int exponent)586 pow30 (int exponent)
587 {
588 if (exponent >= 0)
589 return pow30_nonnegative (exponent);
590 else
591 return 1.L / pow30_nonnegative (-exponent);
592 }
593
594 /* Returns the character corresponding to TRIG. */
595 static int
trig_to_char(int trig)596 trig_to_char (int trig)
597 {
598 assert (trig >= 0 && trig < 30);
599 return "0123456789ABCDEFGHIJKLMNOPQRST"[trig];
600 }
601
602 /* Formats the TRIG_CNT trigs in TRIGS[], writing them as
603 null-terminated STRING. The trigesimal point is inserted
604 after TRIG_PLACES characters have been printed, if necessary
605 adding extra zeros at either end for correctness. Returns the
606 character after the formatted number. */
607 static char *
format_trig_digits(char * string,const char trigs[],int trig_cnt,int trig_places)608 format_trig_digits (char *string,
609 const char trigs[], int trig_cnt, int trig_places)
610 {
611 if (trig_places < 0)
612 {
613 *string++ = '.';
614 while (trig_places++ < 0)
615 *string++ = '0';
616 trig_places = -1;
617 }
618 while (trig_cnt-- > 0)
619 {
620 if (trig_places-- == 0)
621 *string++ = '.';
622 *string++ = trig_to_char (*trigs++);
623 }
624 while (trig_places-- > 0)
625 *string++ = '0';
626 *string = '\0';
627 return string;
628 }
629
630 /* Helper function for format_trig_int() that formats VALUE as a
631 trigesimal integer at CP. VALUE must be nonnegative.
632 Returns the character following the formatted integer. */
633 static char *
recurse_format_trig_int(char * cp,int value)634 recurse_format_trig_int (char *cp, int value)
635 {
636 int trig = value % BASE;
637 value /= BASE;
638 if (value > 0)
639 cp = recurse_format_trig_int (cp, value);
640 *cp++ = trig_to_char (trig);
641 return cp;
642 }
643
644 /* Formats VALUE as a trigesimal integer in null-terminated
645 STRING[]. VALUE must be in the range -DBL_MAX...DBL_MAX. If
646 FORCE_SIGN is true, a sign is always inserted; otherwise, a
647 sign is only inserted if VALUE is negative. */
648 static char *
format_trig_int(int value,bool force_sign,char string[])649 format_trig_int (int value, bool force_sign, char string[])
650 {
651 /* Insert sign. */
652 if (value < 0)
653 {
654 *string++ = '-';
655 value = -value;
656 }
657 else if (force_sign)
658 *string++ = '+';
659
660 /* Format integer. */
661 string = recurse_format_trig_int (string, value);
662 *string = '\0';
663 return string;
664 }
665
666 /* Determines whether the TRIG_CNT trigesimals in TRIGS[] warrant
667 rounding up or down. Returns true if TRIGS[] represents a
668 value greater than half, false if less than half. If TRIGS[]
669 is exactly half, examines TRIGS[-1] and returns true if odd,
670 false if even ("round to even"). */
671 static bool
should_round_up(const char trigs[],int trig_cnt)672 should_round_up (const char trigs[], int trig_cnt)
673 {
674 assert (trig_cnt > 0);
675
676 if (*trigs < BASE / 2)
677 {
678 /* Less than half: round down. */
679 return false;
680 }
681 else if (*trigs > BASE / 2)
682 {
683 /* Greater than half: round up. */
684 return true;
685 }
686 else
687 {
688 /* Approximately half: look more closely. */
689 int i;
690 for (i = 1; i < trig_cnt; i++)
691 if (trigs[i] > 0)
692 {
693 /* Slightly greater than half: round up. */
694 return true;
695 }
696
697 /* Exactly half: round to even. */
698 return trigs[-1] % 2;
699 }
700 }
701
702 /* Rounds up the rightmost trig in the TRIG_CNT trigs in TRIGS[],
703 carrying to the left as necessary. Returns true if
704 successful, false on failure (due to a carry out of the
705 leftmost position). */
706 static bool
try_round_up(char * trigs,int trig_cnt)707 try_round_up (char *trigs, int trig_cnt)
708 {
709 while (trig_cnt > 0)
710 {
711 char *round_trig = trigs + --trig_cnt;
712 if (*round_trig != BASE - 1)
713 {
714 /* Round this trig up to the next value. */
715 ++*round_trig;
716 return true;
717 }
718
719 /* Carry over to the next trig to the left. */
720 *round_trig = 0;
721 }
722
723 /* Ran out of trigs to carry. */
724 return false;
725 }
726
727 /* Converts VALUE to trigesimal format in string OUTPUT[] with the
728 equivalent of at least BASE_10_PRECISION decimal digits of
729 precision. The output format may use conventional or
730 scientific notation. Missing, infinite, and extreme values
731 are represented with "*.". */
732 static void
format_trig_double(long double value,int base_10_precision,char output[])733 format_trig_double (long double value, int base_10_precision, char output[])
734 {
735 /* Original VALUE was negative? */
736 bool negative;
737
738 /* Number of significant trigesimals. */
739 int base_30_precision;
740
741 /* Base-2 significand and exponent for original VALUE. */
742 double base_2_sig;
743 int base_2_exp;
744
745 /* VALUE as a set of trigesimals. */
746 char buffer[DBL_DIG + 16];
747 char *trigs;
748 int trig_cnt;
749
750 /* Number of trigesimal places for trigs.
