editfns.c 84.2 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 ();
52
void set_time_zone_rule ();
53 54 55 56

Lisp_Object Vbuffer_access_fontify_functions;
Lisp_Object Qbuffer_access_fontify_functions;
Lisp_Object Vbuffer_access_fontified_property;
57

58 59
Lisp_Object Fuser_full_name ();

Jim Blandy's avatar
Jim Blandy committed
60 61 62
/* Some static data, and a function to initialize it for each run */

Lisp_Object Vsystem_name;
63 64 65
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
66 67 68 69

void
init_editfns ()
{
Jim Blandy's avatar
Jim Blandy committed
70
  char *user_name;
Jim Blandy's avatar
Jim Blandy committed
71 72 73 74 75
  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.  */
76
  init_system_name ();
Jim Blandy's avatar
Jim Blandy committed
77 78 79 80 81 82 83 84

#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
85 86 87 88
#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.)  */
89
  Vuser_real_login_name = build_string (pw ? pw->pw_name : "root");
Morten Welinder's avatar
Morten Welinder committed
90
#else
91
  Vuser_real_login_name = build_string (pw ? pw->pw_name : "unknown");
Morten Welinder's avatar
Morten Welinder committed
92
#endif
Jim Blandy's avatar
Jim Blandy committed
93

Jim Blandy's avatar
Jim Blandy committed
94 95
  /* Get the effective user name, by consulting environment variables,
     or the effective uid if those are unset.  */
96
  user_name = (char *) getenv ("LOGNAME");
Jim Blandy's avatar
Jim Blandy committed
97
  if (!user_name)
98 99 100
#ifdef WINDOWSNT
    user_name = (char *) getenv ("USERNAME");	/* it's USERNAME on NT */
#else  /* WINDOWSNT */
101
    user_name = (char *) getenv ("USER");
102
#endif /* WINDOWSNT */
Jim Blandy's avatar
Jim Blandy committed
103 104 105 106 107
  if (!user_name)
    {
      pw = (struct passwd *) getpwuid (geteuid ());
      user_name = (char *) (pw ? pw->pw_name : "unknown");
    }
108
  Vuser_login_name = build_string (user_name);
Jim Blandy's avatar
Jim Blandy committed
109

Jim Blandy's avatar
Jim Blandy committed
110 111
  /* If the user name claimed in the environment vars differs from
     the real uid, use the claimed name to find the full name.  */
112
  tem = Fstring_equal (Vuser_login_name, Vuser_real_login_name);
113 114
  Vuser_full_name = Fuser_full_name (NILP (tem)? make_number (geteuid())
				     : Vuser_login_name);
Jim Blandy's avatar
Jim Blandy committed
115
  
116
  p = (unsigned char *) getenv ("NAME");
117 118
  if (p)
    Vuser_full_name = build_string (p);
119 120
  else if (NILP (Vuser_full_name))
    Vuser_full_name = build_string ("unknown");
Jim Blandy's avatar
Jim Blandy committed
121 122 123
}

DEFUN ("char-to-string", Fchar_to_string, Schar_to_string, 1, 1, 0,
Karl Heuer's avatar
Karl Heuer committed
124
  "Convert arg CHAR to a string containing multi-byte form of that character.")
125 126
  (character)
     Lisp_Object character;
Jim Blandy's avatar
Jim Blandy committed
127
{
Karl Heuer's avatar
Karl Heuer committed
128
  int len;
129
  unsigned char workbuf[4], *str;
Karl Heuer's avatar
Karl Heuer committed
130

131
  CHECK_NUMBER (character, 0);
Jim Blandy's avatar
Jim Blandy committed
132

Karl Heuer's avatar
Karl Heuer committed
133 134
  len = CHAR_STRING (XFASTINT (character), workbuf, str);
  return make_string (str, len);
Jim Blandy's avatar
Jim Blandy committed
135 136 137
}

DEFUN ("string-to-char", Fstring_to_char, Sstring_to_char, 1, 1, 0,
Karl Heuer's avatar
Karl Heuer committed
138 139
  "Convert arg STRING to a character, the first character of that string.\n\
A multibyte character is handled correctly.")
140 141
  (string)
     register Lisp_Object string;
Jim Blandy's avatar
Jim Blandy committed
142 143 144
{
  register Lisp_Object val;
  register struct Lisp_String *p;
145 146
  CHECK_STRING (string, 0);
  p = XSTRING (string);
Jim Blandy's avatar
Jim Blandy committed
147
  if (p->size)
Karl Heuer's avatar
Karl Heuer committed
148
    XSETFASTINT (val, STRING_CHAR (p->data, p->size));
Jim Blandy's avatar
Jim Blandy committed
149
  else
150
    XSETFASTINT (val, 0);
Jim Blandy's avatar
Jim Blandy committed
151 152
  return val;
}
Karl Heuer's avatar
Karl Heuer committed
153 154 155 156 157 158 159 160

