386 lines
9.5 KiB
C
386 lines
9.5 KiB
C
/* History.c -- standalone history library */
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/* Copyright (C) 1989, 1992 Free Software Foundation, Inc.
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This file contains the GNU History Library (the Library), a set of
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routines for managing the text of previously typed lines.
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The Library is free software; you can redistribute it and/or modify
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it under the terms of the GNU General Public License as published by
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the Free Software Foundation; either version 1, or (at your option)
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any later version.
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The Library is distributed in the hope that it will be useful, but
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WITHOUT ANY WARRANTY; without even the implied warranty of
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MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
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General Public License for more details.
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The GNU General Public License is often shipped with GNU software, and
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is generally kept in a file called COPYING or LICENSE. If you do not
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have a copy of the license, write to the Free Software Foundation,
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675 Mass Ave, Cambridge, MA 02139, USA. */
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/* The goal is to make the implementation transparent, so that you
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don't have to know what data types are used, just what functions
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you can call. I think I have done that. */
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#define READLINE_LIBRARY
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#if defined (HAVE_CONFIG_H)
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# include <config.h>
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#endif
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#include <stdio.h>
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#if defined (HAVE_STDLIB_H)
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# include <stdlib.h>
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#else
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# include "ansi_stdlib.h"
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#endif /* HAVE_STDLIB_H */
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#if defined (HAVE_UNISTD_H)
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# include <unistd.h>
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#endif
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#if defined (HAVE_STRING_H)
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# include <string.h>
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#else
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# include <strings.h>
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#endif /* !HAVE_STRING_H */
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#include "history.h"
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#include "histlib.h"
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extern char *xmalloc (), *xrealloc ();
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/* The number of slots to increase the_history by. */
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#define DEFAULT_HISTORY_GROW_SIZE 50
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/* **************************************************************** */
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/* */
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/* History Functions */
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/* */
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/* **************************************************************** */
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/* An array of HIST_ENTRY. This is where we store the history. */
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static HIST_ENTRY **the_history = (HIST_ENTRY **)NULL;
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/* Non-zero means that we have enforced a limit on the amount of
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history that we save. */
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static int history_stifled;
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/* If HISTORY_STIFLED is non-zero, then this is the maximum number of
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entries to remember. */
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int max_input_history;
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/* The current location of the interactive history pointer. Just makes
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life easier for outside callers. */
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int history_offset;
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/* The number of strings currently stored in the history list. */
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int history_length;
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/* The current number of slots allocated to the input_history. */
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static int history_size;
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/* The logical `base' of the history array. It defaults to 1. */
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int history_base = 1;
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/* Return the current HISTORY_STATE of the history. */
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HISTORY_STATE *
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history_get_history_state ()
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{
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HISTORY_STATE *state;
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state = (HISTORY_STATE *)xmalloc (sizeof (HISTORY_STATE));
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state->entries = the_history;
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state->offset = history_offset;
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state->length = history_length;
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state->size = history_size;
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state->flags = 0;
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if (history_stifled)
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state->flags |= HS_STIFLED;
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return (state);
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}
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/* Set the state of the current history array to STATE. */
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void
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history_set_history_state (state)
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HISTORY_STATE *state;
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{
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the_history = state->entries;
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history_offset = state->offset;
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history_length = state->length;
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history_size = state->size;
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if (state->flags & HS_STIFLED)
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history_stifled = 1;
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}
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/* Begin a session in which the history functions might be used. This
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initializes interactive variables. */
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void
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using_history ()
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{
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history_offset = history_length;
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}
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/* Return the number of bytes that the primary history entries are using.
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This just adds up the lengths of the_history->lines. */
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int
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history_total_bytes ()
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{
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register int i, result;
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result = 0;
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for (i = 0; the_history && the_history[i]; i++)
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result += strlen (the_history[i]->line);
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return (result);
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}
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/* Returns the magic number which says what history element we are
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looking at now. In this implementation, it returns history_offset. */
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int
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where_history ()
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{
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return (history_offset);
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}
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/* Make the current history item be the one at POS, an absolute index.
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Returns zero if POS is out of range, else non-zero. */
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int
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history_set_pos (pos)
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int pos;
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{
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if (pos > history_length || pos < 0 || !the_history)
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return (0);
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history_offset = pos;
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return (1);
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}
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/* Return the current history array. The caller has to be carefull, since this
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is the actual array of data, and could be bashed or made corrupt easily.
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The array is terminated with a NULL pointer. */
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HIST_ENTRY **
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history_list ()
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{
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return (the_history);
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}
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/* Return the history entry at the current position, as determined by
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history_offset. If there is no entry there, return a NULL pointer. */
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HIST_ENTRY *
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current_history ()
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{
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return ((history_offset == history_length) || the_history == 0)
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? (HIST_ENTRY *)NULL
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: the_history[history_offset];
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}
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/* Back up history_offset to the previous history entry, and return
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a pointer to that entry. If there is no previous entry then return
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a NULL pointer. */
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HIST_ENTRY *
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previous_history ()
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{
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return history_offset ? the_history[--history_offset] : (HIST_ENTRY *)NULL;
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}
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/* Move history_offset forward to the next history entry, and return
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a pointer to that entry. If there is no next entry then return a
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NULL pointer. */
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HIST_ENTRY *
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next_history ()
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{
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return (history_offset == history_length) ? (HIST_ENTRY *)NULL : the_history[++history_offset];
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}
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/* Return the history entry which is logically at OFFSET in the history array.
