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-rw-r--r--contrib/texinfo/info/search.c519
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diff --git a/contrib/texinfo/info/search.c b/contrib/texinfo/info/search.c
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-/* search.c -- How to search large bodies of text. */
-
-/* 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 (bfox@ai.mit.edu). */
-
-#include <ctype.h>
-#include <sys/types.h>
-#include <sys/stat.h>
-#include "general.h"
-#include "search.h"
-#include "nodes.h"
-
-#if !defined (NULL)
-# define NULL 0x0
-#endif /* !NULL */
-
-/* The search functions take two arguments:
-
- 1) a string to search for, and
-
- 2) a pointer to a SEARCH_BINDING which contains the buffer, start,
- and end of the search.
-
- They return a long, which is the offset from the start of the buffer
- at which the match was found. An offset of -1 indicates failure. */
-
-/* A function which makes a binding with buffer and bounds. */
-SEARCH_BINDING *
-make_binding (buffer, start, end)
- char *buffer;
- long start, end;
-{
- SEARCH_BINDING *binding;
-
- binding = (SEARCH_BINDING *)xmalloc (sizeof (SEARCH_BINDING));
- binding->buffer = buffer;
- binding->start = start;
- binding->end = end;
- binding->flags = 0;
-
- return (binding);
-}
-
-/* Make a copy of BINDING without duplicating the data. */
-SEARCH_BINDING *
-copy_binding (binding)
- SEARCH_BINDING *binding;
-{
- SEARCH_BINDING *copy;
-
- copy = make_binding (binding->buffer, binding->start, binding->end);
- copy->flags = binding->flags;
- return (copy);
-}
-
-
-/* **************************************************************** */
-/* */
-/* The Actual Searching Functions */
-/* */
-/* **************************************************************** */
-
-/* Search forwards or backwards for the text delimited by BINDING.
- The search is forwards if BINDING->start is greater than BINDING->end. */
-long
-search (string, binding)
- char *string;
- SEARCH_BINDING *binding;
-{
- long result;
-
- /* If the search is backwards, then search backwards, otherwise forwards. */
- if (binding->start > binding->end)
- result = search_backward (string, binding);
- else
- result = search_forward (string, binding);
-
- return (result);
-}
-
-/* Search forwards for STRING through the text delimited in BINDING. */
-long
-search_forward (string, binding)
- char *string;
- SEARCH_BINDING *binding;
-{
- register int c, i, len;
- register char *buff, *end;
- char *alternate = (char *)NULL;
-
- len = strlen (string);
-
- /* We match characters in the search buffer against STRING and ALTERNATE.
- ALTERNATE is a case reversed version of STRING; this is cheaper than
- case folding each character before comparison. Alternate is only
- used if the case folding bit is turned on in the passed BINDING. */
-
- if (binding->flags & S_FoldCase)
- {
- alternate = strdup (string);
-
- for (i = 0; i < len; i++)
- {
- if (islower (alternate[i]))
- alternate[i] = toupper (alternate[i]);
- else if (isupper (alternate[i]))
- alternate[i] = tolower (alternate[i]);
- }
- }
-
- buff = binding->buffer + binding->start;
- end = binding->buffer + binding->end + 1;
-
- while (buff < (end - len))
- {
- for (i = 0; i < len; i++)
- {
- c = buff[i];
-
- if ((c != string[i]) && (!alternate || c != alternate[i]))
- break;
- }
-
- if (!string[i])
- {
- if (alternate)
- free (alternate);
- if (binding->flags & S_SkipDest)
- buff += len;
- return ((long) (buff - binding->buffer));
- }
-
- buff++;
- }
-
- if (alternate)
- free (alternate);
-
- return ((long) -1);
-}
-
-/* Search for STRING backwards through the text delimited in BINDING. */
-long
-search_backward (input_string, binding)
- char *input_string;
- SEARCH_BINDING *binding;
-{
- register int c, i, len;
- register char *buff, *end;
- char *string;
- char *alternate = (char *)NULL;
-
- len = strlen (input_string);
-
- /* Reverse the characters in the search string. */
- string = (char *)xmalloc (1 + len);
- for (c = 0, i = len - 1; input_string[c]; c++, i--)
- string[i] = input_string[c];
-
- string[c] = '\0';
-
- /* We match characters in the search buffer against STRING and ALTERNATE.
