/**************************************************************************
 *   search.c  --  This file is part of GNU nano.                         *
 *                                                                        *
 *   Copyright (C) 1999-2011, 2013-2019 Free Software Foundation, Inc.    *
 *   Copyright (C) 2015-2018 Benno Schulenberg                            *
 *                                                                        *
 *   GNU nano 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 3 of the License,    *
 *   or (at your option) any later version.                               *
 *                                                                        *
 *   GNU nano 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, see http://www.gnu.org/licenses/.  *
 *                                                                        *
 **************************************************************************/

#include "proto.h"

#include <string.h>
#ifdef DEBUG
#include <time.h>
#endif

static bool came_full_circle = FALSE;
		/* Have we reached the starting line again while searching? */
static bool have_compiled_regexp = FALSE;
		/* Whether we have compiled a regular expression for the search. */

/* Compile the given regular expression and store it in search_regexp.
 * Return TRUE if the expression is valid, and FALSE otherwise. */
bool regexp_init(const char *regexp)
{
	int value = regcomp(&search_regexp, regexp,
				NANO_REG_EXTENDED | (ISSET(CASE_SENSITIVE) ? 0 : REG_ICASE));

	/* If regex compilation failed, show the error message. */
	if (value != 0) {
		size_t len = regerror(value, &search_regexp, NULL, 0);
		char *str = charalloc(len);

		regerror(value, &search_regexp, str, len);
		statusline(ALERT, _("Bad regex \"%s\": %s"), regexp, str);
		free(str);

		return FALSE;
	}

	have_compiled_regexp = TRUE;

	return TRUE;
}

/* Free a compiled regular expression, if one was compiled; and schedule a
 * full screen refresh when the mark is on, in case the cursor has moved. */
void tidy_up_after_search(void)
{
	if (have_compiled_regexp) {
		regfree(&search_regexp);
		have_compiled_regexp = FALSE;
	}
#ifndef NANO_TINY
	if (openfile->mark)
		refresh_needed = TRUE;
#endif
}

/* Prepare the prompt and ask the user what to search for.  Keep looping
 * as long as the user presses a toggle, and only take action and exit
 * when <Enter> is pressed or a non-toggle shortcut was executed. */
void search_init(bool replacing, bool keep_the_answer)
{
	char *thedefault;
		/* What will be searched for when the user typed nothing. */

	/* When starting a new search, clear the current answer. */
	if (!keep_the_answer)
		answer = mallocstrcpy(answer, NULL);

	/* If something was searched for earlier, include it in the prompt. */
	if (*last_search != '\0') {
		char *disp = display_string(last_search, 0, COLS / 3, FALSE, FALSE);

		thedefault = charalloc(strlen(disp) + 7);
		/* We use (COLS / 3) here because we need to see more on the line. */
		sprintf(thedefault, " [%s%s]", disp,
				(strlenpt(last_search) > COLS / 3) ? "..." : "");
		free(disp);
	} else
		thedefault = mallocstrcpy(NULL, "");

	while (TRUE) {
		functionptrtype func;
		/* Ask the user what to search for (or replace). */
		int i = do_prompt(FALSE, FALSE,
					inhelp ? MFINDINHELP : (replacing ? MREPLACE : MWHEREIS),
					answer, &search_history,
					/* TRANSLATORS: This is the main search prompt. */
					edit_refresh, "%s%s%s%s%s%s", _("Search"),
					/* TRANSLATORS: The next four modify the search prompt. */
					ISSET(CASE_SENSITIVE) ? _(" [Case Sensitive]") : "",
					ISSET(USE_REGEXP) ? _(" [Regexp]") : "",
					ISSET(BACKWARDS_SEARCH) ? _(" [Backwards]") : "", replacing ?
#ifndef NANO_TINY
					openfile->mark ? _(" (to replace) in selection") :
#endif
					_(" (to replace)") : "", thedefault);