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;
{
161 162
  register int idxval, len, i;
  register unsigned char *p, *q;
Karl Heuer's avatar
Karl Heuer committed
163 164 165 166 167 168 169
  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);
170

Karl Heuer's avatar
Karl Heuer committed
171
  p = XSTRING (str)->data + idxval;
172 173 174 175 176 177 178 179 180 181 182 183 184 185 186 187 188
  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
189 190 191 192 193 194

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

Jim Blandy's avatar
Jim Blandy committed
195 196 197 198 199 200 201 202 203 204 205 206 207 208 209 210 211

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;
212
  XSETFASTINT (temp, PT);
Jim Blandy's avatar
Jim Blandy committed
213 214 215 216 217 218 219
  return temp;
}

DEFUN ("point-marker", Fpoint_marker, Spoint_marker, 0, 0, 0,
   "Return value of point, as a marker object.")
  ()
{
220
  return buildmark (PT);
Jim Blandy's avatar
Jim Blandy committed
221 222 223 224 225 226 227 228 229 230 231 232 233 234 235 236
}

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
237 238 239 240
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.")
241 242
  (position)
     register Lisp_Object position;
Jim Blandy's avatar
Jim Blandy committed
243
{
Karl Heuer's avatar
Karl Heuer committed
244 245 246
  int pos;
  unsigned char *p;

247
  CHECK_NUMBER_COERCE_MARKER (position, 0);
Jim Blandy's avatar
Jim Blandy committed
248

Karl Heuer's avatar
Karl Heuer committed
249 250 251 252 253 254 255 256 257 258 259 260 261 262 263 264 265 266 267 268 269 270 271
  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);
272
  return position;
Jim Blandy's avatar
Jim Blandy committed
273 274 275 276 277 278
}

static Lisp_Object
region_limit (beginningp)
     int beginningp;
{
279
  extern Lisp_Object Vmark_even_if_inactive; /* Defined in callint.c. */
Jim Blandy's avatar
Jim Blandy committed
280
  register Lisp_Object m;
281 282 283
  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
284
  m = Fmarker_position (current_buffer->mark);
Jim Blandy's avatar
Jim Blandy committed
285
  if (NILP (m)) error ("There is no region now");
286 287
  if ((PT < XFASTINT (m)) == beginningp)
    return (make_number (PT));
Jim Blandy's avatar
Jim Blandy committed
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
  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;
}
314 315 316 317 318 319 320 321 322 323 324 325 326 327 328 329 330 331 332 333 334

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
335

336 337 338 339 340 341 342 343 344 345 346 347 348 349 350 351 352 353 354 355 356
  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
357 358 359
Lisp_Object
save_excursion_save ()
{
360 361
  register int visible = (XBUFFER (XWINDOW (selected_window)->buffer)
			  == current_buffer);
Jim Blandy's avatar
Jim Blandy committed
362 363

  return Fcons (Fpoint_marker (),
364
		Fcons (Fcopy_marker (current_buffer->mark, Qnil),
365 366
		       Fcons (visible ? Qt : Qnil,
			      current_buffer->mark_active)));		       
Jim Blandy's avatar
Jim Blandy committed
367 368 369 370
}

Lisp_Object
save_excursion_restore (info)
371
     Lisp_Object info;
Jim Blandy's avatar
Jim Blandy committed
372
{
373 374
  Lisp_Object tem, tem1, omark, nmark;
  struct gcpro gcpro1, gcpro2, gcpro3;
Jim Blandy's avatar
Jim Blandy committed
375 376 377 378 379 380

  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
381
  if (NILP (tem))
Jim Blandy's avatar
Jim Blandy committed
382
    return Qnil;
383 384 385 386

