1 files changed, 86 insertions, 0 deletions
diff --git a/testing/web-platform/tests/encoding/legacy-mb-tchinese/big5/big5-decoder.js b/testing/web-platform/tests/encoding/legacy-mb-tchinese/big5/big5-decoder.js
new file mode 100644
index 0000000000..2fad1ab2c6
--- /dev/null
+++ b/testing/web-platform/tests/encoding/legacy-mb-tchinese/big5/big5-decoder.js
@@ -0,0 +1,86 @@
+function dec2char(n) {
+	// converts a decimal number to a Unicode character
+	// n: the dec codepoint value to be converted
+	if (n <= 0xffff) {
+		out = String.fromCharCode(n);
+	} else if (n <= 0x10ffff) {
+		n -= 0x10000;
+		out =
+			String.fromCharCode(0xd800 | (n >> 10)) +
+			String.fromCharCode(0xdc00 | (n & 0x3ff));
+	} else out = "dec2char error: Code point out of range: " + n;
+	return out;
+}
+
+function big5Decoder(stream) {
+	stream = stream.replace(/%/g, " ");
+	stream = stream.replace(/[\s]+/g, " ").trim();
+	var bytes = stream.split(" ");
+	for (var i = 0; i < bytes.length; i++) bytes[i] = parseInt(bytes[i], 16);
+	var out = "";
+	var lead, byte, offset, ptr, cp;
+	var big5lead = 0x00;
+	var endofstream = 2000000;
+	var finished = false;
+
+	while (!finished) {
+		if (bytes.length == 0) byte = endofstream;
+		else byte = bytes.shift();
+
+		if (byte == endofstream && big5lead != 0x00) {
+			big5lead = 0x00;
+			out += "�";
+			continue;
+		}
+		if (byte == endofstream && big5lead == 0x00) {
+			finished = true;
+			continue;
+		}
+
+		if (big5lead != 0x00) {
+			lead = big5lead;
+			ptr = null;
+			big5lead = 0x00;
+			if (byte < 0x7f) offset = 0x40;
+			else offset = 0x62;
+			if ((byte >= 0x40 && byte <= 0x7e) || (byte >= 0xa1 && byte <= 0xfe))
+				ptr = (lead - 0x81) * 157 + (byte - offset);
+			// "If there is a row in the table below whose first column is pointer, return the two code points listed in its second column"
+			switch (ptr) {
+				case 1133:
+					out += "Ê̄";
+					continue;
+				case 1135:
+					out += "Ê̌";
+					continue;
+				case 1164:
+					out += "ê̄";
+					continue;
+				case 1166:
+					out += "ê̌";
+					continue;
+			}
+			if (ptr == null) cp = null;
+			else cp = big5[ptr];
+			if (cp == null && byte >= 0x00 && byte <= 0x7f) {
+				bytes.unshift(byte);
+			}
+			if (cp == null) {
+				out += "�";
+				continue;
+			}
+			out += dec2char(cp);
+			continue;
+		}
+		if (byte >= 0x00 && byte <= 0x7f) {
+			out += dec2char(byte);
+			continue;
+		}
+		if (byte >= 0x81 && byte <= 0xfe) {
+			big5lead = byte;
+			continue;
+		}
+		out += "�";
+	}
+	return out;
+}