		/* If the search was cancelled, or we have a blank answer and
		 * nothing was searched for yet during this session, get out. */
		if (i == -1 || (i == -2 && *last_search == '\0')) {
			statusbar(_("Cancelled"));
			tidy_up_after_search();
			free(thedefault);
			return;
		}

		/* If Enter was pressed, prepare to do a replace or a search. */
		if (i == 0 || i == -2) {
			/* If an actual answer was typed, remember it. */
			if (*answer != '\0') {
				last_search = mallocstrcpy(last_search, answer);
#ifdef ENABLE_HISTORIES
				update_history(&search_history, answer);
#endif
			}

			/* When not doing a regular-expression search, just search;
			 * otherwise compile the search string, and only search when
			 * the expression is valid. */
			if (!ISSET(USE_REGEXP) || regexp_init(last_search)) {
				if (replacing)
					ask_for_replacement();
				else
					go_looking();
			}

			tidy_up_after_search();
			free(thedefault);
			return;
		}

		func = func_from_key(&i);

		/* If we're here, one of the five toggles was pressed, or
		 * a shortcut was executed. */
		if (func == case_sens_void) {
			TOGGLE(CASE_SENSITIVE);
		} else if (func == backwards_void) {
			TOGGLE(BACKWARDS_SEARCH);
		} else if (func == regexp_void) {
			TOGGLE(USE_REGEXP);
		} else if (func == flip_replace) {
			if (ISSET(VIEW_MODE)) {
				print_view_warning();
				tidy_up_after_search();
				free(thedefault);
				return;
			}
			replacing = !replacing;
		} else {
			if (func == flip_goto)
				do_gotolinecolumn(openfile->current->lineno,
							openfile->placewewant + 1, TRUE, TRUE);
			tidy_up_after_search();
			free(thedefault);
			return;
		}
	}
}

/* Look for needle, starting at (current, current_x).  begin is the line
 * where we first started searching, at column begin_x.  Return 1 when we
 * found something, 0 when nothing, and -2 on cancel.  When match_len is
 * not NULL, set it to the length of the found string, if any. */
int findnextstr(const char *needle, bool whole_word_only, int modus,
		size_t *match_len, bool skipone, const linestruct *begin, size_t begin_x)
{
	size_t found_len = strlen(needle);
		/* The length of a match -- will be recomputed for a regex. */
	int feedback = 0;
		/* When bigger than zero, show and wipe the "Searching..." message. */
	linestruct *line = openfile->current;
		/* The line that we will search through now. */
	const char *from = line->data + openfile->current_x;
		/* The point in the line from where we start searching. */
	const char *found = NULL;
		/* A pointer to the location of the match, if any. */
	size_t found_x;
		/* The x coordinate of a found occurrence. */
	time_t lastkbcheck = time(NULL);
		/* The time we last looked at the keyboard. */

	/* Set non-blocking input so that we can just peek for a Cancel. */
	disable_waiting();

	if (begin == NULL)
		came_full_circle = FALSE;

	/* Start searching through the lines, looking for the needle. */
	while (TRUE) {
		/* Glance at the keyboard once every second. */
		if (time(NULL) - lastkbcheck > 0) {
			int input = parse_kbinput(edit);

			lastkbcheck = time(NULL);

			/* Consume all waiting keystrokes until a Cancel. */
			while (input != ERR) {
				if (func_from_key(&input) == do_cancel) {
					statusbar(_("Cancelled"));
					enable_waiting();
					return -2;
				}
				input = parse_kbinput(NULL);
			}

			if (++feedback > 0)
				/* TRANSLATORS: This is shown when searching takes
				 * more than half a second. */
				statusbar(_("Searching..."));
		}

