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- ###############################################################################
- #
- # The MIT License (MIT)
- #
- # Copyright (c) typedef int GmbH
- #
- # Permission is hereby granted, free of charge, to any person obtaining a copy
- # of this software and associated documentation files (the "Software"), to deal
- # in the Software without restriction, including without limitation the rights
- # to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
- # copies of the Software, and to permit persons to whom the Software is
- # furnished to do so, subject to the following conditions:
- #
- # The above copyright notice and this permission notice shall be included in
- # all copies or substantial portions of the Software.
- #
- # THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
- # IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
- # FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
- # AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
- # LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
- # OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
- # THE SOFTWARE.
- #
- ###############################################################################
-
- # Note: This code is a Python implementation of the algorithm
- # "Flexible and Economical UTF-8 Decoder" by Bjoern Hoehrmann
- # bjoern@hoehrmann.de, http://bjoern.hoehrmann.de/utf-8/decoder/dfa/
-
- __all__ = ("Utf8Validator",)
-
-
- # DFA transitions
- UTF8VALIDATOR_DFA = (
- 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, # 00..1f
- 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, # 20..3f
- 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, # 40..5f
- 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, # 60..7f
- 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, # 80..9f
- 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, # a0..bf
- 8, 8, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, 2, # c0..df
- 0xa, 0x3, 0x3, 0x3, 0x3, 0x3, 0x3, 0x3, 0x3, 0x3, 0x3, 0x3, 0x3, 0x4, 0x3, 0x3, # e0..ef
- 0xb, 0x6, 0x6, 0x6, 0x5, 0x8, 0x8, 0x8, 0x8, 0x8, 0x8, 0x8, 0x8, 0x8, 0x8, 0x8, # f0..ff
- 0x0, 0x1, 0x2, 0x3, 0x5, 0x8, 0x7, 0x1, 0x1, 0x1, 0x4, 0x6, 0x1, 0x1, 0x1, 0x1, # s0..s0
- 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 0, 1, 1, 1, 1, 1, 0, 1, 0, 1, 1, 1, 1, 1, 1, # s1..s2
- 1, 2, 1, 1, 1, 1, 1, 2, 1, 2, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 2, 1, 1, 1, 1, 1, 1, 1, 1, # s3..s4
- 1, 2, 1, 1, 1, 1, 1, 1, 1, 2, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 3, 1, 3, 1, 1, 1, 1, 1, 1, # s5..s6
- 1, 3, 1, 1, 1, 1, 1, 3, 1, 3, 1, 1, 1, 1, 1, 1, 1, 3, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, # s7..s8
- )
-
- UTF8_ACCEPT = 0
- UTF8_REJECT = 1
-
-
- # use Cython implementation of UTF8 validator if available
- try:
- from wsaccel.utf8validator import Utf8Validator
-
- except ImportError:
-
- # Fallback to pure Python implementation - also for PyPy.
- #
- # Do NOT touch this code unless you know what you are doing!
- # https://github.com/oberstet/scratchbox/tree/master/python/utf8
-
- # Python 3 and above
-
- # convert DFA table to bytes (performance)
- UTF8VALIDATOR_DFA_S = bytes(UTF8VALIDATOR_DFA)
-
- class Utf8Validator(object):
- """
- Incremental UTF-8 validator with constant memory consumption (minimal state).
-
- Implements the algorithm "Flexible and Economical UTF-8 Decoder" by
- Bjoern Hoehrmann (http://bjoern.hoehrmann.de/utf-8/decoder/dfa/).
- """
-
- __slots__ = (
- '_codepoint',
- '_state',
- '_index',
- )
-
- def __init__(self):
- self._codepoint = None
- self._state = None
- self._index = None
- self.reset()
-
- def decode(self, b):
- """
- Eat one UTF-8 octet, and validate on the fly.
-
- Returns ``UTF8_ACCEPT`` when enough octets have been consumed, in which case
- ``self.codepoint`` contains the decoded Unicode code point.
-
- Returns ``UTF8_REJECT`` when invalid UTF-8 was encountered.
-
- Returns some other positive integer when more octets need to be eaten.
- """
- tt = UTF8VALIDATOR_DFA_S[b]
- if self._state != UTF8_ACCEPT:
- self._codepoint = (b & 0x3f) | (self._codepoint << 6)
- else:
- self._codepoint = (0xff >> tt) & b
- self._state = UTF8VALIDATOR_DFA_S[256 + self._state * 16 + tt]
- return self._state
-
- def reset(self):
- """
- Reset validator to start new incremental UTF-8 decode/validation.
- """
- self._state = UTF8_ACCEPT # the empty string is valid UTF8
- self._codepoint = 0
- self._index = 0
-
- def validate(self, ba):
- """
- Incrementally validate a chunk of bytes provided as string.
-
- Will return a quad ``(valid?, endsOnCodePoint?, currentIndex, totalIndex)``.
-
- As soon as an octet is encountered which renders the octet sequence
- invalid, a quad with ``valid? == False`` is returned. ``currentIndex`` returns
- the index within the currently consumed chunk, and ``totalIndex`` the
- index within the total consumed sequence that was the point of bail out.
- When ``valid? == True``, currentIndex will be ``len(ba)`` and ``totalIndex`` the
- total amount of consumed bytes.
- """
- #
- # The code here is written for optimal JITting in PyPy, not for best
- # readability by your grandma or particular elegance. Do NOT touch!
- #
- l = len(ba)
- i = 0
- state = self._state
- while i < l:
- # optimized version of decode(), since we are not interested in actual code points
- state = UTF8VALIDATOR_DFA_S[256 + (state << 4) + UTF8VALIDATOR_DFA_S[ba[i]]]
- if state == UTF8_REJECT:
- self._state = state
- self._index += i
- return False, False, i, self._index
- i += 1
- self._state = state
- self._index += l
- return True, state == UTF8_ACCEPT, l, self._index
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