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######################## 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):
# Jeff Hodges - port to Ruby
# 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 CharDet
MINIMUM_THRESHOLD = 0.20
EPureAscii = 0
EEscAscii = 1
EHighbyte = 2
class UniversalDetector
attr_accessor :result
def initialize
@_highBitDetector = /[\x80-\xFF]/
@_escDetector = /(\033|\~\{)/
@_mEscCharSetProber = nil
@_mCharSetProbers = []
reset()
end
def reset
@result = {'encoding' => nil, 'confidence' => 0.0}
@done = false
@_mStart = true
@_mGotData = false
@_mInputState = EPureAscii
@_mLastChar = ''
if @_mEscCharSetProber
@_mEscCharSetProber.reset()
end
for prober in @_mCharSetProbers
prober.reset()
end
end
def feed(aBuf)
return if @done
aLen = aBuf.length
return if not aLen
if not @_mGotData
# If the data starts with BOM, we know it is UTF
if aBuf[0...3] == "\xEF\xBB\xBF"
# EF BB BF UTF-8 with BOM
@result = {'encoding' => "UTF-8", 'confidence' => 1.0}
elsif aBuf[0...4] == "\xFF\xFE\x00\x00"
# FF FE 00 00 UTF-32, little-endian BOM
@result = {'encoding' => "UTF-32LE", 'confidence' => 1.0}
elsif aBuf[0...4] == "\x00\x00\xFE\xFF"
# 00 00 FE FF UTF-32, big-endian BOM
@result = {'encoding' => "UTF-32BE", 'confidence' => 1.0}
elsif aBuf[0...4] == "\xFE\xFF\x00\x00"
# FE FF 00 00 UCS-4, unusual octet order BOM (3412)
@result = {'encoding' => "X-ISO-10646-UCS-4-3412", 'confidence' => 1.0}
elsif aBuf[0...4] == "\x00\x00\xFF\xFE"
# 00 00 FF FE UCS-4, unusual octet order BOM (2143)
@result = {'encoding' => "X-ISO-10646-UCS-4-2143", 'confidence' => 1.0}
elsif aBuf[0...2] == "\xFF\xFE"
# FF FE UTF-16, little endian BOM
@result = {'encoding' => "UTF-16LE", 'confidence' => 1.0}
elsif aBuf[0...2] == "\xFE\xFF"
# FE FF UTF-16, big endian BOM
@result = {'encoding' => "UTF-16BE", 'confidence' => 1.0}
end
end
@_mGotData = true
if @result['encoding'] and (@result['confidence'] > 0.0)
@done = true
return
end
if @_mInputState == EPureAscii
if @_highBitDetector =~ (aBuf)
@_mInputState = EHighbyte
elsif (@_mInputState == EPureAscii) and @_escDetector =~ (@_mLastChar + aBuf)
@_mInputState = EEscAscii
end
end
@_mLastChar = aBuf[-1..-1]
if @_mInputState == EEscAscii
if not @_mEscCharSetProber
@_mEscCharSetProber = EscCharSetProber.new()
end
if @_mEscCharSetProber.feed(aBuf) == EFoundIt
@result = {'encoding' => self._mEscCharSetProber.get_charset_name(),
'confidence' => @_mEscCharSetProber.get_confidence()
}
@done = true
end
elsif @_mInputState == EHighbyte
if not @_mCharSetProbers or @_mCharSetProbers.empty?
@_mCharSetProbers = [MBCSGroupProber.new(), SBCSGroupProber.new(), Latin1Prober.new()]
end
for prober in @_mCharSetProbers
if prober.feed(aBuf) == EFoundIt
@result = {'encoding' => prober.get_charset_name(),
'confidence' => prober.get_confidence()}
@done = true
break
end
end
end
end
def close
return if @done
if not @_mGotData
$stderr << "no data received!\n" if $debug
return
end
@done = true
if @_mInputState == EPureAscii
@result = {'encoding' => 'ascii', 'confidence' => 1.0}
return @result
end
if @_mInputState == EHighbyte
confidences = {}
@_mCharSetProbers.each{ |prober| confidences[prober] = prober.get_confidence }
maxProber = @_mCharSetProbers.max{ |a,b| confidences[a] <=> confidences[b] }
if maxProber and maxProber.get_confidence > MINIMUM_THRESHOLD
@result = {'encoding' => maxProber.get_charset_name(),
'confidence' => maxProber.get_confidence()}
return @result
end
end
if $debug
$stderr << "no probers hit minimum threshhold\n" if $debug
for prober in @_mCharSetProbers[0]._mProbers
next if not prober
$stderr << "#{prober.get_charset_name} confidence = #{prober.get_confidence}\n" if $debug
end
end
end
end
end
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