info-utils.c

gcc-2.95.3 Linux下最常用的C编译器

/* info-utils.c -- Useful functions for manipulating Info file quirks. */

/* This file is part of GNU Info, a program for reading online documentation
   stored in Info format.

   Copyright (C) 1993 Free Software Foundation, Inc.

   This program 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.

   This program 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.

   You should have received a copy of the GNU General Public License
   along with this program; if not, write to the Free Software
   Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.

   Written by Brian Fox ([e-mail]). */

#include "info.h"
#include "info-utils.h"
#if defined (HANDLE_MAN_PAGES)
#  include "man.h"
#endif /* HANDLE_MAN_PAGES */

/* When non-zero, various display and input functions handle ISO Latin
   character sets correctly. */
int ISO_Latin_p = 0;

/* Variable which holds the most recent filename parsed as a result of
   calling info_parse_xxx (). */
char *info_parsed_filename = (char *)NULL;

/* Variable which holds the most recent nodename parsed as a result of
   calling info_parse_xxx (). */
char *info_parsed_nodename = (char *)NULL;

/* Functions to remember a filename or nodename for later return. */
static void save_filename (), saven_filename ();
static void save_nodename (), saven_nodename ();

/* How to get a reference (either menu or cross). */
static REFERENCE **info_references_internal ();

/* Parse the filename and nodename out of STRING.  If STRING doesn't
   contain a filename (i.e., it is NOT (FILENAME)NODENAME) then set
   INFO_PARSED_FILENAME to NULL.  If second argument NEWLINES_OKAY is
   non-zero, it says to allow the nodename specification to cross a
   newline boundary (i.e., only `,', `.', or `TAB' can end the spec). */
void
info_parse_node (string, newlines_okay)
     char *string;
     int newlines_okay;
{
  register int i = 0;

  /* Default the answer. */
  save_filename ((char *)NULL);
  save_nodename ((char *)NULL);

  /* Special case of nothing passed.  Return nothing. */
  if (!string || !*string)
    return;

  string += skip_whitespace (string);

  /* Check for (FILENAME)NODENAME. */
  if (*string == '(')
    {
      i = 0;
      /* Advance past the opening paren. */
      string++;

      /* Find the closing paren. */
      while (string[i] && string[i] != ')')
        i++;

      /* Remember parsed filename. */
      saven_filename (string, i);

      /* Point directly at the nodename. */
      string += i;

      if (*string)
        string++;
    }

  /* Parse out nodename. */
  i = skip_node_characters (string, newlines_okay);
  saven_nodename (string, i);
  canonicalize_whitespace (info_parsed_nodename);
  if (info_parsed_nodename && !*info_parsed_nodename)
    {
      free (info_parsed_nodename);
      info_parsed_nodename = (char *)NULL;
    }
}

/* Return the node addressed by LABEL in NODE (usually one of "Prev:",
   "Next:", "Up:", "File:", or "Node:".  After a call to this function,
   the global INFO_PARSED_NODENAME and INFO_PARSED_FILENAME contain
   the information. */
void
info_parse_label (label, node)
     char *label;
     NODE *node;
{
  register int i;
  char *nodeline;

  /* Default answer to failure. */
  save_nodename ((char *)NULL);
  save_filename ((char *)NULL);

  /* Find the label in the first line of this node. */
  nodeline = node->contents;
  i = string_in_line (label, nodeline);

  if (i == -1)
    return;

  nodeline += i;
  nodeline += skip_whitespace (nodeline);
  info_parse_node (nodeline, DONT_SKIP_NEWLINES);
}

/* **************************************************************** */
/*                                                                  */
/*                  Finding and Building Menus                      */
/*                                                                  */
/* **************************************************************** */

/* Return a NULL terminated array of REFERENCE * which represents the menu
   found in NODE.  If there is no menu in NODE, just return a NULL pointer. */
REFERENCE **
info_menu_of_node (node)
     NODE *node;
{
  long position;
  SEARCH_BINDING search;
  REFERENCE **menu = (REFERENCE **)NULL;

  search.buffer = node->contents;
  search.start = 0;
  search.end = node->nodelen;
  search.flags = S_FoldCase;

  /* Find the start of the menu. */
  position = search_forward (INFO_MENU_LABEL, &search);

  if (position == -1)
    return ((REFERENCE **) NULL);

  /* We have the start of the menu now.  Glean menu items from the rest
     of the node. */
  search.start = position + strlen (INFO_MENU_LABEL);
  search.start += skip_line (search.buffer + search.start);
  search.start--;
  menu = info_menu_items (&search);
  return (menu);
}

/* Return a NULL terminated array of REFERENCE * which represents the cross
   refrences found in NODE.  If there are no cross references in NODE, just
   return a NULL pointer. */
REFERENCE **
info_xrefs_of_node (node)
     NODE *node;
{
  SEARCH_BINDING search;

