editfns.c 84.3 KB
Newer Older
Jim Blandy's avatar
Jim Blandy committed
1
/* Lisp functions pertaining to editing.
2
   Copyright (C) 1985,86,87,89,93,94,95,96,97 Free Software Foundation, Inc.
Jim Blandy's avatar
Jim Blandy committed
3 4 5 6 7

This file is part of GNU Emacs.

GNU Emacs is free software; you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
Karl Heuer's avatar
Karl Heuer committed
8
the Free Software Foundation; either version 2, or (at your option)
Jim Blandy's avatar
Jim Blandy committed
9 10 11 12 13 14 15 16 17
any later version.

GNU Emacs is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
GNU General Public License for more details.

You should have received a copy of the GNU General Public License
along with GNU Emacs; see the file COPYING.  If not, write to
Richard M. Stallman's avatar
Richard M. Stallman committed
18 19
the Free Software Foundation, Inc., 59 Temple Place - Suite 330,
Boston, MA 02111-1307, USA.  */
Jim Blandy's avatar
Jim Blandy committed
20 21


22 23
#include <sys/types.h>

24
#include <config.h>
Jim Blandy's avatar
Jim Blandy committed
25 26

#ifdef VMS
Jim Blandy's avatar
Jim Blandy committed
27
#include "vms-pwd.h"
Jim Blandy's avatar
Jim Blandy committed
28
#else
Jim Blandy's avatar
Jim Blandy committed
29
#include <pwd.h>
Jim Blandy's avatar
Jim Blandy committed
30 31
#endif

Jim Blandy's avatar
Jim Blandy committed
32
#include "lisp.h"
33
#include "intervals.h"
Jim Blandy's avatar
Jim Blandy committed
34
#include "buffer.h"
Karl Heuer's avatar
Karl Heuer committed
35
#include "charset.h"
Jim Blandy's avatar
Jim Blandy committed
36 37
#include "window.h"

Jim Blandy's avatar
Jim Blandy committed
38
#include "systime.h"
Jim Blandy's avatar
Jim Blandy committed
39 40 41 42

#define min(a, b) ((a) < (b) ? (a) : (b))
#define max(a, b) ((a) > (b) ? (a) : (b))

43 44 45 46
#ifndef NULL
#define NULL 0
#endif

47 48
extern char **environ;
extern Lisp_Object make_time ();
49
extern void insert_from_buffer ();
50
static int tm_diff ();
51
static void update_buffer_properties ();
Paul Eggert's avatar
Paul Eggert committed
52
size_t emacs_strftime ();
53
void set_time_zone_rule ();
54 55 56 57

Lisp_Object Vbuffer_access_fontify_functions;
Lisp_Object Qbuffer_access_fontify_functions;
Lisp_Object Vbuffer_access_fontified_property;
58

59 60
Lisp_Object Fuser_full_name ();

Jim Blandy's avatar
Jim Blandy committed
61 62 63
/* Some static data, and a function to initialize it for each run */

Lisp_Object Vsystem_name;
64 65 66
Lisp_Object Vuser_real_login_name;	/* login name of current user ID */
Lisp_Object Vuser_full_name;		/* full name of current user */
Lisp_Object Vuser_login_name;		/* user name from LOGNAME or USER */
Jim Blandy's avatar
Jim Blandy committed
67 68 69 70

void
init_editfns ()
{
Jim Blandy's avatar
Jim Blandy committed
71
  char *user_name;
Jim Blandy's avatar
Jim Blandy committed
72 73 74 75 76
  register unsigned char *p, *q, *r;
  struct passwd *pw;	/* password entry for the current user */
  Lisp_Object tem;

  /* Set up system_name even when dumping.  */
77
  init_system_name ();
Jim Blandy's avatar
Jim Blandy committed
78 79 80 81 82 83 84 85

#ifndef CANNOT_DUMP
  /* Don't bother with this on initial start when just dumping out */
  if (!initialized)
    return;
#endif /* not CANNOT_DUMP */

  pw = (struct passwd *) getpwuid (getuid ());
Morten Welinder's avatar
Morten Welinder committed
86 87 88 89
#ifdef MSDOS
  /* We let the real user name default to "root" because that's quite
     accurate on MSDOG and because it lets Emacs find the init file.
     (The DVX libraries override the Djgpp libraries here.)  */
90
  Vuser_real_login_name = build_string (pw ? pw->pw_name : "root");
Morten Welinder's avatar
Morten Welinder committed
91
#else
92
  Vuser_real_login_name = build_string (pw ? pw->pw_name : "unknown");
Morten Welinder's avatar
Morten Welinder committed
93
#endif
Jim Blandy's avatar
Jim Blandy committed
94

Jim Blandy's avatar
Jim Blandy committed
95 96
  /* Get the effective user name, by consulting environment variables,
     or the effective uid if those are unset.  */
97
  user_name = (char *) getenv ("LOGNAME");
Jim Blandy's avatar
Jim Blandy committed
98
  if (!user_name)
99 100 101
#ifdef WINDOWSNT
    user_name = (char *) getenv ("USERNAME");	/* it's USERNAME on NT */
#else  /* WINDOWSNT */
102
    user_name = (char *) getenv ("USER");
103
#endif /* WINDOWSNT */
Jim Blandy's avatar
Jim Blandy committed
104 105 106 107 108
  if (!user_name)
    {
      pw = (struct passwd *) getpwuid (geteuid ());
      user_name = (char *) (pw ? pw->pw_name : "unknown");
    }
109
  Vuser_login_name = build_string (user_name);
Jim Blandy's avatar
Jim Blandy committed
110

Jim Blandy's avatar
Jim Blandy committed
111 112
  /* If the user name claimed in the environment vars differs from
     the real uid, use the claimed name to find the full name.  */
113
  tem = Fstring_equal (Vuser_login_name, Vuser_real_login_name);
114 115
  Vuser_full_name = Fuser_full_name (NILP (tem)? make_number (geteuid())
				     : Vuser_login_name);
Jim Blandy's avatar
Jim Blandy committed
116
  
117
  p = (unsigned char *) getenv ("NAME");
118 119
  if (p)
    Vuser_full_name = build_string (p);
120 121
  else if (NILP (Vuser_full_name))
    Vuser_full_name = build_string ("unknown");
Jim Blandy's avatar
Jim Blandy committed
122 123 124
}

DEFUN ("char-to-string", Fchar_to_string, Schar_to_string, 1, 1, 0,
Karl Heuer's avatar
Karl Heuer committed
125
  "Convert arg CHAR to a string containing multi-byte form of that character.")
126 127
  (character)
     Lisp_Object character;
Jim Blandy's avatar
Jim Blandy committed
128
{
Karl Heuer's avatar
Karl Heuer committed
129
  int len;
130
  unsigned char workbuf[4], *str;
Karl Heuer's avatar
Karl Heuer committed
131

