src/hci/readline.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., 675 Mass Ave, Cambridge, MA 02139, USA.
  17  */
  18
  19 FILE_LICENCE ( GPL2_OR_LATER );
  20
  21 #include <stdio.h>
  22 #include <string.h>
  23 #include <stdlib.h>
  24 #include <console.h>
  25 #include <gpxe/keys.h>
  26 #include <gpxe/editstring.h>
  27 #include <readline/readline.h>
  28
  29 /** @file
  30  *
  31  * Minimal readline
  32  *
  33  */
  34
  35 #define READLINE_MAX 256
  36
  37 static void sync_console ( struct edit_string *string ) __nonnull;
  38
  39 /**
  40  * Synchronise console with edited string
  41  *
  42  * @v string            Editable string
  43  */
  44 static void sync_console ( struct edit_string *string ) {
  45         unsigned int mod_start = string->mod_start;
  46         unsigned int mod_end = string->mod_end;
  47         unsigned int cursor = string->last_cursor;
  48         size_t len = strlen ( string->buf );
  49
  50         /* Expand region back to old cursor position if applicable */
  51         if ( mod_start > string->last_cursor )
  52                 mod_start = string->last_cursor;
  53
  54         /* Expand region forward to new cursor position if applicable */
  55         if ( mod_end < string->cursor )
  56                 mod_end = string->cursor;
  57
  58         /* Backspace to start of region */
  59         while ( cursor > mod_start ) {
  60                 putchar ( '\b' );
  61                 cursor--;
  62         }
  63
  64         /* Print modified region */
  65         while ( cursor < mod_end ) {
  66                 putchar ( ( cursor >= len ) ? ' ' : string->buf[cursor] );
  67                 cursor++;
  68         }
  69
  70         /* Backspace to new cursor position */
  71         while ( cursor > string->cursor ) {
  72                 putchar ( '\b' );
  73                 cursor--;
  74         }
  75 }
  76
  77 /**
  78  * Read line from console
  79  *
  80  * @v prompt            Prompt string
  81  * @ret line            Line read from console (excluding terminating newline)
  82  *
  83  * The returned line is allocated with malloc(); the caller must
  84  * eventually call free() to release the storage.
  85  */
  86 char * readline ( const char *prompt ) {
  87         char buf[READLINE_MAX];
  88         struct edit_string string;
  89         int key;
  90         char *line;
  91
  92         if ( prompt )
  93                 printf ( "%s", prompt );
  94
  95         memset ( &string, 0, sizeof ( string ) );
  96         string.buf = buf;
  97         string.len = sizeof ( buf );
  98         buf[0] = '\0';
  99
 100         while ( 1 ) {
 101                 key = edit_string ( &string, getkey() );
 102                 sync_console ( &string );
 103                 switch ( key ) {
 104                 case CR:
 105                 case LF:
 106                         putchar ( '\n' );
 107                         line = strdup ( buf );
 108                         if ( ! line )
 109                                 printf ( "Out of memory\n" );
 110                         return line;
 111                 case CTRL_C:
 112                         putchar ( '\n' );
 113                         return NULL;
 114                 default:
 115                         /* Do nothing */
 116                         break;
 117                 }
 118         }
 119 }