		/* When starting a new search, skip the first character, then
		 * (in either case) search for the needle in the current line. */
		if (skipone) {
			skipone = FALSE;
			if (ISSET(BACKWARDS_SEARCH) && from != line->data) {
				from = line->data + move_mbleft(line->data, from - line->data);
				found = strstrwrapper(line->data, needle, from);
			} else if (!ISSET(BACKWARDS_SEARCH) && *from != '\0') {
				from += move_mbright(from, 0);
				found = strstrwrapper(line->data, needle, from);
			}
		} else
			found = strstrwrapper(line->data, needle, from);

		if (found != NULL) {
			/* When doing a regex search, compute the length of the match. */
			if (ISSET(USE_REGEXP))
				found_len = regmatches[0].rm_eo - regmatches[0].rm_so;
#ifdef ENABLE_SPELLER
			/* When we're spell checking, a match should be a separate word;
			 * if it's not, continue looking in the rest of the line. */
			if (whole_word_only && !is_separate_word(found - line->data,
												found_len, line->data)) {
				from = found + move_mbright(found, 0);
				continue;
			}
#endif
			/* The match is valid. */
			break;
		}

		/* If we're back at the beginning, then there is no needle. */
		if (came_full_circle) {
			enable_waiting();
			return 0;
		}

		/* Move to the previous or next line in the file. */
		if (ISSET(BACKWARDS_SEARCH))
			line = line->prev;
		else
			line = line->next;

		/* If we've reached the start or end of the buffer, wrap around;
		 * but stop when spell-checking or replacing in a region. */
		if (line == NULL) {
			if (whole_word_only || modus == INREGION) {
				enable_waiting();
				return 0;
			}

			if (ISSET(BACKWARDS_SEARCH))
				line = openfile->filebot;
			else
				line = openfile->filetop;

			if (modus == JUSTFIND) {
				statusbar(_("Search Wrapped"));
				/* Delay the "Searching..." message for at least two seconds. */
				feedback = -2;
			}
		}

		/* If we've reached the original starting line, take note. */
		if (line == begin)
			came_full_circle = TRUE;

		/* Set the starting x to the start or end of the line. */
		from = line->data;
		if (ISSET(BACKWARDS_SEARCH))
			from += strlen(line->data);
	}

	found_x = found - line->data;

	enable_waiting();

	/* Ensure that the found occurrence is not beyond the starting x. */
	if (came_full_circle && ((!ISSET(BACKWARDS_SEARCH) && (found_x > begin_x ||
						(modus == REPLACING && found_x == begin_x))) ||
						(ISSET(BACKWARDS_SEARCH) && found_x < begin_x)))
		return 0;

	/* Set the current position to point at what we found. */
	openfile->current = line;
	openfile->current_x = found_x;

	/* When requested, pass back the length of the match. */
	if (match_len != NULL)
		*match_len = found_len;

	/* Wipe the "Searching..." message and unset the suppression flag. */
	if (feedback > 0) {
		wipe_statusbar();
		suppress_cursorpos = FALSE;
	}

	return 1;
}

/* Ask what to search for and then go looking for it. */
void do_search(void)
{
	search_init(FALSE, FALSE);
}

/* Search forward for a string. */
void do_search_forward(void)
{
	UNSET(BACKWARDS_SEARCH);
	do_search();
}

/* Search backwards for a string. */
void do_search_backward(void)
{
	SET(BACKWARDS_SEARCH);
	do_search();
}

/* Search for the last string without prompting. */
void do_research(void)
{
#ifdef ENABLE_HISTORIES
	/* If nothing was searched for yet during this run of nano, but
	 * there is a search history, take the most recent item. */
	if (*last_search == '\0' && searchbot->prev != NULL)
		last_search = mallocstrcpy(last_search, searchbot->prev->data);
#endif

	if (*last_search == '\0') {
		statusbar(_("No current search pattern"));
		return;
	}

	if (ISSET(USE_REGEXP) && !regexp_init(last_search))
		return;

	/* Use the search-menu key bindings, to allow cancelling. */
	currmenu = MWHEREIS;

	go_looking();

	tidy_up_after_search();
}

/* Search in the backward direction for the next occurrence. */
void do_findprevious(void)
{
	SET(BACKWARDS_SEARCH);
	do_research();
}

/* Search in the forward direction for the next occurrence. */
void do_findnext(void)
{
	UNSET(BACKWARDS_SEARCH);
	do_research();
}

