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stbi/Lib/site-packages/pip/_vendor/chardet/universaldetector.py

+######################## BEGIN LICENSE BLOCK ########################
+# The Original Code is Mozilla Universal charset detector code.
+#
+# The Initial Developer of the Original Code is
+# Netscape Communications Corporation.
+# Portions created by the Initial Developer are Copyright (C) 2001
+# the Initial Developer. All Rights Reserved.
+#
+# Contributor(s):
+#   Mark Pilgrim - port to Python
+#   Shy Shalom - original C code
+#
+# This library is free software; you can redistribute it and/or
+# modify it under the terms of the GNU Lesser General Public
+# License as published by the Free Software Foundation; either
+# version 2.1 of the License, or (at your option) any later version.
+#
+# This library is distributed in the hope that it will be useful,
+# but WITHOUT ANY WARRANTY; without even the implied warranty of
+# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+# Lesser General Public License for more details.
+#
+# You should have received a copy of the GNU Lesser General Public
+# License along with this library; if not, write to the Free Software
+# Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA
+# 02110-1301  USA
+######################### END LICENSE BLOCK #########################
+"""
+Module containing the UniversalDetector detector class, which is the primary
+class a user of ``chardet`` should use.
+
+:author: Mark Pilgrim (initial port to Python)
+:author: Shy Shalom (original C code)
+:author: Dan Blanchard (major refactoring for 3.0)
+:author: Ian Cordasco
+"""
+
+
+import codecs
+import logging
+import re
+
+from .charsetgroupprober import CharSetGroupProber
+from .enums import InputState, LanguageFilter, ProbingState
+from .escprober import EscCharSetProber
+from .latin1prober import Latin1Prober
+from .mbcsgroupprober import MBCSGroupProber
+from .sbcsgroupprober import SBCSGroupProber
+
+
+class UniversalDetector(object):
+    """
+    The ``UniversalDetector`` class underlies the ``chardet.detect`` function
+    and coordinates all of the different charset probers.
+
+    To get a ``dict`` containing an encoding and its confidence, you can simply
+    run:
+
+    .. code::
+
+            u = UniversalDetector()
+            u.feed(some_bytes)
+            u.close()
+            detected = u.result
+
+    """
+
+    MINIMUM_THRESHOLD = 0.20
+    HIGH_BYTE_DETECTOR = re.compile(b'[\x80-\xFF]')
+    ESC_DETECTOR = re.compile(b'(\033|~{)')
+    WIN_BYTE_DETECTOR = re.compile(b'[\x80-\x9F]')
+    ISO_WIN_MAP = {'iso-8859-1': 'Windows-1252',
+                   'iso-8859-2': 'Windows-1250',
+                   'iso-8859-5': 'Windows-1251',
+                   'iso-8859-6': 'Windows-1256',
+                   'iso-8859-7': 'Windows-1253',
+                   'iso-8859-8': 'Windows-1255',
+                   'iso-8859-9': 'Windows-1254',
+                   'iso-8859-13': 'Windows-1257'}
+
+    def __init__(self, lang_filter=LanguageFilter.ALL):
+        self._esc_charset_prober = None
+        self._charset_probers = []
+        self.result = None
+        self.done = None
+        self._got_data = None
+        self._input_state = None
+        self._last_char = None
+        self.lang_filter = lang_filter
+        self.logger = logging.getLogger(__name__)
+        self._has_win_bytes = None
+        self.reset()
+
+    def reset(self):
+        """
+        Reset the UniversalDetector and all of its probers back to their
+        initial states.  This is called by ``__init__``, so you only need to
+        call this directly in between analyses of different documents.
+        """
+        self.result = {'encoding': None, 'confidence': 0.0, 'language': None}
+        self.done = False
+        self._got_data = False
+        self._has_win_bytes = False
+        self._input_state = InputState.PURE_ASCII
+        self._last_char = b''
+        if self._esc_charset_prober:
+            self._esc_charset_prober.reset()
+        for prober in self._charset_probers:
+            prober.reset()
+
+    def feed(self, byte_str):
+        """
+        Takes a chunk of a document and feeds it through all of the relevant
+        charset probers.
+
+        After calling ``feed``, you can check the value of the ``done``
+        attribute to see if you need to continue feeding the
+        ``UniversalDetector`` more data, or if it has made a prediction
+        (in the ``result`` attribute).
+
+        .. note::
+           You should always call ``close`` when you're done feeding in your
+           document if ``done`` is not already ``True``.
