1 files changed, 25 insertions, 0 deletions
diff --git a/lib/mbstring/u8tor.c b/lib/mbstring/u8tor.c
new file mode 100644
index 0000000..85c4c19
--- /dev/null
+++ b/lib/mbstring/u8tor.c
@@ -0,0 +1,25 @@
+#include "mbstring.h"
+#include "rune.h"
+
+int
+u8tor(rune *ch, const char8_t *s)
+{
+	if (U8_BYTE_1(s[0])) {
+		*ch = s[0];
+		return 1;
+	} else if (U8_BYTE_2(s[0]) && U8_BYTE_C(s[1])) {
+		*ch = ((s[0] & 0x1F) << 6) | (s[1] & 0x3F);
+		return 2;
+	} else if (U8_BYTE_3(s[0]) && U8_BYTE_C(s[1]) && U8_BYTE_C(s[2])) {
+		*ch = ((s[0] & 0x0F) << 12) | ((s[1] & 0x3F) << 6) | (s[2] & 0x3F);
+		return 3;
+	} else if (U8_BYTE_4(s[0]) && U8_BYTE_C(s[1]) && U8_BYTE_C(s[2])
+				&& U8_BYTE_C(s[3])) {
+		*ch = ((s[0] & 0x07) << 18) | ((s[1] & 0x3F) << 12)
+		    | ((s[2] & 0x3F) << 6) | (s[3] & 0x3F);
+		return 4;
+	}
+
+	*ch = RUNE_ERROR;
+	return 1;
+}