Adding libreadline's source to the MSVC project

1 files changed, 1489 insertions, 0 deletions

diff --git a/MSVC/readline/histexpand.c b/MSVC/readline/histexpand.c
new file mode 100644
index 0000000..dc2a89f
--- /dev/null
+++ b/MSVC/readline/histexpand.c
@@ -0,0 +1,1489 @@
+/* histexpand.c -- history expansion. */
+
+/* Copyright (C) 1989, 1992 Free Software Foundation, Inc.
+
+   This file contains the GNU History Library (the Library), a set of
+   routines for managing the text of previously typed lines.
+
+   The Library is free software; you can redistribute it and/or modify
+   it under the terms of the GNU General Public License as published by
+   the Free Software Foundation; either version 2, or (at your option)
+   any later version.
+
+   The Library 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.
+
+   The GNU General Public License is often shipped with GNU software, and
+   is generally kept in a file called COPYING or LICENSE.  If you do not
+   have a copy of the license, write to the Free Software Foundation,
+   59 Temple Place, Suite 330, Boston, MA 02111 USA. */
+
+#define READLINE_LIBRARY
+
+#include "config.h"
+
+#include <stdio.h>
+
+#if defined (HAVE_STDLIB_H)
+#  include <stdlib.h>
+#else
+#  include "ansi_stdlib.h"
+#endif /* HAVE_STDLIB_H */
+
+#if defined (HAVE_UNISTD_H)
+#  ifndef _MINIX
+#    include <sys/types.h>
+#  endif
+#  include <unistd.h>
+#endif
+
+#include "rlmbutil.h"
+
+#include "history.h"
+#include "histlib.h"
+
+#include "rlshell.h"
+#include "xmalloc.h"
+
+#define HISTORY_WORD_DELIMITERS		" \t\n;&()|<>"
+#define HISTORY_QUOTE_CHARACTERS	"\"'`"
+
+typedef int _hist_search_func_t PARAMS((const char *, int));
+
+extern int rl_byte_oriented;	/* declared in mbutil.c */
+
+static char error_pointer;
+
+static char *subst_lhs;
+static char *subst_rhs;
+static int subst_lhs_len;
+static int subst_rhs_len;
+
+static char *get_history_word_specifier PARAMS((char *, char *, int *));
+static char *history_find_word PARAMS((char *, int));
+
+static char *quote_breaks PARAMS((char *));
+
+/* Variables exported by this file. */
+/* The character that represents the start of a history expansion
+   request.  This is usually `!'. */
+char history_expansion_char = '!';
+
+/* The character that invokes word substitution if found at the start of
+   a line.  This is usually `^'. */
+char history_subst_char = '^';
+
+/* During tokenization, if this character is seen as the first character
+   of a word, then it, and all subsequent characters upto a newline are
+   ignored.  For a Bourne shell, this should be '#'.  Bash special cases
+   the interactive comment character to not be a comment delimiter. */
+char history_comment_char = '\0';
+
+/* The list of characters which inhibit the expansion of text if found
+   immediately following history_expansion_char. */
+char *history_no_expand_chars = " \t\n\r=";
+
+/* If set to a non-zero value, single quotes inhibit history expansion.
+   The default is 0. */
+int history_quotes_inhibit_expansion = 0;
+
+/* Used to split words by history_tokenize_internal. */
+char *history_word_delimiters = HISTORY_WORD_DELIMITERS;
+
+/* If set, this points to a function that is called to verify that a
+   particular history expansion should be performed. */
+rl_linebuf_func_t *history_inhibit_expansion_function;
+
+/* **************************************************************** */
+/*								    */
+/*			History Expansion			    */
+/*								    */
+/* **************************************************************** */
+
+/* Hairy history expansion on text, not tokens.  This is of general
+   use, and thus belongs in this library. */
+
+/* The last string searched for by a !?string? search. */
+static char *search_string;
+
+/* The last string matched by a !?string? search. */
+static char *search_match;
+
+/* Return the event specified at TEXT + OFFSET modifying OFFSET to
+   point to after the event specifier.  Just a pointer to the history
+   line is returned; NULL is returned in the event of a bad specifier.
+   You pass STRING with *INDEX equal to the history_expansion_char that
+   begins this specification.
+   DELIMITING_QUOTE is a character that is allowed to end the string
+   specification for what to search for in addition to the normal
+   characters `:', ` ', `\t', `\n', and sometimes `?'.
+   So you might call this function like:
+   line = get_history_event ("!echo:p", &index, 0);  */
+char *
+get_history_event (string, caller_index, delimiting_quote)
+     const char *string;
+     int *caller_index;
+     int delimiting_quote;
+{
+  register int i;
+  register char c;
+  HIST_ENTRY *entry;
+  int which, sign, local_index, substring_okay;
+  _hist_search_func_t *search_func;
+  char *temp;
+
+  /* The event can be specified in a number of ways.
+
+     !!   the previous command
+     !n   command line N
+     !-n  current command-line minus N
+     !str the most recent command starting with STR
+     !?str[?]
