2 files changed, 116 insertions, 0 deletions
diff --git a/sleekxmpp/util/__init__.py b/sleekxmpp/util/__init__.py
new file mode 100644
index 00000000..e69de29b
--- /dev/null
+++ b/sleekxmpp/util/__init__.py
diff --git a/sleekxmpp/util/stringprep_profiles.py b/sleekxmpp/util/stringprep_profiles.py
new file mode 100644
index 00000000..a75bb9dd
--- /dev/null
+++ b/sleekxmpp/util/stringprep_profiles.py
@@ -0,0 +1,116 @@
+from __future__ import unicode_literals
+
+import sys
+import stringprep
+import unicodedata
+
+
+class StringPrepError(UnicodeError):
+    pass
+
+
+def to_unicode(data):
+    if sys.version_info < (3, 0):
+        return unicode(data)
+    else:
+        return str(data)
+
+
+def b1_mapping(char):
+    return '' if stringprep.in_table_c12(char) else None
+
+
+def c12_mapping(char):
+    return ' ' if stringprep.in_table_c12(char) else None
+
+
+def map_input(data, tables=None):
+    """
+    Each character in the input stream MUST be checked against
+    a mapping table.
+    """
+    result = []
+    for char in data:
+        replacement = None
+
+        for mapping in tables:
+            replacement = mapping(char)
+            if replacement is not None:
+                break
+
+        if replacement is None:
+            replacement = char
+        result.append(replacement)
+    return ''.join(result)
+
+
+def normalize(data, nfkc=True):
+    """
+    A profile can specify one of two options for Unicode normalization:
+        - no normalization
+        - Unicode normalization with form KC
+    """
+    if nfkc:
+        data = unicodedata.normalize('NFKC', data)
+    return data
+
+
+def prohibit_output(data, tables=None):
+    """
+    Before the text can be emitted, it MUST be checked for prohibited
+    code points.
+    """
+    for char in data:
+        for check in tables:
+            if check(char):
+                raise StringPrepError("Prohibited code point: %s" % char)
+
+
+def check_bidi(data):
+    """
+    1) The characters in section 5.8 MUST be prohibited.
+
+    2) If a string contains any RandALCat character, the string MUST NOT
+       contain any LCat character.
+
+    3) If a string contains any RandALCat character, a RandALCat
+       character MUST be the first character of the string, and a
+       RandALCat character MUST be the last character of the string.
+    """
+    has_lcat = False
+    has_randal = False
+
+    for c in data:
+        if stringprep.in_table_c8(c):
+            raise StringPrepError("BIDI violation: seciton 6 (1)")
+        if stringprep.in_table_d1(c):
+            has_randal = True
+        elif stringprep.in_table_d2(c):
+            has_lcat = True
+
+    if has_randal and has_lcat:
+        raise StringPrepError("BIDI violation: section 6 (2)")
+
+    first_randal = stringprep.in_table_d1(data[0])
+    last_randal = stringprep.in_table_d1(data[-1])
+    if has_randal and not (first_randal and last_randal):
+        raise StringPrepError("BIDI violation: section 6 (3)")
+
+
+def create(nfkc=True, bidi=True, mappings=None,
+           prohibited=None, unassigned=None):
+    def profile(data, query=False):
+        try:
+            data = to_unicode(data)
+        except UnicodeError:
+            raise StringPrepError
+
+        data = map_input(data, mappings)
+        data = normalize(data, nfkc)
+        prohibit_output(data, prohibited)
+        if bidi:
+            check_bidi(data)
+        if query and unassigned:
+            check_unassigned(data, unassigned)
+        return data
+    return profile