mc/edit/edit.c

/* editor low level data handling and cursor fundamentals.

   Copyright (C) 1996, 1997, 1998, 2001, 2002, 2003, 2004, 2005, 2006,
   2007 Free Software Foundation, Inc.

   Authors: 1996, 1997 Paul Sheer

   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 of the License, 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., 51 Franklin Street, Fifth Floor, Boston, MA
   02110-1301, USA.
*/

#include <config.h>
#include <stdio.h>
#include <stdarg.h>
#include <sys/types.h>
#include <unistd.h>
#include <string.h>
#include <ctype.h>
#include <errno.h>
#include <sys/stat.h>
#include <stdlib.h>

#include "../src/global.h"

#include "edit.h"
#include "editlock.h"
#include "edit-widget.h"
#include "editcmddef.h"
#include "usermap.h"

#include "../src/cmd.h"		/* view_other_cmd() */
#include "../src/user.h"	/* user_menu_cmd() */
#include "../src/wtools.h"	/* query_dialog() */
#include "../src/timefmt.h"	/* time formatting */
#include "../src/strutil.h"	/* utf string functions */
#include "../src/charsets.h"	/* get_codepage_id */
#include "../src/main.h"	/* source_codepage */

/*
   what editor are we going to emulate? one of EDIT_KEY_EMULATION_NORMAL
   or EDIT_KEY_EMULATION_EMACS
 */
int edit_key_emulation = EDIT_KEY_EMULATION_NORMAL;

int option_word_wrap_line_length = 72;
int option_typewriter_wrap = 0;
int option_auto_para_formatting = 0;
int option_tab_spacing = 8;
int option_fill_tabs_with_spaces = 0;
int option_return_does_auto_indent = 1;
int option_backspace_through_tabs = 0;
int option_fake_half_tabs = 1;
int option_save_mode = EDIT_QUICK_SAVE;
int option_save_position = 1;
int option_max_undo = 32768;
int option_persistent_selections = 1;

int option_edit_right_extreme = 0;
int option_edit_left_extreme = 0;
int option_edit_top_extreme = 0;
int option_edit_bottom_extreme = 0;

const char *option_whole_chars_search = "0123456789abcdefghijklmnopqrstuvwxyz_";
char *option_backup_ext = NULL;

/*-
 *
 * here's a quick sketch of the layout: (don't run this through indent.)
 *
 * (b1 is buffers1 and b2 is buffers2)
 *
 *                                       |
 * \0\0\0\0\0m e _ f i l e . \nf i n . \n|T h i s _ i s _ s o\0\0\0\0\0\0\0\0\0
 * ______________________________________|______________________________________
 *                                       |
 * ...  |  b2[2]   |  b2[1]   |  b2[0]   |  b1[0]   |  b1[1]   |  b1[2]   | ...
 *      |->        |->        |->        |->        |->        |->        |
 *                                       |
 *           _<------------------------->|<----------------->_
 *                   WEdit->curs2        |   WEdit->curs1
 *           ^                           |                   ^
 *           |                          ^|^                  |
 *         cursor                       |||                cursor
 *                                      |||
 *                              file end|||file beginning
 *                                       |
 *                                       |
 *
 *           _
 * This_is_some_file
 * fin.
 */


static void user_menu (WEdit *edit);

int edit_get_byte (WEdit * edit, long byte_index)
{
    unsigned long p;
    if (byte_index >= (edit->curs1 + edit->curs2) || byte_index < 0)
	return '\n';

    if (byte_index >= edit->curs1) {
	p = edit->curs1 + edit->curs2 - byte_index - 1;
	return edit->buffers2[p >> S_EDIT_BUF_SIZE][EDIT_BUF_SIZE - (p & M_EDIT_BUF_SIZE) - 1];
    } else {
	return edit->buffers1[byte_index >> S_EDIT_BUF_SIZE][byte_index & M_EDIT_BUF_SIZE];
    }
}

char *edit_get_byte_ptr (WEdit * edit, long byte_index)
{
    unsigned long p;

    if (byte_index >= (edit->curs1 + edit->curs2) || byte_index < 0)
	return NULL;

    if (byte_index >= edit->curs1) {
	p = edit->curs1 + edit->curs2 - byte_index - 1;
	return (char *) (edit->buffers2[p >> S_EDIT_BUF_SIZE]+(EDIT_BUF_SIZE - (p & M_EDIT_BUF_SIZE) - 1));
    } else {
	return (char *) (edit->buffers1[byte_index >> S_EDIT_BUF_SIZE]+(byte_index & M_EDIT_BUF_SIZE));
    }
}

char *edit_get_buf_ptr (WEdit * edit, long byte_index)
{
    unsigned long p;

    if (byte_index >= (edit->curs1 + edit->curs2) ) {
        byte_index -= 1;
    };

    if ( byte_index < 0 ) {
        return NULL;
    }

    if (byte_index >= edit->curs1) {
	p = edit->curs1 + edit->curs2 - 1;
	return (char *) (edit->buffers2[p >> S_EDIT_BUF_SIZE] + (EDIT_BUF_SIZE - (p & M_EDIT_BUF_SIZE) - 1));
    } else {
	return (char *) (edit->buffers1[byte_index >> S_EDIT_BUF_SIZE] + (0 & M_EDIT_BUF_SIZE));
    }
}

int edit_get_utf (WEdit * edit, long byte_index, int *char_width)
{
    gchar *str = NULL;
    int res = -1;
    gunichar ch;
    gchar *next_ch = NULL;
    int width = 0;

    if (byte_index >= (edit->curs1 + edit->curs2) || byte_index < 0) {
        *char_width = 0;
        return '\n';
    }

    str = edit_get_byte_ptr (edit, byte_index);
    res = g_utf8_get_char_validated (str, -1);

    if ( res < 0 ) {
        ch = *str;
        width = 0;
    } else {
        ch = res;
        /* Calculate UTF-8 char width */
        next_ch = g_utf8_next_char(str);
        if ( next_ch ) {
            if ( next_ch != str ) {
                width = next_ch - str;
            } else {
                width = 0;
            }
        } else {
            ch = 0;
            width = 0;
        }
    }
    *char_width = width;
    return ch;
}

int edit_get_prev_utf (WEdit * edit, long byte_index, int *char_width)
{
    gchar *str, *buf = NULL;
    int res = -1;
    gunichar ch;
    gchar *next_ch = NULL;
    int width = 0;
    gchar *prn_buf=NULL;

    if ( byte_index > 0 ) {
        byte_index--;
    }

    ch = edit_get_utf (edit, byte_index, &width);

    if ( width == 1 ) {
        *char_width = width;
        return ch;
    }

    if ( byte_index >= (edit->curs1 + edit->curs2) || byte_index < 0 ) {
        *char_width = 1;
        return 0;
    }

    str = edit_get_byte_ptr (edit, byte_index);
    buf = edit_get_buf_ptr (edit, byte_index);
    /* get prev utf8 char */
    str = g_utf8_find_prev_char (buf, str);

    res = g_utf8_get_char_validated (str, -1);
    if ( res < 0 ) {
        ch = *str;
        width = 0;
    } else {
        ch = res;
        /* Calculate UTF-8 char width */
        next_ch = g_utf8_next_char(str);
        if ( next_ch ) {
            if ( next_ch != str ) {
                width = next_ch - str;
            } else {
                width = 0;
            }
        } else {
            ch = 0;
            width = 0;
        }
    }
    *char_width = width;
    return ch;
}

/*
 * Initialize the buffers for an empty files.
 */
static void
edit_init_buffers (WEdit *edit)
{
    int j;

    for (j = 0; j <= MAXBUFF; j++) {
	edit->buffers1[j] = NULL;
	edit->buffers2[j] = NULL;
    }

    edit->curs1 = 0;
    edit->curs2 = 0;
    edit->buffers2[0] = g_malloc (EDIT_BUF_SIZE);
}

/*
 * Load file OR text into buffers.  Set cursor to the beginning of file.
 * Return 1 on error.
 */
static int
edit_load_file_fast (WEdit *edit, const char *filename)
{
    long buf, buf2;
    int file = -1;

    edit->curs2 = edit->last_byte;
    buf2 = edit->curs2 >> S_EDIT_BUF_SIZE;
    edit->utf8 = str_isutf8 (get_codepage_id( source_codepage ));

    if ((file = mc_open (filename, O_RDONLY | O_BINARY)) == -1) {
	GString *errmsg = g_string_new(NULL);
	g_string_sprintf(errmsg, _(" Cannot open %s for reading "), filename);
	edit_error_dialog (_("Error"), get_sys_error (errmsg->str));
	g_string_free (errmsg, TRUE);
	return 1;
    }

    if (!edit->buffers2[buf2])
	edit->buffers2[buf2] = g_malloc (EDIT_BUF_SIZE);

    mc_read (file,
	     (char *) edit->buffers2[buf2] + EDIT_BUF_SIZE -
	     (edit->curs2 & M_EDIT_BUF_SIZE),
	     edit->curs2 & M_EDIT_BUF_SIZE);

    for (buf = buf2 - 1; buf >= 0; buf--) {
	/* edit->buffers2[0] is already allocated */
	if (!edit->buffers2[buf])
	    edit->buffers2[buf] = g_malloc (EDIT_BUF_SIZE);
	mc_read (file, (char *) edit->buffers2[buf], EDIT_BUF_SIZE);
    }

    mc_close (file);
    return 0;
}

/* detecting an error on save is easy: just check if every byte has been written. */
/* detecting an error on read, is not so easy 'cos there is not way to tell
   whether you read everything or not. */
/* FIXME: add proper `triple_pipe_open' to read, write and check errors. */
static const struct edit_filters {
    const char *read, *write, *extension;
} all_filters[] = {
    { "lzma -cd %s 2>&1",   "lzma > %s",   ".lzma" },
    { "bzip2 -cd %s 2>&1",  "bzip2 > %s",  ".bz2" },
    { "gzip -cd %s 2>&1",   "gzip > %s",   ".gz"  },
    { "gzip -cd %s 2>&1",   "gzip > %s",   ".Z"   }
};

/* Return index of the filter or -1 is there is no appropriate filter */
static int edit_find_filter (const char *filename)
{
    size_t i, l, e;
    if (!filename)
	return -1;
    l = strlen (filename);
    for (i = 0; i < sizeof (all_filters) / sizeof (all_filters[0]); i++) {
	e = strlen (all_filters[i].extension);
	if (l > e)
	    if (!strcmp (all_filters[i].extension, filename + l - e))
		return i;
    }
    return -1;
}

static char *
edit_get_filter (const char *filename)
{
    int i, l;
    char *p, *quoted_name;
    i = edit_find_filter (filename);
    if (i < 0)
	return 0;
    quoted_name = name_quote (filename, 0);
    l = str_term_width1 (quoted_name);
    p = g_malloc (str_term_width1 (all_filters[i].read) + l + 2);
    sprintf (p, all_filters[i].read, quoted_name);
    g_free (quoted_name);
    return p;
}

char *
edit_get_write_filter (const char *write_name, const char *filename)
{
    int i, l;
    char *p, *writename;
    i = edit_find_filter (filename);
    if (i < 0)
	return 0;
    writename = name_quote (write_name, 0);
    l = str_term_width1 (writename);
    p = g_malloc (str_term_width1 (all_filters[i].write) + l + 2);
    sprintf (p, all_filters[i].write, writename);
    g_free (writename);
    return p;
}

static long
edit_insert_stream (WEdit * edit, FILE * f)
{
    int c;
    long i = 0;
    while ((c = fgetc (f)) >= 0) {
	edit_insert (edit, c);
	i++;
    }
    return i;
}

long edit_write_stream (WEdit * edit, FILE * f)
{
    long i;
    for (i = 0; i < edit->last_byte; i++)
	if (fputc (edit_get_byte (edit, i), f) < 0)
	    break;
    return i;
}