#if defined (HANDLE_MAN_PAGES)
  if (node->flags & N_IsManPage)
    return (xrefs_of_manpage (node));
#endif

  search.buffer = node->contents;
  search.start = 0;
  search.end = node->nodelen;
  search.flags = S_FoldCase;

  return (info_xrefs (&search));
}

/* Glean menu entries from BINDING->buffer + BINDING->start until we
   have looked at the entire contents of BINDING.  Return an array
   of REFERENCE * that represents each menu item in this range. */
REFERENCE **
info_menu_items (binding)
     SEARCH_BINDING *binding;
{
  return (info_references_internal (INFO_MENU_ENTRY_LABEL, binding));
}

/* Glean cross references from BINDING->buffer + BINDING->start until
   BINDING->end.  Return an array of REFERENCE * that represents each
   cross reference in this range. */
REFERENCE **
info_xrefs (binding)
     SEARCH_BINDING *binding;
{
  return (info_references_internal (INFO_XREF_LABEL, binding));
}

/* Glean cross references or menu items from BINDING.  Return an array
   of REFERENCE * that represents the items found. */
static REFERENCE **
info_references_internal (label, binding)
     char *label;
     SEARCH_BINDING *binding;
{
  SEARCH_BINDING search;
  REFERENCE **refs = (REFERENCE **)NULL;
  int refs_index = 0, refs_slots = 0;
  int searching_for_menu_items = 0;
  long position;

  search.buffer = binding->buffer;
  search.start = binding->start;
  search.end = binding->end;
  search.flags = S_FoldCase | S_SkipDest;

  searching_for_menu_items = (strcasecmp (label, INFO_MENU_ENTRY_LABEL) == 0);

  while ((position = search_forward (label, &search)) != -1)
    {
      int offset, start;
      char *refdef;
      REFERENCE *entry;

      search.start = position;
      search.start += skip_whitespace (search.buffer + search.start);
      start = search.start - binding->start;
      refdef = search.buffer + search.start;
      offset = string_in_line (":", refdef);

      /* When searching for menu items, if no colon, there is no
         menu item on this line. */
      if (offset == -1)
        {
          if (searching_for_menu_items)
            continue;
          else
            {
              int temp;

              temp = skip_line (refdef);
              offset = string_in_line (":", refdef + temp);
              if (offset == -1)
                continue;       /* Give up? */
              else
                offset += temp;
            }
        }

      entry = (REFERENCE *)xmalloc (sizeof (REFERENCE));
      entry->filename = (char *)NULL;
      entry->nodename = (char *)NULL;
      entry->label = (char *)xmalloc (offset);
      strncpy (entry->label, refdef, offset - 1);
      entry->label[offset - 1] = '\0';
      canonicalize_whitespace (entry->label);

      refdef += offset;
      entry->start = start;
      entry->end = refdef - binding->buffer;

      /* If this reference entry continues with another ':' then the
         nodename is the same as the label. */
      if (*refdef == ':')
        {
          entry->nodename = xstrdup (entry->label);
        }
      else
        {
          /* This entry continues with a specific nodename.  Parse the
             nodename from the specification. */

          refdef += skip_whitespace_and_newlines (refdef);

          if (searching_for_menu_items)
            info_parse_node (refdef, DONT_SKIP_NEWLINES);
          else
            info_parse_node (refdef, SKIP_NEWLINES);

          if (info_parsed_filename)
            entry->filename = xstrdup (info_parsed_filename);

          if (info_parsed_nodename)
            entry->nodename = xstrdup (info_parsed_nodename);
        }

      add_pointer_to_array
        (entry, refs_index, refs, refs_slots, 50, REFERENCE *);
    }
  return (refs);
}

/* Get the entry associated with LABEL in MENU.  Return a pointer to the
   REFERENCE if found, or NULL. */
REFERENCE *
info_get_labeled_reference (label, references)
     char *label;
     REFERENCE **references;
{
  register int i;
  REFERENCE *entry;

  for (i = 0; references && (entry = references[i]); i++)
    {
      if (strcmp (label, entry->label) == 0)
        return (entry);
    }
  return ((REFERENCE *)NULL);
}

/* A utility function for concatenating REFERENCE **.  Returns a new
   REFERENCE ** which is the concatenation of REF1 and REF2.  The REF1
   and REF2 arrays are freed, but their contents are not. */
REFERENCE **
info_concatenate_references (ref1, ref2)
     REFERENCE **ref1, **ref2;
{
  register int i, j;
  REFERENCE **result;
  int size;

  /* With one argument passed as NULL, simply return the other arg. */
  if (!ref1)