751 trigs[0] has coefficient 30**(trig_places - 1),
752 trigs[1] has coefficient 30**(trig_places - 2),
753 and so on.
754 In other words, the trigesimal point is just before trigs[0].
755 */
756 int trig_places;
757
758 /* Number of trigesimal places left to write into BUFFER. */
759 int trigs_to_output;
760
761 init_pow_tab ();
762
763 /* Handle special cases. */
764 if (value == SYSMIS)
765 goto missing_value;
766 if (value == 0.)
767 goto zero;
768
769 /* Make VALUE positive. */
770 if (value < 0)
771 {
772 value = -value;
773 negative = true;
774 }
775 else
776 negative = false;
777
778 /* Adjust VALUE to roughly 30**3, by shifting the trigesimal
779 point left or right as necessary. We approximate the
780 base-30 exponent by obtaining the base-2 exponent, then
781 multiplying by log30(2). This approximation is sufficient
782 to ensure that the adjusted VALUE is always in the range
783 0...30**6, an invariant of the loop below. */
784 errno = 0;
785 base_2_sig = frexp (value, &base_2_exp);
786 if (errno != 0 || !isfinite (base_2_sig))
787 goto missing_value;
788 if (base_2_exp == 0 && base_2_sig == 0.)
789 goto zero;
790 if (base_2_exp <= INT_MIN / 20379L || base_2_exp >= INT_MAX / 20379L)
791 goto missing_value;
792 trig_places = (base_2_exp * 20379L / 100000L) + CHUNK_SIZE / 2;
793 value *= pow30 (CHUNK_SIZE - trig_places);
794
795 /* Dump all the trigs to buffer[], CHUNK_SIZE at a time. */
796 trigs = buffer;
797 trig_cnt = 0;
798 for (trigs_to_output = DIV_RND_UP (DBL_DIG * 2, 3) + 1 + (CHUNK_SIZE / 2);
799 trigs_to_output > 0;
800 trigs_to_output -= CHUNK_SIZE)
801 {
802 long chunk;
803 int trigs_left;
804
805 /* The current chunk is just the integer part of VALUE,
806 truncated to the nearest integer. The chunk fits in a
807 long. */
808 chunk = value;
809 assert (pow30 (CHUNK_SIZE) <= LONG_MAX);
810 assert (chunk >= 0 && chunk < pow30 (CHUNK_SIZE));
811
812 value -= chunk;
813
814 /* Append the chunk, in base 30, to trigs[]. */
815 for (trigs_left = CHUNK_SIZE; chunk > 0 && trigs_left > 0;)
816 {
817 trigs[trig_cnt + --trigs_left] = chunk % 30;
818 chunk /= 30;
819 }
820 while (trigs_left > 0)
821 trigs[trig_cnt + --trigs_left] = 0;
822 trig_cnt += CHUNK_SIZE;
823
824 /* Proceed to the next chunk. */
825 if (value == 0.)
826 break;
827 value *= pow (LDBASE, CHUNK_SIZE);
828 }
829
830 /* Strip leading zeros. */
831 while (trig_cnt > 1 && *trigs == 0)
832 {
833 trigs++;
834 trig_cnt--;
835 trig_places--;
836 }
837
838 /* Round to requested precision, conservatively estimating the
839 required base-30 precision as 2/3 of the base-10 precision
840 (log30(10) = .68). */
841 assert (base_10_precision > 0);
842 if (base_10_precision > LDBL_DIG)
843 base_10_precision = LDBL_DIG;
844 base_30_precision = DIV_RND_UP (base_10_precision * 2, 3);
845 if (trig_cnt > base_30_precision)
846 {
847 if (should_round_up (trigs + base_30_precision,
848 trig_cnt - base_30_precision))
849 {
850 /* Try to round up. */
851 if (try_round_up (trigs, base_30_precision))
852 {
853 /* Rounding up worked. */
854 trig_cnt = base_30_precision;
855 }
856 else
857 {
858 /* Couldn't round up because we ran out of trigs to
859 carry into. Do the carry here instead. */
860 *trigs = 1;
861 trig_cnt = 1;
862 trig_places++;
863 }
864 }
865 else
866 {
867 /* Round down. */
868 trig_cnt = base_30_precision;
869 }
870 }
871 else
872 {
873 /* No rounding required: fewer digits available than
874 requested. */
875 }
876
877 /* Strip trailing zeros. */
878 while (trig_cnt > 1 && trigs[trig_cnt - 1] == 0)
879 trig_cnt--;
880
881 /* Write output. */
882 if (negative)
883 *output++ = '-';
884 if (trig_places >= -1 && trig_places < trig_cnt + 3)
885 {
886 /* Use conventional notation. */
887 format_trig_digits (output, trigs, trig_cnt, trig_places);
888 }
889 else
890 {
891 /* Use scientific notation. */
892 char *op;
893 op = format_trig_digits (output, trigs, trig_cnt, trig_cnt);
894 op = format_trig_int (trig_places - trig_cnt, true, op);
895 }
896 return;
897
898 zero:
899 strcpy (output, "0");
900 return;
901
902 missing_value:
903 strcpy (output, "*.");
904 return;
905 }
906
907 static const struct casewriter_class por_file_casewriter_class =
908 {
909 por_file_casewriter_write,
910 por_file_casewriter_destroy,
911 NULL,
912 };
913