#define TEMP_BUF_LEN 1024

/* inserts a file at the cursor, returns 1 on success */
int
edit_insert_file (WEdit *edit, const char *filename)
{
    char *p;
    if ((p = edit_get_filter (filename))) {
	FILE *f;
	long current = edit->curs1;
	f = (FILE *) popen (p, "r");
	if (f) {
	    edit_insert_stream (edit, f);
	    edit_cursor_move (edit, current - edit->curs1);
	    if (pclose (f) > 0) {
	        GString *errmsg = g_string_new (NULL);
		g_string_sprintf (errmsg, _(" Error reading from pipe: %s "), p);
		edit_error_dialog (_("Error"), errmsg->str);
		g_string_free (errmsg, TRUE);
		g_free (p);
		return 0;
	    }
	} else {
	    GString *errmsg = g_string_new (NULL);
	    g_string_sprintf (errmsg, _(" Cannot open pipe for reading: %s "), p);
	    edit_error_dialog (_("Error"), errmsg->str);
	    g_string_free (errmsg, TRUE);
	    g_free (p);
	    return 0;
	}
	g_free (p);
    } else {
	int i, file, blocklen;
	long current = edit->curs1;
	unsigned char *buf;
	if ((file = mc_open (filename, O_RDONLY | O_BINARY)) == -1)
	    return 0;
	buf = g_malloc (TEMP_BUF_LEN);
	while ((blocklen = mc_read (file, (char *) buf, TEMP_BUF_LEN)) > 0) {
	    for (i = 0; i < blocklen; i++)
		edit_insert (edit, buf[i]);
	}
	edit_cursor_move (edit, current - edit->curs1);
	g_free (buf);
	mc_close (file);
	if (blocklen)
	    return 0;
    }
    return 1;
}

/* Open file and create it if necessary.  Return 0 for success, 1 for error.  */
static int
check_file_access (WEdit *edit, const char *filename, struct stat *st)
{
    int file;
    GString *errmsg = (GString *) 0;

    /* Try opening an existing file */
    file = mc_open (filename, O_NONBLOCK | O_RDONLY | O_BINARY, 0666);

    if (file < 0) {
	/*
	 * Try creating the file.  O_EXCL prevents following broken links
	 * and opening existing files.
	 */
	file =
	    mc_open (filename,
		     O_NONBLOCK | O_RDONLY | O_BINARY | O_CREAT | O_EXCL,
		     0666);
	if (file < 0) {
	    g_string_sprintf (errmsg = g_string_new (NULL),
		_(" Cannot open %s for reading "), filename);
	    goto cleanup;
	} else {
	    /* New file, delete it if it's not modified or saved */
	    edit->delete_file = 1;
	}
    }

    /* Check what we have opened */
    if (mc_fstat (file, st) < 0) {
	g_string_sprintf (errmsg = g_string_new (NULL),
	    _(" Cannot get size/permissions for %s "), filename);
	goto cleanup;
    }

    /* We want to open regular files only */
    if (!S_ISREG (st->st_mode)) {
	g_string_sprintf (errmsg = g_string_new (NULL),
	    _(" %s is not a regular file "), filename);
	goto cleanup;
    }

    /*
     * Don't delete non-empty files.
     * O_EXCL should prevent it, but let's be on the safe side.
     */
    if (st->st_size > 0) {
	edit->delete_file = 0;
    }

    if (st->st_size >= SIZE_LIMIT) {
        g_string_sprintf (errmsg = g_string_new (NULL),
	    _(" File %s is too large "), filename);
	goto cleanup;
    }

cleanup:
    (void) mc_close (file);
    if (errmsg) {
	edit_error_dialog (_("Error"), errmsg->str);
	g_string_free (errmsg, TRUE);
	return 1;
    }
    return 0;
}

/*
 * Open the file and load it into the buffers, either directly or using
 * a filter.  Return 0 on success, 1 on error.
 *
 * Fast loading (edit_load_file_fast) is used when the file size is
 * known.  In this case the data is read into the buffers by blocks.
 * If the file size is not known, the data is loaded byte by byte in
 * edit_insert_file.
 */
static int
edit_load_file (WEdit *edit)
{
    int fast_load = 1;

    /* Cannot do fast load if a filter is used */
    if (edit_find_filter (edit->filename) >= 0)
	fast_load = 0;

    /*
     * VFS may report file size incorrectly, and slow load is not a big
     * deal considering overhead in VFS.
     */
    if (!vfs_file_is_local (edit->filename))
	fast_load = 0;

    /*
     * FIXME: line end translation should disable fast loading as well
     * Consider doing fseek() to the end and ftell() for the real size.
     */

    if (*edit->filename) {
	/* If we are dealing with a real file, check that it exists */
	if (check_file_access (edit, edit->filename, &edit->stat1))
	    return 1;
    } else {
	/* nothing to load */
	fast_load = 0;
    }

    edit_init_buffers (edit);

    if (fast_load) {
	edit->last_byte = edit->stat1.st_size;
	edit_load_file_fast (edit, edit->filename);
	/* If fast load was used, the number of lines wasn't calculated */
	edit->total_lines = edit_count_lines (edit, 0, edit->last_byte);
    } else {
	edit->last_byte = 0;
	if (*edit->filename) {
	    edit->stack_disable = 1;
	    if (!edit_insert_file (edit, edit->filename)) {
		edit_clean (edit);
		return 1;
	    }
	    edit->stack_disable = 0;
	}
    }
    return 0;
}

/* Restore saved cursor position in the file */
static void
edit_load_position (WEdit *edit)
{
    char *filename;
    long line, column;

    if (!edit->filename || !*edit->filename)
	return;

    filename = vfs_canon (edit->filename);
    load_file_position (filename, &line, &column);
    g_free (filename);

    edit_move_to_line (edit, line - 1);
    edit->prev_col = column;
    edit_move_to_prev_col (edit, edit_bol (edit, edit->curs1));
    edit_move_display (edit, line - (edit->num_widget_lines / 2));
}

/* Save cursor position in the file */
static void
edit_save_position (WEdit *edit)
{
    char *filename;

    if (!edit->filename || !*edit->filename)
	return;

    filename = vfs_canon (edit->filename);
    save_file_position (filename, edit->curs_line + 1, edit->curs_col);
    g_free (filename);
}

/* Clean the WEdit stricture except the widget part */
static inline void
edit_purge_widget (WEdit *edit)
{
    int len = sizeof (WEdit) - sizeof (Widget);
    char *start = (char *) edit + sizeof (Widget);
    memset (start, 0, len);
    edit->macro_i = -1;		/* not recording a macro */
}

#define space_width 1

/*
 * Fill in the edit structure.  Return NULL on failure.  Pass edit as
 * NULL to allocate a new structure.
 *
 * If line is 0, try to restore saved position.  Otherwise put the
 * cursor on that line and show it in the middle of the screen.
 */
WEdit *
edit_init (WEdit *edit, int lines, int columns, const char *filename,
	   long line)
{
    int to_free = 0;
    option_auto_syntax = 1; /* Resetting to auto on every invokation */

    if (!edit) {
#ifdef ENABLE_NLS
	/*
	 * Expand option_whole_chars_search by national letters using
	 * current locale
	 */

	static char option_whole_chars_search_buf[256];

	if (option_whole_chars_search_buf != option_whole_chars_search) {
	    size_t i;
	    size_t len = str_term_width1 (option_whole_chars_search);

	    strcpy (option_whole_chars_search_buf,
		    option_whole_chars_search);

	    for (i = 1; i <= sizeof (option_whole_chars_search_buf); i++) {
		if (g_ascii_islower ((gchar) i) && !strchr (option_whole_chars_search, i)) {
		    option_whole_chars_search_buf[len++] = i;
		}
	    }

	    option_whole_chars_search_buf[len] = 0;
	    option_whole_chars_search = option_whole_chars_search_buf;
	}
#endif				/* ENABLE_NLS */
	edit = g_malloc0 (sizeof (WEdit));
	to_free = 1;
    }
    edit_purge_widget (edit);
    edit->num_widget_lines = lines;
    edit->num_widget_columns = columns;
    edit->stat1.st_mode = S_IRUSR | S_IWUSR | S_IRGRP | S_IROTH;
    edit->stat1.st_uid = getuid ();
    edit->stat1.st_gid = getgid ();
    edit->stat1.st_mtime = 0;
    edit->bracket = -1;
    edit->force |= REDRAW_PAGE;
    edit_set_filename (edit, filename);
    edit->stack_size = START_STACK_SIZE;
    edit->stack_size_mask = START_STACK_SIZE - 1;
    edit->undo_stack = g_malloc ((edit->stack_size + 10) * sizeof (long));
    if (edit_load_file (edit)) {
	/* edit_load_file already gives an error message */
	if (to_free)
	    g_free (edit);
	return 0;
    }
    edit->loading_done = 1;
    edit->modified = 0;
    edit->locked = 0;
    edit_load_syntax (edit, 0, 0);
    {
	int color;
	edit_get_syntax_color (edit, -1, &color);
    }

    /* load saved cursor position */
    if ((line == 0) && option_save_position) {
	edit_load_position (edit);
    } else {
	if (line <= 0)
	    line = 1;
	edit_move_display (edit, line - 1);
	edit_move_to_line (edit, line - 1);
    }

    edit_load_user_map(edit);

    return edit;
}

/* Clear the edit struct, freeing everything in it.  Return 1 on success */
int
edit_clean (WEdit *edit)
{
    int j = 0;

    if (!edit)
	return 0;

    /* a stale lock, remove it */
    if (edit->locked)
	edit->locked = edit_unlock_file (edit->filename);

    /* save cursor position */
    if (option_save_position)
	edit_save_position (edit);

    /* File specified on the mcedit command line and never saved */
    if (edit->delete_file)
	unlink (edit->filename);

    edit_free_syntax_rules (edit);
    book_mark_flush (edit, -1);
    for (; j <= MAXBUFF; j++) {
	g_free (edit->buffers1[j]);
	g_free (edit->buffers2[j]);
    }

    g_free (edit->undo_stack);
    g_free (edit->filename);
    g_free (edit->dir);

    edit_purge_widget (edit);

    return 1;
}


/* returns 1 on success */
int edit_renew (WEdit * edit)
{
    int lines = edit->num_widget_lines;
    int columns = edit->num_widget_columns;
    int retval = 1;

    edit_clean (edit);
    if (!edit_init (edit, lines, columns, "", 0))
	retval = 0;
    return retval;
}

/*
 * Load a new file into the editor.  If it fails, preserve the old file.
 * To do it, allocate a new widget, initialize it and, if the new file
 * was loaded, copy the data to the old widget.
 * Return 1 on success, 0 on failure.
 */
int
edit_reload (WEdit *edit, const char *filename)
{
    WEdit *e;
    int lines = edit->num_widget_lines;
    int columns = edit->num_widget_columns;

    e = g_malloc0 (sizeof (WEdit));
    e->widget = edit->widget;
    if (!edit_init (e, lines, columns, filename, 0)) {
	g_free (e);
	return 0;
    }
    edit_clean (edit);
    memcpy (edit, e, sizeof (WEdit));
    g_free (e);
    return 1;
}

/*
 * Load a new file into the editor and set line.  If it fails, preserve the old file.
 * To do it, allocate a new widget, initialize it and, if the new file
 * was loaded, copy the data to the old widget.
 * Return 1 on success, 0 on failure.
 */
int
edit_reload_line (WEdit *edit, const char *filename, long line)
{
    WEdit *e;
    int lines = edit->num_widget_lines;
    int columns = edit->num_widget_columns;

    e = g_malloc0 (sizeof (WEdit));
    e->widget = edit->widget;
    if (!edit_init (e, lines, columns, filename, line)) {
	g_free (e);
	return 0;
    }
    edit_clean (edit);
    memcpy (edit, e, sizeof (WEdit));
    g_free (e);
    return 1;
}


/*
   Recording stack for undo:
   The following is an implementation of a compressed stack. Identical
   pushes are recorded by a negative prefix indicating the number of times the
   same char was pushed. This saves space for repeated curs-left or curs-right
   delete etc.

   eg:

  pushed:       stored:

   a
   b             a
   b            -3
   b             b
   c  -->       -4
   c             c
   c             d
   c
   d

   If the stack long int is 0-255 it represents a normal insert (from a backspace),
   256-512 is an insert ahead (from a delete), If it is betwen 600 and 700 it is one
   of the cursor functions #define'd in edit.h. 1000 through 700'000'000 is to
   set edit->mark1 position. 700'000'000 through 1400'000'000 is to set edit->mark2
   position.

