histsearch.c revision 35486 
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. */
51extern int history_offset;
52
53/* The list of alternate characters that can delimit a history search
54   string. */
55char *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
67static int
68history_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. */
163int
164history_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. */
172int
173history_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. */
183int
184history_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}
201