+	  the most recent command containing STR
+
+     All values N are determined via HISTORY_BASE. */
+
+  i = *caller_index;
+
+  if (string[i] != history_expansion_char)
+    return ((char *)NULL);
+
+  /* Move on to the specification. */
+  i++;
+
+  sign = 1;
+  substring_okay = 0;
+
+#define RETURN_ENTRY(e, w) \
+	return ((e = history_get (w)) ? e->line : (char *)NULL)
+
+  /* Handle !! case. */
+  if (string[i] == history_expansion_char)
+    {
+      i++;
+      which = history_base + (history_length - 1);
+      *caller_index = i;
+      RETURN_ENTRY (entry, which);
+    }
+
+  /* Hack case of numeric line specification. */
+  if (string[i] == '-')
+    {
+      sign = -1;
+      i++;
+    }
+
+  if (_rl_digit_p (string[i]))
+    {
+      /* Get the extent of the digits and compute the value. */
+      for (which = 0; _rl_digit_p (string[i]); i++)
+	which = (which * 10) + _rl_digit_value (string[i]);
+
+      *caller_index = i;
+
+      if (sign < 0)
+	which = (history_length + history_base) - which;
+
+      RETURN_ENTRY (entry, which);
+    }
+
+  /* This must be something to search for.  If the spec begins with
+     a '?', then the string may be anywhere on the line.  Otherwise,
+     the string must be found at the start of a line. */
+  if (string[i] == '?')
+    {
+      substring_okay++;
+      i++;
+    }
+
+  /* Only a closing `?' or a newline delimit a substring search string. */
+  for (local_index = i; c = string[i]; i++)
+#if defined (HANDLE_MULTIBYTE)
+    if (MB_CUR_MAX > 1 && rl_byte_oriented == 0)
+      {
+	int v;
+	mbstate_t ps;
+
+	memset (&ps, 0, sizeof (mbstate_t));
+	/* These produce warnings because we're passing a const string to a
+	   function that takes a non-const string. */
+	_rl_adjust_point (string, i, &ps);
+	if ((v = _rl_get_char_len (string + i, &ps)) > 1)
+	  {
+	    i += v - 1;
+	    continue;
+	  }
+      }
+    else
+#endif /* HANDLE_MULTIBYTE */
+      if ((!substring_okay && (whitespace (c) || c == ':' ||
+	  (history_search_delimiter_chars && member (c, history_search_delimiter_chars)) ||
+	  string[i] == delimiting_quote)) ||
+	  string[i] == '\n' ||
+	  (substring_okay && string[i] == '?'))
+	break;
+
+  which = i - local_index;
+  temp = (char *)xmalloc (1 + which);
+  if (which)
+    strncpy (temp, string + local_index, which);
+  temp[which] = '\0';
+
+  if (substring_okay && string[i] == '?')
+    i++;
+
+  *caller_index = i;
+
+#define FAIL_SEARCH() \
+  do { \
+    history_offset = history_length; free (temp) ; return (char *)NULL; \
+  } while (0)
+
+  /* If there is no search string, try to use the previous search string,
+     if one exists.  If not, fail immediately. */
+  if (*temp == '\0' && substring_okay)
+    {
+      if (search_string)
+        {
+          free (temp);
+          temp = savestring (search_string);
+        }
+      else
+        FAIL_SEARCH ();
+    }
+
+  search_func = substring_okay ? history_search : history_search_prefix;
+  while (1)
+    {
+      local_index = (*search_func) (temp, -1);
+
+      if (local_index < 0)
+	FAIL_SEARCH ();
+
+      if (local_index == 0 || substring_okay)
+	{
+	  entry = current_history ();
+	  history_offset = history_length;
+	
+	  /* If this was a substring search, then remember the
+	     string that we matched for word substitution. */
+	  if (substring_okay)
+	    {
+	      FREE (search_string);
+	      search_string = temp;
+
+	      FREE (search_match);
+	      search_match = history_find_word (entry->line, local_index);
+	    }
+	  else
+	    free (temp);
+
+	  return (entry->line);
+	}
+
+      if (history_offset)
+	history_offset--;
+      else
+	FAIL_SEARCH ();
+    }
+#undef FAIL_SEARCH
+#undef RETURN_ENTRY
+}
+
+/* Function for extracting single-quoted strings.  Used for inhibiting
+   history expansion within single quotes. */
+
+/* Extract the contents of STRING as if it is enclosed in single quotes.
+   SINDEX, when passed in, is the offset of the character immediately
+   following the opening single quote; on exit, SINDEX is left pointing
+   to the closing single quote. */
+static void
+hist_string_extract_single_quoted (string, sindex)
+     char *string;
+     int *sindex;
+{
+  register int i;
+
+  for (i = *sindex; string[i] && string[i] != '\''; i++)
+    ;
+
+  *sindex = i;
+}
+
+static char *
+quote_breaks (s)
+     char *s;
+{
+  register char *p, *r;
+  char *ret;
+  int len = 3;
+
+  for (p = s; p && *p; p++, len++)
+    {
+      if (*p == '\'')
+	len += 3;
+      else if (whitespace (*p) || *p == '\n')
+	len += 2;
+    }
+
+  r = ret = (char *)xmalloc (len);
+  *r++ = '\'';
+  for (p = s; p && *p; )
+    {
+      if (*p == '\'')
+	{
+	  *r++ = '\'';
+	  *r++ = '\\';
+	  *r++ = '\'';
+	  *r++ = '\'';
+	  p++;
+	}
+      else if (whitespace (*p) || *p == '\n')
+	{
+	  *r++ = '\'';
+	  *r++ = *p++;
+	  *r++ = '\'';
+	}
+      else
+	*r++ = *p++;
+    }
+  *r++ = '\'';
+  *r = '\0';
+  return ret;
+}
+
+static char *
+hist_error(s, start, current, errtype)
+      char *s;
+      int start, current, errtype;
+{
+  char *temp;
+  const char *emsg;
+  int ll, elen;
+
+  ll = current - start;
+
+  switch (errtype)
+    {
+    case EVENT_NOT_FOUND:
+      emsg = "event not found";
+      elen = 15;
+      break;
+    case BAD_WORD_SPEC:
+      emsg = "bad word specifier";
+      elen = 18;
+      break;
+    case SUBST_FAILED:
+      emsg = "substitution failed";
+      elen = 19;
+      break;
+    case BAD_MODIFIER:
+      emsg = "unrecognized history modifier";
+      elen = 29;
+      break;
+    case NO_PREV_SUBST:
+      emsg = "no previous substitution";
+      elen = 24;
+      break;
+    default:
+      emsg = "unknown expansion error";
+      elen = 23;
+      break;
+    }
+
+  temp = (char *)xmalloc (ll + elen + 3);
+  strncpy (temp, s + start, ll);
+  temp[ll] = ':';
+  temp[ll + 1] = ' ';
+  strcpy (temp + ll + 2, emsg);
+  return (temp);
+}
+
+/* Get a history substitution string from STR starting at *IPTR
+   and return it.  The length is returned in LENPTR.
