1 files changed, 66 insertions, 0 deletions
diff --git a/markdown_it/_punycode.py b/markdown_it/_punycode.py
new file mode 100644
index 0000000..9ad2442
--- /dev/null
+++ b/markdown_it/_punycode.py
@@ -0,0 +1,66 @@
+# Copyright 2014 Mathias Bynens <https://mathiasbynens.be/>
+# Copyright 2021 Taneli Hukkinen
+#
+# Permission is hereby granted, free of charge, to any person obtaining
+# a copy of this software and associated documentation files (the
+# "Software"), to deal in the Software without restriction, including
+# without limitation the rights to use, copy, modify, merge, publish,
+# distribute, sublicense, and/or sell copies of the Software, and to
+# permit persons to whom the Software is furnished to do so, subject to
+# the following conditions:
+#
+# The above copyright notice and this permission notice shall be
+# included in all copies or substantial portions of the Software.
+#
+# THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
+# EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
+# MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
+# NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE
+# LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION
+# OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION
+# WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
+
+import codecs
+import re
+
+REGEX_SEPARATORS = re.compile(r"[\x2E\u3002\uFF0E\uFF61]")
+REGEX_NON_ASCII = re.compile(r"[^\0-\x7E]")
+
+
+def encode(uni: str) -> str:
+    return codecs.encode(uni, encoding="punycode").decode()
+
+
+def decode(ascii: str) -> str:
+    return codecs.decode(ascii, encoding="punycode")  # type: ignore[call-overload]
+
+
+def map_domain(string, fn):
+    parts = string.split("@")
+    result = ""
+    if len(parts) > 1:
+        # In email addresses, only the domain name should be punycoded. Leave
+        # the local part (i.e. everything up to `@`) intact.
+        result = parts[0] + "@"
+        string = parts[1]
+    labels = REGEX_SEPARATORS.split(string)
+    encoded = ".".join(fn(label) for label in labels)
+    return result + encoded
+
+
+def to_unicode(obj: str) -> str:
+    def mapping(obj: str) -> str:
+        if obj.startswith("xn--"):
+            return decode(obj[4:].lower())
+        return obj
+
+    return map_domain(obj, mapping)
+
+
+def to_ascii(obj: str) -> str:
+    def mapping(obj: str) -> str:
+        if REGEX_NON_ASCII.search(obj):
+            return "xn--" + encode(obj)
+        return obj
+
+    return map_domain(obj, mapping)