1 /*
2 * Copyright (C) 2006 Michael Brown <mbrown@fensystems.co.uk>.
3 *
4 * This program is free software; you can redistribute it and/or
5 * modify it under the terms of the GNU General Public License as
6 * published by the Free Software Foundation; either version 2 of the
7 * License, or any later version.
8 *
9 * This program is distributed in the hope that it will be useful, but
10 * WITHOUT ANY WARRANTY; without even the implied warranty of
11 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
12 * General Public License for more details.
13 *
14 * You should have received a copy of the GNU General Public License
15 * along with this program; if not, write to the Free Software
16 * Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
17 */
18
19 FILE_LICENCE ( GPL2_OR_LATER );
20
21 #include <assert.h>
22 #include <string.h>
23 #include <gpxe/keys.h>
24 #include <gpxe/editstring.h>
25
26 /** @file
27 *
28 * Editable strings
29 *
30 */
31
32 static void insert_delete ( struct edit_string *string, size_t delete_len,
33 const char *insert_text )
34 __attribute__ (( nonnull (1) ));
35 static void insert_character ( struct edit_string *string,
36 unsigned int character ) __nonnull;
37 static void delete_character ( struct edit_string *string ) __nonnull;
38 static void backspace ( struct edit_string *string ) __nonnull;
39 static void kill_eol ( struct edit_string *string ) __nonnull;
40
41 /**
42 * Insert and/or delete text within an editable string
43 *
44 * @v string Editable string
45 * @v delete_len Length of text to delete from current cursor position
46 * @v insert_text Text to insert at current cursor position, or NULL
47 */
insert_delete(struct edit_string * string,size_t delete_len,const char * insert_text)48 static void insert_delete ( struct edit_string *string, size_t delete_len,
49 const char *insert_text ) {
50 size_t old_len, max_delete_len, insert_len, max_insert_len, new_len;
51
52 /* Calculate lengths */
53 old_len = strlen ( string->buf );
54 assert ( string->cursor <= old_len );
55 max_delete_len = ( old_len - string->cursor );
56 if ( delete_len > max_delete_len )
57 delete_len = max_delete_len;
58 insert_len = ( insert_text ? strlen ( insert_text ) : 0 );
59 max_insert_len = ( ( string->len - 1 ) - ( old_len - delete_len ) );
60 if ( insert_len > max_insert_len )
61 insert_len = max_insert_len;
62 new_len = ( old_len - delete_len + insert_len );
63
64 /* Fill in edit history */
65 string->mod_start = string->cursor;
66 string->mod_end = ( ( new_len > old_len ) ? new_len : old_len );
67
68 /* Move data following the cursor */
69 memmove ( ( string->buf + string->cursor + insert_len ),
70 ( string->buf + string->cursor + delete_len ),
71 ( max_delete_len + 1 - delete_len ) );
72
73 /* Copy inserted text to cursor position */
74 memcpy ( ( string->buf + string->cursor ), insert_text, insert_len );
75 string->cursor += insert_len;
76 }
77
78 /**
79 * Insert character at current cursor position
80 *
81 * @v string Editable string
82 * @v character Character to insert
83 */
insert_character(struct edit_string * string,unsigned int character)84 static void insert_character ( struct edit_string *string,
85 unsigned int character ) {
86 char insert_text[2] = { character, '\0' };
87 insert_delete ( string, 0, insert_text );
88 }
89
90 /**
91 * Delete character at current cursor position
92 *
93 * @v string Editable string
94 */
delete_character(struct edit_string * string)95 static void delete_character ( struct edit_string *string ) {
96 insert_delete ( string, 1, NULL );
97 }
98
99 /**
100 * Delete character to left of current cursor position
101 *
102 * @v string Editable string
103 */
backspace(struct edit_string * string)104 static void backspace ( struct edit_string *string ) {
105 if ( string->cursor > 0 ) {
106 string->cursor--;
107 delete_character ( string );
108 }
109 }
110
111 /**
112 * Delete to end of line
113 *
114 * @v string Editable string
115 */
kill_eol(struct edit_string * string)116 static void kill_eol ( struct edit_string *string ) {
117 insert_delete ( string, ~( ( size_t ) 0 ), NULL );
118 }
119
120 /**
121 * Edit editable string
122 *
123 * @v string Editable string
124 * @v key Key pressed by user
125 * @ret key Key returned to application, or zero
126 *
127 * Handles keypresses and updates the content of the editable string.
128 * Basic line editing facilities (delete/insert/cursor) are supported.
129 * If edit_string() understands and uses the keypress it will return
130 * zero, otherwise it will return the original key.
131 *
132 * This function does not update the display in any way.
133 *
134 * The string's edit history will be updated to allow the caller to
135 * efficiently bring the display into sync with the string content.
136 */
edit_string(struct edit_string * string,int key)137 int edit_string ( struct edit_string *string, int key ) {
138 int retval = 0;
139 size_t len = strlen ( string->buf );
140
141 /* Prepare edit history */
142 string->last_cursor = string->cursor;
143 string->mod_start = string->cursor;
144 string->mod_end = string->cursor;
145
146 /* Interpret key */
147 if ( ( key >= 0x20 ) && ( key <= 0x7e ) ) {
148 /* Printable character; insert at current position */
149 insert_character ( string, key );
150 } else switch ( key ) {
151 case KEY_BACKSPACE:
152 /* Backspace */
153 backspace ( string );
154 break;
155 case KEY_DC:
156 case CTRL_D:
157 /* Delete character */
158 delete_character ( string );
159 break;
160 case CTRL_K:
161 /* Delete to end of line */
162 kill_eol ( string );
163 break;
164 case KEY_HOME:
165 case CTRL_A:
166 /* Start of line */
167 string->cursor = 0;
168 break;
169 case KEY_END:
170 case CTRL_E:
171 /* End of line */
172 string->cursor = len;
173 break;
174 case KEY_LEFT:
175 case CTRL_B:
176 /* Cursor left */
177 if ( string->cursor > 0 )
178 string->cursor--;
179 break;
180 case KEY_RIGHT:
181 case CTRL_F:
182 /* Cursor right */
183 if ( string->cursor < len )
184 string->cursor++;
185 break;
186 default:
187 retval = key;
188 break;
189 }
190
191 return retval;
192 }
193