+
+   A backslash can quote the delimiter.  If the string is the
+   empty string, the previous pattern is used.  If there is
+   no previous pattern for the lhs, the last history search
+   string is used.
+
+   If IS_RHS is 1, we ignore empty strings and set the pattern
+   to "" anyway.  subst_lhs is not changed if the lhs is empty;
+   subst_rhs is allowed to be set to the empty string. */
+
+static char *
+get_subst_pattern (str, iptr, delimiter, is_rhs, lenptr)
+     char *str;
+     int *iptr, delimiter, is_rhs, *lenptr;
+{
+  register int si, i, j, k;
+  char *s;
+#if defined (HANDLE_MULTIBYTE)
+  mbstate_t ps;
+#endif
+
+  s = (char *)NULL;
+  i = *iptr;
+
+#if defined (HANDLE_MULTIBYTE)
+  memset (&ps, 0, sizeof (mbstate_t));
+  _rl_adjust_point (str, i, &ps);
+#endif
+
+  for (si = i; str[si] && str[si] != delimiter; si++)
+#if defined (HANDLE_MULTIBYTE)
+    if (MB_CUR_MAX > 1 && rl_byte_oriented == 0)
+      {
+	int v;
+	if ((v = _rl_get_char_len (str + si, &ps)) > 1)
+	  si += v - 1;
+	else if (str[si] == '\\' && str[si + 1] == delimiter)
+	  si++;
+      }
+    else
+#endif /* HANDLE_MULTIBYTE */
+      if (str[si] == '\\' && str[si + 1] == delimiter)
+	si++;
+
+  if (si > i || is_rhs)
+    {
+      s = (char *)xmalloc (si - i + 1);
+      for (j = 0, k = i; k < si; j++, k++)
+	{
+	  /* Remove a backslash quoting the search string delimiter. */
+	  if (str[k] == '\\' && str[k + 1] == delimiter)
+	    k++;
+	  s[j] = str[k];
+	}
+      s[j] = '\0';
+      if (lenptr)
+	*lenptr = j;
+    }
+
+  i = si;
+  if (str[i])
+    i++;
+  *iptr = i;
+
+  return s;
+}
+
+static void
+postproc_subst_rhs ()
+{
+  char *new;
+  int i, j, new_size;
+
+  new = (char *)xmalloc (new_size = subst_rhs_len + subst_lhs_len);
+  for (i = j = 0; i < subst_rhs_len; i++)
+    {
+      if (subst_rhs[i] == '&')
+	{
+	  if (j + subst_lhs_len >= new_size)
+	    new = (char *)xrealloc (new, (new_size = new_size * 2 + subst_lhs_len));
+	  strcpy (new + j, subst_lhs);
+	  j += subst_lhs_len;
+	}
+      else
+	{
+	  /* a single backslash protects the `&' from lhs interpolation */
+	  if (subst_rhs[i] == '\\' && subst_rhs[i + 1] == '&')
+	    i++;
+	  if (j >= new_size)
+	    new = (char *)xrealloc (new, new_size *= 2);
+	  new[j++] = subst_rhs[i];
+	}
+    }
+  new[j] = '\0';
+  free (subst_rhs);
+  subst_rhs = new;
+  subst_rhs_len = j;
+}
+
+/* Expand the bulk of a history specifier starting at STRING[START].
