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110 lines
4.6 KiB
110 lines
4.6 KiB
# Protocol Buffers - Google's data interchange format |
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# Copyright 2008 Google Inc. All rights reserved. |
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# https://developers.google.com/protocol-buffers/ |
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# |
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# Redistribution and use in source and binary forms, with or without |
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# modification, are permitted provided that the following conditions are |
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# met: |
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# |
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# * Redistributions of source code must retain the above copyright |
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# notice, this list of conditions and the following disclaimer. |
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# * Redistributions in binary form must reproduce the above |
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# copyright notice, this list of conditions and the following disclaimer |
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# in the documentation and/or other materials provided with the |
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# distribution. |
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# * Neither the name of Google Inc. nor the names of its |
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# contributors may be used to endorse or promote products derived from |
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# this software without specific prior written permission. |
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# |
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# THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS |
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# "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT |
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# LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR |
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# A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT |
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# OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, |
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# SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT |
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# LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, |
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# DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY |
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# THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT |
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# (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE |
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# OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. |
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#PY25 compatible for GAE. |
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# |
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"""Encoding related utilities.""" |
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import re |
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import sys ##PY25 |
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# Lookup table for utf8 |
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_cescape_utf8_to_str = [chr(i) for i in xrange(0, 256)] |
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_cescape_utf8_to_str[9] = r'\t' # optional escape |
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_cescape_utf8_to_str[10] = r'\n' # optional escape |
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_cescape_utf8_to_str[13] = r'\r' # optional escape |
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_cescape_utf8_to_str[39] = r"\'" # optional escape |
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_cescape_utf8_to_str[34] = r'\"' # necessary escape |
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_cescape_utf8_to_str[92] = r'\\' # necessary escape |
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# Lookup table for non-utf8, with necessary escapes at (o >= 127 or o < 32) |
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_cescape_byte_to_str = ([r'\%03o' % i for i in xrange(0, 32)] + |
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[chr(i) for i in xrange(32, 127)] + |
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[r'\%03o' % i for i in xrange(127, 256)]) |
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_cescape_byte_to_str[9] = r'\t' # optional escape |
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_cescape_byte_to_str[10] = r'\n' # optional escape |
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_cescape_byte_to_str[13] = r'\r' # optional escape |
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_cescape_byte_to_str[39] = r"\'" # optional escape |
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_cescape_byte_to_str[34] = r'\"' # necessary escape |
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_cescape_byte_to_str[92] = r'\\' # necessary escape |
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def CEscape(text, as_utf8): |
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"""Escape a bytes string for use in an ascii protocol buffer. |
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text.encode('string_escape') does not seem to satisfy our needs as it |
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encodes unprintable characters using two-digit hex escapes whereas our |
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C++ unescaping function allows hex escapes to be any length. So, |
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"\0011".encode('string_escape') ends up being "\\x011", which will be |
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decoded in C++ as a single-character string with char code 0x11. |
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Args: |
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text: A byte string to be escaped |
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as_utf8: Specifies if result should be returned in UTF-8 encoding |
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Returns: |
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Escaped string |
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""" |
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# PY3 hack: make Ord work for str and bytes: |
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# //platforms/networking/data uses unicode here, hence basestring. |
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Ord = ord if isinstance(text, basestring) else lambda x: x |
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if as_utf8: |
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return ''.join(_cescape_utf8_to_str[Ord(c)] for c in text) |
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return ''.join(_cescape_byte_to_str[Ord(c)] for c in text) |
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_CUNESCAPE_HEX = re.compile(r'(\\+)x([0-9a-fA-F])(?![0-9a-fA-F])') |
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_cescape_highbit_to_str = ([chr(i) for i in range(0, 127)] + |
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[r'\%03o' % i for i in range(127, 256)]) |
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def CUnescape(text): |
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"""Unescape a text string with C-style escape sequences to UTF-8 bytes.""" |
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def ReplaceHex(m): |
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# Only replace the match if the number of leading back slashes is odd. i.e. |
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# the slash itself is not escaped. |
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if len(m.group(1)) & 1: |
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return m.group(1) + 'x0' + m.group(2) |
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return m.group(0) |
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# This is required because the 'string_escape' encoding doesn't |
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# allow single-digit hex escapes (like '\xf'). |
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result = _CUNESCAPE_HEX.sub(ReplaceHex, text) |
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if sys.version_info[0] < 3: ##PY25 |
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##!PY25 if str is bytes: # PY2 |
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return result.decode('string_escape') |
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result = ''.join(_cescape_highbit_to_str[ord(c)] for c in result) |
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return (result.encode('ascii') # Make it bytes to allow decode. |
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.decode('unicode_escape') |
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# Make it bytes again to return the proper type. |
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.encode('raw_unicode_escape'))
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