Cleanup by moving various (mostly horrible) little bits handling UTF-8 grid

data into functions in a new file, grid-utf8.c, and use sizeof intead of
UTF8_DATA.

Also nuke trailing whitespace from tmux.1, reminded by jmc.

grid-utf8.c

@@ -0,0 +1,96 @@
+/* $OpenBSD$ */
+
+/*
+ * Copyright (c) 2009 Nicholas Marriott <nicm@users.sourceforge.net>
+ *
+ * Permission to use, copy, modify, and distribute this software for any
+ * purpose with or without fee is hereby granted, provided that the above
+ * copyright notice and this permission notice appear in all copies.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
+ * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
+ * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
+ * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
+ * WHATSOEVER RESULTING FROM LOSS OF MIND, USE, DATA OR PROFITS, WHETHER
+ * IN AN ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING
+ * OUT OF OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
+ */
+
+#include <sys/types.h>
+
+#include <string.h>
+
+#include "tmux.h"
+
+/*
+ * Grid UTF-8 utility functions.
+ */
+
+/* Calculate UTF-8 grid cell size. Data is terminated by 0xff. */
+size_t
+grid_utf8_size(const struct grid_utf8 *gu)
+{
+	size_t	size;
+
+	for (size = 0; size < sizeof gu->data; size++) {
+		if (gu->data[size] == 0xff)
+			break;
+	}
+	return (size);
+}
+
+/* Copy UTF-8 out into a buffer. */
+size_t
+grid_utf8_copy(const struct grid_utf8 *gu, char *buf, size_t len)
+{
+	size_t	size;
+
+	size = grid_utf8_size(gu);
+	if (size > len)
+		fatalx("UTF-8 copy overflow");
+	memcpy(buf, gu->data, size);
+	return (size);
+}
+
+/* Set UTF-8 grid data from input UTF-8. */
+void
+grid_utf8_set(struct grid_utf8 *gu, const struct utf8_data *utf8data)
+{
+	if (utf8data->size == 0)
+		fatalx("UTF-8 data empty");
+	if (utf8data->size > sizeof gu->data)
+		fatalx("UTF-8 data too long");
+	memcpy(gu->data, utf8data->data, utf8data->size);
+	if (utf8data->size != sizeof gu->data)
+		gu->data[utf8data->size] = 0xff;
+	gu->width = utf8data->width;
+}
+
+/* Append UTF-8 character onto the cell data (for combined characters). */
+int
+grid_utf8_append(struct grid_utf8 *gu, const struct utf8_data *utf8data)
+{
+	size_t	old_size;
+
+	old_size = grid_utf8_size(gu);
+	if (old_size + utf8data->size > sizeof gu->data)
+		return (-1);
+	memcpy(gu->data + old_size, utf8data->data, utf8data->size);
+	if (old_size + utf8data->size != sizeof gu->data)
+		gu->data[old_size + utf8data->size] = 0xff;
+	return (0);
+}
+
+/* Compare two UTF-8 cells. */
+int
+grid_utf8_compare(const struct grid_utf8 *gu1, const struct grid_utf8 *gu2)
+{
+	size_t	size;
+
+	size = grid_utf8_size(gu1);
+	if (size != grid_utf8_size(gu2))
+		return (0);
+	if (memcmp(gu1->data, gu2->data, size) != 0)
+		return (0);
+	return (1);	
+}