   The only way the cursor moves or the buffer is changed is through the routines:
   insert, backspace, insert_ahead, delete, and cursor_move.
   These record the reverse undo movements onto the stack each time they are
   called.

   Each key press results in a set of actions (insert; delete ...). So each time
   a key is pressed the current position of start_display is pushed as
   KEY_PRESS + start_display. Then for undoing, we pop until we get to a number
   over KEY_PRESS. We then assign this number less KEY_PRESS to start_display. So undo
   tracks scrolling and key actions exactly. (KEY_PRESS is about (2^31) * (2/3) = 1400'000'000)

*/

void edit_push_action (WEdit * edit, long c,...)
{
    unsigned long sp = edit->stack_pointer;
    unsigned long spm1;
    long *t;

/* first enlarge the stack if necessary */
    if (sp > edit->stack_size - 10) {	/* say */
	if (option_max_undo < 256)
	    option_max_undo = 256;
	if (edit->stack_size < (unsigned long) option_max_undo) {
	    t = g_realloc (edit->undo_stack, (edit->stack_size * 2 + 10) * sizeof (long));
	    if (t) {
		edit->undo_stack = t;
		edit->stack_size <<= 1;
		edit->stack_size_mask = edit->stack_size - 1;
	    }
	}
    }
    spm1 = (edit->stack_pointer - 1) & edit->stack_size_mask;
    if (edit->stack_disable)
	return;

#ifdef FAST_MOVE_CURSOR
    if (c == CURS_LEFT_LOTS || c == CURS_RIGHT_LOTS) {
	va_list ap;
	edit->undo_stack[sp] = c == CURS_LEFT_LOTS ? CURS_LEFT : CURS_RIGHT;
	edit->stack_pointer = (edit->stack_pointer + 1) & edit->stack_size_mask;
	va_start (ap, c);
	c = -(va_arg (ap, int));
	va_end (ap);
    } else
#endif				/* ! FAST_MOVE_CURSOR */
    if (edit->stack_bottom != sp
	&& spm1 != edit->stack_bottom
	&& ((sp - 2) & edit->stack_size_mask) != edit->stack_bottom) {
	int d;
	if (edit->undo_stack[spm1] < 0) {
	    d = edit->undo_stack[(sp - 2) & edit->stack_size_mask];
	    if (d == c) {
		if (edit->undo_stack[spm1] > -1000000000) {
		    if (c < KEY_PRESS)	/* --> no need to push multiple do-nothings */
			edit->undo_stack[spm1]--;
		    return;
		}
	    }
/* #define NO_STACK_CURSMOVE_ANIHILATION */
#ifndef NO_STACK_CURSMOVE_ANIHILATION
	    else if ((c == CURS_LEFT && d == CURS_RIGHT)
		     || (c == CURS_RIGHT && d == CURS_LEFT)) {	/* a left then a right anihilate each other */
		if (edit->undo_stack[spm1] == -2)
		    edit->stack_pointer = spm1;
		else
		    edit->undo_stack[spm1]++;
		return;
	    }
#endif
	} else {
	    d = edit->undo_stack[spm1];
	    if (d == c) {
		if (c >= KEY_PRESS)
		    return;	/* --> no need to push multiple do-nothings */
		edit->undo_stack[sp] = -2;
		goto check_bottom;
	    }
#ifndef NO_STACK_CURSMOVE_ANIHILATION
	    else if ((c == CURS_LEFT && d == CURS_RIGHT)
		     || (c == CURS_RIGHT && d == CURS_LEFT)) {	/* a left then a right anihilate each other */
		edit->stack_pointer = spm1;
		return;
	    }
#endif
	}
    }
    edit->undo_stack[sp] = c;
  check_bottom:

    edit->stack_pointer = (edit->stack_pointer + 1) & edit->stack_size_mask;

    /* if the sp wraps round and catches the stack_bottom then erase
     * the first set of actions on the stack to make space - by moving
     * stack_bottom forward one "key press" */
    c = (edit->stack_pointer + 2) & edit->stack_size_mask;
    if ((unsigned long) c == edit->stack_bottom ||
       (((unsigned long) c + 1) & edit->stack_size_mask) == edit->stack_bottom)
	do {
	    edit->stack_bottom = (edit->stack_bottom + 1) & edit->stack_size_mask;
	} while (edit->undo_stack[edit->stack_bottom] < KEY_PRESS && edit->stack_bottom != edit->stack_pointer);

/*If a single key produced enough pushes to wrap all the way round then we would notice that the [stack_bottom] does not contain KEY_PRESS. The stack is then initialised: */
    if (edit->stack_pointer != edit->stack_bottom && edit->undo_stack[edit->stack_bottom] < KEY_PRESS)
	edit->stack_bottom = edit->stack_pointer = 0;
}

/*
   TODO: if the user undos until the stack bottom, and the stack has not wrapped,
   then the file should be as it was when he loaded up. Then set edit->modified to 0.
 */
static long
pop_action (WEdit * edit)
{
    long c;
    unsigned long sp = edit->stack_pointer;
    if (sp == edit->stack_bottom) {
	return STACK_BOTTOM;
    }
    sp = (sp - 1) & edit->stack_size_mask;
    if ((c = edit->undo_stack[sp]) >= 0) {
/*	edit->undo_stack[sp] = '@'; */
	edit->stack_pointer = (edit->stack_pointer - 1) & edit->stack_size_mask;
	return c;
    }
    if (sp == edit->stack_bottom) {
	return STACK_BOTTOM;
    }
    c = edit->undo_stack[(sp - 1) & edit->stack_size_mask];
    if (edit->undo_stack[sp] == -2) {
/*      edit->undo_stack[sp] = '@'; */
	edit->stack_pointer = sp;
    } else
	edit->undo_stack[sp]++;

    return c;
}

/* is called whenever a modification is made by one of the four routines below */
static inline void edit_modification (WEdit * edit)
{
    edit->caches_valid = 0;
    edit->screen_modified = 1;

    /* raise lock when file modified */
    if (!edit->modified && !edit->delete_file)
	edit->locked = edit_lock_file (edit->filename);
    edit->modified = 1;
}

/*
   Basic low level single character buffer alterations and movements at the cursor.
   Returns char passed over, inserted or removed.
 */

void
edit_insert (WEdit *edit, int c)
{
    /* check if file has grown to large */
    if (edit->last_byte >= SIZE_LIMIT)
	return;

    /* first we must update the position of the display window */
    if (edit->curs1 < edit->start_display) {
	edit->start_display++;
	if (c == '\n')
	    edit->start_line++;
    }

    /* Mark file as modified, unless the file hasn't been fully loaded */
    if (edit->loading_done) {
	edit_modification (edit);
    }

    /* now we must update some info on the file and check if a redraw is required */
    if (c == '\n') {
	if (edit->book_mark)
	    book_mark_inc (edit, edit->curs_line);
	edit->curs_line++;
	edit->total_lines++;
	edit->force |= REDRAW_LINE_ABOVE | REDRAW_AFTER_CURSOR;
    }

    /* save the reverse command onto the undo stack */
    edit_push_action (edit, BACKSPACE);

    /* update markers */
    edit->mark1 += (edit->mark1 > edit->curs1);
    edit->mark2 += (edit->mark2 > edit->curs1);
    edit->last_get_rule += (edit->last_get_rule > edit->curs1);

    /* add a new buffer if we've reached the end of the last one */
    if (!(edit->curs1 & M_EDIT_BUF_SIZE))
	edit->buffers1[edit->curs1 >> S_EDIT_BUF_SIZE] =
	    g_malloc (EDIT_BUF_SIZE);

    /* perform the insertion */
    edit->buffers1[edit->curs1 >> S_EDIT_BUF_SIZE][edit->
						   curs1 & M_EDIT_BUF_SIZE]
	= (unsigned char) c;

    /* update file length */
    edit->last_byte++;

    /* update cursor position */
    edit->curs1++;
}


/* same as edit_insert and move left */
void edit_insert_ahead (WEdit * edit, int c)
{
    if (edit->last_byte >= SIZE_LIMIT)
	return;
    if (edit->curs1 < edit->start_display) {
	edit->start_display++;
	if (c == '\n')
	    edit->start_line++;
    }
    edit_modification (edit);
    if (c == '\n') {
	if (edit->book_mark)
	    book_mark_inc (edit, edit->curs_line);
	edit->total_lines++;
	edit->force |= REDRAW_AFTER_CURSOR;
    }
    edit_push_action (edit, DELCHAR);

    edit->mark1 += (edit->mark1 >= edit->curs1);
    edit->mark2 += (edit->mark2 >= edit->curs1);
    edit->last_get_rule += (edit->last_get_rule >= edit->curs1);

    if (!((edit->curs2 + 1) & M_EDIT_BUF_SIZE))
	edit->buffers2[(edit->curs2 + 1) >> S_EDIT_BUF_SIZE] = g_malloc (EDIT_BUF_SIZE);
    edit->buffers2[edit->curs2 >> S_EDIT_BUF_SIZE][EDIT_BUF_SIZE - (edit->curs2 & M_EDIT_BUF_SIZE) - 1] = c;

    edit->last_byte++;
    edit->curs2++;
}


int edit_delete (WEdit * edit)
{
    int p;
    int cw = 1;

    if (!edit->curs2)
	return 0;

    edit->mark1 -= (edit->mark1 > edit->curs1);
    edit->mark2 -= (edit->mark2 > edit->curs1);
    edit->last_get_rule -= (edit->last_get_rule > edit->curs1);

    cw = 1;
    if ( edit->utf8 ) {
        edit_get_utf (edit, edit->curs1, &cw);
        if ( cw < 1 )
            cw = 1;
    }
    for ( int i = 1; i<= cw; i++ ) {
        p = edit->buffers2[(edit->curs2 - 1) >> S_EDIT_BUF_SIZE][EDIT_BUF_SIZE - ((edit->curs2 - 1) & M_EDIT_BUF_SIZE) - 1];

        if (!(edit->curs2 & M_EDIT_BUF_SIZE)) {
	    g_free (edit->buffers2[edit->curs2 >> S_EDIT_BUF_SIZE]);
	    edit->buffers2[edit->curs2 >> S_EDIT_BUF_SIZE] = NULL;
        }
        edit->last_byte--;
        edit->curs2--;
    }

