######################## 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 #########################

import constants, sys
from latin1prober import Latin1Prober # windows-1252
from mbcsgroupprober import MBCSGroupProber # multi-byte character sets
from sbcsgroupprober import SBCSGroupProber # single-byte character sets
from escprober import EscCharSetProber # ISO-2122, etc.
import re

MINIMUM_THRESHOLD = 0.20
ePureAscii = 0
eEscAscii = 1
eHighbyte = 2

class UniversalDetector:
	def __init__(self):
		self._highBitDetector = re.compile(r'[\x80-\xFF]')
		self._escDetector = re.compile(r'(\033|~{)')
		self._mEscCharSetProber = None
		self._mCharSetProbers = []
		self.reset()

	def reset(self):
		self.result = {'encoding': None, 'confidence': 0.0}
		self.done = constants.False
		self._mStart = constants.True
		self._mGotData = constants.False
		self._mInputState = ePureAscii
		self._mLastChar = ''
		if self._mEscCharSetProber:
			self._mEscCharSetProber.reset()
		for prober in self._mCharSetProbers:
			prober.reset()

	def feed(self, aBuf):
		if self.done: return

		aLen = len(aBuf)
		if not aLen: return

		if not self._mGotData:
			aBuff = ''.join([hex(ord(tmp))[2:] for tmp in aBuf[:4]]).upper()
			if aBuff[:6] == 'EFBBBF': self.result = {'encoding': "UTF-8", 'confidence': 1.0}
			elif aBuff[:8] == 'FFFE0000': self.result = {'encoding': "UTF-32LE", 'confidence': 1.0}
			elif aBuff[:8] == '0000FEFF': self.result = {'encoding': "UTF-32BE", 'confidence': 1.0}
			elif aBuff[:8] == 'FEFF0000': self.result = {'encoding': "X-ISO-10646-UCS-4-3412", 'confidence': 1.0}
			elif aBuff[:8] == '0000FFFE': self.result = {'encoding': "X-ISO-10646-UCS-4-2143", 'confidence': 1.0}
			elif aBuff[:4] == 'FFFE': self.result = {'encoding': "UTF-16LE", 'confidence': 1.0}
			elif aBuff[:4] == 'FEFF': self.result = {'encoding': "UTF-16BE", 'confidence': 1.0}

		self._mGotData = constants.True
		if self.result['encoding'] and (self.result['confidence'] > 0.0):
			self.done = constants.True
			return

		if self._mInputState == ePureAscii:
			if self._highBitDetector.search(aBuf):
				self._mInputState = eHighbyte
			elif (self._mInputState == ePureAscii) and self._escDetector.search(self._mLastChar + aBuf):
				self._mInputState = eEscAscii

		self._mLastChar = aBuf[-1]

		if self._mInputState == eEscAscii:
			if not self._mEscCharSetProber:
				self._mEscCharSetProber = EscCharSetProber()
			if self._mEscCharSetProber.feed(aBuf) == constants.eFoundIt:
				self.result = {'encoding': self._mEscCharSetProber.get_charset_name(),
							   'confidence': self._mEscCharSetProber.get_confidence()}
				self.done = constants.True
		elif self._mInputState == eHighbyte:
			if not self._mCharSetProbers:
				self._mCharSetProbers = [MBCSGroupProber(), SBCSGroupProber(), Latin1Prober()]
			for prober in self._mCharSetProbers:
				if prober.feed(aBuf) == constants.eFoundIt:
					self.result = {'encoding': prober.get_charset_name(),
								   'confidence': prober.get_confidence()}
					self.done = constants.True
					break

	def close(self):
		if self.done: return
		if not self._mGotData:
			if constants._debug:
				sys.stderr.write('no data received!\n')
			return
		self.done = constants.True

		if self._mInputState == ePureAscii:
			self.result = {'encoding': 'ascii', 'confidence': 1.0}
			return self.result

		if self._mInputState == eHighbyte:
			proberConfidence = None
			maxProberConfidence = 0.0
			maxProber = None
			for prober in self._mCharSetProbers:
				if not prober: continue
				proberConfidence = prober.get_confidence()
				if proberConfidence > maxProberConfidence:
					maxProberConfidence = proberConfidence
					maxProber = prober
			if maxProber and (maxProberConfidence > MINIMUM_THRESHOLD):
				self.result = {'encoding': maxProber.get_charset_name(),
							   'confidence': maxProber.get_confidence()}
				return self.result

		if constants._debug:
			sys.stderr.write('no probers hit minimum threshhold\n')
			for prober in self._mCharSetProbers[0].mProbers:
				if not prober: continue
				sys.stderr.write('%s confidence = %s\n' % \
								 (prober.get_charset_name(), \
								  prober.get_confidence()))