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/*
* Copyright (C) 2006 Michael Brown <mbrown@fensystems.co.uk>.
*
* 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 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., 675 Mass Ave, Cambridge, MA 02139, USA.
*/
#include <assert.h>
#include <string.h>
#include <gpxe/editstring.h>
/** @file
*
* Editable strings
*
*/
/**
* Insert and/or delete text within an editable string
*
* @v string Editable string
* @v delete_len Length of text to delete from current cursor position
* @v insert_text Text to insert at current cursor position, or NULL
*/
static void insert_delete ( struct edit_string *string, size_t delete_len,
const char *insert_text ) {
size_t old_len, max_delete_len, insert_len, max_insert_len;
/* Calculate lengths */
old_len = strlen ( string->buf );
assert ( string->cursor <= old_len );
max_delete_len = ( old_len - string->cursor );
if ( delete_len > max_delete_len )
delete_len = max_delete_len;
insert_len = ( insert_text ? strlen ( insert_text ) : 0 );
max_insert_len = ( ( string->len - 1 ) - ( old_len - delete_len ) );
if ( insert_len > max_insert_len )
insert_len = max_insert_len;
/* Move data following the cursor */
memmove ( ( string->buf + string->cursor + insert_len ),
( string->buf + string->cursor + delete_len ),
( max_delete_len + 1 - delete_len ) );
/* Copy inserted text to cursor position */
memcpy ( ( string->buf + string->cursor ), insert_text, insert_len );
string->cursor += insert_len;
}
/**
* Insert character at current cursor position
*
* @v string Editable string
* @v character Character to insert
*/
static void insert_character ( struct edit_string *string,
unsigned int character ) {
char insert_text[2] = { character, '\0' };
insert_delete ( string, 0, insert_text );
}
/**
* Delete character at current cursor position
*
* @v string Editable string
*/
static void delete_character ( struct edit_string *string ) {
insert_delete ( string, 1, NULL );
}
/**
* Delete character to left of current cursor position
*
* @v string Editable string
*/
static void backspace ( struct edit_string *string ) {
if ( string->cursor > 0 ) {
string->cursor--;
delete_character ( string );
}
}
/**
* Delete to end of line
*
* @v string Editable string
*/
static void kill_eol ( struct edit_string *string ) {
insert_delete ( string, ~( ( size_t ) 0 ), NULL );
}
/**
* Edit editable string
*
* @v string Editable string
* @v key Key pressed by user
* @ret key Key returned to application, or zero
*
* Handles keypresses and updates the content of the editable string.
* Basic line editing facilities (delete/insert/cursor) are supported.
* If edit_string() understands and uses the keypress it will return
* zero, otherwise it will return the original key.
*
* This function does not update the display in any way.
*/
int edit_string ( struct edit_string *string, int key ) {
int retval = 0;
if ( ( key >= 0x20 ) && ( key <= 0x7e ) ) {
/* Printable character; insert at current position */
insert_character ( string, key );
} else switch ( key ) {
case 0x08: /* Ctrl-H */
/* Backspace */
backspace ( string );
break;
case 0x04: /* Ctrl-D */
/* Delete character */
delete_character ( string );
break;
case 0x0b: /* Ctrl-K */
kill_eol ( string );
break;
case 0x01: /* Ctrl-A */
/* Start of line */
string->cursor = 0;
break;
case 0x05: /* Ctrl-E */
/* End of line */
string->cursor = strlen ( string->buf );
break;
case 0x02: /* Ctrl-B */
/* Cursor left */
if ( string->cursor > 0 )
string->cursor--;
break;
case 0x06: /* Ctrl-F */
/* Cursor right */
if ( string->cursor < ( string->len - 1 ) )
string->cursor++;
break;
default:
retval = key;
break;
}
return retval;
}
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