lib/readline/histsearch.c

   1 /* histsearch.c -- searching the history list. */
   2
   3 /* Copyright (C) 1989, 1992 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 1, 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    675 Mass Ave, Cambridge, MA 02139, USA. */
  22
  23 #define READLINE_LIBRARY
  24
  25 #if defined (HAVE_CONFIG_H)
  26 #  include <config.h>
  27 #endif
  28
  29 #include <stdio.h>
  30 #if defined (HAVE_STDLIB_H)
  31 #  include <stdlib.h>
  32 #else
  33 #  include "ansi_stdlib.h"
  34 #endif /* HAVE_STDLIB_H */
  35 #if defined (HAVE_UNISTD_H)
  36 #  ifdef _MINIX
  37 #    include <sys/types.h>
  38 #  endif
  39 #  include <unistd.h>
  40 #endif
  41 #if defined (HAVE_STRING_H)
  42 #  include <string.h>
  43 #else
  44 #  include <strings.h>
  45 #endif /* !HAVE_STRING_H */
  46
  47 #include "history.h"
  48 #include "histlib.h"
  49
  50 /* Variables imported from other history library files. */
  51 extern int history_offset;
  52
  53 /* The list of alternate characters that can delimit a history search
  54    string. */
  55 char *history_search_delimiter_chars = (char *)NULL;
  56
  57 /* Search the history for STRING, starting at history_offset.
  58    If DIRECTION < 0, then the search is through previous entries, else
  59    through subsequent.  If ANCHORED is non-zero, the string must
  60    appear at the beginning of a history line, otherwise, the string
  61    may appear anywhere in the line.  If the string is found, then
  62    current_history () is the history entry, and the value of this
  63    function is the offset in the line of that history entry that the
  64    string was found in.  Otherwise, nothing is changed, and a -1 is
  65    returned. */
  66
  67 static int
  68 history_search_internal (string, direction, anchored)
  69      char *string;
  70      int direction, anchored;
  71 {
  72   register int i, reverse;
  73   register char *line;
  74   register int line_index;
  75   int string_len;
  76   HIST_ENTRY **the_history;     /* local */
  77
  78   i = history_offset;
  79   reverse = (direction < 0);
  80
  81   /* Take care of trivial cases first. */
  82   if (string == 0 || *string == '\0')
  83     return (-1);
  84
  85   if (!history_length || ((i == history_length) && !reverse))
  86     return (-1);
  87
  88   if (reverse && (i == history_length))
  89     i--;
  90
  91 #define NEXT_LINE() do { if (reverse) i--; else i++; } while (0)
  92
  93   the_history = history_list ();
  94   string_len = strlen (string);
  95   while (1)
  96     {
  97       /* Search each line in the history list for STRING. */
  98
  99       /* At limit for direction? */
 100       if ((reverse && i < 0) || (!reverse && i == history_length))
 101         return (-1);
 102
 103       line = the_history[i]->line;
 104       line_index = strlen (line);
 105
 106       /* If STRING is longer than line, no match. */
 107       if (string_len > line_index)
 108         {
 109           NEXT_LINE ();
 110           continue;
 111         }
 112
 113       /* Handle anchored searches first. */
 114       if (anchored == ANCHORED_SEARCH)
 115         {
 116           if (STREQN (string, line, string_len))
 117             {
 118               history_offset = i;
 119               return (0);
 120             }
 121
 122           NEXT_LINE ();
 123           continue;
 124         }
 125
 126       /* Do substring search. */
 127       if (reverse)
 128         {
 129           line_index -= string_len;
 130
 131           while (line_index >= 0)
 132             {
 133               if (STREQN (string, line + line_index, string_len))
 134                 {
 135                   history_offset = i;
 136                   return (line_index);
 137                 }
 138               line_index--;
 139             }
 140         }
 141       else
 142         {
 143           register int limit;
 144
 145           limit = line_index - string_len + 1;
 146           line_index = 0;
 147
 148           while (line_index < limit)
 149             {
 150               if (STREQN (string, line + line_index, string_len))
 151                 {
 152                   history_offset = i;
 153                   return (line_index);
 154                 }
 155               line_index++;
 156             }
 157         }
 158       NEXT_LINE ();
 159     }
 160 }
 161
 162 /* Do a non-anchored search for STRING through the history in DIRECTION. */
 163 int
 164 history_search (string, direction)
 165      char *string;
 166      int direction;
 167 {
 168   return (history_search_internal (string, direction, NON_ANCHORED_SEARCH));
 169 }
 170
 171 /* Do an anchored search for string through the history in DIRECTION. */
 172 int
 173 history_search_prefix (string, direction)
 174      char *string;
 175      int direction;
 176 {
 177   return (history_search_internal (string, direction, ANCHORED_SEARCH));
 178 }
 179
 180 /* Search for STRING in the history list.  DIR is < 0 for searching
 181    backwards.  POS is an absolute index into the history list at
 182    which point to begin searching. */
 183 int
 184 history_search_pos (string, dir, pos)
 185      char *string;
 186      int dir, pos;
 187 {
 188   int ret, old;
 189
 190   old = where_history ();
 191   history_set_pos (pos);
 192   if (history_search (string, dir) == -1)
 193     {
 194       history_set_pos (old);
 195       return (-1);
 196     }
 197   ret = where_history ();
 198   history_set_pos (old);
 199   return ret;
 200 }