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

Jim Blandy's avatar
Jim Blandy committed
387 388 389 390 391
  Fset_buffer (tem);
  tem = Fcar (info);
  Fgoto_char (tem);
  unchain_marker (tem);
  tem = Fcar (Fcdr (info));
392
  omark = Fmarker_position (current_buffer->mark);
Jim Blandy's avatar
Jim Blandy committed
393
  Fset_marker (current_buffer->mark, tem, Fcurrent_buffer ());
394
  nmark = Fmarker_position (tem);
Jim Blandy's avatar
Jim Blandy committed
395 396
  unchain_marker (tem);
  tem = Fcdr (Fcdr (info));
397 398 399 400
#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.  */
401 402
  tem1 = Fcar (tem);
  if (!NILP (tem1)
403
      && current_buffer != XBUFFER (XWINDOW (selected_window)->buffer))
Jim Blandy's avatar
Jim Blandy committed
404
    Fswitch_to_buffer (Fcurrent_buffer (), Qnil);
405
#endif /* 0 */
406 407 408

  tem1 = current_buffer->mark_active;
  current_buffer->mark_active = Fcdr (tem);
409 410
  if (!NILP (Vrun_hooks))
    {
411 412
      /* If mark is active now, and either was not active
	 or was at a different place, run the activate hook.  */
413
      if (! NILP (current_buffer->mark_active))
414 415 416 417 418
	{
	  if (! EQ (omark, nmark))
	    call1 (Vrun_hooks, intern ("activate-mark-hook"));
	}
      /* If mark has ceased to be active, run deactivate hook.  */
419 420 421
      else if (! NILP (tem1))
	call1 (Vrun_hooks, intern ("deactivate-mark-hook"));
    }
422
  UNGCPRO;
Jim Blandy's avatar
Jim Blandy committed
423 424 425 426 427 428 429
  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\
430 431
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
432 433 434 435 436 437 438
  (args)
     Lisp_Object args;
{
  register Lisp_Object val;
  int count = specpdl_ptr - specpdl;

  record_unwind_protect (save_excursion_restore, save_excursion_save ());
439 440 441 442 443 444 445 446 447 448 449 450 451 452 453 454

  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
455 456 457 458 459 460 461 462 463
  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;
464
  XSETFASTINT (temp, Z - BEG);
Jim Blandy's avatar
Jim Blandy committed
465 466 467 468 469
  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
470
This is 1, unless narrowing (a buffer restriction) is in effect.")
Jim Blandy's avatar
Jim Blandy committed
471 472 473
  ()
{
  Lisp_Object temp;
474
  XSETFASTINT (temp, BEGV);
Jim Blandy's avatar
Jim Blandy committed
475 476 477 478 479
  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
480
This is the beginning, unless narrowing (a buffer restriction) is in effect.")
Jim Blandy's avatar
Jim Blandy committed
481 482 483 484 485 486 487
  ()
{
  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
488 489
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
490 491 492
  ()
{
  Lisp_Object temp;
493
  XSETFASTINT (temp, ZV);
Jim Blandy's avatar
Jim Blandy committed
494 495 496 497 498
  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
499 500
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
501 502 503 504 505
  ()
{
  return buildmark (ZV);
}

Jim Blandy's avatar
Jim Blandy committed
506 507
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
508 509 510 511
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
512 513 514
  ()
{
  Lisp_Object temp;
515
  if (PT >= ZV)
516
    XSETFASTINT (temp, 0);
Jim Blandy's avatar
Jim Blandy committed
517
  else
518
    XSETFASTINT (temp, FETCH_CHAR (PT));
Jim Blandy's avatar
Jim Blandy committed
519 520 521
  return temp;
}

Jim Blandy's avatar
Jim Blandy committed
522 523
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
524 525 526 527
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
528 529 530
  ()
{
  Lisp_Object temp;
531
  if (PT <= BEGV)
532
    XSETFASTINT (temp, 0);
Karl Heuer's avatar
Karl Heuer committed
533 534 535 536 537 538
  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
539
  else
540
    XSETFASTINT (temp, FETCH_BYTE (PT - 1));
Jim Blandy's avatar
Jim Blandy committed
541 542 543 544 545 546 547 548
  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.")
  ()
{
549
  if (PT == BEGV)
Jim Blandy's avatar
Jim Blandy committed
550 551 552 553 554 555 556 557 558
    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.")
  ()
{
559
  if (PT == ZV)
Jim Blandy's avatar
Jim Blandy committed
560 561 562 563 564 565 566 567
    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
568
  if (PT == BEGV || FETCH_BYTE (PT - 1) == '\n')
Jim Blandy's avatar
Jim Blandy committed
569 570 571 572 573 574 575 576 577
    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
578
  if (PT == ZV || FETCH_BYTE (PT) == '\n')
Jim Blandy's avatar
Jim Blandy committed
579 580 581 582
    return Qt;
  return Qnil;
}

