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