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OFFSET is relative to history_base. */
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HIST_ENTRY *
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history_get (offset)
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int offset;
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{
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int local_index;
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local_index = offset - history_base;
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return (local_index >= history_length || local_index < 0 || !the_history)
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? (HIST_ENTRY *)NULL
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: the_history[local_index];
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}
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/* Place STRING at the end of the history list. The data field
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is set to NULL. */
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void
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add_history (string)
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char *string;
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{
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HIST_ENTRY *temp;
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if (history_stifled && (history_length == max_input_history))
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{
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register int i;
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/* If the history is stifled, and history_length is zero,
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and it equals max_input_history, we don't save items. */
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if (history_length == 0)
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return;
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/* If there is something in the slot, then remove it. */
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if (the_history[0])
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{
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free (the_history[0]->line);
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free (the_history[0]);
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}
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/* Copy the rest of the entries, moving down one slot. */
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for (i = 0; i < history_length; i++)
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the_history[i] = the_history[i + 1];
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history_base++;
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}
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else
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{
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if (history_size == 0)
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{
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history_size = DEFAULT_HISTORY_GROW_SIZE;
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the_history = (HIST_ENTRY **)xmalloc (history_size * sizeof (HIST_ENTRY *));
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history_length = 1;
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}
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else
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{
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if (history_length == (history_size - 1))
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{
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history_size += DEFAULT_HISTORY_GROW_SIZE;
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the_history = (HIST_ENTRY **)
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xrealloc (the_history, history_size * sizeof (HIST_ENTRY *));
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}
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history_length++;
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}
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}
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temp = (HIST_ENTRY *)xmalloc (sizeof (HIST_ENTRY));
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temp->line = savestring (string);
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temp->data = (char *)NULL;
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the_history[history_length] = (HIST_ENTRY *)NULL;
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the_history[history_length - 1] = temp;
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}
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/* Make the history entry at WHICH have LINE and DATA. This returns
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the old entry so you can dispose of the data. In the case of an
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invalid WHICH, a NULL pointer is returned. */
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HIST_ENTRY *
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replace_history_entry (which, line, data)
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int which;
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char *line;
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char *data;
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{
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HIST_ENTRY *temp = (HIST_ENTRY *)xmalloc (sizeof (HIST_ENTRY));
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HIST_ENTRY *old_value;
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if (which >= history_length)
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return ((HIST_ENTRY *)NULL);
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old_value = the_history[which];
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temp->line = savestring (line);
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temp->data = data;
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the_history[which] = temp;
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return (old_value);
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}
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/* Remove history element WHICH from the history. The removed
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element is returned to you so you can free the line, data,
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and containing structure. */
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HIST_ENTRY *
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remove_history (which)
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int which;
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{
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HIST_ENTRY *return_value;
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if (which >= history_length || !history_length)
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return_value = (HIST_ENTRY *)NULL;
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else
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{
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register int i;
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return_value = the_history[which];
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for (i = which; i < history_length; i++)
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the_history[i] = the_history[i + 1];
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history_length--;
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}
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return (return_value);
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}
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/* Stifle the history list, remembering only MAX number of lines. */
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void
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stifle_history (max)
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int max;
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{
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if (max < 0)
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max = 0;
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if (history_length > max)
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{
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register int i, j;
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/* This loses because we cannot free the data. */
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for (i = 0, j = history_length - max; i < j; i++)
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{
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free (the_history[i]->line);
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free (the_history[i]);
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}
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history_base = i;
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for (j = 0, i = history_length - max; j < max; i++, j++)
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the_history[j] = the_history[i];
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the_history[j] = (HIST_ENTRY *)NULL;
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history_length = j;
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}
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history_stifled = 1;
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max_input_history = max;
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}
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/* Stop stifling the history. This returns the previous amount the
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history was stifled by. The value is positive if the history was
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stifled, negative if it wasn't. */
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int
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unstifle_history ()
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{
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if (history_stifled)
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{
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history_stifled = 0;
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return (-max_input_history);
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}
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return (max_input_history);
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}
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int
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history_is_stifled ()
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{
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return (history_stifled);
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}
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void
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clear_history ()
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{
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register int i;
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/* This loses because we cannot free the data. */
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for (i = 0; i < history_length; i++)
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{
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free (the_history[i]->line);
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free (the_history[i]);
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the_history[i] = (HIST_ENTRY *)NULL;
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}
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history_offset = history_length = 0;
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}
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