From 5560a99873b1a77021e4050c0aac7e8277e0e329 Mon Sep 17 00:00:00 2001
From: Max Kellermann <max@duempel.org>
Date: Tue, 20 Oct 2009 08:00:09 +0200
Subject: [PATCH] charset: added function utf8_cut_width()

This function helps printing UTF-8 strings on limited screen space.
---
 src/charset.c | 62 +++++++++++++++++++++++++++++++++++++++++++++++++++
 src/charset.h |  9 ++++++++
 2 files changed, 71 insertions(+)

diff --git a/src/charset.c b/src/charset.c
index 59d1a26..8e7ed0f 100644
--- a/src/charset.c
+++ b/src/charset.c
@@ -62,6 +62,68 @@ utf8_width(const char *str)
 #endif
 }
 
+static inline unsigned
+ascii_cut_width(char *p, unsigned max_width)
+{
+	size_t length = strlen(p);
+	if (length <= (size_t)max_width)
+		return (unsigned)length;
+
+	p[max_width] = 0;
+	return max_width;
+}
+
+static inline unsigned
+narrow_cut_width(char *p, unsigned max_width)
+{
+	size_t length = g_utf8_strlen(p, -1);
+	if (length <= (size_t)max_width)
+		return (unsigned)length;
+
+	*g_utf8_offset_to_pointer(p, max_width) = 0;
+	return max_width;
+}
+
+static inline unsigned
+wide_cut_width(char *p, unsigned max_width)
+{
+	size_t length = g_utf8_strlen(p, -1);
+	unsigned width = 0, prev_width;
+	gunichar c;
+
+	while (length-- > 0) {
+		c = g_utf8_get_char(p);
+		prev_width = width;
+		width += g_unichar_iswide(c) ? 2 : 1;
+		if (width > max_width) {
+			/* too wide - cut the rest off */
+			*p = 0;
+			return prev_width;
+		}
+
+		p += g_unichar_to_utf8(c, NULL);
+	}
+
+	return width;
+}
+
+unsigned
+utf8_cut_width(char *p, unsigned max_width)
+{
+	assert(p != NULL);
+
+#ifdef ENABLE_WIDE
+	if (!g_utf8_validate(p, -1, NULL))
+		return ascii_cut_width(p, max_width);
+
+	return wide_cut_width(p, max_width);
+#elif defined(ENABLE_MULTIBYTE) && !defined(ENABLE_WIDE)
+	return narrow_cut_width(p, max_width);
+#else
+	return ascii_cut_width(p, max_width);
+#endif
+}
+
 char *
 utf8_to_locale(const char *utf8str)
 {
diff --git a/src/charset.h b/src/charset.h
index a08054b..e64eb19 100644
--- a/src/charset.h
+++ b/src/charset.h
@@ -38,6 +38,15 @@ G_GNUC_PURE
 unsigned
 utf8_width(const char *str);
 
+/**
+ * Limits the width of the specified string.  Cuts it off before the
+ * specified width is exceeded.
+ *
+ * @return the resulting width of the string
+ */
+unsigned
+utf8_cut_width(char *p, unsigned max_width);
+
 char *utf8_to_locale(const char *str);
 char *locale_to_utf8(const char *str);
 
-- 
2.30.2