diff --git a/check_emoji_sequences.py b/check_emoji_sequences.py
new file mode 100755
index 000000000..97f5508af
--- /dev/null
+++ b/check_emoji_sequences.py
@@ -0,0 +1,168 @@
+#!/usr/bin/python
+#
+# Copyright 2016 Google Inc. All rights reserved.
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+# http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+
+"""Compare emoji image file namings against unicode property data."""
+
+import argparse
+import collections
+import glob
+from os import path
+import re
+import sys
+
+from nototools import unicode_data
+
+def _is_regional_indicator(cp):
+ return 0x1f1e6 <= cp <= 0x1f1ff
+
+
+def _is_skintone_modifier(cp):
+ return 0x1f3fb <= cp <= 0x1f3ff
+
+
+def _seq_string(seq):
+ return '_'.join('%04x' % cp for cp in seq)
+
+
+def _check_valid_emoji(sorted_seqs):
+ """Ensure all emoji are either valid emoji or specific chars."""
+
+ valid_cps = set(unicode_data.get_emoji() | unicode_data.proposed_emoji_cps())
+ valid_cps.add(0x200d) # ZWJ
+ valid_cps.add(0x20e3) # combining enclosing keycap
+ valid_cps.add(0xfe0f) # variation selector (emoji presentation)
+ valid_cps.add(0xfe82b) # PUA value for unknown flag
+
+ not_emoji = set()
+ for seq in sorted_seqs:
+ for cp in seq:
+ if cp not in valid_cps:
+ not_emoji.add(cp)
+
+ if len(not_emoji):
+ print >> sys.stderr, '%d non-emoji found:' % len(not_emoji)
+ for cp in sorted(not_emoji):
+ print >> sys.stderr, '%04X' % cp
+
+
+def _check_zwj(sorted_seqs):
+ """Ensure zwj is only between two appropriate emoji."""
+ ZWJ = 0x200D
+ EMOJI_PRESENTATION_VS = 0xFE0F
+
+ for seq in sorted_seqs:
+ if ZWJ not in seq:
+ continue
+ if seq[0] == 0x200d:
+ print >> sys.stderr, 'zwj at head of sequence'
+ if len(seq) == 1:
+ continue
+ if seq[-1] == 0x200d:
+ print >> sys.stderr, 'zwj at end of sequence'
+ for i, cp in enumerate(seq):
+ if cp == ZWJ:
+ pcp = seq[i-1]
+ if pcp != EMOJI_PRESENTATION_VS and not unicode_data.is_emoji(pcp):
+ print >> sys.stderr, 'non-emoji %04X preceeds ZWJ' % pcp
+ fcp = seq[i+1]
+ if not unicode_data.is_emoji(fcp):
+ print >> sys.stderr, 'non-emoji %04X follows ZWJ' % fcp
+
+
+def _check_flags(sorted_seqs):
+ """Ensure regional indicators are only in sequences of one or two, and
+ never mixed."""
+ for seq in sorted_seqs:
+ have_reg = None
+ for cp in seq:
+ is_reg = _is_regional_indicator(cp)
+ if have_reg == None:
+ have_reg = is_reg
+ elif have_reg != is_reg:
+ print >> sys.stderr, ('mix of regional and non-regional in %s' %
+ _seq_string(seq))
+ if have_reg and len(seq) > 2:
+ # We provide dummy glyphs for regional indicators, so there are sequences
+ # with single regional indicator symbols.
+ print >> sys.stderr, ('regional indicator sequence length != 2: %s' %
+ _seq_string(seq))
+
+
+def _check_skintone(sorted_seqs):
+ """Ensure skin tone modifiers are not applied to emoji that are not defined
+ to take them. May appear standalone, though. Also check that emoji that take
+ skin tone modifiers have a complete set."""
+ base_to_modifiers = collections.defaultdict(set)
+ for seq in sorted_seqs:
+ for i, cp in enumerate(seq):
+ if _is_skintone_modifier(cp):
+ if i == 0:
+ if len(seq) > 1:
+ print >> sys.stderr, 'skin color selector first in sequence %s'
+ # standalone are ok
+ continue
+ pcp = seq[i-1]
+ if not unicode_data.is_emoji_modifier_base(pcp):
+ print >> sys.stderr, (
+ 'emoji skintone modifier applied to non-base at %d: %s' % (
+ i, _seq_string(seq)))
+ elif unicode_data.is_emoji_modifier_base(cp):
+ if i < len(seq) - 1 and _is_skintone_modifier(seq[i+1]):
+ base_to_modifiers[cp].add(seq[i+1])
+ elif cp not in base_to_modifiers:
+ base_to_modifiers[cp] = set()
+ for cp, modifiers in sorted(base_to_modifiers.iteritems()):
+ if len(modifiers) != 5:
+ print 'emoji base %04X has %d modifiers defined (%s)' % (
+ cp, len(modifiers),
+ ', '.join('%04x' % cp for cp in sorted(modifiers)))
+
+def check_sequences(seqs):
+ sorted_seqs = sorted(seqs)
+ _check_valid_emoji(sorted_seqs)
+ _check_zwj(sorted_seqs)
+ _check_flags(sorted_seqs)
+ _check_skintone(sorted_seqs)
+
+
+def _collect_sequences(dirs, prefix='emoji_u'):
+ seqs = set()
+ path_re = re.compile('%s([a-zA-Z0-9_]+)\.png' % prefix)
+ for d in dirs:
+ for f in glob.glob(path.join(d, '%s*.png' % prefix)):
+ m = path_re.match(path.basename(f))
+ if not m:
+ print >> sys.stderr, 'could not match file "%s"' % f
+ continue
+ seq = tuple(int(s, 16) for s in m.group(1).split('_'))
+ if seq in seqs:
+ print >> sys.stderr, 'duplicate sequence for "%s"' % f
+ continue
+ seqs.add(seq)
+ return seqs
+
+
+def main():
+ parser = argparse.ArgumentParser()
+ parser.add_argument(
+ '-d', '--dirs', help='directories containing emoji images',
+ metavar='dir', nargs='+', required=True)
+ args = parser.parse_args()
+ check_sequences(_collect_sequences(args.dirs))
+
+
+if __name__ == '__main__':
+ main()