583
DEFUN ("char-after", Fchar_after, Schar_after, 0, 1, 0,
Jim Blandy's avatar
Jim Blandy committed
584 585
  "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
586 587 588 589
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
590 591 592 593 594 595
  (pos)
     Lisp_Object pos;
{
  register Lisp_Object val;
  register int n;

596 597 598 599 600
  if (NILP (pos))
    n = PT;
  else
    {
      CHECK_NUMBER_COERCE_MARKER (pos, 0);
Jim Blandy's avatar
Jim Blandy committed
601

602 603 604 605
      n = XINT (pos);
      if (n < BEGV || n >= ZV)
	return Qnil;
    }
Jim Blandy's avatar
Jim Blandy committed
606

607
  XSETFASTINT (val, FETCH_CHAR (n));
Jim Blandy's avatar
Jim Blandy committed
608 609
  return val;
}
Karl Heuer's avatar
Karl Heuer committed
610

611
DEFUN ("char-before", Fchar_before, Schar_before, 0, 1, 0,
Karl Heuer's avatar
Karl Heuer committed
612 613 614 615 616 617 618 619 620 621 622 623
  "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;

624 625 626 627 628
  if (NILP (pos))
    n = PT;
  else
    {
      CHECK_NUMBER_COERCE_MARKER (pos, 0);
Karl Heuer's avatar
Karl Heuer committed
629

630 631
      n = XINT (pos);
    }
Karl Heuer's avatar
Karl Heuer committed
632

633 634 635
  if (n <= BEGV || n > ZV)
    return Qnil;

Karl Heuer's avatar
Karl Heuer committed
636 637
  if (!NILP (current_buffer->enable_multibyte_characters))
    {
638 639
      DEC_POS (n);
      XSETFASTINT (val, FETCH_CHAR (n));
Karl Heuer's avatar
Karl Heuer committed
640 641 642
    }
  else
    {
643 644
      n--;
      XSETFASTINT (val, FETCH_BYTE (n));
Karl Heuer's avatar
Karl Heuer committed
645 646 647
    }
   return val;
}
Jim Blandy's avatar
Jim Blandy committed
648

Morten Welinder's avatar
Morten Welinder committed
649
DEFUN ("user-login-name", Fuser_login_name, Suser_login_name, 0, 1, 0,
Jim Blandy's avatar
Jim Blandy committed
650 651
  "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\
652
Also, if the environment variable LOGNAME or USER is set,\n\
Morten Welinder's avatar
Morten Welinder committed
653 654 655 656 657
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
658
{
Morten Welinder's avatar
Morten Welinder committed
659 660
  struct passwd *pw;

661 662 663
  /* 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.  */
664
  if (INTEGERP (Vuser_login_name))
665
    init_editfns ();
Morten Welinder's avatar
Morten Welinder committed
666 667

  if (NILP (uid))
668
    return Vuser_login_name;
Morten Welinder's avatar
Morten Welinder committed
669 670 671 672

  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
673 674 675 676 677
}

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\
678
This ignores the environment variables LOGNAME and USER, so it differs from\n\
Karl Heuer's avatar
Karl Heuer committed
679
`user-login-name' when running under `su'.")
Jim Blandy's avatar
Jim Blandy committed
680 681
  ()
{
682 683 684
  /* 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.  */
685
  if (INTEGERP (Vuser_login_name))
686
    init_editfns ();
687
  return Vuser_real_login_name;
Jim Blandy's avatar
Jim Blandy committed
688 689 690 691 692 693 694 695 696 697 698 699 700 701 702 703
}

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 ());
}

704 705 706
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
707
with that uid, or \"unknown\" if there is no such user.\n\
708 709
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.")
710 711
  (uid)
     Lisp_Object uid;
Jim Blandy's avatar
Jim Blandy committed
712
{
713
  struct passwd *pw;
714
  register unsigned char *p, *q;
715 716
  extern char *index ();
  Lisp_Object full;
717 718

  if (NILP (uid))
719 720 721 722 723 724 725
    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");
726

727
  if (!pw)
728
    return Qnil;
729 730 731 732 733 734 735 736 737 738 739 740
  
  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)
    {
741
      register unsigned char *r;
742 743 744 745 746 747 748 749 750 751 752 753 754 755
      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
756 757 758 759 760 761 762 763 764
}

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;
}

765 766 767 768
/* For the benefit of callers who don't want to include lisp.h */
char *
get_system_name ()
{
769 770 771 772
  if (STRINGP (Vsystem_name))
    return (char *) XSTRING (Vsystem_name)->data;
  else
    return "";
773 774
}