132
  CHECK_NUMBER (character, 0);
Jim Blandy's avatar
Jim Blandy committed
133

Karl Heuer's avatar
Karl Heuer committed
134 135
  len = CHAR_STRING (XFASTINT (character), workbuf, str);
  return make_string (str, len);
Jim Blandy's avatar
Jim Blandy committed
136 137 138
}

DEFUN ("string-to-char", Fstring_to_char, Sstring_to_char, 1, 1, 0,
Karl Heuer's avatar
Karl Heuer committed
139 140
  "Convert arg STRING to a character, the first character of that string.\n\
A multibyte character is handled correctly.")
141 142
  (string)
     register Lisp_Object string;
Jim Blandy's avatar
Jim Blandy committed
143 144 145
{
  register Lisp_Object val;
  register struct Lisp_String *p;
146 147
  CHECK_STRING (string, 0);
  p = XSTRING (string);
Jim Blandy's avatar
Jim Blandy committed
148
  if (p->size)
Karl Heuer's avatar
Karl Heuer committed
149
    XSETFASTINT (val, STRING_CHAR (p->data, p->size));
Jim Blandy's avatar
Jim Blandy committed
150
  else
151
    XSETFASTINT (val, 0);
Jim Blandy's avatar
Jim Blandy committed
152 153
  return val;
}
Karl Heuer's avatar
Karl Heuer committed
154 155 156 157 158 159 160 161

DEFUN ("sref", Fsref, Ssref, 2, 2, 0,
  "Return the character in STRING at INDEX.  INDEX starts at 0.\n\
A multibyte character is handled correctly.\n\
INDEX not pointing at character boundary is an error.")
  (str, idx)
     Lisp_Object str, idx;
{
162 163
  register int idxval, len, i;
  register unsigned char *p, *q;
Karl Heuer's avatar
Karl Heuer committed
164 165 166 167 168 169 170
  register Lisp_Object val;

  CHECK_STRING (str, 0);
  CHECK_NUMBER (idx, 1);
  idxval = XINT (idx);
  if (idxval < 0 || idxval >= (len = XVECTOR (str)->size))
    args_out_of_range (str, idx);
171

Karl Heuer's avatar
Karl Heuer committed
172
  p = XSTRING (str)->data + idxval;
173 174 175 176 177 178 179 180 181 182 183 184 185 186 187 188 189
  if (!NILP (current_buffer->enable_multibyte_characters)
      && !CHAR_HEAD_P (p)
      && idxval > 0)
    {
      /* We must check if P points to a tailing byte of a multibyte
         form.  If so, we signal error.  */
      i = idxval - 1;
      q = p - 1;
      while (i > 0 && *q >= 0xA0) i--, q--;

      if (*q == LEADING_CODE_COMPOSITION)
	i = multibyte_form_length (XSTRING (str)->data + i, len - i);
      else
	i = BYTES_BY_CHAR_HEAD (*q);
      if (q + i > p)
	error ("Not character boundary");
    }
Karl Heuer's avatar
Karl Heuer committed
190 191 192 193 194 195

  len = XSTRING (str)->size - idxval;
  XSETFASTINT (val, STRING_CHAR (p, len));
  return val;
}

Jim Blandy's avatar
Jim Blandy committed
196 197 198 199 200 201 202 203 204 205 206 207 208 209 210 211 212

static Lisp_Object
buildmark (val)
     int val;
{
  register Lisp_Object mark;
  mark = Fmake_marker ();
  Fset_marker (mark, make_number (val), Qnil);
  return mark;
}

DEFUN ("point", Fpoint, Spoint, 0, 0, 0,
  "Return value of point, as an integer.\n\
Beginning of buffer is position (point-min)")
  ()
{
  Lisp_Object temp;
213
  XSETFASTINT (temp, PT);
Jim Blandy's avatar
Jim Blandy committed
214 215 216 217 218 219 220
  return temp;
}

DEFUN ("point-marker", Fpoint_marker, Spoint_marker, 0, 0, 0,
   "Return value of point, as a marker object.")
  ()
{
221
  return buildmark (PT);
Jim Blandy's avatar
Jim Blandy committed
222 223 224 225 226 227 228 229 230 231 232 233 234 235 236 237
}

int
clip_to_bounds (lower, num, upper)
     int lower, num, upper;
{
  if (num < lower)
    return lower;
  else if (num > upper)
    return upper;
  else
    return num;
}

DEFUN ("goto-char", Fgoto_char, Sgoto_char, 1, 1, "NGoto char: ",
  "Set point to POSITION, a number or marker.\n\
Karl Heuer's avatar
Karl Heuer committed
238 239 240 241
Beginning of buffer is position (point-min), end is (point-max).\n\
If the position is in the middle of a multibyte form,\n\
the actual point is set at the head of the multibyte form\n\
except in the case that `enable-multibyte-characters' is nil.")
242 243
  (position)
     register Lisp_Object position;
Jim Blandy's avatar
Jim Blandy committed
244
{
Karl Heuer's avatar
Karl Heuer committed
245 246 247
  int pos;
  unsigned char *p;

248
  CHECK_NUMBER_COERCE_MARKER (position, 0);
Jim Blandy's avatar
Jim Blandy committed
249

Karl Heuer's avatar
Karl Heuer committed
250 251 252 253 254 255 256 257 258 259 260 261 262 263 264 265 266 267 268 269 270 271 272
  pos = clip_to_bounds (BEGV, XINT (position), ZV);
  /* If POS is in a middle of multi-byte form (i.e. *P >= 0xA0), we
     must decrement POS until it points the head of the multi-byte
     form.  */
  if (!NILP (current_buffer->enable_multibyte_characters)
      && *(p = POS_ADDR (pos)) >= 0xA0
      && pos > BEGV)
    {
      /* Since a multi-byte form does not contain the gap, POS should
         not stride over the gap while it is being decreased.  So, we
         set the limit as below.  */
      unsigned char *p_min = pos < GPT ? BEG_ADDR : GAP_END_ADDR;
      unsigned int saved_pos = pos;

      do {
	p--, pos--;
      } while (p > p_min && *p >= 0xA0);
      if (*p < 0x80)
	/* This was an invalid multi-byte form.  */
	pos = saved_pos;
      XSETFASTINT (position, pos);
    }
  SET_PT (pos);
273
  return position;
Jim Blandy's avatar
Jim Blandy committed
274 275 276 277 278 279
}

static Lisp_Object
region_limit (beginningp)
     int beginningp;
{
280
  extern Lisp_Object Vmark_even_if_inactive; /* Defined in callint.c. */
Jim Blandy's avatar
Jim Blandy committed
281
  register Lisp_Object m;
282 283 284
  if (!NILP (Vtransient_mark_mode) && NILP (Vmark_even_if_inactive)
      && NILP (current_buffer->mark_active))
    Fsignal (Qmark_inactive, Qnil);
Jim Blandy's avatar
Jim Blandy committed
285
  m = Fmarker_position (current_buffer->mark);
Jim Blandy's avatar
Jim Blandy committed
286
  if (NILP (m)) error ("There is no region now");
287 288
  if ((PT < XFASTINT (m)) == beginningp)
    return (make_number (PT));
Jim Blandy's avatar
Jim Blandy committed
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
  else
    return (m);
}