    edit_modification (edit);
    if (p == '\n') {
	if (edit->book_mark)
	    book_mark_dec (edit, edit->curs_line);
	edit->total_lines--;
	edit->force |= REDRAW_AFTER_CURSOR;
    }
    edit_push_action (edit, p + 256);
    if (edit->curs1 < edit->start_display) {
	edit->start_display--;
	if (p == '\n')
	    edit->start_line--;
    }

    return p;
}


static int
edit_backspace (WEdit * edit)
{
    int p;
    int cw = 1;

    if (!edit->curs1)
	return 0;

    edit->mark1 -= (edit->mark1 >= edit->curs1);
    edit->mark2 -= (edit->mark2 >= edit->curs1);
    edit->last_get_rule -= (edit->last_get_rule >= edit->curs1);

    cw = 1;
    if ( edit->utf8 ) {
        edit_get_prev_utf (edit, edit->curs1, &cw);
        if ( cw < 1 )
            cw = 1;
    }
    for ( int i = 1; i<= cw; i++ ) {
        p = *(edit->buffers1[(edit->curs1 - 1) >> S_EDIT_BUF_SIZE] + ((edit->curs1 - 1) & M_EDIT_BUF_SIZE));
        if (!((edit->curs1 - 1) & M_EDIT_BUF_SIZE)) {
	    g_free (edit->buffers1[edit->curs1 >> S_EDIT_BUF_SIZE]);
	    edit->buffers1[edit->curs1 >> S_EDIT_BUF_SIZE] = NULL;
        }
        edit->last_byte--;
        edit->curs1--;
    }
    edit_modification (edit);
    if (p == '\n') {
	if (edit->book_mark)
	    book_mark_dec (edit, edit->curs_line);
	edit->curs_line--;
	edit->total_lines--;
	edit->force |= REDRAW_AFTER_CURSOR;
    }
    edit_push_action (edit, p);

    if (edit->curs1 < edit->start_display) {
	edit->start_display--;
	if (p == '\n')
	    edit->start_line--;
    }

    return p;
}

#ifdef FAST_MOVE_CURSOR

static void memqcpy (WEdit * edit, unsigned char *dest, unsigned char *src, int n)
{
    unsigned long next;
    while ((next = (unsigned long) memccpy (dest, src, '\n', n))) {
	edit->curs_line--;
	next -= (unsigned long) dest;
	n -= next;
	src += next;
	dest += next;
    }
}

int
edit_move_backward_lots (WEdit *edit, long increment)
{
    int r, s, t;
    unsigned char *p;

    if (increment > edit->curs1)
	increment = edit->curs1;
    if (increment <= 0)
	return -1;
    edit_push_action (edit, CURS_RIGHT_LOTS, increment);

    t = r = EDIT_BUF_SIZE - (edit->curs2 & M_EDIT_BUF_SIZE);
    if (r > increment)
	r = increment;
    s = edit->curs1 & M_EDIT_BUF_SIZE;

    p = 0;
    if (s > r) {
	memqcpy (edit,
		 edit->buffers2[edit->curs2 >> S_EDIT_BUF_SIZE] + t - r,
		 edit->buffers1[edit->curs1 >> S_EDIT_BUF_SIZE] + s - r,
		 r);
    } else {
	if (s) {
	    memqcpy (edit,
		     edit->buffers2[edit->curs2 >> S_EDIT_BUF_SIZE] + t -
		     s, edit->buffers1[edit->curs1 >> S_EDIT_BUF_SIZE], s);
	    p = edit->buffers1[edit->curs1 >> S_EDIT_BUF_SIZE];
	    edit->buffers1[edit->curs1 >> S_EDIT_BUF_SIZE] = 0;
	}
	memqcpy (edit,
		 edit->buffers2[edit->curs2 >> S_EDIT_BUF_SIZE] + t - r,
		 edit->buffers1[(edit->curs1 >> S_EDIT_BUF_SIZE) - 1] +
		 EDIT_BUF_SIZE - (r - s), r - s);
    }
    increment -= r;
    edit->curs1 -= r;
    edit->curs2 += r;
    if (!(edit->curs2 & M_EDIT_BUF_SIZE)) {
	if (p)
	    edit->buffers2[edit->curs2 >> S_EDIT_BUF_SIZE] = p;
	else
	    edit->buffers2[edit->curs2 >> S_EDIT_BUF_SIZE] =
		g_malloc (EDIT_BUF_SIZE);
    } else {
	g_free (p);
    }

    s = edit->curs1 & M_EDIT_BUF_SIZE;
    while (increment) {
	p = 0;
	r = EDIT_BUF_SIZE;
	if (r > increment)
	    r = increment;
	t = s;
	if (r < t)
	    t = r;
	memqcpy (edit,
		 edit->buffers2[edit->curs2 >> S_EDIT_BUF_SIZE] +
		 EDIT_BUF_SIZE - t,
		 edit->buffers1[edit->curs1 >> S_EDIT_BUF_SIZE] + s - t,
		 t);
	if (r >= s) {
	    if (t) {
		p = edit->buffers1[edit->curs1 >> S_EDIT_BUF_SIZE];
		edit->buffers1[edit->curs1 >> S_EDIT_BUF_SIZE] = 0;
	    }
	    memqcpy (edit,
		     edit->buffers2[edit->curs2 >> S_EDIT_BUF_SIZE] +
		     EDIT_BUF_SIZE - r,
		     edit->buffers1[(edit->curs1 >> S_EDIT_BUF_SIZE) - 1] +
		     EDIT_BUF_SIZE - (r - s), r - s);
	}
	increment -= r;
	edit->curs1 -= r;
	edit->curs2 += r;
	if (!(edit->curs2 & M_EDIT_BUF_SIZE)) {
	    if (p)
		edit->buffers2[edit->curs2 >> S_EDIT_BUF_SIZE] = p;
	    else
		edit->buffers2[edit->curs2 >> S_EDIT_BUF_SIZE] =
		    g_malloc (EDIT_BUF_SIZE);
	} else {
	    g_free (p);
	}
    }
    return edit_get_byte (edit, edit->curs1);
}

#endif		/* ! FAST_MOVE_CURSOR */

/* moves the cursor right or left: increment positive or negative respectively */
void edit_cursor_move (WEdit * edit, long increment)
{
/* this is the same as a combination of two of the above routines, with only one push onto the undo stack */
    int c;
    long curs1 = edit->curs1;
    long curs2 = edit->curs2;
    int cw = 1;
    int char_step = 0;

    /* one char move*/
    if ( increment == -1 || increment == 1)
        char_step = 1;

#ifdef FAST_MOVE_CURSOR
    if (increment < -256) {
	edit->force |= REDRAW_PAGE;
	edit_move_backward_lots (edit, -increment);
	return;
    }
#endif		/* ! FAST_MOVE_CURSOR */

    if (increment < 0) {
	for (; increment < 0; increment++) {
	    if (!edit->curs1)
		return;

	    edit_push_action (edit, CURS_RIGHT);

	    cw = 1;
	    if ( edit->utf8 && char_step ) {
	        edit_get_prev_utf (edit, curs1, &cw);
	        if ( cw < 1 )
	            cw = 1;
	    }
	    for ( int i = 1; i<= cw; i++ ) {
	        c = edit_get_byte (edit, curs1 - 1);
	        if (!((curs2 + 1) & M_EDIT_BUF_SIZE))
		    edit->buffers2[(curs2 + 1) >> S_EDIT_BUF_SIZE] = g_malloc (EDIT_BUF_SIZE);
	        edit->buffers2[edit->curs2 >> S_EDIT_BUF_SIZE][EDIT_BUF_SIZE - (curs2 & M_EDIT_BUF_SIZE) - 1] = c;
	        curs2++;
	        c = edit->buffers1[(curs1 - 1) >> S_EDIT_BUF_SIZE][(curs1 - 1) & M_EDIT_BUF_SIZE];
	        if (!((curs1 - 1) & M_EDIT_BUF_SIZE)) {
		    g_free (edit->buffers1[curs1 >> S_EDIT_BUF_SIZE]);
		    edit->buffers1[curs1 >> S_EDIT_BUF_SIZE] = NULL;
	        }
	        curs1--;
	    }
	    edit->curs1 = curs1;
	    edit->curs2 = curs2;
	    if (c == '\n') {
		edit->curs_line--;
		edit->force |= REDRAW_LINE_BELOW;
	    }
	}

    } else if (increment > 0) {
	for (; increment > 0; increment--) {
	    if (!edit->curs2)
		return;

	    edit_push_action (edit, CURS_LEFT);

	    cw = 1;
	    if ( edit->utf8 && char_step ) {
	        edit_get_utf (edit, curs1, &cw);
	        if ( cw < 1 )
	            cw = 1;
	    }
	    for ( int i = 1; i<= cw; i++ ) {
	        c = edit_get_byte (edit, curs1);
	        if (!(curs1 & M_EDIT_BUF_SIZE))
		    edit->buffers1[curs1 >> S_EDIT_BUF_SIZE] = g_malloc (EDIT_BUF_SIZE);
	        edit->buffers1[curs1 >> S_EDIT_BUF_SIZE][curs1 & M_EDIT_BUF_SIZE] = c;
	        curs1++;
	        c = edit->buffers2[(curs2 - 1) >> S_EDIT_BUF_SIZE][EDIT_BUF_SIZE - ((curs2 - 1) & M_EDIT_BUF_SIZE) - 1];
	        if (!(curs2 & M_EDIT_BUF_SIZE)) {
		    g_free (edit->buffers2[curs2 >> S_EDIT_BUF_SIZE]);
		    edit->buffers2[curs2 >> S_EDIT_BUF_SIZE] = 0;
	        }
	        curs2--;
	    }
	    edit->curs1 = curs1;
	    edit->curs2 = curs2;
	    if (c == '\n') {
		edit->curs_line++;
		edit->force |= REDRAW_LINE_ABOVE;
	    }
	}
    }
}

/* These functions return positions relative to lines */

/* returns index of last char on line + 1 */
long edit_eol (WEdit * edit, long current)
{
    if (current < edit->last_byte) {
	for (;; current++)
	    if (edit_get_byte (edit, current) == '\n')
		break;
    } else
	return edit->last_byte;
    return current;
}

/* returns index of first char on line */
long edit_bol (WEdit * edit, long current)
{
    if (current > 0) {
	for (;; current--)
	    if (edit_get_byte (edit, current - 1) == '\n')
		break;
    } else
	return 0;
    return current;
}


int edit_count_lines (WEdit * edit, long current, int upto)
{
    int lines = 0;
    if (upto > edit->last_byte)
	upto = edit->last_byte;
    if (current < 0)
	current = 0;
    while (current < upto)
	if (edit_get_byte (edit, current++) == '\n')
	    lines++;
    return lines;
}


/* If lines is zero this returns the count of lines from current to upto. */
/* If upto is zero returns index of lines forward current. */
long edit_move_forward (WEdit * edit, long current, int lines, long upto)
{
    if (upto) {
	return edit_count_lines (edit, current, upto);
    } else {
	int next;
	if (lines < 0)
	    lines = 0;
	while (lines--) {
	    next = edit_eol (edit, current) + 1;
	    if (next > edit->last_byte)
		break;
	    else
		current = next;
	}
	return current;
    }
}


/* Returns offset of 'lines' lines up from current */
long edit_move_backward (WEdit * edit, long current, int lines)
{
    if (lines < 0)
	lines = 0;
    current = edit_bol (edit, current);
    while((lines--) && current != 0)
	current = edit_bol (edit, current - 1);
    return current;
}