/* Report on the status bar that the given string was not found. */
void not_found_msg(const char *str)
{
	char *disp = display_string(str, 0, (COLS / 2) + 1, FALSE, FALSE);
	size_t numchars = actual_x(disp, strnlenpt(disp, COLS / 2));

	statusline(HUSH, _("\"%.*s%s\" not found"), numchars, disp,
						(disp[numchars] == '\0') ? "" : "...");
	free(disp);
}

/* Search for the global string 'last_search'.  Inform the user when
 * the string occurs only once. */
void go_looking(void)
{
	linestruct *was_current = openfile->current;
	size_t was_current_x = openfile->current_x;
#ifdef DEBUG
	clock_t start = clock();
#endif

	came_full_circle = FALSE;

	didfind = findnextstr(last_search, FALSE, JUSTFIND, NULL, TRUE,
								openfile->current, openfile->current_x);

	/* If we found something, and we're back at the exact same spot
	 * where we started searching, then this is the only occurrence. */
	if (didfind == 1 && openfile->current == was_current &&
				openfile->current_x == was_current_x)
		statusbar(_("This is the only occurrence"));
	else if (didfind == 0)
		not_found_msg(last_search);

#ifdef DEBUG
	statusline(HUSH, "Took: %.2f", (double)(clock() - start) / CLOCKS_PER_SEC);
#endif

	edit_redraw(was_current, CENTERING);
}

/* Calculate the size of the replacement text, taking possible
 * subexpressions \1 to \9 into account.  Return the replacement
 * text in the passed string only when create is TRUE. */
int replace_regexp(char *string, bool create)
{
	const char *c = answer;
	size_t replacement_size = 0;

	/* Iterate through the replacement text to handle subexpression
	 * replacement using \1, \2, \3, etc. */
	while (*c != '\0') {
		int num = (*(c + 1) - '0');

		if (*c != '\\' || num < 1 || num > 9 || num > search_regexp.re_nsub) {
			if (create)
				*string++ = *c;
			c++;
			replacement_size++;
		} else {
			size_t i = regmatches[num].rm_eo - regmatches[num].rm_so;

			/* Skip over the replacement expression. */
			c += 2;

			/* But add the length of the subexpression to new_size. */
			replacement_size += i;

			/* And if create is TRUE, append the result of the
			 * subexpression match to the new line. */
			if (create) {
				strncpy(string, openfile->current->data +
										regmatches[num].rm_so, i);
				string += i;
			}
		}
	}

	if (create)
		*string = '\0';

	return replacement_size;
}

/* Return a copy of the current line with one needle replaced. */
char *replace_line(const char *needle)
{
	char *copy;
	size_t match_len;
	size_t new_line_size = strlen(openfile->current->data) + 1;

	/* First adjust the size of the new line for the change. */
	if (ISSET(USE_REGEXP)) {
		match_len = regmatches[0].rm_eo - regmatches[0].rm_so;
		new_line_size += replace_regexp(NULL, FALSE) - match_len;
	} else {
		match_len = strlen(needle);
		new_line_size += strlen(answer) - match_len;
	}

	/* Create the buffer. */
	copy = charalloc(new_line_size);

	/* Copy the head of the original line. */
	strncpy(copy, openfile->current->data, openfile->current_x);

	/* Add the replacement text. */
	if (ISSET(USE_REGEXP))
		replace_regexp(copy + openfile->current_x, TRUE);
	else
		strcpy(copy + openfile->current_x, answer);

	assert(openfile->current_x + match_len <= strlen(openfile->current->data));

