readline/history.c

   1 /* history.c -- standalone history library */
   2
   3 /* Copyright (C) 1989-2005 Free Software Foundation, Inc.
   4
   5    This file contains the GNU History Library (the Library), a set of
   6    routines for managing the text of previously typed lines.
   7
   8    The Library is free software; you can redistribute it and/or modify
   9    it under the terms of the GNU General Public License as published by
  10    the Free Software Foundation; either version 2, or (at your option)
  11    any later version.
  12
  13    The Library is distributed in the hope that it will be useful, but
  14    WITHOUT ANY WARRANTY; without even the implied warranty of
  15    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  16    General Public License for more details.
  17
  18    The GNU General Public License is often shipped with GNU software, and
  19    is generally kept in a file called COPYING or LICENSE.  If you do not
  20    have a copy of the license, write to the Free Software Foundation,
  21    59 Temple Place, Suite 330, Boston, MA 02111 USA. */
  22
  23 /* The goal is to make the implementation transparent, so that you
  24    don't have to know what data types are used, just what functions
  25    you can call.  I think I have done that. */
  26 #define READLINE_LIBRARY
  27
  28 #if defined (HAVE_CONFIG_H)
  29 #  include <config.h>
  30 #endif
  31
  32 #include <stdio.h>
  33
  34 #if defined (HAVE_STDLIB_H)
  35 #  include <stdlib.h>
  36 #else
  37 #  include "ansi_stdlib.h"
  38 #endif /* HAVE_STDLIB_H */
  39
  40 #if defined (HAVE_UNISTD_H)
  41 #  ifdef _MINIX
  42 #    include <sys/types.h>
  43 #  endif
  44 #  include <unistd.h>
  45 #endif
  46
  47 #include "history.h"
  48 #include "histlib.h"
  49
  50 #include "xmalloc.h"
  51
  52 /* The number of slots to increase the_history by. */
  53 #define DEFAULT_HISTORY_GROW_SIZE 50
  54
  55 static char *hist_inittime PARAMS((void));
  56
  57 /* **************************************************************** */
  58 /*                                                                  */
  59 /*                      History Functions                           */
  60 /*                                                                  */
  61 /* **************************************************************** */
  62
  63 /* An array of HIST_ENTRY.  This is where we store the history. */
  64 static HIST_ENTRY **the_history = (HIST_ENTRY **)NULL;
  65
  66 /* Non-zero means that we have enforced a limit on the amount of
  67    history that we save. */
  68 static int history_stifled;
  69
  70 /* The current number of slots allocated to the input_history. */
  71 static int history_size;
  72
  73 /* If HISTORY_STIFLED is non-zero, then this is the maximum number of
  74    entries to remember. */
  75 int history_max_entries;
  76 int max_input_history;  /* backwards compatibility */
  77
  78 /* The current location of the interactive history pointer.  Just makes
  79    life easier for outside callers. */
  80 int history_offset;
  81
  82 /* The number of strings currently stored in the history list. */
  83 int history_length;
  84
  85 /* The logical `base' of the history array.  It defaults to 1. */
  86 int history_base = 1;
  87
  88 /* Return the current HISTORY_STATE of the history. */
  89 HISTORY_STATE *
  90 history_get_history_state ()
  91 {
  92   HISTORY_STATE *state;
  93
  94   state = (HISTORY_STATE *)xmalloc (sizeof (HISTORY_STATE));
  95   state->entries = the_history;
  96   state->offset = history_offset;
  97   state->length = history_length;
  98   state->size = history_size;
  99   state->flags = 0;
 100   if (history_stifled)
 101     state->flags |= HS_STIFLED;
 102
 103   return (state);
 104 }
 105
 106 /* Set the state of the current history array to STATE. */
 107 void
 108 history_set_history_state (state)
 109      HISTORY_STATE *state;
 110 {
 111   the_history = state->entries;
 112   history_offset = state->offset;
 113   history_length = state->length;
 114   history_size = state->size;
 115   if (state->flags & HS_STIFLED)
 116     history_stifled = 1;
 117 }
 118
 119 /* Begin a session in which the history functions might be used.  This
 120    initializes interactive variables. */
 121 void
 122 using_history ()
 123 {
 124   history_offset = history_length;
 125 }
 126
 127 /* Return the number of bytes that the primary history entries are using.
 128    This just adds up the lengths of the_history->lines and the associated
 129    timestamps. */
 130 int
 131 history_total_bytes ()
 132 {
 133   register int i, result;
 134
 135   for (i = result = 0; the_history && the_history[i]; i++)
 136     result += HISTENT_BYTES (the_history[i]);
 137
 138   return (result);
 139 }
 140
 141 /* Returns the magic number which says what history element we are
 142    looking at now.  In this implementation, it returns history_offset. */
 143 int
 144 where_history ()
 145 {
 146   return (history_offset);
 147 }
 148
 149 /* Make the current history item be the one at POS, an absolute index.