DEFUN ("region-beginning", Fregion_beginning, Sregion_beginning, 0, 0, 0,
  "Return position of beginning of region, as an integer.")
  ()
{
  return (region_limit (1));
}

DEFUN ("region-end", Fregion_end, Sregion_end, 0, 0, 0,
  "Return position of end of region, as an integer.")
  ()
{
  return (region_limit (0));
}

DEFUN ("mark-marker", Fmark_marker, Smark_marker, 0, 0, 0,
  "Return this buffer's mark, as a marker object.\n\
Watch out!  Moving this marker changes the mark position.\n\
If you set the marker not to point anywhere, the buffer will have no mark.")
  ()
{
  return current_buffer->mark;
}
315 316 317 318 319 320 321 322 323 324 325 326 327 328 329 330 331 332 333 334 335

DEFUN ("line-beginning-position", Fline_beginning_position, Sline_beginning_position,
  0, 1, 0,
  "Return the character position of the first character on the current line.\n\
With argument N not nil or 1, move forward N - 1 lines first.\n\
If scan reaches end of buffer, return that position.\n\
This function does not move point.")
  (n)
     Lisp_Object n;
{
  register int orig, end;

  if (NILP (n))
    XSETFASTINT (n, 1);
  else
    CHECK_NUMBER (n, 0);

  orig = PT;
  Fforward_line (make_number (XINT (n) - 1));
  end = PT;
  SET_PT (orig);
Jim Blandy's avatar
Jim Blandy committed
336

337 338 339 340 341 342 343 344 345 346 347 348 349 350 351 352 353 354 355 356 357
  return make_number (end);
}

DEFUN ("line-end-position", Fline_end_position, Sline_end_position,
  0, 1, 0,
  "Return the character position of the last character on the current line.\n\
With argument N not nil or 1, move forward N - 1 lines first.\n\
If scan reaches end of buffer, return that position.\n\
This function does not move point.")
  (n)
     Lisp_Object n;
{
  if (NILP (n))
    XSETFASTINT (n, 1);
  else
    CHECK_NUMBER (n, 0);

  return make_number (find_before_next_newline 
		      (PT, 0, XINT (n) - (XINT (n) <= 0)));
}

Jim Blandy's avatar
Jim Blandy committed
358 359 360
Lisp_Object
save_excursion_save ()
{
361 362
  register int visible = (XBUFFER (XWINDOW (selected_window)->buffer)
			  == current_buffer);
Jim Blandy's avatar
Jim Blandy committed
363 364

  return Fcons (Fpoint_marker (),
365
		Fcons (Fcopy_marker (current_buffer->mark, Qnil),
366 367
		       Fcons (visible ? Qt : Qnil,
			      current_buffer->mark_active)));		       
Jim Blandy's avatar
Jim Blandy committed
368 369 370 371
}

Lisp_Object
save_excursion_restore (info)
372
     Lisp_Object info;
Jim Blandy's avatar
Jim Blandy committed
373
{
374 375
  Lisp_Object tem, tem1, omark, nmark;
  struct gcpro gcpro1, gcpro2, gcpro3;
Jim Blandy's avatar
Jim Blandy committed
376 377 378 379 380 381

  tem = Fmarker_buffer (Fcar (info));
  /* If buffer being returned to is now deleted, avoid error */
  /* Otherwise could get error here while unwinding to top level
     and crash */
  /* In that case, Fmarker_buffer returns nil now.  */
Jim Blandy's avatar
Jim Blandy committed
382
  if (NILP (tem))
Jim Blandy's avatar
Jim Blandy committed
383
    return Qnil;
384 385 386 387

  omark = nmark = Qnil;
  GCPRO3 (info, omark, nmark);

Jim Blandy's avatar
Jim Blandy committed
388 389 390 391 392
  Fset_buffer (tem);
  tem = Fcar (info);
  Fgoto_char (tem);
  unchain_marker (tem);
  tem = Fcar (Fcdr (info));
393
  omark = Fmarker_position (current_buffer->mark);
Jim Blandy's avatar
Jim Blandy committed
394
  Fset_marker (current_buffer->mark, tem, Fcurrent_buffer ());
395
  nmark = Fmarker_position (tem);
Jim Blandy's avatar
Jim Blandy committed
396 397
  unchain_marker (tem);
  tem = Fcdr (Fcdr (info));
398 399 400 401
#if 0 /* We used to make the current buffer visible in the selected window
	 if that was true previously.  That avoids some anomalies.
	 But it creates others, and it wasn't documented, and it is simpler
	 and cleaner never to alter the window/buffer connections.  */
402 403
  tem1 = Fcar (tem);
  if (!NILP (tem1)
404
      && current_buffer != XBUFFER (XWINDOW (selected_window)->buffer))
Jim Blandy's avatar
Jim Blandy committed
405
    Fswitch_to_buffer (Fcurrent_buffer (), Qnil);
406
#endif /* 0 */
407 408 409

  tem1 = current_buffer->mark_active;
  current_buffer->mark_active = Fcdr (tem);
410 411
  if (!NILP (Vrun_hooks))
    {
412 413
      /* If mark is active now, and either was not active
	 or was at a different place, run the activate hook.  */
414
      if (! NILP (current_buffer->mark_active))
415 416 417 418 419
	{
	  if (! EQ (omark, nmark))
	    call1 (Vrun_hooks, intern ("activate-mark-hook"));
	}
      /* If mark has ceased to be active, run deactivate hook.  */
420 421 422
      else if (! NILP (tem1))
	call1 (Vrun_hooks, intern ("deactivate-mark-hook"));
    }
423
  UNGCPRO;
Jim Blandy's avatar
Jim Blandy committed
424 425 426 427 428 429 430
  return Qnil;
}