	/* Copy the tail of the original line. */
	strcat(copy, openfile->current->data + openfile->current_x + match_len);

	return copy;
}

/* Step through each occurrence of the search string and prompt the user
 * before replacing it.  We seek for needle, and replace it with answer.
 * The parameters real_current and real_current_x are needed in order to
 * allow the cursor position to be updated when a word before the cursor
 * is replaced by a shorter word.  Return -1 if needle isn't found, -2 if
 * the seeking is aborted, else the number of replacements performed. */
ssize_t do_replace_loop(const char *needle, bool whole_word_only,
		const linestruct *real_current, size_t *real_current_x)
{
	ssize_t numreplaced = -1;
	size_t match_len;
	bool replaceall = FALSE;
	bool skipone = ISSET(BACKWARDS_SEARCH);
	int modus = REPLACING;
#ifndef NANO_TINY
	linestruct *was_mark = openfile->mark;
	linestruct *top, *bot;
	size_t top_x, bot_x;
	bool right_side_up = FALSE;
		/* TRUE if (mark_begin, mark_begin_x) is the top of the mark,
		 * FALSE if (current, current_x) is. */

	/* If the mark is on, frame the region, and turn the mark off. */
	if (openfile->mark) {
		mark_order((const linestruct **)&top, &top_x,
						(const linestruct **)&bot, &bot_x, &right_side_up);
		openfile->mark = NULL;
		modus = INREGION;

		/* Start either at the top or the bottom of the marked region. */
		if (!ISSET(BACKWARDS_SEARCH)) {
			openfile->current = top;
			openfile->current_x = top_x;
		} else {
			openfile->current = bot;
			openfile->current_x = bot_x;
		}
	}
#endif /* !NANO_TINY */

	came_full_circle = FALSE;

	while (TRUE) {
		int choice = 0;
		int result = findnextstr(needle, whole_word_only, modus,
						&match_len, skipone, real_current, *real_current_x);

		/* If nothing more was found, or the user aborted, stop looping. */
		if (result < 1) {
			if (result < 0)
				numreplaced = -2;  /* It's a Cancel instead of Not found. */
			break;
		}

#ifndef NANO_TINY
		/* An occurrence outside of the marked region means we're done. */
		if (was_mark && (openfile->current->lineno > bot->lineno ||
								openfile->current->lineno < top->lineno ||
								(openfile->current == bot &&
								openfile->current_x + match_len > bot_x) ||
								(openfile->current == top &&
								openfile->current_x < top_x)))
			break;
#endif

		/* Indicate that we found the search string. */
		if (numreplaced == -1)
			numreplaced = 0;

		if (!replaceall) {
			spotlighted = TRUE;
			light_from_col = xplustabs();
			light_to_col = strnlenpt(openfile->current->data,
										openfile->current_x + match_len);

			/* Refresh the edit window, scrolling it if necessary. */
			edit_refresh();

			/* TRANSLATORS: This is a prompt. */
			choice = do_yesno_prompt(TRUE, _("Replace this instance?"));

			spotlighted = FALSE;

			if (choice == -1)  /* The replacing was cancelled. */
				break;
			else if (choice == 2)
				replaceall = TRUE;

			/* When "No" or moving backwards, the search routine should
			 * first move one character further before continuing. */
			skipone = (choice == 0 || ISSET(BACKWARDS_SEARCH));
		}

		if (choice == 1 || replaceall) {  /* Yes, replace it. */
			char *copy;
			size_t length_change;

#ifndef NANO_TINY
			add_undo(REPLACE);
#endif
			copy = replace_line(needle);

			length_change = strlen(copy) - strlen(openfile->current->data);

#ifndef NANO_TINY
			/* If the mark was on and it was located after the cursor,
			 * then adjust its x position for any text length changes. */
			if (was_mark && !right_side_up) {
				if (openfile->current == was_mark &&
						openfile->mark_x > openfile->current_x) {
					if (openfile->mark_x < openfile->current_x + match_len)
						openfile->mark_x = openfile->current_x;
					else
						openfile->mark_x += length_change;
					bot_x = openfile->mark_x;
				}
			}

			/* If the mark was not on or it was before the cursor, then
			 * adjust the cursor's x position for any text length changes. */
			if (!was_mark || right_side_up) {
#endif
				if (openfile->current == real_current &&
						openfile->current_x < *real_current_x) {
					if (*real_current_x < openfile->current_x + match_len)
						*real_current_x = openfile->current_x + match_len;
					*real_current_x += length_change;
#ifndef NANO_TINY
					bot_x = *real_current_x;
				}
#endif
			}