- ALTERNATE is a case reversed version of STRING; this is cheaper than
- case folding each character before comparison. ALTERNATE is only
- used if the case folding bit is turned on in the passed BINDING. */
-
- if (binding->flags & S_FoldCase)
- {
- alternate = strdup (string);
-
- for (i = 0; i < len; i++)
- {
- if (islower (alternate[i]))
- alternate[i] = toupper (alternate[i]);
- else if (isupper (alternate[i]))
- alternate[i] = tolower (alternate[i]);
- }
- }
-
- buff = binding->buffer + binding->start - 1;
- end = binding->buffer + binding->end;
-
- while (buff > (end + len))
- {
- for (i = 0; i < len; i++)
- {
- c = *(buff - i);
-
- if (c != string[i] && (alternate && c != alternate[i]))
- break;
- }
-
- if (!string[i])
- {
- free (string);
- if (alternate)
- free (alternate);
-
- if (binding->flags & S_SkipDest)
- buff -= len;
- return ((long) (1 + (buff - binding->buffer)));
- }
-
- buff--;
- }
-
- free (string);
- if (alternate)
- free (alternate);
-
- return ((long) -1);
-}
-
-/* Find STRING in LINE, returning the offset of the end of the string.
- Return an offset of -1 if STRING does not appear in LINE. The search
- is bound by the end of the line (i.e., either NEWLINE or 0). */
-int
-string_in_line (string, line)
- char *string, *line;
-{
- register int end;
- SEARCH_BINDING binding;
-
- /* Find the end of the line. */
- for (end = 0; line[end] && line[end] != '\n'; end++);
-
- /* Search for STRING within these confines. */
- binding.buffer = line;
- binding.start = 0;
- binding.end = end;
- binding.flags = S_FoldCase | S_SkipDest;
-
- return (search_forward (string, &binding));
-}
-
-/* Return non-zero if STRING is the first text to appear at BINDING. */
-int
-looking_at (string, binding)
- char *string;
- SEARCH_BINDING *binding;
-{
- long search_end;
-
- search_end = search (string, binding);
-
- /* If the string was not found, SEARCH_END is -1. If the string was found,
- but not right away, SEARCH_END is != binding->start. Otherwise, the
- string was found at binding->start. */
- return (search_end == binding->start);
-}
-
-/* **************************************************************** */
-/* */
-/* Small String Searches */
-/* */
-/* **************************************************************** */
-
-/* Function names that start with "skip" are passed a string, and return
- an offset from the start of that string. Function names that start
- with "find" are passed a SEARCH_BINDING, and return an absolute position
- marker of the item being searched for. "Find" functions return a value
- of -1 if the item being looked for couldn't be found. */
-
-/* Return the index of the first non-whitespace character in STRING. */
-int
-skip_whitespace (string)
- char *string;
-{
- register int i;
-
- for (i = 0; string && whitespace (string[i]); i++);
- return (i);
-}
-
-/* Return the index of the first non-whitespace or newline character in
- STRING. */
-int
-skip_whitespace_and_newlines (string)
- char *string;
-{
- register int i;
-
- for (i = 0; string && (whitespace (string[i]) || string[i] == '\n'); i++);
- return (i);
-}
-
-/* Return the index of the first whitespace character in STRING. */
-int
-skip_non_whitespace (string)
- char *string;
-{
- register int i;
-
- for (i = 0; string && !whitespace (string[i]); i++);
- return (i);
-}
-
-/* Return the index of the first non-node character in STRING. Note that
- this function contains quite a bit of hair to ignore periods in some
- special cases. This is because we here at GNU ship some info files which
- contain nodenames that contain periods. No such nodename can start with
- a period, or continue with whitespace, newline, or ')' immediately following
- the period. If second argument NEWLINES_OKAY is non-zero, newlines should
- be skipped while parsing out the nodename specification. */
-int
-skip_node_characters (string, newlines_okay)
- char *string;
- int newlines_okay;
-{
- register int c, i = 0;
- int paren_seen = 0;
- int paren = 0;
-
- /* Handle special case. This is when another function has parsed out the
- filename component of the node name, and we just want to parse out the
- nodename proper. In that case, a period at the start of the nodename
- indicates an empty nodename. */
- if (string && *string == '.')