DEFUN ("save-excursion", Fsave_excursion, Ssave_excursion, 0, UNEVALLED, 0,
  "Save point, mark, and current buffer; execute BODY; restore those things.\n\
Executes BODY just like `progn'.\n\
The values of point, mark and the current buffer are restored\n\
431 432
even in case of abnormal exit (throw or error).\n\
The state of activation of the mark is also restored.")
Jim Blandy's avatar
Jim Blandy committed
433 434 435 436 437 438 439
  (args)
     Lisp_Object args;
{
  register Lisp_Object val;
  int count = specpdl_ptr - specpdl;

  record_unwind_protect (save_excursion_restore, save_excursion_save ());
440 441 442 443 444 445 446 447 448 449 450 451 452 453 454 455

  val = Fprogn (args);
  return unbind_to (count, val);
}

DEFUN ("save-current-buffer", Fsave_current_buffer, Ssave_current_buffer, 0, UNEVALLED, 0,
  "Save the current buffer; execute BODY; restore the current buffer.\n\
Executes BODY just like `progn'.")
  (args)
     Lisp_Object args;
{
  register Lisp_Object val;
  int count = specpdl_ptr - specpdl;

  record_unwind_protect (Fset_buffer, Fcurrent_buffer ());

Jim Blandy's avatar
Jim Blandy committed
456 457 458 459 460 461 462 463 464
  val = Fprogn (args);
  return unbind_to (count, val);
}

DEFUN ("buffer-size", Fbufsize, Sbufsize, 0, 0, 0,
  "Return the number of characters in the current buffer.")
  ()
{
  Lisp_Object temp;
465
  XSETFASTINT (temp, Z - BEG);
Jim Blandy's avatar
Jim Blandy committed
466 467 468 469 470
  return temp;
}

DEFUN ("point-min", Fpoint_min, Spoint_min, 0, 0, 0,
  "Return the minimum permissible value of point in the current buffer.\n\
Richard M. Stallman's avatar
Richard M. Stallman committed
471
This is 1, unless narrowing (a buffer restriction) is in effect.")
Jim Blandy's avatar
Jim Blandy committed
472 473 474
  ()
{
  Lisp_Object temp;
475
  XSETFASTINT (temp, BEGV);
Jim Blandy's avatar
Jim Blandy committed
476 477 478 479 480
  return temp;
}

DEFUN ("point-min-marker", Fpoint_min_marker, Spoint_min_marker, 0, 0, 0,
  "Return a marker to the minimum permissible value of point in this buffer.\n\
Richard M. Stallman's avatar
Richard M. Stallman committed
481
This is the beginning, unless narrowing (a buffer restriction) is in effect.")
Jim Blandy's avatar
Jim Blandy committed
482 483 484 485 486 487 488
  ()
{
  return buildmark (BEGV);
}

DEFUN ("point-max", Fpoint_max, Spoint_max, 0, 0, 0,
  "Return the maximum permissible value of point in the current buffer.\n\
Richard M. Stallman's avatar
Richard M. Stallman committed
489 490
This is (1+ (buffer-size)), unless narrowing (a buffer restriction)\n\
is in effect, in which case it is less.")
Jim Blandy's avatar
Jim Blandy committed
491 492 493
  ()
{
  Lisp_Object temp;
494
  XSETFASTINT (temp, ZV);
Jim Blandy's avatar
Jim Blandy committed
495 496 497 498 499
  return temp;
}

DEFUN ("point-max-marker", Fpoint_max_marker, Spoint_max_marker, 0, 0, 0,
  "Return a marker to the maximum permissible value of point in this buffer.\n\
Richard M. Stallman's avatar
Richard M. Stallman committed
500 501
This is (1+ (buffer-size)), unless narrowing (a buffer restriction)\n\
is in effect, in which case it is less.")
Jim Blandy's avatar
Jim Blandy committed
502 503 504 505 506
  ()
{
  return buildmark (ZV);
}

Jim Blandy's avatar
Jim Blandy committed
507 508
DEFUN ("following-char", Ffollowing_char, Sfollowing_char, 0, 0, 0,
  "Return the character following point, as a number.\n\
Karl Heuer's avatar
Karl Heuer committed
509 510 511 512
At the end of the buffer or accessible region, return 0.\n\
If `enable-multibyte-characters' is nil or point is not\n\
 at character boundary,  multibyte form is ignored,\n\
 and only one byte following point is returned as a character.")
Jim Blandy's avatar
Jim Blandy committed
513 514 515
  ()
{
  Lisp_Object temp;
516
  if (PT >= ZV)
517
    XSETFASTINT (temp, 0);
Jim Blandy's avatar
Jim Blandy committed
518
  else
519
    XSETFASTINT (temp, FETCH_CHAR (PT));
Jim Blandy's avatar
Jim Blandy committed
520 521 522
  return temp;
}

Jim Blandy's avatar
Jim Blandy committed
523 524
DEFUN ("preceding-char", Fprevious_char, Sprevious_char, 0, 0, 0,
  "Return the character preceding point, as a number.\n\
Karl Heuer's avatar
Karl Heuer committed
525 526 527 528
At the beginning of the buffer or accessible region, return 0.\n\
If `enable-multibyte-characters' is nil or point is not\n\
 at character boundary, multi-byte form is ignored,\n\
 and only one byte preceding point is returned as a character.")
Jim Blandy's avatar
Jim Blandy committed
529 530 531
  ()
{
  Lisp_Object temp;
532
  if (PT <= BEGV)
533
    XSETFASTINT (temp, 0);
Karl Heuer's avatar
Karl Heuer committed
534 535 536 537 538 539
  else if (!NILP (current_buffer->enable_multibyte_characters))
    {
      int pos = PT;
      DEC_POS (pos);
      XSETFASTINT (temp, FETCH_CHAR (pos));
    }
Jim Blandy's avatar
Jim Blandy committed
540
  else
541
    XSETFASTINT (temp, FETCH_BYTE (PT - 1));
Jim Blandy's avatar
Jim Blandy committed
542 543 544 545 546 547 548 549
  return temp;
}

DEFUN ("bobp", Fbobp, Sbobp, 0, 0, 0,
  "Return T if point is at the beginning of the buffer.\n\
If the buffer is narrowed, this means the beginning of the narrowed part.")
  ()
{
550
  if (PT == BEGV)
Jim Blandy's avatar
Jim Blandy committed
551 552 553 554 555 556 557 558 559
    return Qt;
  return Qnil;
}

DEFUN ("eobp", Feobp, Seobp, 0, 0, 0,
  "Return T if point is at the end of the buffer.\n\
If the buffer is narrowed, this means the end of the narrowed part.")
  ()
{
560
  if (PT == ZV)
Jim Blandy's avatar
Jim Blandy committed
561 562 563 564 565 566 567 568
    return Qt;
  return Qnil;
}

DEFUN ("bolp", Fbolp, Sbolp, 0, 0, 0,
  "Return T if point is at the beginning of a line.")
  ()
{
Karl Heuer's avatar
Karl Heuer committed
569
  if (PT == BEGV || FETCH_BYTE (PT - 1) == '\n')
Jim Blandy's avatar
Jim Blandy committed
570 571 572 573 574 575 576 577 578
    return Qt;
  return Qnil;
}