			/* Don't find the same zero-length or BOL match again. */
			if (match_len == 0 || (*needle == '^' && ISSET(USE_REGEXP)))
				skipone = TRUE;

			/* When moving forward, put the cursor just after the replacement
			 * text, so that searching will continue there. */
			if (!ISSET(BACKWARDS_SEARCH))
				openfile->current_x += match_len + length_change;

			/* Update the file size, and put the changed line into place. */
			openfile->totsize += mbstrlen(copy) - mbstrlen(openfile->current->data);
			free(openfile->current->data);
			openfile->current->data = copy;

			if (!replaceall) {
#ifdef ENABLE_COLOR
				/* When doing syntax coloring, the replacement might require
				 * a change of colors, so refresh the whole edit window. */
				if (openfile->colorstrings != NULL && !ISSET(NO_COLOR_SYNTAX))
					edit_refresh();
				else
#endif
					update_line(openfile->current, openfile->current_x);
			}

			set_modified();
			as_an_at = TRUE;
			numreplaced++;
		}
	}

	if (numreplaced == -1)
		not_found_msg(needle);
#ifdef ENABLE_COLOR
	else if (numreplaced > 0)
		refresh_needed = TRUE;
#endif
#ifndef NANO_TINY
	openfile->mark = was_mark;
#endif

	/* If "automatic newline" is enabled, and text has been added to the
	 * magic line, make a new magic line. */
	if (ISSET(FINAL_NEWLINE) && openfile->filebot->data[0] != '\0')
		new_magicline();

	return numreplaced;
}

/* Replace a string. */
void do_replace(void)
{
	if (ISSET(VIEW_MODE))
		print_view_warning();
	else {
		UNSET(BACKWARDS_SEARCH);
		search_init(TRUE, FALSE);
	}
}

/* Ask the user what the already given search string should be replaced with. */
void ask_for_replacement(void)
{
	linestruct *edittop_save, *begin;
	size_t firstcolumn_save, begin_x;
	ssize_t numreplaced;
	int i = do_prompt(FALSE, FALSE, MREPLACEWITH, NULL, &replace_history,
				/* TRANSLATORS: This is a prompt. */
				edit_refresh, _("Replace with"));

#ifdef ENABLE_HISTORIES
	/* If the replace string is not "", add it to the replace history list. */
	if (i == 0)
		update_history(&replace_history, answer);
#endif

	/* When cancelled, or when a function was run, get out. */
	if (i == -1 || i > 0) {
		if (i == -1)
			statusbar(_("Cancelled"));
		return;
	}

	/* Save where we are. */
	edittop_save = openfile->edittop;
	firstcolumn_save = openfile->firstcolumn;
	begin = openfile->current;
	begin_x = openfile->current_x;

	numreplaced = do_replace_loop(last_search, FALSE, begin, &begin_x);

	/* Restore where we were. */
	openfile->edittop = edittop_save;
	openfile->firstcolumn = firstcolumn_save;
	openfile->current = begin;
	openfile->current_x = begin_x;
	refresh_needed = TRUE;

	if (numreplaced >= 0)
		statusline(HUSH, P_("Replaced %zd occurrence",
				"Replaced %zd occurrences", numreplaced), numreplaced);
}

/* Go to the specified line and x position. */
void goto_line_posx(ssize_t line, size_t pos_x)
{
	for (openfile->current = openfile->filetop; line > 1 &&
				openfile->current != openfile->filebot; line--)
		openfile->current = openfile->current->next;

	openfile->current_x = pos_x;
	openfile->placewewant = xplustabs();

	refresh_needed = TRUE;
}

/* Go to the specified line and column, or ask for them if interactive
 * is TRUE.  In the latter case also update the screen afterwards.
 * Note that both the line and column number should be one-based. */
void do_gotolinecolumn(ssize_t line, ssize_t column, bool use_answer,
		bool interactive)
{
	if (interactive) {
		/* Ask for the line and column. */
		int i = do_prompt(FALSE, FALSE, MGOTOLINE,
				use_answer ? answer : NULL, NULL,
				/* TRANSLATORS: This is a prompt. */
				edit_refresh, _("Enter line number, column number"));