- return (0);
-
- if (string && *string == '(')
- {
- paren++;
- paren_seen++;
- i++;
- }
-
- for (; string && (c = string[i]); i++)
- {
- if (paren)
- {
- if (c == '(')
- paren++;
- else if (c == ')')
- paren--;
-
- continue;
- }
-
- /* If the character following the close paren is a space or period,
- then this node name has no more characters associated with it. */
- if (c == '\t' ||
- c == ',' ||
- c == INFO_TAGSEP ||
- ((!newlines_okay) && (c == '\n')) ||
- ((paren_seen && string[i - 1] == ')') &&
- (c == ' ' || c == '.')) ||
- (c == '.' &&
- ((!string[i + 1]) ||
- (whitespace_or_newline (string[i + 1])) ||
- (string[i + 1] == ')'))))
- break;
- }
- return (i);
-}
-
-
-/* **************************************************************** */
-/* */
-/* Searching FILE_BUFFER's */
-/* */
-/* **************************************************************** */
-
-/* Return the absolute position of the first occurence of a node separator in
- BINDING-buffer. The search starts at BINDING->start. Return -1 if no node
- separator was found. */
-long
-find_node_separator (binding)
- SEARCH_BINDING *binding;
-{
- register long i;
- char *body;
-
- body = binding->buffer;
-
- /* A node is started by [^L]^_[^L]\n. That is to say, the C-l's are
- optional, but the DELETE and NEWLINE are not. This separator holds
- true for all separated elements in an Info file, including the tags
- table (if present) and the indirect tags table (if present). */
- for (i = binding->start; i < binding->end - 1; i++)
- if (((body[i] == INFO_FF && body[i + 1] == INFO_COOKIE) &&
- (body[i + 2] == '\n' ||
- (body[i + 2] == INFO_FF && body[i + 3] == '\n'))) ||
- ((body[i] == INFO_COOKIE) &&
- (body[i + 1] == '\n' ||
- (body[i + 1] == INFO_FF && body[i + 2] == '\n'))))
- return (i);
- return (-1);
-}
-
-/* Return the length of the node separator characters that BODY is
- currently pointing at. */
-int
-skip_node_separator (body)
- char *body;
-{
- register int i;
-
- i = 0;
-
- if (body[i] == INFO_FF)
- i++;
-
- if (body[i++] != INFO_COOKIE)
- return (0);
-
- if (body[i] == INFO_FF)
- i++;
-
- if (body[i++] != '\n')
- return (0);
-
- return (i);
-}
-
-/* Return the number of characters from STRING to the start of
- the next line. */
-int
-skip_line (string)
- char *string;
-{
- register int i;
-
- for (i = 0; string && string[i] && string[i] != '\n'; i++);
-
- if (string[i] == '\n')
- i++;
-
- return (i);
-}
-
-/* Return the absolute position of the beginning of a tags table in this
- binding starting the search at binding->start. */
-long
-find_tags_table (binding)
- SEARCH_BINDING *binding;
-{
- SEARCH_BINDING search;
- long position;
-
- search.buffer = binding->buffer;
- search.start = binding->start;
- search.end = binding->end;
- search.flags = S_FoldCase;
-
- while ((position = find_node_separator (&search)) != -1 )
- {
- search.start = position;
- search.start += skip_node_separator (search.buffer + search.start);
-
- if (looking_at (TAGS_TABLE_BEG_LABEL, &search))
- return (position);
- }
- return (-1);
-}
-
-/* Return the absolute position of the node named NODENAME in BINDING.
- This is a brute force search, and we wish to avoid it when possible.
- This function is called when a tag (indirect or otherwise) doesn't
- really point to the right node. It returns the absolute position of
- the separator preceding the node. */
-long
-find_node_in_binding (nodename, binding)
- char *nodename;
- SEARCH_BINDING *binding;
-{
- register long position;
- register int offset, namelen;
- SEARCH_BINDING search;
-
- namelen = strlen (nodename);
-
- search.buffer = binding->buffer;
- search.start = binding->start;
- search.end = binding->end;
- search.flags = 0;
-
- while ((position = find_node_separator (&search)) != -1)
- {
- search.start = position;
- search.start += skip_node_separator (search.buffer + search.start);
-
- offset = string_in_line (INFO_NODE_LABEL, search.buffer + search.start);
-
- if (offset == -1)
- continue;
-
- search.start += offset;
- search.start += skip_whitespace (search.buffer + search.start);
- offset = skip_node_characters
- (search.buffer + search.start, DONT_SKIP_NEWLINES);
-
- /* Notice that this is an exact match. You cannot grovel through
- the buffer with this function looking for random nodes. */
- if ((offset == namelen) &&
- (search.buffer[search.start] == nodename[0]) &&
- (strncmp (search.buffer + search.start, nodename, offset) == 0))
- return (position);
- }
- return (-1);
-}
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