DEFUN ("eolp", Feolp, Seolp, 0, 0, 0,
  "Return T if point is at the end of a line.\n\
`End of a line' includes point being at the end of the buffer.")
  ()
{
Karl Heuer's avatar
Karl Heuer committed
579
  if (PT == ZV || FETCH_BYTE (PT) == '\n')
Jim Blandy's avatar
Jim Blandy committed
580 581 582 583
    return Qt;
  return Qnil;
}

584
DEFUN ("char-after", Fchar_after, Schar_after, 0, 1, 0,
Jim Blandy's avatar
Jim Blandy committed
585 586
  "Return character in current buffer at position POS.\n\
POS is an integer or a buffer pointer.\n\
Karl Heuer's avatar
Karl Heuer committed
587 588 589 590
If POS is out of range, the value is nil.\n\
If `enable-multibyte-characters' is nil or POS is not at character boundary,\n\
 multi-byte form is ignored, and only one byte at POS\n\
 is returned as a character.")
Jim Blandy's avatar
Jim Blandy committed
591 592 593 594 595 596
  (pos)
     Lisp_Object pos;
{
  register Lisp_Object val;
  register int n;

597 598 599 600 601
  if (NILP (pos))
    n = PT;
  else
    {
      CHECK_NUMBER_COERCE_MARKER (pos, 0);
Jim Blandy's avatar
Jim Blandy committed
602

603 604 605 606
      n = XINT (pos);
      if (n < BEGV || n >= ZV)
	return Qnil;
    }
Jim Blandy's avatar
Jim Blandy committed
607

608
  XSETFASTINT (val, FETCH_CHAR (n));
Jim Blandy's avatar
Jim Blandy committed
609 610
  return val;
}
Karl Heuer's avatar
Karl Heuer committed
611

612
DEFUN ("char-before", Fchar_before, Schar_before, 0, 1, 0,
Karl Heuer's avatar
Karl Heuer committed
613 614 615 616 617 618 619 620 621 622 623 624
  "Return character in current buffer preceding position POS.\n\
POS is an integer or a buffer pointer.\n\
If POS is out of range, the value is nil.\n\
If `enable-multibyte-characters' is nil or POS is not at character boundary,\n\
multi-byte form is ignored, and only one byte preceding POS\n\
is returned as a character.")
  (pos)
     Lisp_Object pos;
{
  register Lisp_Object val;
  register int n;

625 626 627 628 629
  if (NILP (pos))
    n = PT;
  else
    {
      CHECK_NUMBER_COERCE_MARKER (pos, 0);
Karl Heuer's avatar
Karl Heuer committed
630

631 632
      n = XINT (pos);
    }
Karl Heuer's avatar
Karl Heuer committed
633

634 635 636
  if (n <= BEGV || n > ZV)
    return Qnil;

Karl Heuer's avatar
Karl Heuer committed
637 638
  if (!NILP (current_buffer->enable_multibyte_characters))
    {
639 640
      DEC_POS (n);
      XSETFASTINT (val, FETCH_CHAR (n));
Karl Heuer's avatar
Karl Heuer committed
641 642 643
    }
  else
    {
644 645
      n--;
      XSETFASTINT (val, FETCH_BYTE (n));
Karl Heuer's avatar
Karl Heuer committed
646 647 648
    }
   return val;
}
Jim Blandy's avatar
Jim Blandy committed
649

Morten Welinder's avatar
Morten Welinder committed
650
DEFUN ("user-login-name", Fuser_login_name, Suser_login_name, 0, 1, 0,
Jim Blandy's avatar
Jim Blandy committed
651 652
  "Return the name under which the user logged in, as a string.\n\
This is based on the effective uid, not the real uid.\n\
653
Also, if the environment variable LOGNAME or USER is set,\n\
Morten Welinder's avatar
Morten Welinder committed
654 655 656 657 658
that determines the value of this function.\n\n\
If optional argument UID is an integer, return the login name of the user\n\
with that uid, or nil if there is no such user.")
  (uid)
     Lisp_Object uid;
Jim Blandy's avatar
Jim Blandy committed
659
{
Morten Welinder's avatar
Morten Welinder committed
660 661
  struct passwd *pw;

662 663 664
  /* Set up the user name info if we didn't do it before.
     (That can happen if Emacs is dumpable
     but you decide to run `temacs -l loadup' and not dump.  */
665
  if (INTEGERP (Vuser_login_name))
666
    init_editfns ();
Morten Welinder's avatar
Morten Welinder committed
667 668

  if (NILP (uid))
669
    return Vuser_login_name;
Morten Welinder's avatar
Morten Welinder committed
670 671 672 673

  CHECK_NUMBER (uid, 0);
  pw = (struct passwd *) getpwuid (XINT (uid));
  return (pw ? build_string (pw->pw_name) : Qnil);
Jim Blandy's avatar
Jim Blandy committed
674 675 676 677 678
}

DEFUN ("user-real-login-name", Fuser_real_login_name, Suser_real_login_name,
  0, 0, 0,
  "Return the name of the user's real uid, as a string.\n\
679
This ignores the environment variables LOGNAME and USER, so it differs from\n\
Karl Heuer's avatar
Karl Heuer committed
680
`user-login-name' when running under `su'.")
Jim Blandy's avatar
Jim Blandy committed
681 682
  ()
{
683 684 685
  /* Set up the user name info if we didn't do it before.
     (That can happen if Emacs is dumpable
     but you decide to run `temacs -l loadup' and not dump.  */
686
  if (INTEGERP (Vuser_login_name))
687
    init_editfns ();
688
  return Vuser_real_login_name;
Jim Blandy's avatar
Jim Blandy committed
689 690 691 692 693 694 695 696 697 698 699 700 701 702 703 704
}

DEFUN ("user-uid", Fuser_uid, Suser_uid, 0, 0, 0,
  "Return the effective uid of Emacs, as an integer.")
  ()
{
  return make_number (geteuid ());
}

DEFUN ("user-real-uid", Fuser_real_uid, Suser_real_uid, 0, 0, 0,
  "Return the real uid of Emacs, as an integer.")
  ()
{
  return make_number (getuid ());
}

705 706 707
DEFUN ("user-full-name", Fuser_full_name, Suser_full_name, 0, 1, 0,
  "Return the full name of the user logged in, as a string.\n\
If optional argument UID is an integer, return the full name of the user\n\
Kenichi Handa's avatar
Kenichi Handa committed
708
with that uid, or \"unknown\" if there is no such user.\n\
709 710
If UID is a string, return the full name of the user with that login\n\
name, or \"unknown\" if no such user could be found.")
711 712
  (uid)
     Lisp_Object uid;
Jim Blandy's avatar
Jim Blandy committed
713
{
714
  struct passwd *pw;
715
  register unsigned char *p, *q;
716 717
  extern char *index ();
  Lisp_Object full;
718 719

  if (NILP (uid))
720 721 722 723 724 725 726
    return Vuser_full_name; 
  else if (NUMBERP (uid))
    pw = (struct passwd *) getpwuid (XINT (uid));
  else if (STRINGP (uid)) 
    pw = (struct passwd *) getpwnam (XSTRING (uid)->data);
  else
    error ("Invalid UID specification");
727