+   Returns 0 if everything is OK, -1 if an error occurred, and 1
+   if the `p' modifier was supplied and the caller should just print
+   the returned string.  Returns the new index into string in
+   *END_INDEX_PTR, and the expanded specifier in *RET_STRING. */
+static int
+history_expand_internal (string, start, end_index_ptr, ret_string, current_line)
+     char *string;
+     int start, *end_index_ptr;
+     char **ret_string;
+     char *current_line;	/* for !# */
+{
+  int i, n, starting_index;
+  int substitute_globally, want_quotes, print_only;
+  char *event, *temp, *result, *tstr, *t, c, *word_spec;
+  int result_len;
+#if defined (HANDLE_MULTIBYTE)
+  mbstate_t ps;
+
+  memset (&ps, 0, sizeof (mbstate_t));
+#endif
+
+  result = (char *)xmalloc (result_len = 128);
+
+  i = start;
+
+  /* If it is followed by something that starts a word specifier,
+     then !! is implied as the event specifier. */
+
+  if (member (string[i + 1], ":$*%^"))
+    {
+      char fake_s[3];
+      int fake_i = 0;
+      i++;
+      fake_s[0] = fake_s[1] = history_expansion_char;
+      fake_s[2] = '\0';
+      event = get_history_event (fake_s, &fake_i, 0);
+    }
+  else if (string[i + 1] == '#')
+    {
+      i += 2;
+      event = current_line;
+    }
+  else
+    {
+      int quoted_search_delimiter = 0;
+
+      /* If the character before this `!' is a double or single
+	 quote, then this expansion takes place inside of the
+	 quoted string.  If we have to search for some text ("!foo"),
+	 allow the delimiter to end the search string. */
+#if defined (HANDLE_MULTIBYTE)
+      if (MB_CUR_MAX > 1 && rl_byte_oriented == 0)
+	{
+	  int c, l;
+	  l = _rl_find_prev_mbchar (string, i, MB_FIND_ANY);
+	  c = string[l];
+	  /* XXX - original patch had i - 1 ???  If i == 0 it would fail. */
+	  if (i && (c == '\'' || c == '"'))
+	    quoted_search_delimiter = c;
+	}
+      else
+#endif /* HANDLE_MULTIBYTE */	  
+	if (i && (string[i - 1] == '\'' || string[i - 1] == '"'))
+	  quoted_search_delimiter = string[i - 1];
+
+      event = get_history_event (string, &i, quoted_search_delimiter);
+    }
+	  
+  if (event == 0)
+    {
+      *ret_string = hist_error (string, start, i, EVENT_NOT_FOUND);
+      free (result);
+      return (-1);
+    }
+
+  /* If a word specifier is found, then do what that requires. */
+  starting_index = i;
+  word_spec = get_history_word_specifier (string, event, &i);
+
+  /* There is no such thing as a `malformed word specifier'.  However,
+     it is possible for a specifier that has no match.  In that case,
+     we complain. */
+  if (word_spec == (char *)&error_pointer)
+    {
+      *ret_string = hist_error (string, starting_index, i, BAD_WORD_SPEC);
+      free (result);
+      return (-1);
+    }
+
+  /* If no word specifier, than the thing of interest was the event. */
+  temp = word_spec ? savestring (word_spec) : savestring (event);
+  FREE (word_spec);
+
+  /* Perhaps there are other modifiers involved.  Do what they say. */
+  want_quotes = substitute_globally = print_only = 0;
+  starting_index = i;
+
+  while (string[i] == ':')
+    {
+      c = string[i + 1];
+
+      if (c == 'g')
+	{
+	  substitute_globally = 1;
+	  i++;
+	  c = string[i + 1];
+	}
+
+      switch (c)
+	{
+	default:
+	  *ret_string = hist_error (string, i+1, i+2, BAD_MODIFIER);
+	  free (result);
+	  free (temp);
+	  return -1;
+
+	case 'q':
+	  want_quotes = 'q';
+	  break;
+
+	case 'x':
+	  want_quotes = 'x';
+	  break;
+
+	  /* :p means make this the last executed line.  So we
+	     return an error state after adding this line to the
+	     history. */
+	case 'p':
+	  print_only++;
+	  break;
+
+	  /* :t discards all but the last part of the pathname. */
+	case 't':
+	  tstr = strrchr (temp, '/');
+	  if (tstr)
+	    {
+	      tstr++;
+	      t = savestring (tstr);
+	      free (temp);
+	      temp = t;
+	    }
+	  break;
+
+	  /* :h discards the last part of a pathname. */
+	case 'h':
+	  tstr = strrchr (temp, '/');
+	  if (tstr)
+	    *tstr = '\0';
+	  break;
+
+	  /* :r discards the suffix. */
+	case 'r':
+	  tstr = strrchr (temp, '.');
+	  if (tstr)
+	    *tstr = '\0';
+	  break;
+
+	  /* :e discards everything but the suffix. */
+	case 'e':
+	  tstr = strrchr (temp, '.');
+	  if (tstr)
+	    {
+	      t = savestring (tstr);
+	      free (temp);
+	      temp = t;
+	    }
+	  break;
+
+	/* :s/this/that substitutes `that' for the first
+	   occurrence of `this'.  :gs/this/that substitutes `that'
+	   for each occurrence of `this'.  :& repeats the last
+	   substitution.  :g& repeats the last substitution
+	   globally. */
+
+	case '&':
+	case 's':
+	  {
+	    char *new_event;
+	    int delimiter, failed, si, l_temp;
+
+	    if (c == 's')
+	      {
+		if (i + 2 < (int)strlen (string))
+		  {
+#if defined (HANDLE_MULTIBYTE)
+		    if (MB_CUR_MAX > 1 && rl_byte_oriented == 0)
+		      {
+			_rl_adjust_point (string, i + 2, &ps);
+			if (_rl_get_char_len (string + i + 2, &ps) > 1)
+			  delimiter = 0;
+			else
+			  delimiter = string[i + 2];
+		      }
+		    else
+#endif /* HANDLE_MULTIBYTE */
+		      delimiter = string[i + 2];
+		  }
+		else
+		  break;	/* no search delimiter */
+
+		i += 3;
+
+		t = get_subst_pattern (string, &i, delimiter, 0, &subst_lhs_len);
+		/* An empty substitution lhs with no previous substitution
+		   uses the last search string as the lhs. */
+		if (t)
+		  {
+		    FREE (subst_lhs);
+		    subst_lhs = t;
+		  }
+		else if (!subst_lhs)
+		  {
+		    if (search_string && *search_string)
+		      {
+			subst_lhs = savestring (search_string);
+			subst_lhs_len = strlen (subst_lhs);
+		      }
+		    else
+		      {
+			subst_lhs = (char *) NULL;
+			subst_lhs_len = 0;
+		      }
+		  }
+
+		FREE (subst_rhs);
+		subst_rhs = get_subst_pattern (string, &i, delimiter, 1, &subst_rhs_len);
