src/hci/editstring.c

   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., 51 Franklin Street, Fifth Floor, Boston, MA
  17  * 02110-1301, USA.
  18  *
  19  * You can also choose to distribute this program under the terms of
  20  * the Unmodified Binary Distribution Licence (as given in the file
  21  * COPYING.UBDL), provided that you have satisfied its requirements.
  22  */
  23
  24 FILE_LICENCE ( GPL2_OR_LATER_OR_UBDL );
  25
  26 #include <assert.h>
  27 #include <string.h>
  28 #include <ctype.h>
  29 #include <ipxe/keys.h>
  30 #include <ipxe/editstring.h>
  31
  32 /** @file
  33  *
  34  * Editable strings
  35  *
  36  */
  37
  38 static void insert_delete ( struct edit_string *string, size_t delete_len,
  39                             const char *insert_text )
  40                             __attribute__ (( nonnull (1) ));
  41 static void insert_character ( struct edit_string *string,
  42                                unsigned int character ) __nonnull;
  43 static void delete_character ( struct edit_string *string ) __nonnull;
  44 static void backspace ( struct edit_string *string ) __nonnull;
  45 static void previous_word ( struct edit_string *string ) __nonnull;
  46 static void kill_word ( struct edit_string *string ) __nonnull;
  47 static void kill_sol ( struct edit_string *string ) __nonnull;
  48 static void kill_eol ( struct edit_string *string ) __nonnull;
  49
  50 /**
  51  * Insert and/or delete text within an editable string
  52  *
  53  * @v string            Editable string
  54  * @v delete_len        Length of text to delete from current cursor position
  55  * @v insert_text       Text to insert at current cursor position, or NULL
  56  */
  57 static void insert_delete ( struct edit_string *string, size_t delete_len,
  58                             const char *insert_text ) {
  59         size_t old_len, max_delete_len, insert_len, max_insert_len, new_len;
  60
  61         /* Calculate lengths */
  62         old_len = strlen ( string->buf );
  63         assert ( string->cursor <= old_len );
  64         max_delete_len = ( old_len - string->cursor );
  65         if ( delete_len > max_delete_len )
  66                 delete_len = max_delete_len;
  67         insert_len = ( insert_text ? strlen ( insert_text ) : 0 );
  68         max_insert_len = ( ( string->len - 1 ) - ( old_len - delete_len ) );
  69         if ( insert_len > max_insert_len )
  70                 insert_len = max_insert_len;
  71         new_len = ( old_len - delete_len + insert_len );
  72
  73         /* Fill in edit history */
  74         string->mod_start = string->cursor;
  75         string->mod_end = ( ( new_len > old_len ) ? new_len : old_len );
  76
  77         /* Move data following the cursor */
  78         memmove ( ( string->buf + string->cursor + insert_len ),
  79                   ( string->buf + string->cursor + delete_len ),
  80                   ( max_delete_len + 1 - delete_len ) );
  81
  82         /* Copy inserted text to cursor position */
  83         memcpy ( ( string->buf + string->cursor ), insert_text, insert_len );
  84         string->cursor += insert_len;
  85 }
  86
  87 /**
  88  * Insert character at current cursor position
  89  *
  90  * @v string            Editable string
  91  * @v character         Character to insert
  92  */
  93 static void insert_character ( struct edit_string *string,
  94                               unsigned int character ) {
  95         char insert_text[2] = { character, '\0' };
  96         insert_delete ( string, 0, insert_text );
  97 }
  98
  99 /**
 100  * Delete character at current cursor position
 101  *
 102  * @v string            Editable string
 103  */
 104 static void delete_character ( struct edit_string *string ) {
 105         insert_delete ( string, 1, NULL );
 106 }
 107
 108 /**
 109  * Delete character to left of current cursor position
 110  *
 111  * @v string            Editable string
 112  */
 113 static void backspace ( struct edit_string *string ) {
 114         if ( string->cursor > 0 ) {
 115                 string->cursor--;
 116                 delete_character ( string );
 117         }
 118 }
 119
 120 /**
 121  * Move to start of previous word
 122  *
 123  * @v string            Editable string
 124  */
 125 static void previous_word ( struct edit_string *string ) {
 126         while ( string->cursor &&
 127                 isspace ( string->buf[ string->cursor - 1 ] ) ) {