/* If cols is zero this returns the count of columns from current to upto. */
/* If upto is zero returns index of cols across from current. */
long edit_move_forward3 (WEdit * edit, long current, int cols, long upto)
{
    long p, q;
    int col = 0;
    int cw = 1;
    if (upto) {
	q = upto;
	cols = -10;
    } else
	q = edit->last_byte + 2;

    for (col = 0, p = current; p < q; p++) {
	int c;
	if (cols != -10) {
	    if (col == cols)
		return p;
	    if (col > cols)
		return p - 1;
	}
	if ( !edit->utf8 ) {
	    c = edit_get_byte (edit, p);
	} else {
	    cw = 1;
	    c = edit_get_byte (edit, p);
	    edit_get_utf (edit, p, &cw);
	}
	if (c == '\t')
	    col += TAB_SIZE - col % TAB_SIZE;
	else if (c == '\n') {
	    if (upto)
		return col;
	    else
		return p;
	} else if (c < 32 || c == 127)
	    col += 2; /* Caret notation for control characters */
	else
	    col++;
	if ( cw > 1 )
	    col -= cw-1;
    }
    return col;
}

/* returns the current column position of the cursor */
int edit_get_col (WEdit * edit)
{
    return edit_move_forward3 (edit, edit_bol (edit, edit->curs1), 0, edit->curs1);
}


/* Scrolling functions */

void edit_update_curs_row (WEdit * edit)
{
    edit->curs_row = edit->curs_line - edit->start_line;
}

void edit_update_curs_col (WEdit * edit)
{
    edit->curs_col = edit_move_forward3(edit, edit_bol(edit, edit->curs1), 0, edit->curs1);
}

/*moves the display start position up by i lines */
void edit_scroll_upward (WEdit * edit, unsigned long i)
{
    unsigned long lines_above = edit->start_line;
    if (i > lines_above)
	i = lines_above;
    if (i) {
	edit->start_line -= i;
	edit->start_display = edit_move_backward (edit, edit->start_display, i);
	edit->force |= REDRAW_PAGE;
	edit->force &= (0xfff - REDRAW_CHAR_ONLY);
    }
    edit_update_curs_row (edit);
}


/* returns 1 if could scroll, 0 otherwise */
void edit_scroll_downward (WEdit * edit, int i)
{
    int lines_below;
    lines_below = edit->total_lines - edit->start_line - (edit->num_widget_lines - 1);
    if (lines_below > 0) {
	if (i > lines_below)
	    i = lines_below;
	edit->start_line += i;
	edit->start_display = edit_move_forward (edit, edit->start_display, i, 0);
	edit->force |= REDRAW_PAGE;
	edit->force &= (0xfff - REDRAW_CHAR_ONLY);
    }
    edit_update_curs_row (edit);
}

void edit_scroll_right (WEdit * edit, int i)
{
    edit->force |= REDRAW_PAGE;
    edit->force &= (0xfff - REDRAW_CHAR_ONLY);
    edit->start_col -= i;
}

void edit_scroll_left (WEdit * edit, int i)
{
    if (edit->start_col) {
	edit->start_col += i;
	if (edit->start_col > 0)
	    edit->start_col = 0;
	edit->force |= REDRAW_PAGE;
	edit->force &= (0xfff - REDRAW_CHAR_ONLY);
    }
}

/* high level cursor movement commands */

static int is_in_indent (WEdit *edit)
{
    long p = edit_bol (edit, edit->curs1);
    while (p < edit->curs1)
	if (!strchr (" \t", edit_get_byte (edit, p++)))
	    return 0;
    return 1;
}

static int left_of_four_spaces (WEdit *edit);

void
edit_move_to_prev_col (WEdit * edit, long p)
{
    edit_cursor_move (edit, edit_move_forward3 (edit, p, edit->prev_col, 0) - edit->curs1);

    if (is_in_indent (edit) && option_fake_half_tabs) {
	edit_update_curs_col (edit);
	if (space_width)
	if (edit->curs_col % (HALF_TAB_SIZE * space_width)) {
	    int q = edit->curs_col;
	    edit->curs_col -= (edit->curs_col % (HALF_TAB_SIZE * space_width));
	    p = edit_bol (edit, edit->curs1);
	    edit_cursor_move (edit, edit_move_forward3 (edit, p, edit->curs_col, 0) - edit->curs1);
	    if (!left_of_four_spaces (edit))
		edit_cursor_move (edit, edit_move_forward3 (edit, p, q, 0) - edit->curs1);
	}
    }
}


/* move i lines */
void edit_move_up (WEdit * edit, unsigned long i, int scroll)
{
    unsigned long p, l = edit->curs_line;

    if (i > l)
	i = l;
    if (i) {
	if (i > 1)
	    edit->force |= REDRAW_PAGE;
	if (scroll)
	    edit_scroll_upward (edit, i);

	p = edit_bol (edit, edit->curs1);
	edit_cursor_move (edit, (p = edit_move_backward (edit, p, i)) - edit->curs1);
	edit_move_to_prev_col (edit, p);

	edit->search_start = edit->curs1;
	edit->found_len = 0;
    }
}

static int
is_blank (WEdit *edit, long offset)
{
    long s, f;
    int c;
    s = edit_bol (edit, offset);
    f = edit_eol (edit, offset) - 1;
    while (s <= f) {
	c = edit_get_byte (edit, s++);
	if (!isspace (c))
	    return 0;
    }
    return 1;
}


/* returns the offset of line i */
static long
edit_find_line (WEdit *edit, int line)
{
    int i, j = 0;
    int m = 2000000000;
    if (!edit->caches_valid) {
	for (i = 0; i < N_LINE_CACHES; i++)
	    edit->line_numbers[i] = edit->line_offsets[i] = 0;
/* three offsets that we *know* are line 0 at 0 and these two: */
	edit->line_numbers[1] = edit->curs_line;
	edit->line_offsets[1] = edit_bol (edit, edit->curs1);
	edit->line_numbers[2] = edit->total_lines;
	edit->line_offsets[2] = edit_bol (edit, edit->last_byte);
	edit->caches_valid = 1;
    }
    if (line >= edit->total_lines)
	return edit->line_offsets[2];
    if (line <= 0)
	return 0;
/* find the closest known point */
    for (i = 0; i < N_LINE_CACHES; i++) {
	int n;
	n = abs (edit->line_numbers[i] - line);
	if (n < m) {
	    m = n;
	    j = i;
	}
    }
    if (m == 0)
	return edit->line_offsets[j];	/* know the offset exactly */
    if (m == 1 && j >= 3)
	i = j;			/* one line different - caller might be looping, so stay in this cache */
    else
	i = 3 + (rand () % (N_LINE_CACHES - 3));
    if (line > edit->line_numbers[j])
	edit->line_offsets[i] = edit_move_forward (edit, edit->line_offsets[j], line - edit->line_numbers[j], 0);
    else
	edit->line_offsets[i] = edit_move_backward (edit, edit->line_offsets[j], edit->line_numbers[j] - line);
    edit->line_numbers[i] = line;
    return edit->line_offsets[i];
}

int line_is_blank (WEdit * edit, long line)
{
    return is_blank (edit, edit_find_line (edit, line));
}

/* moves up until a blank line is reached, or until just
   before a non-blank line is reached */
static void edit_move_up_paragraph (WEdit * edit, int scroll)
{
    int i;
    if (edit->curs_line <= 1) {
	i = 0;
    } else {
	if (line_is_blank (edit, edit->curs_line)) {
	    if (line_is_blank (edit, edit->curs_line - 1)) {
		for (i = edit->curs_line - 1; i; i--)
		    if (!line_is_blank (edit, i)) {
			i++;
			break;
		    }
	    } else {
		for (i = edit->curs_line - 1; i; i--)
		    if (line_is_blank (edit, i))
			break;
	    }
	} else {
	    for (i = edit->curs_line - 1; i; i--)
		if (line_is_blank (edit, i))
		    break;
	}
    }
    edit_move_up (edit, edit->curs_line - i, scroll);
}

/* move i lines */
void edit_move_down (WEdit * edit, int i, int scroll)
{
    long p, l = edit->total_lines - edit->curs_line;

    if (i > l)
	i = l;
    if (i) {
	if (i > 1)
	    edit->force |= REDRAW_PAGE;
	if (scroll)
	    edit_scroll_downward (edit, i);
	p = edit_bol (edit, edit->curs1);
	edit_cursor_move (edit, (p = edit_move_forward (edit, p, i, 0)) - edit->curs1);
	edit_move_to_prev_col (edit, p);

	edit->search_start = edit->curs1;
	edit->found_len = 0;
    }
}

/* moves down until a blank line is reached, or until just
   before a non-blank line is reached */
static void edit_move_down_paragraph (WEdit * edit, int scroll)
{
    int i;
    if (edit->curs_line >= edit->total_lines - 1) {
	i = edit->total_lines;
    } else {
	if (line_is_blank (edit, edit->curs_line)) {
	    if (line_is_blank (edit, edit->curs_line + 1)) {
		for (i = edit->curs_line + 1; i; i++)
		    if (!line_is_blank (edit, i) || i > edit->total_lines) {
			i--;
			break;
		    }
	    } else {
		for (i = edit->curs_line + 1; i; i++)
		    if (line_is_blank (edit, i) || i >= edit->total_lines)
			break;
	    }
	} else {
	    for (i = edit->curs_line + 1; i; i++)
		if (line_is_blank (edit, i) || i >= edit->total_lines)
		    break;
	}
    }
    edit_move_down (edit, i - edit->curs_line, scroll);
}

static void edit_begin_page (WEdit *edit)
{
    edit_update_curs_row (edit);
    edit_move_up (edit, edit->curs_row, 0);
}

static void edit_end_page (WEdit *edit)
{
    edit_update_curs_row (edit);
    edit_move_down (edit, edit->num_widget_lines - edit->curs_row - 1, 0);
}


/* goto beginning of text */
static void edit_move_to_top (WEdit * edit)
{
    if (edit->curs_line) {
	edit_cursor_move (edit, -edit->curs1);
	edit_move_to_prev_col (edit, 0);
	edit->force |= REDRAW_PAGE;
	edit->search_start = 0;
	edit_update_curs_row(edit);
    }
}


/* goto end of text */
static void edit_move_to_bottom (WEdit * edit)
{
    if (edit->curs_line < edit->total_lines) {
	edit_cursor_move (edit, edit->curs2);
	edit->start_display = edit->last_byte;
	edit->start_line = edit->total_lines;
	edit_update_curs_row(edit);
	edit_scroll_upward (edit, edit->num_widget_lines - 1);
	edit->force |= REDRAW_PAGE;
    }
}

/* goto beginning of line */
static void edit_cursor_to_bol (WEdit * edit)
{
    edit_cursor_move (edit, edit_bol (edit, edit->curs1) - edit->curs1);
    edit->search_start = edit->curs1;
    edit->prev_col = edit_get_col (edit);
}

/* goto end of line */
static void edit_cursor_to_eol (WEdit * edit)
{
    edit_cursor_move (edit, edit_eol (edit, edit->curs1) - edit->curs1);
    edit->search_start = edit->curs1;
    edit->prev_col = edit_get_col (edit);
}

/* move cursor to line 'line' */
void edit_move_to_line (WEdit * e, long line)
{
    if(line < e->curs_line)
	edit_move_up (e, e->curs_line - line, 0);
    else
	edit_move_down (e, line - e->curs_line, 0);
    edit_scroll_screen_over_cursor (e);
}