775 776 777 778 779 780 781
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
782
DEFUN ("current-time", Fcurrent_time, Scurrent_time, 0, 0, 0,
783
  "Return the current time, as the number of seconds since 1970-01-01 00:00:00.\n\
Jim Blandy's avatar
Jim Blandy committed
784 785 786 787 788 789 790
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
791 792
  ()
{
Jim Blandy's avatar
Jim Blandy committed
793 794 795 796
  EMACS_TIME t;
  Lisp_Object result[3];

  EMACS_GET_TIME (t);
797 798 799
  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
800 801

  return Flist (3, result);
Jim Blandy's avatar
Jim Blandy committed
802 803 804
}


805 806 807 808 809 810 811 812 813 814 815 816 817
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);
818
      if (CONSP (low))
819 820 821 822 823 824 825
	low = Fcar (low);
      CHECK_NUMBER (low, 0);
      *result = (XINT (high) << 16) + (XINT (low) & 0xffff);
      return *result >> 16 == XINT (high);
    }
}

826
/*
827 828 829 830 831 832 833 834
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\
835
\n\
836 837 838 839 840 841 842 843 844 845 846 847 848 849 850 851 852 853 854 855 856 857 858 859 860 861 862
%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\
%m is the numeric month, %b and %h the abbreviated name, %B the full name.\n\
%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\
%a is the abbreviated name of the day of week, %A the full name.\n\
%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\
%p is AM or PM.\n\
%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\
Finally, %n is like \n, %t is like \t, %% is a literal %.\n\
\n\
863
Certain flags and modifiers are available with some format controls.\n\
864 865 866 867 868 869 870 871 872
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\".")
873
  (format_string, time, universal)
874 875 876 877
*/

DEFUN ("format-time-string", Fformat_time_string, Sformat_time_string, 1, 3, 0,
  0 /* See immediately above */)
878 879
  (format_string, time, universal)
     Lisp_Object format_string, time, universal;
880 881 882 883 884 885 886 887 888 889 890 891 892 893
{
  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)
    {
894 895 896
      char *buf = (char *) alloca (size + 1);
      int result;

897
      buf[0] = '\1';
898 899 900
      result = emacs_strftime (buf, size, XSTRING (format_string)->data,
			       (NILP (universal) ? localtime (&value)
				: gmtime (&value)));
901
      if ((result > 0 && result < size) || (result == 0 && buf[0] == '\0'))
902
	return build_string (buf);
903 904

      /* If buffer was too small, make it bigger and try again.  */
905
      result = emacs_strftime (NULL, 0x7fffffff, XSTRING (format_string)->data,
906 907 908
			       (NILP (universal) ? localtime (&value)
				: gmtime (&value)));
      size = result + 1;
909 910 911
    }
}

912 913 914 915 916
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
917 918
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\
919 920 921 922 923
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
924
\(Note that Common Lisp has different meanings for DOW and ZONE.)")
925 926 927 928
  (specified_time)
     Lisp_Object specified_time;
{
  time_t time_spec;
929
  struct tm save_tm;
930 931 932 933 934 935 936
  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);
937 938 939 940 941
  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);
942
  XSETINT (list_args[5], decoded_time->tm_year + 1900);
943
  XSETFASTINT (list_args[6], decoded_time->tm_wday);
944
  list_args[7] = (decoded_time->tm_isdst)? Qt : Qnil;
945 946 947 948 949 950 951

  /* 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
952
    XSETINT (list_args[8], tm_diff (&save_tm, decoded_time));
953 954 955
  return Flist (9, list_args);
}

956
DEFUN ("encode-time", Fencode_time, Sencode_time, 6, MANY, 0,
957
  "Convert SECOND, MINUTE, HOUR, DAY, MONTH, YEAR and ZONE to internal time.\n\
958 959
This is the reverse operation of `decode-time', which see.\n\
ZONE defaults to the current time zone rule.  This can\n\
960
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
961
\(as from `current-time-zone') or an integer (as from `decode-time')\n\
962
applied without consideration for daylight savings time.\n\
963 964 965 966 967 968
\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\
969 970
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\
971
Year numbers less than 100 are treated just like other year numbers.\n\
972
If you want them to stand for years in this century, you must do that yourself.")
973 974 975
  (nargs, args)
     int nargs;
     register Lisp_Object *args;
976
{
977
  time_t time;
978
  struct tm tm;
Richard M. Stallman's avatar
Richard M. Stallman committed
979
  Lisp_Object zone = (nargs > 6 ? args[nargs - 1] : Qnil);
980 981 982 983 984 985 986 987 988 989 990 991 992 993