728
  if (!pw)
729
    return Qnil;
730 731 732 733 734 735 736 737 738 739 740 741
  
  p = (unsigned char *) USER_FULL_NAME;
  /* Chop off everything after the first comma. */
  q = (unsigned char *) index (p, ',');
  full = make_string (p, q ? q - p : strlen (p));
  
#ifdef AMPERSAND_FULL_NAME
  p = XSTRING (full)->data;
  q = (unsigned char *) index (p, '&');
  /* Substitute the login name for the &, upcasing the first character.  */
  if (q)
    {
742
      register unsigned char *r;
743 744 745 746 747 748 749 750 751 752 753 754 755 756
      Lisp_Object login;

      login = Fuser_login_name (make_number (pw->pw_uid));
      r = (unsigned char *) alloca (strlen (p) + XSTRING (login)->size + 1);
      bcopy (p, r, q - p);
      r[q - p] = 0;
      strcat (r, XSTRING (login)->data);
      r[q - p] = UPCASE (r[q - p]);
      strcat (r, q + 1);
      full = build_string (r);
    }
#endif /* AMPERSAND_FULL_NAME */

  return full;
Jim Blandy's avatar
Jim Blandy committed
757 758 759 760 761 762 763 764 765
}

DEFUN ("system-name", Fsystem_name, Ssystem_name, 0, 0, 0,
  "Return the name of the machine you are running on, as a string.")
  ()
{
  return Vsystem_name;
}

766 767 768 769
/* For the benefit of callers who don't want to include lisp.h */
char *
get_system_name ()
{
770 771 772 773
  if (STRINGP (Vsystem_name))
    return (char *) XSTRING (Vsystem_name)->data;
  else
    return "";
774 775
}

776 777 778 779 780 781 782
DEFUN ("emacs-pid", Femacs_pid, Semacs_pid, 0, 0, 0,
  "Return the process ID of Emacs, as an integer.")
  ()
{
  return make_number (getpid ());
}

Jim Blandy's avatar
Jim Blandy committed
783
DEFUN ("current-time", Fcurrent_time, Scurrent_time, 0, 0, 0,
784
  "Return the current time, as the number of seconds since 1970-01-01 00:00:00.\n\
Jim Blandy's avatar
Jim Blandy committed
785 786 787 788 789 790 791
The time is returned as a list of three integers.  The first has the\n\
most significant 16 bits of the seconds, while the second has the\n\
least significant 16 bits.  The third integer gives the microsecond\n\
count.\n\
\n\
The microsecond count is zero on systems that do not provide\n\
resolution finer than a second.")
Jim Blandy's avatar
Jim Blandy committed
792 793
  ()
{
Jim Blandy's avatar
Jim Blandy committed
794 795 796 797
  EMACS_TIME t;
  Lisp_Object result[3];

  EMACS_GET_TIME (t);
798 799 800
  XSETINT (result[0], (EMACS_SECS (t) >> 16) & 0xffff);
  XSETINT (result[1], (EMACS_SECS (t) >> 0)  & 0xffff);
  XSETINT (result[2], EMACS_USECS (t));
Jim Blandy's avatar
Jim Blandy committed
801 802

  return Flist (3, result);
Jim Blandy's avatar
Jim Blandy committed
803 804 805
}


806 807 808 809 810 811 812 813 814 815 816 817 818
static int
lisp_time_argument (specified_time, result)
     Lisp_Object specified_time;
     time_t *result;
{
  if (NILP (specified_time))
    return time (result) != -1;
  else
    {
      Lisp_Object high, low;
      high = Fcar (specified_time);
      CHECK_NUMBER (high, 0);
      low = Fcdr (specified_time);
819
      if (CONSP (low))
820 821 822 823 824 825 826
	low = Fcar (low);
      CHECK_NUMBER (low, 0);
      *result = (XINT (high) << 16) + (XINT (low) & 0xffff);
      return *result >> 16 == XINT (high);
    }
}

827
/*
828 829 830 831 832 833 834 835
DEFUN ("format-time-string", Fformat_time_string, Sformat_time_string, 1, 3, 0,
  "Use FORMAT-STRING to format the time TIME, or now if omitted.\n\
TIME is specified as (HIGH LOW . IGNORED) or (HIGH . LOW), as returned by\n\
`current-time' or `file-attributes'.\n\
The third, optional, argument UNIVERSAL, if non-nil, means describe TIME\n\
as Universal Time; nil means describe TIME in the local time zone.\n\
The value is a copy of FORMAT-STRING, but with certain constructs replaced\n\
by text that describes the specified date and time in TIME:\n\
836
\n\
837 838
%Y is the year, %y within the century, %C the century.\n\
%G is the year corresponding to the ISO week, %g within the century.\n\
Paul Eggert's avatar
Paul Eggert committed
839 840
%m is the numeric month.\n\
%b and %h are the locale's abbreviated month name, %B the full name.\n\
841 842
%d is the day of the month, zero-padded, %e is blank-padded.\n\
%u is the numeric day of week from 1 (Monday) to 7, %w from 0 (Sunday) to 6.\n\
Paul Eggert's avatar
Paul Eggert committed
843
%a is the locale's abbreviated name of the day of week, %A the full name.\n\
844 845 846 847 848 849
%U is the week number starting on Sunday, %W starting on Monday,\n\
 %V according to ISO 8601.\n\
%j is the day of the year.\n\
\n\
%H is the hour on a 24-hour clock, %I is on a 12-hour clock, %k is like %H\n\
 only blank-padded, %l is like %I blank-padded.\n\
Paul Eggert's avatar
Paul Eggert committed
850
%p is the locale's equivalent of either AM or PM.\n\
851 852 853 854 855 856 857 858 859 860 861 862
%M is the minute.\n\
%S is the second.\n\
%Z is the time zone name, %z is the numeric form.\n\
%s is the number of seconds since 1970-01-01 00:00:00 +0000.\n\
\n\
%c is the locale's date and time format.\n\
%x is the locale's \"preferred\" date format.\n\
%D is like \"%m/%d/%y\".\n\
\n\
%R is like \"%H:%M\", %T is like \"%H:%M:%S\", %r is like \"%I:%M:%S %p\".\n\
%X is the locale's \"preferred\" time format.\n\
\n\
Paul Eggert's avatar
Paul Eggert committed
863
Finally, %n is a newline, %t is a tab, %% is a literal %.\n\
864
\n\
865
Certain flags and modifiers are available with some format controls.\n\
866 867 868 869 870 871 872 873 874
The flags are `_' and `-'.  For certain characters X, %_X is like %X,\n\
but padded with blanks; %-X is like %X, but without padding.\n\
%NX (where N stands for an integer) is like %X,\n\
but takes up at least N (a number) positions.\n\
The modifiers are `E' and `O'.  For certain characters X,\n\
%EX is a locale's alternative version of %X;\n\
%OX is like %X, but uses the locale's number symbols.\n\
\n\
For example, to produce full ISO 8601 format, use \"%Y-%m-%dT%T%z\".")
875
  (format_string, time, universal)
876 877 878 879
*/

