1 files changed, 79 insertions, 0 deletions
diff --git a/lib/encode.c b/lib/encode.c
new file mode 100644
index 0000000..10b5971
--- /dev/null
+++ b/lib/encode.c
@@ -0,0 +1,79 @@
+/*
+ * Based on code from libblkid,
+ *
+ * Copyright (C) 2008 Kay Sievers <kay.sievers@vrfy.org>
+ * Copyright (C) 2009 Karel Zak <kzak@redhat.com>
+ * Copyright (C) 2020 Pali Rohár <pali.rohar@gmail.com>
+ *
+ * This file may be redistributed under the terms of the
+ * GNU Lesser General Public License.
+ */
+#include "c.h"
+#include "encode.h"
+
+size_t ul_encode_to_utf8(int enc, unsigned char *dest, size_t len,
+			const unsigned char *src, size_t count)
+{
+	size_t i, j;
+	uint32_t c;
+	uint16_t c2;
+
+	for (j = i = 0; i < count; i++) {
+		if (enc == UL_ENCODE_UTF16LE) {
+			if (i+2 > count)
+				break;
+			c = (src[i+1] << 8) | src[i];
+			i++;
+		} else if (enc == UL_ENCODE_UTF16BE) {
+			if (i+2 > count)
+				break;
+			c = (src[i] << 8) | src[i+1];
+			i++;
+		} else if (enc == UL_ENCODE_LATIN1) {
+			c = src[i];
+		} else {
+			return 0;
+		}
+		if ((enc == UL_ENCODE_UTF16LE || enc == UL_ENCODE_UTF16BE) &&
+		    c >= 0xD800 && c <= 0xDBFF && i+2 < count) {
+			if (enc == UL_ENCODE_UTF16LE)
+				c2 = (src[i+2] << 8) | src[i+1];
+			else
+				c2 = (src[i+1] << 8) | src[i+2];
+			if (c2 >= 0xDC00 && c2 <= 0xDFFF) {
+				c = 0x10000 + ((c - 0xD800) << 10) + (c2 - 0xDC00);
+				i += 2;
+			}
+		}
+		if (c == 0) {
+			dest[j] = '\0';
+			break;
+		}
+
+		if (c < 0x80) {
+			if (j+1 >= len)
+				break;
+			dest[j++] = (uint8_t) c;
+		} else if (c < 0x800) {
+			if (j+2 >= len)
+				break;
+			dest[j++] = (uint8_t) (0xc0 | (c >> 6));
+			dest[j++] = (uint8_t) (0x80 | (c & 0x3f));
+		} else if (c < 0x10000) {
+			if (j+3 >= len)
+				break;
+			dest[j++] = (uint8_t) (0xe0 | (c >> 12));
+			dest[j++] = (uint8_t) (0x80 | ((c >> 6) & 0x3f));
+			dest[j++] = (uint8_t) (0x80 | (c & 0x3f));
+		} else {
+			if (j+4 >= len)
+				break;
+			dest[j++] = (uint8_t) (0xf0 | (c >> 18));
+			dest[j++] = (uint8_t) (0x80 | ((c >> 12) & 0x3f));
+			dest[j++] = (uint8_t) (0x80 | ((c >> 6) & 0x3f));
+			dest[j++] = (uint8_t) (0x80 | (c & 0x3f));
+		}
+	}
+	dest[j] = '\0';
+	return j;
+}