 150    Returns zero if POS is out of range, else non-zero. */
 151 int
 152 history_set_pos (pos)
 153      int pos;
 154 {
 155   if (pos > history_length || pos < 0 || !the_history)
 156     return (0);
 157   history_offset = pos;
 158   return (1);
 159 }
 160
 161 /* Return the current history array.  The caller has to be carefull, since this
 162    is the actual array of data, and could be bashed or made corrupt easily.
 163    The array is terminated with a NULL pointer. */
 164 HIST_ENTRY **
 165 history_list ()
 166 {
 167   return (the_history);
 168 }
 169
 170 /* Return the history entry at the current position, as determined by
 171    history_offset.  If there is no entry there, return a NULL pointer. */
 172 HIST_ENTRY *
 173 current_history ()
 174 {
 175   return ((history_offset == history_length) || the_history == 0)
 176                 ? (HIST_ENTRY *)NULL
 177                 : the_history[history_offset];
 178 }
 179
 180 /* Back up history_offset to the previous history entry, and return
 181    a pointer to that entry.  If there is no previous entry then return
 182    a NULL pointer. */
 183 HIST_ENTRY *
 184 previous_history ()
 185 {
 186   return history_offset ? the_history[--history_offset] : (HIST_ENTRY *)NULL;
 187 }
 188
 189 /* Move history_offset forward to the next history entry, and return
 190    a pointer to that entry.  If there is no next entry then return a
 191    NULL pointer. */
 192 HIST_ENTRY *
 193 next_history ()
 194 {
 195   return (history_offset == history_length) ? (HIST_ENTRY *)NULL : the_history[++history_offset];
 196 }
 197
 198 /* Return the history entry which is logically at OFFSET in the history array.
 199    OFFSET is relative to history_base. */
 200 HIST_ENTRY *
 201 history_get (offset)
 202      int offset;
 203 {
 204   int local_index;
 205
 206   local_index = offset - history_base;
 207   return (local_index >= history_length || local_index < 0 || the_history == 0)
 208                 ? (HIST_ENTRY *)NULL
 209                 : the_history[local_index];
 210 }
 211
 212 time_t
 213 history_get_time (hist)
 214      HIST_ENTRY *hist;
 215 {
 216   char *ts;
 217   time_t t;
 218
 219   if (hist == 0 || hist->timestamp == 0)
 220     return 0;
 221   ts = hist->timestamp;
 222   if (ts[0] != history_comment_char)
 223     return 0;
 224   t = (time_t) atol (ts + 1);           /* XXX - should use strtol() here */
 225   return t;
 226 }
 227
 228 static char *
 229 hist_inittime ()
 230 {
 231   time_t t;
 232   char ts[64], *ret;
 233
 234   t = (time_t) time ((time_t *)0);
 235 #if defined (HAVE_VSNPRINTF)            /* assume snprintf if vsnprintf exists */
 236   snprintf (ts, sizeof (ts) - 1, "X%lu", (unsigned long) t);
 237 #else
 238   sprintf (ts, "X%lu", (unsigned long) t);
 239 #endif
 240   ret = savestring (ts);
 241   ret[0] = history_comment_char;
 242
 243   return ret;
 244 }
 245
 246 /* Place STRING at the end of the history list.  The data field
 247    is  set to NULL. */
 248 void
 249 add_history (string)
 250      const char *string;
 251 {
 252   HIST_ENTRY *temp;
 253
 254   if (history_stifled && (history_length == history_max_entries))
 255     {
 256       register int i;
 257
 258       /* If the history is stifled, and history_length is zero,
 259          and it equals history_max_entries, we don't save items. */
 260       if (history_length == 0)
 261         return;
 262
 263       /* If there is something in the slot, then remove it. */
 264       if (the_history[0])
 265         (void) free_history_entry (the_history[0]);
 266
 267       /* Copy the rest of the entries, moving down one slot. */
 268       for (i = 0; i < history_length; i++)
 269         the_history[i] = the_history[i + 1];
 270
 271       history_base++;
 272     }
 273   else
 274     {
 275       if (history_size == 0)
 276         {
 277           history_size = DEFAULT_HISTORY_GROW_SIZE;
 278           the_history = (HIST_ENTRY **)xmalloc (history_size * sizeof (HIST_ENTRY *));
 279           history_length = 1;
 280         }
 281       else
 282         {
 283           if (history_length == (history_size - 1))
 284             {
 285               history_size += DEFAULT_HISTORY_GROW_SIZE;
 286               the_history = (HIST_ENTRY **)