DEFUN ("format-time-string", Fformat_time_string, Sformat_time_string, 1, 3, 0,
  0 /* See immediately above */)
880 881
  (format_string, time, universal)
     Lisp_Object format_string, time, universal;
882 883 884 885 886 887 888 889 890 891 892 893 894 895
{
  time_t value;
  int size;

  CHECK_STRING (format_string, 1);

  if (! lisp_time_argument (time, &value))
    error ("Invalid time specification");

  /* This is probably enough.  */
  size = XSTRING (format_string)->size * 6 + 50;

  while (1)
    {
896 897 898
      char *buf = (char *) alloca (size + 1);
      int result;

899
      buf[0] = '\1';
900 901 902
      result = emacs_strftime (buf, size, XSTRING (format_string)->data,
			       (NILP (universal) ? localtime (&value)
				: gmtime (&value)));
903
      if ((result > 0 && result < size) || (result == 0 && buf[0] == '\0'))
904
	return build_string (buf);
905 906

      /* If buffer was too small, make it bigger and try again.  */
907
      result = emacs_strftime (NULL, 0x7fffffff, XSTRING (format_string)->data,
908 909 910
			       (NILP (universal) ? localtime (&value)
				: gmtime (&value)));
      size = result + 1;
911 912 913
    }
}

914 915 916 917 918
DEFUN ("decode-time", Fdecode_time, Sdecode_time, 0, 1, 0,
  "Decode a time value as (SEC MINUTE HOUR DAY MONTH YEAR DOW DST ZONE).\n\
The optional SPECIFIED-TIME should be a list of (HIGH LOW . IGNORED)\n\
or (HIGH . LOW), as from `current-time' and `file-attributes', or `nil'\n\
to use the current time.  The list has the following nine members:\n\
Richard M. Stallman's avatar
Richard M. Stallman committed
919 920
SEC is an integer between 0 and 60; SEC is 60 for a leap second, which\n\
only some operating systems support.  MINUTE is an integer between 0 and 59.\n\
921 922 923 924 925
HOUR is an integer between 0 and 23.  DAY is an integer between 1 and 31.\n\
MONTH is an integer between 1 and 12.  YEAR is an integer indicating the\n\
four-digit year.  DOW is the day of week, an integer between 0 and 6, where\n\
0 is Sunday.  DST is t if daylight savings time is effect, otherwise nil.\n\
ZONE is an integer indicating the number of seconds east of Greenwich.\n\
Richard M. Stallman's avatar
Richard M. Stallman committed
926
\(Note that Common Lisp has different meanings for DOW and ZONE.)")
927 928 929 930
  (specified_time)
     Lisp_Object specified_time;
{
  time_t time_spec;
931
  struct tm save_tm;
932 933 934 935 936 937 938
  struct tm *decoded_time;
  Lisp_Object list_args[9];
  
  if (! lisp_time_argument (specified_time, &time_spec))
    error ("Invalid time specification");

  decoded_time = localtime (&time_spec);
939 940 941 942 943
  XSETFASTINT (list_args[0], decoded_time->tm_sec);
  XSETFASTINT (list_args[1], decoded_time->tm_min);
  XSETFASTINT (list_args[2], decoded_time->tm_hour);
  XSETFASTINT (list_args[3], decoded_time->tm_mday);
  XSETFASTINT (list_args[4], decoded_time->tm_mon + 1);
944
  XSETINT (list_args[5], decoded_time->tm_year + 1900);
945
  XSETFASTINT (list_args[6], decoded_time->tm_wday);
946
  list_args[7] = (decoded_time->tm_isdst)? Qt : Qnil;
947 948 949 950 951 952 953

  /* Make a copy, in case gmtime modifies the struct.  */
  save_tm = *decoded_time;
  decoded_time = gmtime (&time_spec);
  if (decoded_time == 0)
    list_args[8] = Qnil;
  else
954
    XSETINT (list_args[8], tm_diff (&save_tm, decoded_time));
955 956 957
  return Flist (9, list_args);
}

958
DEFUN ("encode-time", Fencode_time, Sencode_time, 6, MANY, 0,
959
  "Convert SECOND, MINUTE, HOUR, DAY, MONTH, YEAR and ZONE to internal time.\n\
960 961
This is the reverse operation of `decode-time', which see.\n\
ZONE defaults to the current time zone rule.  This can\n\
962
be a string or t (as from `set-time-zone-rule'), or it can be a list\n\
Richard M. Stallman's avatar
Richard M. Stallman committed
963
\(as from `current-time-zone') or an integer (as from `decode-time')\n\
964
applied without consideration for daylight savings time.\n\
965 966 967 968 969 970
\n\
You can pass more than 7 arguments; then the first six arguments\n\
are used as SECOND through YEAR, and the *last* argument is used as ZONE.\n\
The intervening arguments are ignored.\n\
This feature lets (apply 'encode-time (decode-time ...)) work.\n\
\n\
971 972
Out-of-range values for SEC, MINUTE, HOUR, DAY, or MONTH are allowed;\n\
for example, a DAY of 0 means the day preceding the given month.\n\
973
Year numbers less than 100 are treated just like other year numbers.\n\
974
If you want them to stand for years in this century, you must do that yourself.")
975 976 977
  (nargs, args)
     int nargs;
     register Lisp_Object *args;
978
{
979
  time_t time;
980
  struct tm tm;
Richard M. Stallman's avatar
Richard M. Stallman committed
981
  Lisp_Object zone = (nargs > 6 ? args[nargs - 1] : Qnil);
982 983 984 985 986 987 988 989 990 991 992 993 994 995