/* scroll window so that first visible line is 'line' */
void edit_move_display (WEdit * e, long line)
{
    if(line < e->start_line)
	edit_scroll_upward (e, e->start_line - line);
    else
	edit_scroll_downward (e, line - e->start_line);
}

/* save markers onto undo stack */
void edit_push_markers (WEdit * edit)
{
    edit_push_action (edit, MARK_1 + edit->mark1);
    edit_push_action (edit, MARK_2 + edit->mark2);
}

void edit_set_markers (WEdit * edit, long m1, long m2, int c1, int c2)
{
    edit->mark1 = m1;
    edit->mark2 = m2;
    edit->column1 = c1;
    edit->column2 = c2;
}


/* highlight marker toggle */
void edit_mark_cmd (WEdit * edit, int unmark)
{
    edit_push_markers (edit);
    if (unmark) {
	edit_set_markers (edit, 0, 0, 0, 0);
	edit->force |= REDRAW_PAGE;
    } else {
	if (edit->mark2 >= 0) {
	    edit_set_markers (edit, edit->curs1, -1, edit->curs_col, edit->curs_col);
	    edit->force |= REDRAW_PAGE;
	} else
	    edit_set_markers (edit, edit->mark1, edit->curs1, edit->column1, edit->curs_col);
    }
}

static unsigned long
my_type_of (int c)
{
    int x, r = 0;
    const char *p, *q;
    const char option_chars_move_whole_word[] =
	"!=&|<>^~ !:;, !'!`!.?!\"!( !) !Aa0 !+-*/= |<> ![ !] !\\#! ";

    if (!c)
	return 0;
    if (c == '!') {
	if (*option_chars_move_whole_word == '!')
	    return 2;
	return 0x80000000UL;
    }
    if (g_ascii_isupper ((gchar) c))
	c = 'A';
    else if (g_ascii_islower ((gchar) c))
	c = 'a';
    else if (g_ascii_isalpha (c))
	c = 'a';
    else if (isdigit (c))
	c = '0';
    else if (isspace (c))
	c = ' ';
    q = strchr (option_chars_move_whole_word, c);
    if (!q)
	return 0xFFFFFFFFUL;
    do {
	for (x = 1, p = option_chars_move_whole_word; p < q; p++)
	    if (*p == '!')
		x <<= 1;
	r |= x;
    } while ((q = strchr (q + 1, c)));
    return r;
}

static void
edit_left_word_move (WEdit *edit, int s)
{
    for (;;) {
	int c1, c2;
	edit_cursor_move (edit, -1);
	if (!edit->curs1)
	    break;
	c1 = edit_get_byte (edit, edit->curs1 - 1);
	c2 = edit_get_byte (edit, edit->curs1);
	if (!(my_type_of (c1) & my_type_of (c2)))
	    break;
	if (isspace (c1) && !isspace (c2))
	    break;
	if (s)
	    if (!isspace (c1) && isspace (c2))
		break;
    }
}

static void edit_left_word_move_cmd (WEdit * edit)
{
    edit_left_word_move (edit, 0);
    edit->force |= REDRAW_PAGE;
}

static void
edit_right_word_move (WEdit *edit, int s)
{
    for (;;) {
	int c1, c2;
	edit_cursor_move (edit, 1);
	if (edit->curs1 >= edit->last_byte)
	    break;
	c1 = edit_get_byte (edit, edit->curs1 - 1);
	c2 = edit_get_byte (edit, edit->curs1);
	if (!(my_type_of (c1) & my_type_of (c2)))
	    break;
	if (isspace (c1) && !isspace (c2))
	    break;
	if (s)
	    if (!isspace (c1) && isspace (c2))
		break;
    }
}

static void edit_right_word_move_cmd (WEdit * edit)
{
    edit_right_word_move (edit, 0);
    edit->force |= REDRAW_PAGE;
}


static void edit_right_delete_word (WEdit * edit)
{
    int c1, c2;
    for (;;) {
	if (edit->curs1 >= edit->last_byte)
	    break;
	c1 = edit_delete (edit);
	c2 = edit_get_byte (edit, edit->curs1);
	if ((isspace (c1) == 0) != (isspace (c2) == 0))
	    break;
	if (!(my_type_of (c1) & my_type_of (c2)))
	    break;
    }
}

static void edit_left_delete_word (WEdit * edit)
{
    int c1, c2;
    for (;;) {
	if (edit->curs1 <= 0)
	    break;
	c1 = edit_backspace (edit);
	c2 = edit_get_byte (edit, edit->curs1 - 1);
	if ((isspace (c1) == 0) != (isspace (c2) == 0))
	    break;
	if (!(my_type_of (c1) & my_type_of (c2)))
	    break;
    }
}

/*
   the start column position is not recorded, and hence does not
   undo as it happed. But who would notice.
 */
static void
edit_do_undo (WEdit * edit)
{
    long ac;
    long count = 0;

    edit->stack_disable = 1;	/* don't record undo's onto undo stack! */

    while ((ac = pop_action (edit)) < KEY_PRESS) {
	switch ((int) ac) {
	case STACK_BOTTOM:
	    goto done_undo;
	case CURS_RIGHT:
	    edit_cursor_move (edit, 1);
	    break;
	case CURS_LEFT:
	    edit_cursor_move (edit, -1);
	    break;
	case BACKSPACE:
	    edit_backspace (edit);
	    break;
	case DELCHAR:
	    edit_delete (edit);
	    break;
	case COLUMN_ON:
	    column_highlighting = 1;
	    break;
	case COLUMN_OFF:
	    column_highlighting = 0;
	    break;
	}
	if (ac >= 256 && ac < 512)
	    edit_insert_ahead (edit, ac - 256);
	if (ac >= 0 && ac < 256)
	    edit_insert (edit, ac);

	if (ac >= MARK_1 - 2 && ac < MARK_2 - 2) {
	    edit->mark1 = ac - MARK_1;
	    edit->column1 = edit_move_forward3 (edit, edit_bol (edit, edit->mark1), 0, edit->mark1);
	} else if (ac >= MARK_2 - 2 && ac < KEY_PRESS) {
	    edit->mark2 = ac - MARK_2;
	    edit->column2 = edit_move_forward3 (edit, edit_bol (edit, edit->mark2), 0, edit->mark2);
	}
	if (count++)
	    edit->force |= REDRAW_PAGE;		/* more than one pop usually means something big */
    }

    if (edit->start_display > ac - KEY_PRESS) {
	edit->start_line -= edit_count_lines (edit, ac - KEY_PRESS, edit->start_display);
	edit->force |= REDRAW_PAGE;
    } else if (edit->start_display < ac - KEY_PRESS) {
	edit->start_line += edit_count_lines (edit, edit->start_display, ac - KEY_PRESS);
	edit->force |= REDRAW_PAGE;
    }
    edit->start_display = ac - KEY_PRESS;	/* see push and pop above */
    edit_update_curs_row (edit);

  done_undo:;
    edit->stack_disable = 0;
}

static void edit_delete_to_line_end (WEdit * edit)
{
    while (edit_get_byte (edit, edit->curs1) != '\n') {
	if (!edit->curs2)
	    break;
	edit_delete (edit);
    }
}

static void edit_delete_to_line_begin (WEdit * edit)
{
    while (edit_get_byte (edit, edit->curs1 - 1) != '\n') {
	if (!edit->curs1)
	    break;
	edit_backspace (edit);
    }
}

void
edit_delete_line (WEdit *edit)
{
    /*
     * Delete right part of the line.
     * Note that edit_get_byte() returns '\n' when byte position is
     *   beyond EOF.
     */
    while (edit_get_byte (edit, edit->curs1) != '\n') {
	(void) edit_delete (edit);
    }

    /*
     * Delete '\n' char.
     * Note that edit_delete() will not corrupt anything if called while
     *   cursor position is EOF.
     */
    (void) edit_delete (edit);

    /*
     * Delete left part of the line.
     * Note, that edit_get_byte() returns '\n' when byte position is < 0.
     */
    while (edit_get_byte (edit, edit->curs1 - 1) != '\n') {
	(void) edit_backspace (edit);
    };
}

static void insert_spaces_tab (WEdit * edit, int half)
{
    int i;
    edit_update_curs_col (edit);
    i = ((edit->curs_col / (option_tab_spacing * space_width / (half + 1))) + 1) * (option_tab_spacing * space_width / (half + 1)) - edit->curs_col;
    while (i > 0) {
	edit_insert (edit, ' ');
	i -= space_width;
    }
}

static int is_aligned_on_a_tab (WEdit * edit)
{
    edit_update_curs_col (edit);
    if ((edit->curs_col % (TAB_SIZE * space_width)) && edit->curs_col % (TAB_SIZE * space_width) != (HALF_TAB_SIZE * space_width))
	return 0;		/* not alligned on a tab */
    return 1;
}

static int right_of_four_spaces (WEdit *edit)
{
    int i, ch = 0;
    for (i = 1; i <= HALF_TAB_SIZE; i++)
	ch |= edit_get_byte (edit, edit->curs1 - i);
    if (ch == ' ')
	return is_aligned_on_a_tab (edit);
    return 0;
}

static int left_of_four_spaces (WEdit *edit)
{
    int i, ch = 0;
    for (i = 0; i < HALF_TAB_SIZE; i++)
	ch |= edit_get_byte (edit, edit->curs1 + i);
    if (ch == ' ')
	return is_aligned_on_a_tab (edit);
    return 0;
}

int edit_indent_width (WEdit * edit, long p)
{
    long q = p;
    while (strchr ("\t ", edit_get_byte (edit, q)) && q < edit->last_byte - 1)	/* move to the end of the leading whitespace of the line */
	q++;
    return edit_move_forward3 (edit, p, 0, q);	/* count the number of columns of indentation */
}

void edit_insert_indent (WEdit * edit, int indent)
{
    if (!option_fill_tabs_with_spaces) {
	while (indent >= TAB_SIZE) {
	    edit_insert (edit, '\t');
	    indent -= TAB_SIZE;
	}
    }
    while (indent-- > 0)
	edit_insert (edit, ' ');
}

static void
edit_auto_indent (WEdit * edit)
{
    long p;
    char c;
    p = edit->curs1;
    /* use the previous line as a template */
    p = edit_move_backward (edit, p, 1);
    /* copy the leading whitespace of the line */
    for (;;) {	/* no range check - the line _is_ \n-terminated */
	c = edit_get_byte (edit, p++);
	if (c != ' ' && c != '\t')
	    break;
	edit_insert (edit, c);
    }
}

static void edit_double_newline (WEdit * edit)
{
    edit_insert (edit, '\n');
    if (edit_get_byte (edit, edit->curs1) == '\n')
	return;
    if (edit_get_byte (edit, edit->curs1 - 2) == '\n')
	return;
    edit->force |= REDRAW_PAGE;
    edit_insert (edit, '\n');
}

static void edit_tab_cmd (WEdit * edit)
{
    int i;

    if (option_fake_half_tabs) {
	if (is_in_indent (edit)) {
	    /*insert a half tab (usually four spaces) unless there is a
	       half tab already behind, then delete it and insert a
	       full tab. */
	    if (!option_fill_tabs_with_spaces && right_of_four_spaces (edit)) {
		for (i = 1; i <= HALF_TAB_SIZE; i++)
		    edit_backspace (edit);
		edit_insert (edit, '\t');
	    } else {
		insert_spaces_tab (edit, 1);
	    }
	    return;
	}
    }
    if (option_fill_tabs_with_spaces) {
	insert_spaces_tab (edit, 0);
    } else {
	edit_insert (edit, '\t');
    }
    return;
}

static void check_and_wrap_line (WEdit * edit)
{
    int curs, c;
    if (!option_typewriter_wrap)
	return;
    edit_update_curs_col (edit);
    if (edit->curs_col < option_word_wrap_line_length)
	return;
    curs = edit->curs1;
    for (;;) {
	curs--;
	c = edit_get_byte (edit, curs);
	if (c == '\n' || curs <= 0) {
	    edit_insert (edit, '\n');
	    return;
	}
	if (c == ' ' || c == '\t') {
	    int current = edit->curs1;
	    edit_cursor_move (edit, curs - edit->curs1 + 1);
	    edit_insert (edit, '\n');
	    edit_cursor_move (edit, current - edit->curs1 + 1);
	    return;
	}
    }
}

static void edit_execute_macro (WEdit *edit, struct macro macro[], int n);

void edit_push_key_press (WEdit * edit)
{
    edit_push_action (edit, KEY_PRESS + edit->start_display);
    if (edit->mark2 == -1)
	edit_push_action (edit, MARK_1 + edit->mark1);
}

