--- /dev/null
+require 'rexml/encoding'
+
+module REXML
+ # Generates Source-s. USE THIS CLASS.
+ class SourceFactory
+ # Generates a Source object
+ # @param arg Either a String, or an IO
+ # @return a Source, or nil if a bad argument was given
+ def SourceFactory::create_from(arg)
+ if arg.respond_to? :read and
+ arg.respond_to? :readline and
+ arg.respond_to? :nil? and
+ arg.respond_to? :eof?
+ IOSource.new(arg)
+ elsif arg.respond_to? :to_str
+ require 'stringio'
+ IOSource.new(StringIO.new(arg))
+ elsif arg.kind_of? Source
+ arg
+ else
+ raise "#{arg.class} is not a valid input stream. It must walk \n"+
+ "like either a String, an IO, or a Source."
+ end
+ end
+ end
+
+ # A Source can be searched for patterns, and wraps buffers and other
+ # objects and provides consumption of text
+ class Source
+ include Encoding
+ # The current buffer (what we're going to read next)
+ attr_reader :buffer
+ # The line number of the last consumed text
+ attr_reader :line
+ attr_reader :encoding
+
+ # Constructor
+ # @param arg must be a String, and should be a valid XML document
+ # @param encoding if non-null, sets the encoding of the source to this
+ # value, overriding all encoding detection
+ def initialize(arg, encoding=nil)
+ @orig = @buffer = arg
+ if encoding
+ self.encoding = encoding
+ else
+ self.encoding = check_encoding( @buffer )
+ end
+ @line = 0
+ end
+
+
+ # Inherited from Encoding
+ # Overridden to support optimized en/decoding
+ def encoding=(enc)
+ return unless super
+ @line_break = encode( '>' )
+ if enc != UTF_8
+ @buffer = decode(@buffer)
+ @to_utf = true
+ else
+ @to_utf = false
+ if @buffer.respond_to? :force_encoding
+ @buffer.force_encoding Encoding::UTF_8
+ end
+ end
+ end
+
+ # Scans the source for a given pattern. Note, that this is not your
+ # usual scan() method. For one thing, the pattern argument has some
+ # requirements; for another, the source can be consumed. You can easily
+ # confuse this method. Originally, the patterns were easier
+ # to construct and this method more robust, because this method
+ # generated search regexes on the fly; however, this was
+ # computationally expensive and slowed down the entire REXML package
+ # considerably, since this is by far the most commonly called method.
+ # @param pattern must be a Regexp, and must be in the form of
+ # /^\s*(#{your pattern, with no groups})(.*)/. The first group
+ # will be returned; the second group is used if the consume flag is
+ # set.
+ # @param consume if true, the pattern returned will be consumed, leaving
+ # everything after it in the Source.
+ # @return the pattern, if found, or nil if the Source is empty or the
+ # pattern is not found.
+ def scan(pattern, cons=false)
+ return nil if @buffer.nil?
+ rv = @buffer.scan(pattern)
+ @buffer = $' if cons and rv.size>0
+ rv
+ end
+
+ def read
+ end
+
+ def consume( pattern )
+ @buffer = $' if pattern.match( @buffer )
+ end
+
+ def match_to( char, pattern )
+ return pattern.match(@buffer)
+ end
+
+ def match_to_consume( char, pattern )
+ md = pattern.match(@buffer)
+ @buffer = $'
+ return md
+ end
+
+ def match(pattern, cons=false)
+ md = pattern.match(@buffer)
+ @buffer = $' if cons and md
+ return md
+ end
+
+ # @return true if the Source is exhausted
+ def empty?
+ @buffer == ""
+ end
+
+ def position
+ @orig.index( @buffer )
+ end
+
+ # @return the current line in the source
+ def current_line
+ lines = @orig.split
+ res = lines.grep @buffer[0..30]
+ res = res[-1] if res.kind_of? Array
+ lines.index( res ) if res
+ end
+ end
+
+ # A Source that wraps an IO. See the Source class for method
+ # documentation
+ class IOSource < Source
+ #attr_reader :block_size
+
+ # block_size has been deprecated
+ def initialize(arg, block_size=500, encoding=nil)
+ @er_source = @source = arg
+ @to_utf = false
+
+ # Determining the encoding is a deceptively difficult issue to resolve.
+ # First, we check the first two bytes for UTF-16. Then we
+ # assume that the encoding is at least ASCII enough for the '>', and
+ # we read until we get one of those. This gives us the XML declaration,
+ # if there is one. If there isn't one, the file MUST be UTF-8, as per
+ # the XML spec. If there is one, we can determine the encoding from
+ # it.
+ @buffer = ""
+ str = @source.read( 2 ) || ''
+ if encoding
+ self.encoding = encoding
+ elsif str[0,2] == "\xfe\xff"
+ @line_break = "\000>"
+ elsif str[0,2] == "\xff\xfe"
+ @line_break = ">\000"
+ elsif str[0,2] == "\xef\xbb"
+ str += @source.read(1)
+ str = '' if (str[2,1] == "\xBF")
+ @line_break = ">"
+ else
+ @line_break = ">"
+ end
+ super( @source.eof? ? str : str+@source.readline( @line_break ) )
+ end
+
+ def scan(pattern, cons=false)
+ rv = super
+ # You'll notice that this next section is very similar to the same
+ # section in match(), but just a liiittle different. This is
+ # because it is a touch faster to do it this way with scan()
+ # than the way match() does it; enough faster to warrent duplicating
+ # some code
+ if rv.size == 0
+ until @buffer =~ pattern or @source.nil?
+ begin
+ # READLINE OPT
+ #str = @source.read(@block_size)
+ str = @source.readline(@line_break)
+ str = decode(str) if @to_utf and str
+ @buffer << str
+ rescue Iconv::IllegalSequence
+ raise
+ rescue
+ @source = nil
+ end
+ end
+ rv = super
+ end
+ rv.taint
+ rv
+ end
+
+ def read
+ begin
+ str = @source.readline(@line_break)
+ str = decode(str) if @to_utf and str
+ @buffer << str
+ if not @to_utf and @buffer.respond_to? :force_encoding
+ @buffer.force_encoding Encoding::UTF_8
+ end
+ rescue Exception, NameError
+ @source = nil
+ end
+ end
+
+ def consume( pattern )
+ match( pattern, true )
+ end
+
+ def match( pattern, cons=false )
+ rv = pattern.match(@buffer)
+ @buffer = $' if cons and rv
+ while !rv and @source
+ begin
+ str = @source.readline(@line_break)
+ str = decode(str) if @to_utf and str
+ @buffer << str
+ rv = pattern.match(@buffer)
+ @buffer = $' if cons and rv
+ rescue
+ @source = nil
+ end
+ end
+ rv.taint
+ rv
+ end
+
+ def empty?
+ super and ( @source.nil? || @source.eof? )
+ end
+
+ def position
+ @er_source.pos rescue 0
+ end
+
+ # @return the current line in the source
+ def current_line
+ begin
+ pos = @er_source.pos # The byte position in the source
+ lineno = @er_source.lineno # The XML < position in the source
+ @er_source.rewind
+ line = 0 # The \r\n position in the source
+ begin
+ while @er_source.pos < pos
+ @er_source.readline
+ line += 1
+ end
+ rescue
+ end
+ rescue IOError
+ pos = -1
+ line = -1
+ end
+ [pos, lineno, line]
+ end
+ end
+end
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