+
+		/* If `&' appears in the rhs, it's supposed to be replaced
+		   with the lhs. */
+		if (member ('&', subst_rhs))
+		  postproc_subst_rhs ();
+	      }
+	    else
+	      i += 2;
+
+	    /* If there is no lhs, the substitution can't succeed. */
+	    if (subst_lhs_len == 0)
+	      {
+		*ret_string = hist_error (string, starting_index, i, NO_PREV_SUBST);
+		free (result);
+		free (temp);
+		return -1;
+	      }
+
+	    l_temp = strlen (temp);
+	    /* Ignore impossible cases. */
+	    if (subst_lhs_len > l_temp)
+	      {
+		*ret_string = hist_error (string, starting_index, i, SUBST_FAILED);
+		free (result);
+		free (temp);
+		return (-1);
+	      }
+
+	    /* Find the first occurrence of THIS in TEMP. */
+	    si = 0;
+	    for (failed = 1; (si + subst_lhs_len) <= l_temp; si++)
+	      if (STREQN (temp+si, subst_lhs, subst_lhs_len))
+		{
+		  int len = subst_rhs_len - subst_lhs_len + l_temp;
+		  new_event = (char *)xmalloc (1 + len);
+		  strncpy (new_event, temp, si);
+		  strncpy (new_event + si, subst_rhs, subst_rhs_len);
+		  strncpy (new_event + si + subst_rhs_len,
+			   temp + si + subst_lhs_len,
+			   l_temp - (si + subst_lhs_len));
+		  new_event[len] = '\0';
+		  free (temp);
+		  temp = new_event;
+
+		  failed = 0;
+
+		  if (substitute_globally)
+		    {
+		      si += subst_rhs_len;
+		      l_temp = strlen (temp);
+		      substitute_globally++;
+		      continue;
+		    }
+		  else
+		    break;
+		}
+
+	    if (substitute_globally > 1)
+	      {
+		substitute_globally = 0;
+		continue;	/* don't want to increment i */
+	      }
+
+	    if (failed == 0)
+	      continue;		/* don't want to increment i */
+
+	    *ret_string = hist_error (string, starting_index, i, SUBST_FAILED);
+	    free (result);
+	    free (temp);
+	    return (-1);
+	  }
+	}
+      i += 2;
+    }
+  /* Done with modfiers. */
+  /* Believe it or not, we have to back the pointer up by one. */
+  --i;
+
+  if (want_quotes)
+    {
+      char *x;
+
+      if (want_quotes == 'q')
+	x = sh_single_quote (temp);
+      else if (want_quotes == 'x')
+	x = quote_breaks (temp);
+      else
+	x = savestring (temp);
+
+      free (temp);
+      temp = x;
+    }
+
+  n = strlen (temp);
+  if (n >= result_len)
+    result = (char *)xrealloc (result, n + 2);
+  strcpy (result, temp);
+  free (temp);
+
+  *end_index_ptr = i;
+  *ret_string = result;
+  return (print_only);
+}
+
+/* Expand the string STRING, placing the result into OUTPUT, a pointer
+   to a string.  Returns:
+
+  -1) If there was an error in expansion.
+   0) If no expansions took place (or, if the only change in
+      the text was the de-slashifying of the history expansion
+      character)
+   1) If expansions did take place
+   2) If the `p' modifier was given and the caller should print the result
+
+  If an error ocurred in expansion, then OUTPUT contains a descriptive
+  error message. */
+
+#define ADD_STRING(s) \
+	do \
+	  { \
+	    int sl = strlen (s); \
+	    j += sl; \
+	    if (j >= result_len) \
+	      { \
+		while (j >= result_len) \
+		  result_len += 128; \
+		result = (char *)xrealloc (result, result_len); \
+	      } \
+	    strcpy (result + j - sl, s); \
+	  } \
+	while (0)
+
+#define ADD_CHAR(c) \
+	do \
+	  { \
+	    if (j >= result_len - 1) \
+	      result = (char *)xrealloc (result, result_len += 64); \
+	    result[j++] = c; \
+	    result[j] = '\0'; \
+	  } \
+	while (0)
+
+int
+history_expand (hstring, output)
+     char *hstring;
+     char **output;
+{
+  register int j;
+  int i, r, l, passc, cc, modified, eindex, only_printing;
+  char *string;
+
+  /* The output string, and its length. */
+  int result_len;
+  char *result;
+
+#if defined (HANDLE_MULTIBYTE)
+  char mb[MB_LEN_MAX];
+  mbstate_t ps;
+#endif
+
+  /* Used when adding the string. */
+  char *temp;
+
+  if (output == 0)
+    return 0;
+
+  /* Setting the history expansion character to 0 inhibits all
+     history expansion. */
+  if (history_expansion_char == 0)
+    {
+      *output = savestring (hstring);
+      return (0);
+    }
+    
+  /* Prepare the buffer for printing error messages. */
+  result = (char *)xmalloc (result_len = 256);
+  result[0] = '\0';
+
+  only_printing = modified = 0;
+  l = strlen (hstring);
+
+  /* Grovel the string.  Only backslash and single quotes can quote the
+     history escape character.  We also handle arg specifiers. */
+
+  /* Before we grovel forever, see if the history_expansion_char appears
+     anywhere within the text. */
+
+  /* The quick substitution character is a history expansion all right.  That
+     is to say, "^this^that^" is equivalent to "!!:s^this^that^", and in fact,
+     that is the substitution that we do. */
+  if (hstring[0] == history_subst_char)
+    {
+      string = (char *)xmalloc (l + 5);
+
+      string[0] = string[1] = history_expansion_char;
+      string[2] = ':';
+      string[3] = 's';
+      strcpy (string + 4, hstring);
+      l += 4;
+    }
+  else
+    {
+#if defined (HANDLE_MULTIBYTE)
+      memset (&ps, 0, sizeof (mbstate_t));
+#endif
+
+      string = hstring;
+      /* If not quick substitution, still maybe have to do expansion. */
+
+      /* `!' followed by one of the characters in history_no_expand_chars
+	 is NOT an expansion. */
+      for (i = 0; string[i]; i++)
+	{
+#if defined (HANDLE_MULTIBYTE)
+	  if (MB_CUR_MAX > 1 && rl_byte_oriented == 0)
+	    {
+	      int v;
+	      v = _rl_get_char_len (string + i, &ps);
+	      if (v > 1)
+		{
+		  i += v - 1;
+		  continue;
+		}
+	    }
+#endif /* HANDLE_MULTIBYTE */
+
+	  cc = string[i + 1];
+	  /* The history_comment_char, if set, appearing at the beginning
+	     of a word signifies that the rest of the line should not have
+	     history expansion performed on it.