		/* If the user cancelled or gave a blank answer, get out. */
		if (i < 0) {
			statusbar(_("Cancelled"));
			return;
		}

		if (func_from_key(&i) == flip_goto) {
			UNSET(BACKWARDS_SEARCH);
			/* Retain what the user typed so far and switch to searching. */
			search_init(FALSE, TRUE);
			return;
		}

		/* If a function was executed, we're done here. */
		if (i > 0)
			return;

		/* Try to extract one or two numbers from the user's response. */
		if (!parse_line_column(answer, &line, &column)) {
			statusline(ALERT, _("Invalid line or column number"));
			return;
		}
	} else {
		if (line == 0)
			line = openfile->current->lineno;

		if (column == 0)
			column = openfile->placewewant + 1;
	}

	/* Take a negative line number to mean: from the end of the file. */
	if (line < 0)
		line = openfile->filebot->lineno + line + 1;
	if (line < 1)
		line = 1;

	/* Iterate to the requested line. */
	for (openfile->current = openfile->filetop; line > 1 &&
				openfile->current != openfile->filebot; line--)
		openfile->current = openfile->current->next;

	/* Take a negative column number to mean: from the end of the line. */
	if (column < 0)
		column = strlenpt(openfile->current->data) + column + 2;
	if (column < 1)
		column = 1;

	/* Set the x position that corresponds to the requested column. */
	openfile->current_x = actual_x(openfile->current->data, column - 1);
	openfile->placewewant = column - 1;

#ifndef NANO_TINY
	if (ISSET(SOFTWRAP) && openfile->placewewant / editwincols >
						strlenpt(openfile->current->data) / editwincols)
		openfile->placewewant = strlenpt(openfile->current->data);
#endif

	/* When the position was manually given, center the target line. */
	if (interactive) {
		adjust_viewport(CENTERING);
		refresh_needed = TRUE;
	} else {
		int rows_from_tail;

#ifndef NANO_TINY
		if (ISSET(SOFTWRAP)) {
			linestruct *currentline = openfile->current;
			size_t leftedge = leftedge_for(xplustabs(), openfile->current);

			rows_from_tail = (editwinrows / 2) - go_forward_chunks(
								editwinrows / 2, &currentline, &leftedge);
		} else
#endif
			rows_from_tail = openfile->filebot->lineno -
								openfile->current->lineno;

		/* If the target line is close to the tail of the file, put the last
		 * line or chunk on the bottom line of the screen; otherwise, just
		 * center the target line. */
		if (rows_from_tail < editwinrows / 2 && !ISSET(JUMPY_SCROLLING)) {
			openfile->current_y = editwinrows - 1 - rows_from_tail;
			adjust_viewport(STATIONARY);
		} else
			adjust_viewport(CENTERING);
	}
}

/* Go to the specified line and column, asking for them beforehand. */
void do_gotolinecolumn_void(void)
{
	do_gotolinecolumn(openfile->current->lineno,
		openfile->placewewant + 1, FALSE, TRUE);
}

#ifndef NANO_TINY
/* Search, startting from the current position, for any of the two characters
 * in bracket_set.  If reverse is TRUE, search backwards, otherwise forwards.
 * Return TRUE when a match was found, and FALSE otherwise. */
bool find_bracket_match(bool reverse, const char *bracket_set)
{
	linestruct *line = openfile->current;
	const char *pointer = NULL, *found = NULL;

	/* pointer might end up 1 character before the start or after the
	 * end of the line.  This won't be a problem because we'll skip over
	 * it below in that case, and pointer will be properly set when
	 * the search continues on the previous or next line. */
	if (reverse)
		pointer = line->data + (openfile->current_x - 1);
	else
		pointer = line->data + (openfile->current_x + 1);