/* this find the matching bracket in either direction, and sets edit->bracket */
static long edit_get_bracket (WEdit * edit, int in_screen, unsigned long furthest_bracket_search)
{
    const char * const b = "{}{[][()(", *p;
    int i = 1, a, inc = -1, c, d, n = 0;
    unsigned long j = 0;
    long q;
    edit_update_curs_row (edit);
    c = edit_get_byte (edit, edit->curs1);
    p = strchr (b, c);
/* no limit */
    if (!furthest_bracket_search)
	furthest_bracket_search--;
/* not on a bracket at all */
    if (!p)
	return -1;
/* the matching bracket */
    d = p[1];
/* going left or right? */
    if (strchr ("{[(", c))
	inc = 1;
    for (q = edit->curs1 + inc;; q += inc) {
/* out of buffer? */
	if (q >= edit->last_byte || q < 0)
	    break;
	a = edit_get_byte (edit, q);
/* don't want to eat CPU */
	if (j++ > furthest_bracket_search)
	    break;
/* out of screen? */
	if (in_screen) {
	    if (q < edit->start_display)
		break;
/* count lines if searching downward */
	    if (inc > 0 && a == '\n')
		if (n++ >= edit->num_widget_lines - edit->curs_row)	/* out of screen */
		    break;
	}
/* count bracket depth */
	i += (a == c) - (a == d);
/* return if bracket depth is zero */
	if (!i)
	    return q;
    }
/* no match */
    return -1;
}

static long last_bracket = -1;

void edit_find_bracket (WEdit * edit)
{
    edit->bracket = edit_get_bracket (edit, 1, 10000);
    if (last_bracket != edit->bracket)
	edit->force |= REDRAW_PAGE;
    last_bracket = edit->bracket;
}

static void edit_goto_matching_bracket (WEdit *edit)
{
    long q;
    q = edit_get_bracket (edit, 0, 0);
    if (q < 0)
	return;
    edit->bracket = edit->curs1;
    edit->force |= REDRAW_PAGE;
    edit_cursor_move (edit, q - edit->curs1);
}

/*
 * This executes a command as though the user initiated it through a key
 * press.  Callback with WIDGET_KEY as a message calls this after
 * translating the key press.  This function can be used to pass any
 * command to the editor.  Note that the screen wouldn't update
 * automatically.  Either of command or char_for_insertion must be
 * passed as -1.  Commands are executed, and char_for_insertion is
 * inserted at the cursor.
 */
void edit_execute_key_command (WEdit *edit, int command, int char_for_insertion)
{
    if (command == CK_Begin_Record_Macro) {
	edit->macro_i = 0;
	edit->force |= REDRAW_CHAR_ONLY | REDRAW_LINE;
	return;
    }
    if (command == CK_End_Record_Macro && edit->macro_i != -1) {
	edit->force |= REDRAW_COMPLETELY;
	edit_save_macro_cmd (edit, edit->macro, edit->macro_i);
	edit->macro_i = -1;
	return;
    }
    if (edit->macro_i >= 0 && edit->macro_i < MAX_MACRO_LENGTH - 1) {
	edit->macro[edit->macro_i].command = command;
	edit->macro[edit->macro_i++].ch = char_for_insertion;
    }
/* record the beginning of a set of editing actions initiated by a key press */
    if (command != CK_Undo && command != CK_Ext_Mode)
	edit_push_key_press (edit);

    edit_execute_cmd (edit, command, char_for_insertion);
    if (column_highlighting)
	edit->force |= REDRAW_PAGE;
}

static const char * const shell_cmd[] = SHELL_COMMANDS_i;

/*
   This executes a command at a lower level than macro recording.
   It also does not push a key_press onto the undo stack. This means
   that if it is called many times, a single undo command will undo
   all of them. It also does not check for the Undo command.
 */
void
edit_execute_cmd (WEdit *edit, int command, int char_for_insertion)
{
    edit->force |= REDRAW_LINE;

    /* The next key press will unhighlight the found string, so update
     * the whole page */
    if (edit->found_len || column_highlighting)
	edit->force |= REDRAW_PAGE;

    if (command / 100 == 6) {	/* a highlight command like shift-arrow */
	column_highlighting = 0;
	if (!edit->highlight
	    || (edit->mark2 != -1 && edit->mark1 != edit->mark2)) {
	    edit_mark_cmd (edit, 1);	/* clear */
	    edit_mark_cmd (edit, 0);	/* marking on */
	}
	edit->highlight = 1;
    } else {			/* any other command */
	if (edit->highlight)
	    edit_mark_cmd (edit, 0);	/* clear */
	edit->highlight = 0;
    }

    /* first check for undo */
    if (command == CK_Undo) {
	edit_do_undo (edit);
	edit->found_len = 0;
	edit->prev_col = edit_get_col (edit);
	edit->search_start = edit->curs1;
	return;
    }

    /* An ordinary key press */
    if (char_for_insertion >= 0) {
	if (edit->overwrite) {
	    if (edit_get_byte (edit, edit->curs1) != '\n')
		edit_delete (edit);
	}
	edit_insert (edit, char_for_insertion);
	if (option_auto_para_formatting) {
	    format_paragraph (edit, 0);
	    edit->force |= REDRAW_PAGE;
	} else
	    check_and_wrap_line (edit);
	edit->found_len = 0;
	edit->prev_col = edit_get_col (edit);
	edit->search_start = edit->curs1;
	edit_find_bracket (edit);
	return;
    }

    switch (command) {
    case CK_Begin_Page:
    case CK_End_Page:
    case CK_Begin_Page_Highlight:
    case CK_End_Page_Highlight:
    case CK_Word_Left:
    case CK_Word_Right:
    case CK_Up:
    case CK_Down:
    case CK_Left:
    case CK_Right:
        if ( edit->mark2 >= 0 ) {
            if ( !option_persistent_selections ) {
                if (column_highlighting)
                    edit_push_action (edit, COLUMN_ON);
                column_highlighting = 0;
                edit_mark_cmd (edit, 1);
            }
        }
    }

    switch (command) {
    case CK_Begin_Page:
    case CK_End_Page:
    case CK_Begin_Page_Highlight:
    case CK_End_Page_Highlight:
    case CK_Word_Left:
    case CK_Word_Right:
    case CK_Up:
    case CK_Down:
    case CK_Word_Left_Highlight:
    case CK_Word_Right_Highlight:
    case CK_Up_Highlight:
    case CK_Down_Highlight:
	if (edit->mark2 == -1)
	    break;		/*marking is following the cursor: may need to highlight a whole line */
    case CK_Left:
    case CK_Right:
    case CK_Left_Highlight:
    case CK_Right_Highlight:
	edit->force |= REDRAW_CHAR_ONLY;
    }

    /* basic cursor key commands */
    switch (command) {
    case CK_BackSpace:
        /* if non persistent selection and text selected */
        if ( !option_persistent_selections ) {
            if ( edit->mark1 != edit->mark2 ) {
                edit_block_delete_cmd (edit);
                break;
            }
        }
	if (option_backspace_through_tabs && is_in_indent (edit)) {
	    while (edit_get_byte (edit, edit->curs1 - 1) != '\n'
		   && edit->curs1 > 0)
		edit_backspace (edit);
	    break;
	} else {
	    if (option_fake_half_tabs) {
		int i;
		if (is_in_indent (edit) && right_of_four_spaces (edit)) {
		    for (i = 0; i < HALF_TAB_SIZE; i++)
			edit_backspace (edit);
		    break;
		}
	    }
	}
	edit_backspace (edit);
	break;
    case CK_Delete:
        /* if non persistent selection and text selected */
        if ( !option_persistent_selections ) {
            if ( edit->mark1 != edit->mark2 ) {
                edit_block_delete_cmd (edit);
                break;
            }
        }
	if (option_fake_half_tabs) {
	    int i;
	    if (is_in_indent (edit) && left_of_four_spaces (edit)) {
		for (i = 1; i <= HALF_TAB_SIZE; i++)
		    edit_delete (edit);
		break;
	    }
	}
	edit_delete (edit);
	break;
    case CK_Delete_Word_Left:
	edit_left_delete_word (edit);
	break;
    case CK_Delete_Word_Right:
	edit_right_delete_word (edit);
	break;
    case CK_Delete_Line:
	edit_delete_line (edit);
	break;
    case CK_Delete_To_Line_End:
	edit_delete_to_line_end (edit);
	break;
    case CK_Delete_To_Line_Begin:
	edit_delete_to_line_begin (edit);
	break;
    case CK_Enter:
	if (option_auto_para_formatting) {
	    edit_double_newline (edit);
	    if (option_return_does_auto_indent)
		edit_auto_indent (edit);
	    format_paragraph (edit, 0);
	} else {
	    edit_insert (edit, '\n');
	    if (option_return_does_auto_indent) {
		edit_auto_indent (edit);
	    }
	}
	break;
    case CK_Return:
	edit_insert (edit, '\n');
	break;

    case CK_Page_Up:
    case CK_Page_Up_Highlight:
	edit_move_up (edit, edit->num_widget_lines - 1, 1);
	break;
    case CK_Page_Down:
    case CK_Page_Down_Highlight:
	edit_move_down (edit, edit->num_widget_lines - 1, 1);
	break;
    case CK_Left:
    case CK_Left_Highlight:
	if (option_fake_half_tabs) {
	    if (is_in_indent (edit) && right_of_four_spaces (edit)) {
		edit_cursor_move (edit, -HALF_TAB_SIZE);
		edit->force &= (0xFFF - REDRAW_CHAR_ONLY);
		break;
	    }
	}
	edit_cursor_move (edit, -1);
	break;
    case CK_Right:
    case CK_Right_Highlight:
	if (option_fake_half_tabs) {
	    if (is_in_indent (edit) && left_of_four_spaces (edit)) {
		edit_cursor_move (edit, HALF_TAB_SIZE);
		edit->force &= (0xFFF - REDRAW_CHAR_ONLY);
		break;
	    }
	}
	edit_cursor_move (edit, 1);
	break;
    case CK_Begin_Page:
    case CK_Begin_Page_Highlight:
	edit_begin_page (edit);
	break;
    case CK_End_Page:
    case CK_End_Page_Highlight:
	edit_end_page (edit);
	break;
    case CK_Word_Left:
    case CK_Word_Left_Highlight:
	edit_left_word_move_cmd (edit);
	break;
    case CK_Word_Right:
    case CK_Word_Right_Highlight:
	edit_right_word_move_cmd (edit);
	break;
    case CK_Up:
    case CK_Up_Highlight:
	edit_move_up (edit, 1, 0);
	break;
    case CK_Down:
    case CK_Down_Highlight:
	edit_move_down (edit, 1, 0);
	break;
    case CK_Paragraph_Up:
    case CK_Paragraph_Up_Highlight:
	edit_move_up_paragraph (edit, 0);
	break;
    case CK_Paragraph_Down:
    case CK_Paragraph_Down_Highlight:
	edit_move_down_paragraph (edit, 0);
	break;
    case CK_Scroll_Up:
    case CK_Scroll_Up_Highlight:
	edit_move_up (edit, 1, 1);
	break;
    case CK_Scroll_Down:
    case CK_Scroll_Down_Highlight:
	edit_move_down (edit, 1, 1);
	break;
    case CK_Home:
    case CK_Home_Highlight:
	edit_cursor_to_bol (edit);
	break;
    case CK_End:
    case CK_End_Highlight:
	edit_cursor_to_eol (edit);
	break;