+	     Skip the rest of the line and break out of the loop. */
+	  if (history_comment_char && string[i] == history_comment_char &&
+	      (i == 0 || member (string[i - 1], history_word_delimiters)))
+	    {
+	      while (string[i])
+		i++;
+	      break;
+	    }
+	  else if (string[i] == history_expansion_char)
+	    {
+	      if (!cc || member (cc, history_no_expand_chars))
+		continue;
+	      /* If the calling application has set
+		 history_inhibit_expansion_function to a function that checks
+		 for special cases that should not be history expanded,
+		 call the function and skip the expansion if it returns a
+		 non-zero value. */
+	      else if (history_inhibit_expansion_function &&
+			(*history_inhibit_expansion_function) (string, i))
+		continue;
+	      else
+		break;
+	    }
+	  /* XXX - at some point, might want to extend this to handle
+		   double quotes as well. */
+	  else if (history_quotes_inhibit_expansion && string[i] == '\'')
+	    {
+	      /* If this is bash, single quotes inhibit history expansion. */
+	      i++;
+	      hist_string_extract_single_quoted (string, &i);
+	    }
+	  else if (history_quotes_inhibit_expansion && string[i] == '\\')
+	    {
+	      /* If this is bash, allow backslashes to quote single
+		 quotes and the history expansion character. */
+	      if (cc == '\'' || cc == history_expansion_char)
+		i++;
+	    }
+	}
+	  
+      if (string[i] != history_expansion_char)
+	{
+	  free (result);
+	  *output = savestring (string);
+	  return (0);
+	}
+    }
+
+  /* Extract and perform the substitution. */
+  for (passc = i = j = 0; i < l; i++)
+    {
+      int tchar = string[i];
+
+      if (passc)
+	{
+	  passc = 0;
+	  ADD_CHAR (tchar);
+	  continue;
+	}
+
+#if defined (HANDLE_MULTIBYTE)
+      if (MB_CUR_MAX > 1 && rl_byte_oriented == 0)
+	{
+	  int k, c;
+
+	  c = tchar;
+	  memset (mb, 0, sizeof (mb));
+	  for (k = 0; k < MB_LEN_MAX; k++)
+	    {
+	      mb[k] = (char)c;
+	      memset (&ps, 0, sizeof (mbstate_t));
+	      if (_rl_get_char_len (mb, &ps) == -2)
+		c = string[++i];
+	      else
+		break;
+	    }
+	  if (strlen (mb) > 1)
+	    {
+	      ADD_STRING (mb);
+	      break;
+	    }
+	}
+#endif /* HANDLE_MULTIBYTE */
+
+      if (tchar == history_expansion_char)
+	tchar = -3;
+      else if (tchar == history_comment_char)
+	tchar = -2;
+
+      switch (tchar)
+	{
+	default:
+	  ADD_CHAR (string[i]);
+	  break;
+
+	case '\\':
+	  passc++;
+	  ADD_CHAR (tchar);
+	  break;
+
+	case '\'':
+	  {
+	    /* If history_quotes_inhibit_expansion is set, single quotes
+	       inhibit history expansion. */
+	    if (history_quotes_inhibit_expansion)
+	      {
+		int quote, slen;
+
+		quote = i++;
+		hist_string_extract_single_quoted (string, &i);
+
+		slen = i - quote + 2;
+		temp = (char *)xmalloc (slen);
+		strncpy (temp, string + quote, slen);
+		temp[slen - 1] = '\0';
+		ADD_STRING (temp);
+		free (temp);
+	      }
+	    else
+	      ADD_CHAR (string[i]);
+	    break;
+	  }
+
+	case -2:		/* history_comment_char */
+	  if (i == 0 || member (string[i - 1], history_word_delimiters))
+	    {
+	      temp = (char *)xmalloc (l - i + 1);
+	      strcpy (temp, string + i);
+	      ADD_STRING (temp);
+	      free (temp);
+	      i = l;
+	    }
+	  else
+	    ADD_CHAR (string[i]);
+	  break;
+
+	case -3:		/* history_expansion_char */
+	  cc = string[i + 1];
+
+	  /* If the history_expansion_char is followed by one of the
+	     characters in history_no_expand_chars, then it is not a
+	     candidate for expansion of any kind. */
+	  if (member (cc, history_no_expand_chars))
+	    {
+	      ADD_CHAR (string[i]);
+	      break;
+	    }
+
+#if defined (NO_BANG_HASH_MODIFIERS)
+	  /* There is something that is listed as a `word specifier' in csh
+	     documentation which means `the expanded text to this point'.