+        """
+        if self.done:
+            return
+
+        if not len(byte_str):
+            return
+
+        if not isinstance(byte_str, bytearray):
+            byte_str = bytearray(byte_str)
+
+        # First check for known BOMs, since these are guaranteed to be correct
+        if not self._got_data:
+            # If the data starts with BOM, we know it is UTF
+            if byte_str.startswith(codecs.BOM_UTF8):
+                # EF BB BF  UTF-8 with BOM
+                self.result = {'encoding': "UTF-8-SIG",
+                               'confidence': 1.0,
+                               'language': ''}
+            elif byte_str.startswith((codecs.BOM_UTF32_LE,
+                                      codecs.BOM_UTF32_BE)):
+                # FF FE 00 00  UTF-32, little-endian BOM
+                # 00 00 FE FF  UTF-32, big-endian BOM
+                self.result = {'encoding': "UTF-32",
+                               'confidence': 1.0,
+                               'language': ''}
+            elif byte_str.startswith(b'\xFE\xFF\x00\x00'):
+                # FE FF 00 00  UCS-4, unusual octet order BOM (3412)
+                self.result = {'encoding': "X-ISO-10646-UCS-4-3412",
+                               'confidence': 1.0,
+                               'language': ''}
+            elif byte_str.startswith(b'\x00\x00\xFF\xFE'):
+                # 00 00 FF FE  UCS-4, unusual octet order BOM (2143)
+                self.result = {'encoding': "X-ISO-10646-UCS-4-2143",
+                               'confidence': 1.0,
+                               'language': ''}
+            elif byte_str.startswith((codecs.BOM_LE, codecs.BOM_BE)):
+                # FF FE  UTF-16, little endian BOM
+                # FE FF  UTF-16, big endian BOM
+                self.result = {'encoding': "UTF-16",
+                               'confidence': 1.0,
+                               'language': ''}
+
+            self._got_data = True
+            if self.result['encoding'] is not None:
+                self.done = True
+                return
+
+        # If none of those matched and we've only see ASCII so far, check
+        # for high bytes and escape sequences
+        if self._input_state == InputState.PURE_ASCII:
+            if self.HIGH_BYTE_DETECTOR.search(byte_str):
+                self._input_state = InputState.HIGH_BYTE
+            elif self._input_state == InputState.PURE_ASCII and \
+                    self.ESC_DETECTOR.search(self._last_char + byte_str):
+                self._input_state = InputState.ESC_ASCII
+
+        self._last_char = byte_str[-1:]
+
+        # If we've seen escape sequences, use the EscCharSetProber, which
+        # uses a simple state machine to check for known escape sequences in
+        # HZ and ISO-2022 encodings, since those are the only encodings that
+        # use such sequences.
+        if self._input_state == InputState.ESC_ASCII:
+            if not self._esc_charset_prober:
+                self._esc_charset_prober = EscCharSetProber(self.lang_filter)
+            if self._esc_charset_prober.feed(byte_str) == ProbingState.FOUND_IT:
+                self.result = {'encoding':
+                               self._esc_charset_prober.charset_name,
+                               'confidence':
+                               self._esc_charset_prober.get_confidence(),
+                               'language':
+                               self._esc_charset_prober.language}
+                self.done = True
+        # If we've seen high bytes (i.e., those with values greater than 127),
+        # we need to do more complicated checks using all our multi-byte and
+        # single-byte probers that are left.  The single-byte probers
+        # use character bigram distributions to determine the encoding, whereas
+        # the multi-byte probers use a combination of character unigram and
+        # bigram distributions.
+        elif self._input_state == InputState.HIGH_BYTE:
+            if not self._charset_probers:
+                self._charset_probers = [MBCSGroupProber(self.lang_filter)]
+                # If we're checking non-CJK encodings, use single-byte prober
+                if self.lang_filter & LanguageFilter.NON_CJK:
+                    self._charset_probers.append(SBCSGroupProber())
+                self._charset_probers.append(Latin1Prober())
+            for prober in self._charset_probers:
+                if prober.feed(byte_str) == ProbingState.FOUND_IT:
+                    self.result = {'encoding': prober.charset_name,
+                                   'confidence': prober.get_confidence(),
+                                   'language': prober.language}
+                    self.done = True
+                    break
+            if self.WIN_BYTE_DETECTOR.search(byte_str):
+                self._has_win_bytes = True
+
+    def close(self):
+        """
+        Stop analyzing the current document and come up with a final
+        prediction.
+
+        :returns:  The ``result`` attribute, a ``dict`` with the keys
+                   `encoding`, `confidence`, and `language`.
+        """
+        # Don't bother with checks if we're already done
+        if self.done:
+            return self.result
+        self.done = True
+
+        if not self._got_data:
+            self.logger.debug('no data received!')
+
+        # Default to ASCII if it is all we've seen so far
+        elif self._input_state == InputState.PURE_ASCII:
+            self.result = {'encoding': 'ascii',
+                           'confidence': 1.0,
+                           'language': ''}
+
+        # If we have seen non-ASCII, return the best that met MINIMUM_THRESHOLD
+        elif self._input_state == InputState.HIGH_BYTE:
+            prober_confidence = None
+            max_prober_confidence = 0.0
+            max_prober = None
+            for prober in self._charset_probers:
+                if not prober:
+                    continue
+                prober_confidence = prober.get_confidence()
+                if prober_confidence > max_prober_confidence:
+                    max_prober_confidence = prober_confidence
+                    max_prober = prober
+            if max_prober and (max_prober_confidence > self.MINIMUM_THRESHOLD):
+                charset_name = max_prober.charset_name
+                lower_charset_name = max_prober.charset_name.lower()
+                confidence = max_prober.get_confidence()
+                # Use Windows encoding name instead of ISO-8859 if we saw any
+                # extra Windows-specific bytes
+                if lower_charset_name.startswith('iso-8859'):
+                    if self._has_win_bytes:
+                        charset_name = self.ISO_WIN_MAP.get(lower_charset_name,
+                                                            charset_name)
+                self.result = {'encoding': charset_name,
+                               'confidence': confidence,
+                               'language': max_prober.language}
+
+        # Log all prober confidences if none met MINIMUM_THRESHOLD
+        if self.logger.getEffectiveLevel() == logging.DEBUG:
+            if self.result['encoding'] is None:
+                self.logger.debug('no probers hit minimum threshold')
+                for group_prober in self._charset_probers:
+                    if not group_prober:
+                        continue
+                    if isinstance(group_prober, CharSetGroupProber):
+                        for prober in group_prober.probers:
+                            self.logger.debug('%s %s confidence = %s',
+                                              prober.charset_name,
+                                              prober.language,
+                                              prober.get_confidence())
+                    else:
+                        self.logger.debug('%s %s confidence = %s',
+                                          prober.charset_name,
+                                          prober.language,
+                                          prober.get_confidence())
+        return self.result