[syslog] Separate out generic line-based console functionality

Abstract out the generic line-handling portions of the syslog
putchar() routine, to allow use by other console types.

Signed-off-by: Michael Brown <mcb30@ipxe.org>

src/core/lineconsole.c

@@ -0,0 +1,76 @@
+/*
+ * Copyright (C) 2012 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.
+ */
+
+FILE_LICENCE ( GPL2_OR_LATER );
+
+/** @file
+ *
+ * Line-based console
+ *
+ */
+
+#include <stdint.h>
+#include <stddef.h>
+#include <ipxe/ansiesc.h>
+#include <ipxe/lineconsole.h>
+
+/** Line-based console ANSI escape sequence handlers */
+static struct ansiesc_handler line_ansiesc_handlers[] = {
+	{ 0, NULL }
+};
+
+/** Line-based console ANSI escape sequence context */
+static struct ansiesc_context line_ansiesc_ctx = {
+	.handlers = line_ansiesc_handlers,
+};
+
+/**
+ * Print a character to a line-based console
+ *
+ * @v character		Character to be printed
+ * @ret print		Print line
+ */
+size_t line_putchar ( struct line_console *line, int character ) {
+
+	/* Strip ANSI escape sequences */
+	character = ansiesc_process ( &line_ansiesc_ctx, character );
+	if ( character < 0 )
+		return 0;
+
+	/* Ignore carriage return */
+	if ( character == '\r' )
+		return 0;
+
+	/* Treat newline as a terminator */
+	if ( character == '\n' )
+		character = 0;
+
+	/* Add character to buffer */
+	line->buffer[line->index++] = character;
+
+	/* Do nothing more unless we reach end-of-line (or end-of-buffer) */
+	if ( ( character != 0 ) &&
+	     ( line->index < ( line->len - 1 /* NUL */ ) ) ) {
+		return 0;
+	}
+
+	/* Reset to start of buffer */
+	line->index = 0;
+
+	return 1;
+}