+	     That is not a word specifier, it is an event specifier.  If we
+	     don't want to allow modifiers with `!#', just stick the current
+	     output line in again. */
+	  if (cc == '#')
+	    {
+	      if (result)
+		{
+		  temp = (char *)xmalloc (1 + strlen (result));
+		  strcpy (temp, result);
+		  ADD_STRING (temp);
+		  free (temp);
+		}
+	      i++;
+	      break;
+	    }
+#endif
+
+	  r = history_expand_internal (string, i, &eindex, &temp, result);
+	  if (r < 0)
+	    {
+	      *output = temp;
+	      free (result);
+	      if (string != hstring)
+		free (string);
+	      return -1;
+	    }
+	  else
+	    {
+	      if (temp)
+		{
+		  modified++;
+		  if (*temp)
+		    ADD_STRING (temp);
+		  free (temp);
+		}
+	      only_printing = r == 1;
+	      i = eindex;
+	    }
+	  break;
+	}
+    }
+
+  *output = result;
+  if (string != hstring)
+    free (string);
+
+  if (only_printing)
+    {
+      add_history (result);
+      return (2);
+    }
+
+  return (modified != 0);
+}
+
+/* Return a consed string which is the word specified in SPEC, and found
+   in FROM.  NULL is returned if there is no spec.  The address of
+   ERROR_POINTER is returned if the word specified cannot be found.
+   CALLER_INDEX is the offset in SPEC to start looking; it is updated
+   to point to just after the last character parsed. */
+static char *
+get_history_word_specifier (spec, from, caller_index)
+     char *spec, *from;
+     int *caller_index;
+{
+  register int i = *caller_index;
+  int first, last;
+  int expecting_word_spec = 0;
+  char *result;
+
+  /* The range of words to return doesn't exist yet. */
+  first = last = 0;
+  result = (char *)NULL;
+
+  /* If we found a colon, then this *must* be a word specification.  If
+     it isn't, then it is an error. */
+  if (spec[i] == ':')
+    {
+      i++;
+      expecting_word_spec++;
+    }
+
+  /* Handle special cases first. */
+
+  /* `%' is the word last searched for. */
+  if (spec[i] == '%')
+    {
+      *caller_index = i + 1;
+      return (search_match ? savestring (search_match) : savestring (""));
+    }
+
+  /* `*' matches all of the arguments, but not the command. */
+  if (spec[i] == '*')
+    {
+      *caller_index = i + 1;
+      result = history_arg_extract (1, '$', from);
+      return (result ? result : savestring (""));
+    }
+
+  /* `$' is last arg. */
+  if (spec[i] == '$')
+    {
+      *caller_index = i + 1;
+      return (history_arg_extract ('$', '$', from));
+    }
+
+  /* Try to get FIRST and LAST figured out. */
+
+  if (spec[i] == '-')
+    first = 0;
+  else if (spec[i] == '^')
+    first = 1;
+  else if (_rl_digit_p (spec[i]) && expecting_word_spec)
+    {
+      for (first = 0; _rl_digit_p (spec[i]); i++)
+	first = (first * 10) + _rl_digit_value (spec[i]);
+    }
+  else
+    return ((char *)NULL);	/* no valid `first' for word specifier */
+
+  if (spec[i] == '^' || spec[i] == '*')
+    {
+      last = (spec[i] == '^') ? 1 : '$';	/* x* abbreviates x-$ */
+      i++;
+    }
+  else if (spec[i] != '-')
+    last = first;
+  else
+    {
+      i++;
+
+      if (_rl_digit_p (spec[i]))
+	{
+	  for (last = 0; _rl_digit_p (spec[i]); i++)
+	    last = (last * 10) + _rl_digit_value (spec[i]);
+	}
+      else if (spec[i] == '$')
+	{
+	  i++;
+	  last = '$';
+	}
+#if 0
+      else if (!spec[i] || spec[i] == ':')
+	/* check against `:' because there could be a modifier separator */
+#else
+      else
+	/* csh seems to allow anything to terminate the word spec here,
+	   leaving it as an abbreviation. */
+#endif
+	last = -1;		/* x- abbreviates x-$ omitting word `$' */
+    }
+
+  *caller_index = i;
+
+  if (last >= first || last == '$' || last < 0)
+    result = history_arg_extract (first, last, from);
+
+  return (result ? result : (char *)&error_pointer);
+}
+
+/* Extract the args specified, starting at FIRST, and ending at LAST.
+   The args are taken from STRING.  If either FIRST or LAST is < 0,
+   then make that arg count from the right (subtract from the number of
+   tokens, so that FIRST = -1 means the next to last token on the line).
