Start of generic editable string support

1 files changed, 159 insertions, 0 deletions

diff --git a/src/hci/editstring.c b/src/hci/editstring.c
new file mode 100644
index 000000000..a17b57619
--- /dev/null
+++ b/src/hci/editstring.c
@@ -0,0 +1,159 @@
+/*
+ * 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;
+}