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Start of generic editable string support
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Michael Brown
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Dec 19, 2006
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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. | ||
*/ | ||
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#include <assert.h> | ||
#include <string.h> | ||
#include <gpxe/editstring.h> | ||
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/** @file | ||
* | ||
* Editable strings | ||
* | ||
*/ | ||
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/** | ||
* 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; | ||
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/* 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; | ||
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/* Move data following the cursor */ | ||
memmove ( ( string->buf + string->cursor + insert_len ), | ||
( string->buf + string->cursor + delete_len ), | ||
( max_delete_len + 1 - delete_len ) ); | ||
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/* Copy inserted text to cursor position */ | ||
memcpy ( ( string->buf + string->cursor ), insert_text, insert_len ); | ||
string->cursor += insert_len; | ||
} | ||
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/** | ||
* 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 ); | ||
} | ||
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/** | ||
* Delete character at current cursor position | ||
* | ||
* @v string Editable string | ||
*/ | ||
static void delete_character ( struct edit_string *string ) { | ||
insert_delete ( string, 1, NULL ); | ||
} | ||
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/** | ||
* 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 ); | ||
} | ||
} | ||
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/** | ||
* Delete to end of line | ||
* | ||
* @v string Editable string | ||
*/ | ||
static void kill_eol ( struct edit_string *string ) { | ||
insert_delete ( string, ~( ( size_t ) 0 ), NULL ); | ||
} | ||
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/** | ||
* 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; | ||
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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; | ||
} | ||
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return retval; | ||
} |
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#ifndef _EDITSTRING_H | ||
#define _EDITSTRING_H | ||
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/** @file | ||
* | ||
* Editable strings | ||
* | ||
*/ | ||
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/** An editable string */ | ||
struct edit_string { | ||
/** Buffer for string */ | ||
char *buf; | ||
/** Size of buffer (including terminating NUL) */ | ||
size_t len; | ||
/** Cursor position */ | ||
unsigned int cursor; | ||
}; | ||
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extern int edit_string ( struct edit_string *string, int key ); | ||
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#endif /* _EDITSTRING_H */ |