2 # Copyright (c) 2012 The Chromium Authors. All rights reserved.
3 # Use of this source code is governed by a BSD-style license that can be
4 # found in the LICENSE file.
6 '''Utility to remove comments from JSON files so that they can be parsed by
13 def _Rcount(string, chars):
14 '''Returns the number of consecutive characters from |chars| that occur at the
17 return len(string) - len(string.rstrip(chars))
20 def _FindNextToken(string, tokens, start):
21 '''Finds the next token in |tokens| that occurs in |string| from |start|.
22 Returns a tuple (index, token key).
24 min_index, min_key = (-1, None)
26 index = string.find(k, start)
27 if index != -1 and (min_index == -1 or index < min_index):
28 min_index, min_key = (index, k)
29 return (min_index, min_key)
32 def _ReadString(input, start, output):
34 start_range, end_range = (start, input.find('"', start))
35 # \" escapes the ", \\" doesn't, \\\" does, etc.
36 while (end_range != -1 and
37 _Rcount(input[start_range:end_range], '\\') % 2 == 1):
38 start_range, end_range = (end_range, input.find('"', end_range + 1))
40 return start_range + 1
41 output.append(input[start:end_range + 1])
45 def _ReadComment(input, start, output):
46 eol_tokens = ('\n', '\r')
47 eol_token_index, eol_token = _FindNextToken(input, eol_tokens, start)
50 output.append(eol_token)
51 return eol_token_index + len(eol_token)
61 while pos < len(input):
62 token_index, token = _FindNextToken(input, token_actions.keys(), pos)
64 output.append(input[pos:])
66 output.append(input[pos:token_index])
67 pos = token_actions[token](input, token_index + len(token), output)
68 return ''.join(output)
71 if __name__ == '__main__':
72 sys.stdout.write(Nom(sys.stdin.read()))