+   If LAST is `$' the last arg from STRING is used. */
+char *
+history_arg_extract (first, last, string)
+     int first, last;
+     const char *string;
+{
+  register int i, len;
+  char *result;
+  int size, offset;
+  char **list;
+
+  /* XXX - think about making history_tokenize return a struct array,
+     each struct in array being a string and a length to avoid the
+     calls to strlen below. */
+  if ((list = history_tokenize (string)) == NULL)
+    return ((char *)NULL);
+
+  for (len = 0; list[len]; len++)
+    ;
+
+  if (last < 0)
+    last = len + last - 1;
+
+  if (first < 0)
+    first = len + first - 1;
+
+  if (last == '$')
+    last = len - 1;
+
+  if (first == '$')
+    first = len - 1;
+
+  last++;
+
+  if (first >= len || last > len || first < 0 || last < 0 || first > last)
+    result = ((char *)NULL);
+  else
+    {
+      for (size = 0, i = first; i < last; i++)
+	size += strlen (list[i]) + 1;
+      result = (char *)xmalloc (size + 1);
+      result[0] = '\0';
+
+      for (i = first, offset = 0; i < last; i++)
+	{
+	  strcpy (result + offset, list[i]);
+	  offset += strlen (list[i]);
+	  if (i + 1 < last)
+	    {
+      	      result[offset++] = ' ';
+	      result[offset] = 0;
+	    }
+	}
+    }
+
+  for (i = 0; i < len; i++)
+    free (list[i]);
+  free (list);
+
+  return (result);
+}
+
+#define slashify_in_quotes "\\`\"$"
+
+/* Parse STRING into tokens and return an array of strings.  If WIND is
+   not -1 and INDP is not null, we also want the word surrounding index
+   WIND.  The position in the returned array of strings is returned in
+   *INDP. */
+static char **
+history_tokenize_internal (string, wind, indp)
+     const char *string;
+     int wind, *indp;
+{
+  char **result;
+  register int i, start, result_index, size;
+  int len, delimiter;
+
+  /* If we're searching for a string that's not part of a word (e.g., " "),
+     make sure we set *INDP to a reasonable value. */
+  if (indp && wind != -1)
+    *indp = -1;
+
+  /* Get a token, and stuff it into RESULT.  The tokens are split
+     exactly where the shell would split them. */
+  for (i = result_index = size = 0, result = (char **)NULL; string[i]; )
+    {
+      delimiter = 0;
+
+      /* Skip leading whitespace. */
+      for (; string[i] && whitespace (string[i]); i++)
+	;
+      if (string[i] == 0 || string[i] == history_comment_char)
+	return (result);
+
+      start = i;
+      
+      if (member (string[i], "()\n"))
+	{
+	  i++;
+	  goto got_token;
+	}
+
+      if (member (string[i], "<>;&|$"))
+	{
+	  int peek = string[i + 1];
+
+	  if (peek == string[i] && peek != '$')
+	    {
+	      if (peek == '<' && string[i + 2] == '-')
+		i++;
+	      i += 2;
+	      goto got_token;
+	    }
+	  else
+	    {
+	      if ((peek == '&' && (string[i] == '>' || string[i] == '<')) ||
+		  ((peek == '>') && (string[i] == '&')) ||
+		  ((peek == '(') && (string[i] == '$')))
+		{
+		  i += 2;
+		  goto got_token;
+		}
+	    }
+	  if (string[i] != '$')
+	    {
+	      i++;
+	      goto got_token;
+	    }
+	}
+
+      /* Get word from string + i; */
+
+      if (member (string[i], HISTORY_QUOTE_CHARACTERS))
+	delimiter = string[i++];
+
+      for (; string[i]; i++)
+	{
+	  if (string[i] == '\\' && string[i + 1] == '\n')
+	    {
+	      i++;
+	      continue;
+	    }
+
+	  if (string[i] == '\\' && delimiter != '\'' &&
+	      (delimiter != '"' || member (string[i], slashify_in_quotes)))
+	    {
+	      i++;
+	      continue;
+	    }
+
+	  if (delimiter && string[i] == delimiter)
+	    {
+	      delimiter = 0;
+	      continue;
+	    }
+
+	  if (!delimiter && (member (string[i], history_word_delimiters)))
+	    break;
+
+	  if (!delimiter && member (string[i], HISTORY_QUOTE_CHARACTERS))
+	    delimiter = string[i];
+	}
+
+    got_token:
+
+      /* If we are looking for the word in which the character at a
+	 particular index falls, remember it. */
+      if (indp && wind != -1 && wind >= start && wind < i)
+        *indp = result_index;
+
+      len = i - start;
+      if (result_index + 2 >= size)
+	result = (char **)xrealloc (result, ((size += 10) * sizeof (char *)));
+      result[result_index] = (char *)xmalloc (1 + len);
+      strncpy (result[result_index], string + start, len);
+      result[result_index][len] = '\0';
+      result[++result_index] = (char *)NULL;
+    }
+
+  return (result);
+}
+
+/* Return an array of tokens, much as the shell might.  The tokens are
+   parsed out of STRING. */
+char **
+history_tokenize (string)
+     const char *string;
+{
+  return (history_tokenize_internal (string, -1, (int *)NULL));
+}
+
+/* Find and return the word which contains the character at index IND
+   in the history line LINE.  Used to save the word matched by the
+   last history !?string? search. */
+static char *
+history_find_word (line, ind)
+     char *line;
+     int ind;
+{
+  char **words, *s;
+  int i, wind;
+
+  words = history_tokenize_internal (line, ind, &wind);
+  if (wind == -1 || words == 0)
+    return ((char *)NULL);
+  s = words[wind];
+  for (i = 0; i < wind; i++)
+    free (words[i]);
+  for (i = wind + 1; words[i]; i++)
+    free (words[i]);
+  free (words);
+  return s;
+}