  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;
994 995 996 997
  tm.tm_isdst = -1;

  if (CONSP (zone))
    zone = Fcar (zone);
998
  if (NILP (zone))
999 1000
    time = mktime (&tm);
  else
1001
    {
1002 1003 1004 1005
      char tzbuf[100];
      char *tzstring;
      char **oldenv = environ, **newenv;
      
1006
      if (EQ (zone, Qt))
1007 1008
	tzstring = "UTC0";
      else if (STRINGP (zone))
1009
	tzstring = (char *) XSTRING (zone)->data;
1010
      else if (INTEGERP (zone))
1011
	{
1012 1013 1014 1015
	  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;
1016
	}
1017 1018 1019 1020 1021 1022 1023 1024 1025 1026 1027 1028
      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;
1029
      xfree (newenv);
1030 1031 1032
#ifdef LOCALTIME_CACHE
      tzset ();
#endif
1033 1034
    }

1035 1036 1037 1038
  if (time == (time_t) -1)
    error ("Specified time is not representable");

  return make_time (time);
1039 1040
}

1041
DEFUN ("current-time-string", Fcurrent_time_string, Scurrent_time_string, 0, 1, 0,
Jim Blandy's avatar
Jim Blandy committed
1042
  "Return the current time, as a human-readable string.\n\
1043 1044 1045
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\
1046 1047 1048
However, see also the functions `decode-time' and `format-time-string'\n\
which provide a much more powerful and general facility.\n\
\n\
1049 1050 1051 1052 1053 1054 1055 1056 1057 1058
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;
{
1059
  time_t value;
Jim Blandy's avatar
Jim Blandy committed
1060
  char buf[30];
1061 1062
  register char *tem;

1063 1064
  if (! lisp_time_argument (specified_time, &value))
    value = -1;
1065
  tem = (char *) ctime (&value);
Jim Blandy's avatar
Jim Blandy committed
1066 1067 1068 1069 1070 1071

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

  return build_string (buf);
}
1072

1073
#define TM_YEAR_BASE 1900
1074

1075 1076 1077 1078
/* Yield A - B, measured in seconds.
   This function is copied from the GNU C Library.  */
static int
tm_diff (a, b)
1079 1080
     struct tm *a, *b;
{
1081 1082 1083 1084 1085 1086 1087 1088 1089 1090 1091 1092 1093 1094 1095
  /* 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
1096
	  + (a->tm_sec - b->tm_sec));
1097 1098 1099 1100 1101 1102 1103 1104 1105 1106 1107 1108 1109 1110 1111
}

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\
1112 1113
\n\
Some operating systems cannot provide all this information to Emacs;\n\
1114
in this case, `current-time-zone' returns a list containing nil for\n\
1115
the data it can't find.")
1116 1117
  (specified_time)
     Lisp_Object specified_time;
1118
{
1119 1120
  time_t value;
  struct tm *t;
1121

1122
  if (lisp_time_argument (specified_time, &value)
1123
      && (t = gmtime (&value)) != 0)
1124
    {
1125
      struct tm gmt;
1126
      int offset;
1127
      char *s, buf[6];
1128 1129 1130

      gmt = *t;		/* Make a copy, in case localtime modifies *t.  */
      t = localtime (&value);
1131
      offset = tm_diff (t, &gmt);
1132 1133 1134
      s = 0;
#ifdef HAVE_TM_ZONE
      if (t->tm_zone)
1135
	s = (char *)t->tm_zone;
1136 1137 1138 1139
#else /* not HAVE_TM_ZONE */
#ifdef HAVE_TZNAME
      if (t->tm_isdst == 0 || t->tm_isdst == 1)
	s = tzname[t->tm_isdst];
1140
#endif
1141
#endif /* not HAVE_TM_ZONE */
1142 1143 1144
      if (!s)
	{
	  /* No local time zone name is available; use "+-NNNN" instead.  */
1145
	  int am = (offset < 0 ? -offset : offset) / 60;
1146 1147 1148 1149 1150 1151
	  sprintf (buf, "%c%02d%02d", (offset < 0 ? '-' : '+'), am/60, am%60);
	  s = buf;
	}
      return Fcons (make_number (offset), Fcons (build_string (s), Qnil));
    }
  else
1152
    return Fmake_list (make_number (2), Qnil);