	/* Look for either of the two characters in bracket_set.  pointer
	 * can be 1 character before the start or after the end of the line.
	 * In either case, just act as though no match is found. */
	while (TRUE) {
		if ((pointer > line->data && *(pointer - 1) == '\0') ||
						pointer < line->data)
			found = NULL;
		else if (reverse)
			found = mbrevstrpbrk(line->data, bracket_set, pointer);
		else
			found = mbstrpbrk(pointer, bracket_set);

		if (found)
			break;

		if (reverse)
			line = line->prev;
		else
			line = line->next;

		/* If we've reached the start or end of the buffer, get out. */
		if (line == NULL)
			return FALSE;

		pointer = line->data;
		if (reverse)
			pointer += strlen(line->data);
	}

	/* Set the current position to the found matching bracket. */
	openfile->current = line;
	openfile->current_x = found - line->data;

	return TRUE;
}

/* Search for a match to the bracket at the current cursor position, if
 * there is one. */
void do_find_bracket(void)
{
	linestruct *was_current = openfile->current;
	size_t was_current_x = openfile->current_x;
		/* The current cursor position, in case we don't find a complement. */
	const char *ch;
		/* The location in matchbrackets of the bracket under the cursor. */
	int ch_len;
		/* The length of ch in bytes. */
	const char *wanted_ch;
		/* The location in matchbrackets of the complementing bracket. */
	int wanted_ch_len;
		/* The length of wanted_ch in bytes. */
	char bracket_set[MAXCHARLEN * 2 + 1];
		/* The pair of characters in ch and wanted_ch. */
	size_t halfway = 0;
		/* The index in matchbrackets where the closing brackets start. */
	size_t charcount = mbstrlen(matchbrackets) / 2;
		/* Half the number of characters in matchbrackets. */
	size_t balance = 1;
		/* The initial bracket count. */
	bool reverse;
		/* The direction we search. */

	ch = mbstrchr(matchbrackets, openfile->current->data + openfile->current_x);

	if (ch == NULL) {
		statusbar(_("Not a bracket"));
		return;
	}

	/* Find the halfway point in matchbrackets, where the closing ones start. */
	for (size_t i = 0; i < charcount; i++)
		halfway += parse_mbchar(matchbrackets + halfway, NULL, NULL);

	/* When on a closing bracket, we have to search backwards for a matching
	 * opening bracket; otherwise, forward for a matching closing bracket. */
	reverse = (ch >= (matchbrackets + halfway));

	/* Step half the number of total characters either backwards or forwards
	 * through matchbrackets to find the wanted complementary bracket. */
	wanted_ch = ch;
	while (charcount-- > 0) {
		if (reverse)
			wanted_ch = matchbrackets + move_mbleft(matchbrackets,
								wanted_ch - matchbrackets);
		else
			wanted_ch += move_mbright(wanted_ch, 0);
	}

	ch_len = parse_mbchar(ch, NULL, NULL);
	wanted_ch_len = parse_mbchar(wanted_ch, NULL, NULL);

	/* Fill bracket_set in with the values of ch and wanted_ch. */
	strncpy(bracket_set, ch, ch_len);
	strncpy(bracket_set + ch_len, wanted_ch, wanted_ch_len);
	bracket_set[ch_len + wanted_ch_len] = '\0';

	while (TRUE) {
		if (find_bracket_match(reverse, bracket_set)) {
			/* If we found an identical bracket, increment balance.  If we
			 * found a complementary bracket, decrement it. */
			balance += (strncmp(openfile->current->data + openfile->current_x,
								ch, ch_len) == 0) ? 1 : -1;

			/* If balance is zero, we've found a matching bracket.  Update
			 * the screen and get out. */
			if (balance == 0) {
				edit_redraw(was_current, FLOWING);
				break;
			}
		} else {
			/* We didn't find either an opening or closing bracket.
			 * Indicate this, restore where we were, and get out. */
			statusbar(_("No matching bracket"));
			openfile->current = was_current;
			openfile->current_x = was_current_x;
			break;
		}
	}
}
#endif /* !NANO_TINY */