 128                 string->cursor--;
 129         }
 130         while ( string->cursor &&
 131                 ( ! isspace ( string->buf[ string->cursor - 1 ] ) ) ) {
 132                 string->cursor--;
 133         }
 134 }
 135
 136 /**
 137  * Delete to end of previous word
 138  *
 139  * @v string            Editable string
 140  */
 141 static void kill_word ( struct edit_string *string ) {
 142         size_t old_cursor = string->cursor;
 143         previous_word ( string );
 144         insert_delete ( string, ( old_cursor - string->cursor ), NULL );
 145 }
 146
 147 /**
 148  * Delete to start of line
 149  *
 150  * @v string            Editable string
 151  */
 152 static void kill_sol ( struct edit_string *string ) {
 153         size_t old_cursor = string->cursor;
 154         string->cursor = 0;
 155         insert_delete ( string, old_cursor, NULL );
 156 }
 157
 158 /**
 159  * Delete to end of line
 160  *
 161  * @v string            Editable string
 162  */
 163 static void kill_eol ( struct edit_string *string ) {
 164         insert_delete ( string, ~( ( size_t ) 0 ), NULL );
 165 }
 166
 167 /**
 168  * Replace editable string
 169  *
 170  * @v string            Editable string
 171  * @v replacement       Replacement string
 172  */
 173 void replace_string ( struct edit_string *string, const char *replacement ) {
 174         string->cursor = 0;
 175         insert_delete ( string, ~( ( size_t ) 0 ), replacement );
 176 }
 177
 178 /**
 179  * Edit editable string
 180  *
 181  * @v string            Editable string
 182  * @v key               Key pressed by user
 183  * @ret key             Key returned to application, or zero
 184  *
 185  * Handles keypresses and updates the content of the editable string.
 186  * Basic line editing facilities (delete/insert/cursor) are supported.
 187  * If edit_string() understands and uses the keypress it will return
 188  * zero, otherwise it will return the original key.
 189  *
 190  * This function does not update the display in any way.
 191  *
 192  * The string's edit history will be updated to allow the caller to
 193  * efficiently bring the display into sync with the string content.
 194  */
 195 int edit_string ( struct edit_string *string, int key ) {
 196         int retval = 0;
 197         size_t len = strlen ( string->buf );
 198
 199         /* Prepare edit history */
 200         string->last_cursor = string->cursor;
 201         string->mod_start = string->cursor;
 202         string->mod_end = string->cursor;
 203
 204         /* Interpret key */
 205         if ( ( key >= 0x20 ) && ( key <= 0x7e ) ) {
 206                 /* Printable character; insert at current position */
 207                 insert_character ( string, key );
 208         } else switch ( key ) {
 209         case KEY_BACKSPACE:
 210                 /* Backspace */
 211                 backspace ( string );
 212                 break;
 213         case KEY_DC:
 214         case CTRL_D:
 215                 /* Delete character */
 216                 delete_character ( string );
 217                 break;
 218         case CTRL_W:
 219                 /* Delete word */
 220                 kill_word ( string );
 221                 break;
 222         case CTRL_U:
 223                 /* Delete to start of line */
 224                 kill_sol ( string );
 225                 break;
 226         case CTRL_K:
 227                 /* Delete to end of line */
 228                 kill_eol ( string );
 229                 break;
 230         case KEY_HOME:
 231         case CTRL_A:
 232                 /* Start of line */
 233                 string->cursor = 0;
 234                 break;
 235         case KEY_END:
 236         case CTRL_E:
 237                 /* End of line */
 238                 string->cursor = len;
 239                 break;
 240         case KEY_LEFT:
 241         case CTRL_B:
 242                 /* Cursor left */
 243                 if ( string->cursor > 0 )
 244                         string->cursor--;
 245                 break;
 246         case KEY_RIGHT:
 247         case CTRL_F:
 248                 /* Cursor right */
 249                 if ( string->cursor < len )
 250                         string->cursor++;
 251                 break;
 252         default:
 253                 retval = key;
 254                 break;
 255         }
 256
 257         return retval;
 258 }