    case CK_Tab:
	edit_tab_cmd (edit);
	if (option_auto_para_formatting) {
	    format_paragraph (edit, 0);
	    edit->force |= REDRAW_PAGE;
	} else
	    check_and_wrap_line (edit);
	break;

    case CK_Toggle_Insert:
	edit->overwrite = (edit->overwrite == 0);
	break;

    case CK_Mark:
	if (edit->mark2 >= 0) {
	    if (column_highlighting)
		edit_push_action (edit, COLUMN_ON);
	    column_highlighting = 0;
	}
	edit_mark_cmd (edit, 0);
	break;
    case CK_Column_Mark:
	if (!column_highlighting)
	    edit_push_action (edit, COLUMN_OFF);
	column_highlighting = 1;
	edit_mark_cmd (edit, 0);
	break;
    case CK_Unmark:
	if (column_highlighting)
	    edit_push_action (edit, COLUMN_ON);
	column_highlighting = 0;
	edit_mark_cmd (edit, 1);
	break;

    case CK_Toggle_Bookmark:
	book_mark_clear (edit, edit->curs_line, BOOK_MARK_FOUND_COLOR);
	if (book_mark_query_color (edit, edit->curs_line, BOOK_MARK_COLOR))
	    book_mark_clear (edit, edit->curs_line, BOOK_MARK_COLOR);
	else
	    book_mark_insert (edit, edit->curs_line, BOOK_MARK_COLOR);
	break;
    case CK_Flush_Bookmarks:
	book_mark_flush (edit, BOOK_MARK_COLOR);
	book_mark_flush (edit, BOOK_MARK_FOUND_COLOR);
	edit->force |= REDRAW_PAGE;
	break;
    case CK_Next_Bookmark:
	if (edit->book_mark) {
	    struct _book_mark *p;
	    p = (struct _book_mark *) book_mark_find (edit,
						      edit->curs_line);
	    if (p->next) {
		p = p->next;
		if (p->line >= edit->start_line + edit->num_widget_lines
		    || p->line < edit->start_line)
		    edit_move_display (edit,
				       p->line -
				       edit->num_widget_lines / 2);
		edit_move_to_line (edit, p->line);
	    }
	}
	break;
    case CK_Prev_Bookmark:
	if (edit->book_mark) {
	    struct _book_mark *p;
	    p = (struct _book_mark *) book_mark_find (edit,
						      edit->curs_line);
	    while (p->line == edit->curs_line)
		if (p->prev)
		    p = p->prev;
	    if (p->line >= 0) {
		if (p->line >= edit->start_line + edit->num_widget_lines
		    || p->line < edit->start_line)
		    edit_move_display (edit,
				       p->line -
				       edit->num_widget_lines / 2);
		edit_move_to_line (edit, p->line);
	    }
	}
	break;

    case CK_Beginning_Of_Text:
    case CK_Beginning_Of_Text_Highlight:
	edit_move_to_top (edit);
	break;
    case CK_End_Of_Text:
    case CK_End_Of_Text_Highlight:
	edit_move_to_bottom (edit);
	break;

    case CK_Copy:
	edit_block_copy_cmd (edit);
	break;
    case CK_Remove:
	edit_block_delete_cmd (edit);
	break;
    case CK_Move:
	edit_block_move_cmd (edit);
	break;

    case CK_XStore:
	edit_copy_to_X_buf_cmd (edit);
	break;
    case CK_XCut:
	edit_cut_to_X_buf_cmd (edit);
	break;
    case CK_XPaste:
	edit_paste_from_X_buf_cmd (edit);
	break;
    case CK_Selection_History:
	edit_paste_from_history (edit);
	break;

    case CK_Save_As:
	edit_save_as_cmd (edit);
	break;
    case CK_Save:
	edit_save_confirm_cmd (edit);
	break;
    case CK_Load:
	edit_load_cmd (edit);
	break;
    case CK_Save_Block:
	edit_save_block_cmd (edit);
	break;
    case CK_Insert_File:
	edit_insert_file_cmd (edit);
	break;

    case CK_Load_Prev_File:
	edit_load_back_cmd (edit);
	break;
    case CK_Load_Next_File:
	edit_load_forward_cmd (edit);
	break;

    case CK_Toggle_Syntax:
	if ((option_syntax_highlighting ^= 1) == 1)
	    edit_load_syntax (edit, NULL, option_syntax_type);
	edit->force |= REDRAW_PAGE;
	break;

    case CK_Find:
	edit_search_cmd (edit, 0);
	break;
    case CK_Find_Again:
	edit_search_cmd (edit, 1);
	break;
    case CK_Replace:
	edit_replace_cmd (edit, 0);
	break;
    case CK_Replace_Again:
	edit_replace_cmd (edit, 1);
	break;
    case CK_Complete_Word:
	edit_complete_word_cmd (edit);
	break;
    case CK_Find_Definition:
	edit_get_match_keyword_cmd (edit);
	break;

    case CK_Exit:
	dlg_stop (edit->widget.parent);
	break;
    case CK_New:
	edit_new_cmd (edit);
	break;

    case CK_Help:
	edit_help_cmd (edit);
	break;

    case CK_Refresh:
	edit_refresh_cmd (edit);
	break;

    case CK_Date:{
	    char s[1024];
	    /* fool gcc to prevent a Y2K warning */
	    char time_format[] = "_c";
	    time_format[0] = '%';

	    FMT_LOCALTIME_CURRENT(s, sizeof(s), time_format);
	    edit_print_string (edit, s);
	    edit->force |= REDRAW_PAGE;
	    break;
	}
    case CK_Goto:
	edit_goto_cmd (edit);
	break;
    case CK_Paragraph_Format:
	format_paragraph (edit, 1);
	edit->force |= REDRAW_PAGE;
	break;
    case CK_Delete_Macro:
	edit_delete_macro_cmd (edit);
	break;
    case CK_Match_Bracket:
	edit_goto_matching_bracket (edit);
	break;
    case CK_User_Menu:
	user_menu (edit);
	break;
    case CK_Sort:
	edit_sort_cmd (edit);
	break;
    case CK_ExtCmd:
	edit_ext_cmd (edit);
	break;
    case CK_Mail:
	edit_mail_dialog (edit);
	break;
    case CK_Shell:
	view_other_cmd ();
	break;
    case CK_Select_Codepage:
	edit_select_codepage_cmd (edit);
	break;
    case CK_Insert_Literal:
	edit_insert_literal_cmd (edit);
	break;
    case CK_Execute_Macro:
	edit_execute_macro_cmd (edit);
	break;
    case CK_Begin_End_Macro:
	edit_begin_end_macro_cmd (edit);
	break;
    case CK_Ext_Mode:
	edit->extmod = 1;
	break;
    default:
	break;
    }

    /* CK_Pipe_Block */
    if ((command / 1000) == 1)	/* a shell command */
	edit_block_process_cmd (edit, shell_cmd[command - 1000], 1);
    if (command > CK_Macro (0) && command <= CK_Last_Macro) {	/* a macro command */
	struct macro m[MAX_MACRO_LENGTH];
	int nm;
	if (edit_load_macro_cmd (edit, m, &nm, command - 2000))
	    edit_execute_macro (edit, m, nm);
    }

    /* keys which must set the col position, and the search vars */
    switch (command) {
    case CK_Find:
    case CK_Find_Again:
    case CK_Replace:
    case CK_Replace_Again:
    case CK_Complete_Word:
	edit->prev_col = edit_get_col (edit);
	break;
    case CK_Up:
    case CK_Up_Highlight:
    case CK_Down:
    case CK_Down_Highlight:
    case CK_Page_Up:
    case CK_Page_Up_Highlight:
    case CK_Page_Down:
    case CK_Page_Down_Highlight:
    case CK_Beginning_Of_Text:
    case CK_Beginning_Of_Text_Highlight:
    case CK_End_Of_Text:
    case CK_End_Of_Text_Highlight:
    case CK_Paragraph_Up:
    case CK_Paragraph_Up_Highlight:
    case CK_Paragraph_Down:
    case CK_Paragraph_Down_Highlight:
    case CK_Scroll_Up:
    case CK_Scroll_Up_Highlight:
    case CK_Scroll_Down:
    case CK_Scroll_Down_Highlight:
	edit->search_start = edit->curs1;
	edit->found_len = 0;
	break;
    default:
	edit->found_len = 0;
	edit->prev_col = edit_get_col (edit);
	edit->search_start = edit->curs1;
    }
    edit_find_bracket (edit);

    if (option_auto_para_formatting) {
	switch (command) {
	case CK_BackSpace:
	case CK_Delete:
	case CK_Delete_Word_Left:
	case CK_Delete_Word_Right:
	case CK_Delete_To_Line_End:
	case CK_Delete_To_Line_Begin:
	    format_paragraph (edit, 0);
	    edit->force |= REDRAW_PAGE;
	}
    }
}


static void
edit_execute_macro (WEdit *edit, struct macro macro[], int n)
{
    int i = 0;

    if (edit->macro_depth++ > 256) {
	edit_error_dialog (_("Error"), _("Macro recursion is too deep"));
	edit->macro_depth--;
	return;
    }
    edit->force |= REDRAW_PAGE;
    for (; i < n; i++) {
	edit_execute_cmd (edit, macro[i].command, macro[i].ch);
    }
    edit_update_screen (edit);
    edit->macro_depth--;
}

/* User edit menu, like user menu (F2) but only in editor. */
static void
user_menu (WEdit * edit)
{
    FILE *fd;
    int nomark;
    struct stat status;
    long start_mark, end_mark;
    char *block_file = concat_dir_and_file (home_dir, BLOCK_FILE);
    int rc = 0;

    nomark = eval_marks (edit, &start_mark, &end_mark);
    if (!nomark)		/* remember marked or not */
	edit_save_block (edit, block_file, start_mark, end_mark);

    /* run shell scripts from menu */
    user_menu_cmd (edit);

    if (mc_stat (block_file, &status) != 0 || !status.st_size) {
	/* no block messages */
	goto cleanup;
    }

    if (!nomark) {
	/* i.e. we have marked block */
	rc = edit_block_delete_cmd (edit);
    }

    if (!rc) {
	edit_insert_file (edit, block_file);
    }

    /* truncate block file */
    if ((fd = fopen (block_file, "w"))) {
	fclose (fd);
    }

    edit_refresh_cmd (edit);
    edit->force |= REDRAW_COMPLETELY;

cleanup:
    g_free (block_file);
}