  CHECK_NUMBER (args[0], 0);	/* second */
  CHECK_NUMBER (args[1], 1);	/* minute */
  CHECK_NUMBER (args[2], 2);	/* hour */
  CHECK_NUMBER (args[3], 3);	/* day */
  CHECK_NUMBER (args[4], 4);	/* month */
  CHECK_NUMBER (args[5], 5);	/* year */

  tm.tm_sec = XINT (args[0]);
  tm.tm_min = XINT (args[1]);
  tm.tm_hour = XINT (args[2]);
  tm.tm_mday = XINT (args[3]);
  tm.tm_mon = XINT (args[4]) - 1;
  tm.tm_year = XINT (args[5]) - 1900;
996 997 998 999
  tm.tm_isdst = -1;

  if (CONSP (zone))
    zone = Fcar (zone);
1000
  if (NILP (zone))
1001 1002
    time = mktime (&tm);
  else
1003
    {
1004 1005 1006 1007
      char tzbuf[100];
      char *tzstring;
      char **oldenv = environ, **newenv;
      
1008
      if (EQ (zone, Qt))
1009 1010
	tzstring = "UTC0";
      else if (STRINGP (zone))
1011
	tzstring = (char *) XSTRING (zone)->data;
1012
      else if (INTEGERP (zone))
1013
	{
1014 1015 1016 1017
	  int abszone = abs (XINT (zone));
	  sprintf (tzbuf, "XXX%s%d:%02d:%02d", "-" + (XINT (zone) < 0),
		   abszone / (60*60), (abszone/60) % 60, abszone % 60);
	  tzstring = tzbuf;
1018
	}
1019 1020 1021 1022 1023 1024 1025 1026 1027 1028 1029 1030
      else
	error ("Invalid time zone specification");

      /* Set TZ before calling mktime; merely adjusting mktime's returned 
	 value doesn't suffice, since that would mishandle leap seconds.  */
      set_time_zone_rule (tzstring);

      time = mktime (&tm);

      /* Restore TZ to previous value.  */
      newenv = environ;
      environ = oldenv;
1031
      xfree (newenv);
1032 1033 1034
#ifdef LOCALTIME_CACHE
      tzset ();
#endif
1035 1036
    }

1037 1038 1039 1040
  if (time == (time_t) -1)
    error ("Specified time is not representable");

  return make_time (time);
1041 1042
}

1043
DEFUN ("current-time-string", Fcurrent_time_string, Scurrent_time_string, 0, 1, 0,
Jim Blandy's avatar
Jim Blandy committed
1044
  "Return the current time, as a human-readable string.\n\
1045 1046 1047
Programs can use this function to decode a time,\n\
since the number of columns in each field is fixed.\n\
The format is `Sun Sep 16 01:03:52 1973'.\n\
1048 1049 1050
However, see also the functions `decode-time' and `format-time-string'\n\
which provide a much more powerful and general facility.\n\
\n\
1051 1052 1053 1054 1055 1056 1057 1058 1059 1060
If an argument is given, it specifies a time to format\n\
instead of the current time.  The argument should have the form:\n\
  (HIGH . LOW)\n\
or the form:\n\
  (HIGH LOW . IGNORED).\n\
Thus, you can use times obtained from `current-time'\n\
and from `file-attributes'.")
  (specified_time)
     Lisp_Object specified_time;
{
1061
  time_t value;
Jim Blandy's avatar
Jim Blandy committed
1062
  char buf[30];
1063 1064
  register char *tem;

1065 1066
  if (! lisp_time_argument (specified_time, &value))
    value = -1;
1067
  tem = (char *) ctime (&value);
Jim Blandy's avatar
Jim Blandy committed
1068 1069 1070 1071 1072 1073

  strncpy (buf, tem, 24);
  buf[24] = 0;

  return build_string (buf);
}
1074

1075
#define TM_YEAR_BASE 1900
1076

1077 1078 1079 1080
/* Yield A - B, measured in seconds.
   This function is copied from the GNU C Library.  */
static int
tm_diff (a, b)
1081 1082
     struct tm *a, *b;
{
1083 1084 1085 1086 1087 1088 1089 1090 1091 1092 1093 1094 1095 1096 1097
  /* Compute intervening leap days correctly even if year is negative.
     Take care to avoid int overflow in leap day calculations,
     but it's OK to assume that A and B are close to each other.  */
  int a4 = (a->tm_year >> 2) + (TM_YEAR_BASE >> 2) - ! (a->tm_year & 3);
  int b4 = (b->tm_year >> 2) + (TM_YEAR_BASE >> 2) - ! (b->tm_year & 3);
  int a100 = a4 / 25 - (a4 % 25 < 0);
  int b100 = b4 / 25 - (b4 % 25 < 0);
  int a400 = a100 >> 2;
  int b400 = b100 >> 2;
  int intervening_leap_days = (a4 - b4) - (a100 - b100) + (a400 - b400);
  int years = a->tm_year - b->tm_year;
  int days = (365 * years + intervening_leap_days
	      + (a->tm_yday - b->tm_yday));
  return (60 * (60 * (24 * days + (a->tm_hour - b->tm_hour))
		+ (a->tm_min - b->tm_min))
Karl Heuer's avatar
Karl Heuer committed
1098
	  + (a->tm_sec - b->tm_sec));
1099 1100 1101 1102 1103 1104 1105 1106 1107 1108 1109 1110 1111 1112 1113
}

DEFUN ("current-time-zone", Fcurrent_time_zone, Scurrent_time_zone, 0, 1, 0,
  "Return the offset and name for the local time zone.\n\
This returns a list of the form (OFFSET NAME).\n\
OFFSET is an integer number of seconds ahead of UTC (east of Greenwich).\n\
    A negative value means west of Greenwich.\n\
NAME is a string giving the name of the time zone.\n\
If an argument is given, it specifies when the time zone offset is determined\n\
instead of using the current time.  The argument should have the form:\n\
  (HIGH . LOW)\n\
or the form:\n\
  (HIGH LOW . IGNORED).\n\
Thus, you can use times obtained from `current-time'\n\
and from `file-attributes'.\n\
1114 1115
\n\
Some operating systems cannot provide all this information to Emacs;\n\
1116
in this case, `current-time-zone' returns a list containing nil for\n\
1117
the data it can't find.")
1118 1119
  (specified_time)
     Lisp_Object specified_time;
1120
{
1121 1122
  time_t value;
  struct tm *t;
1123

1124
  if (lisp_time_argument (specified_time, &value)
1125
      && (t = gmtime (&value)) != 0)
1126
    {
1127
      struct tm gmt;
1128
      int offset;
1129
      char *s, buf[6];
1130 1131 1132

      gmt = *t;		/* Make a copy, in case localtime modifies *t.  */
      t = localtime (&value);
1133
      offset = tm_diff (t, &gmt);
1134 1135 1136
      s = 0;
#ifdef HAVE_TM_ZONE
      if (t->tm_zone)
1137
	s = (char *)t->tm_zone;
1138 1139 1140 1141
#else /* not HAVE_TM_ZONE */
#ifdef HAVE_TZNAME
      if (t->tm_isdst == 0 || t->tm_isdst == 1)
	s = tzname[t->tm_isdst];