 287                 xrealloc (the_history, history_size * sizeof (HIST_ENTRY *));
 288             }
 289           history_length++;
 290         }
 291     }
 292
 293   temp = (HIST_ENTRY *)xmalloc (sizeof (HIST_ENTRY));
 294   temp->line = savestring (string);
 295   temp->data = (char *)NULL;
 296
 297   temp->timestamp = hist_inittime ();
 298
 299   the_history[history_length] = (HIST_ENTRY *)NULL;
 300   the_history[history_length - 1] = temp;
 301 }
 302
 303 /* Change the time stamp of the most recent history entry to STRING. */
 304 void
 305 add_history_time (string)
 306      const char *string;
 307 {
 308   HIST_ENTRY *hs;
 309
 310   hs = the_history[history_length - 1];
 311   FREE (hs->timestamp);
 312   hs->timestamp = savestring (string);
 313 }
 314
 315 /* Free HIST and return the data so the calling application can free it
 316    if necessary and desired. */
 317 histdata_t
 318 free_history_entry (hist)
 319      HIST_ENTRY *hist;
 320 {
 321   histdata_t x;
 322
 323   if (hist == 0)
 324     return ((histdata_t) 0);
 325   FREE (hist->line);
 326   FREE (hist->timestamp);
 327   x = hist->data;
 328   free (hist);
 329   return (x);
 330 }
 331
 332 /* Make the history entry at WHICH have LINE and DATA.  This returns
 333    the old entry so you can dispose of the data.  In the case of an
 334    invalid WHICH, a NULL pointer is returned. */
 335 HIST_ENTRY *
 336 replace_history_entry (which, line, data)
 337      int which;
 338      const char *line;
 339      histdata_t data;
 340 {
 341   HIST_ENTRY *temp, *old_value;
 342
 343   if (which < 0 || which >= history_length)
 344     return ((HIST_ENTRY *)NULL);
 345
 346   temp = (HIST_ENTRY *)xmalloc (sizeof (HIST_ENTRY));
 347   old_value = the_history[which];
 348
 349   temp->line = savestring (line);
 350   temp->data = data;
 351   temp->timestamp = savestring (old_value->timestamp);
 352   the_history[which] = temp;
 353
 354   return (old_value);
 355 }
 356
 357 /* Remove history element WHICH from the history.  The removed
 358    element is returned to you so you can free the line, data,
 359    and containing structure. */
 360 HIST_ENTRY *
 361 remove_history (which)
 362      int which;
 363 {
 364   HIST_ENTRY *return_value;
 365   register int i;
 366
 367   if (which < 0 || which >= history_length || history_length ==  0 || the_history == 0)
 368     return ((HIST_ENTRY *)NULL);
 369
 370   return_value = the_history[which];
 371
 372   for (i = which; i < history_length; i++)
 373     the_history[i] = the_history[i + 1];
 374
 375   history_length--;
 376
 377   return (return_value);
 378 }
 379
 380 /* Stifle the history list, remembering only MAX number of lines. */
 381 void
 382 stifle_history (max)
 383      int max;
 384 {
 385   register int i, j;
 386
 387   if (max < 0)
 388     max = 0;
 389
 390   if (history_length > max)
 391     {
 392       /* This loses because we cannot free the data. */
 393       for (i = 0, j = history_length - max; i < j; i++)
 394         free_history_entry (the_history[i]);
 395
 396       history_base = i;
 397       for (j = 0, i = history_length - max; j < max; i++, j++)
 398         the_history[j] = the_history[i];
 399       the_history[j] = (HIST_ENTRY *)NULL;
 400       history_length = j;
 401     }
 402
 403   history_stifled = 1;
 404   max_input_history = history_max_entries = max;
 405 }
 406
 407 /* Stop stifling the history.  This returns the previous maximum
 408    number of history entries.  The value is positive if the history
 409    was stifled,  negative if it wasn't. */
 410 int
 411 unstifle_history ()
 412 {
 413   if (history_stifled)
 414     {
 415       history_stifled = 0;
 416       return (history_max_entries);
 417     }
 418   else
 419     return (-history_max_entries);
 420 }
 421
 422 int
 423 history_is_stifled ()
 424 {
 425   return (history_stifled);
 426 }
 427
 428 void
 429 clear_history ()
 430 {
 431   register int i;
 432
 433   /* This loses because we cannot free the data. */
 434   for (i = 0; i < history_length; i++)
 435     {
 436       free_history_entry (the_history[i]);
 437       the_history[i] = (HIST_ENTRY *)NULL;
 438     }
 439
 440   history_offset = history_length = 0;
 441 }