lib/rbyaml/reader.rb

   1 # This is a more or less straight translation of PyYAML3000 to Ruby
   2
   3 # the big difference in this implementation is that unicode support is not here...
   4
   5 require 'rbyaml/error'
   6
   7 module RbYAML
   8
   9   # Reader:
  10   # - checks if characters are in allowed range,
  11   # - adds '\0' to the end.
  12   # Reader accepts
  13   #  - a String object
  14   #  - a duck-typed IO object
  15   module Reader
  16     def initialize_reader(stream)
  17       @stream = nil
  18       @stream_pointer = 0
  19       @eof = true
  20       @buffer = ""
  21       @pointer = 0
  22       @index = 0
  23       @line = 0
  24       @column = 0
  25       if String === stream
  26         @name = "<string>"
  27         @raw_buffer = stream
  28       else
  29         @stream = stream
  30         @name = stream.respond_to?(:path) ? stream.path : stream.inspect
  31         @eof = false
  32         @raw_buffer = ""
  33       end
  34     end
  35
  36     def peek(index=0)
  37       update(index+1) if @pointer+index+1 >= @buffer.length
  38       @buffer[@pointer+index]
  39     end
  40
  41     def prefix(length=1)
  42       update(length) if @pointer+length >= @buffer.length
  43       @buffer[@pointer...@pointer+length]
  44     end
  45
  46     def forward(length=1)
  47       update(length+1) if @pointer+length+1 >= @buffer.length
  48       length.times { |k|
  49         ch = @buffer[@pointer]
  50         @pointer += 1
  51         @index += 1
  52         if "\n\x85".include?(ch) || (ch == ?\r && @buffer[@pointer+1] != ?\n)
  53           @line += 1
  54           @column = 0
  55         else
  56           @column += 1
  57         end
  58       }
  59     end
  60
  61     def get_mark
  62       if @stream.nil?
  63         Mark.new(@name,@index,@line,@column,@buffer,@pointer)
  64       else
  65         Mark.new(@name,@index,@line,@column,nil,nil)
  66       end
  67     end
  68
  69     NON_PRINTABLE = /[^\x09\x0A\x0D\x20-\x7E\x85\xA0-\xFF]/
  70     def check_printable(data)
  71       if NON_PRINTABLE =~ data
  72         position = @index+@buffer.length-@pointer+($~.offset(0)[0])
  73         raise ReaderError.new(@name, position, $&,"unicode","special characters are not allowed"),"special characters are not allowed"
  74       end
  75     end
  76
  77     def update(length)
  78       return if @raw_buffer.nil?
  79       @buffer = @buffer[@pointer..-1]
  80       @pointer = 0
  81       while @buffer.length < length
  82         unless @eof
  83           update_raw
  84         end
  85         data = @raw_buffer
  86         converted = data.length
  87         check_printable(data)
  88         @buffer << data
  89         @raw_buffer = @raw_buffer[converted..-1]
  90         if @eof
  91           @buffer << ?\0
  92           @raw_buffer = nil
  93           break
  94         end
  95       end
  96     end
  97
  98     def update_raw(size=1024)
  99       data = @stream.read(size)
 100       if data && !data.empty?
 101         @raw_buffer << data
 102         @stream_pointer += data.length
 103       else
 104         @eof = true
 105       end
 106     end
 107   end
 108
 109   class ReaderError < YAMLError
 110     def initialize(name, position, character, encoding, reason)
 111       @name = name
 112       @position = position
 113       @character = character
 114       @encoding = encoding
 115       @reason = reason
 116     end
 117
 118     def to_s
 119       if String === @character
 120         "'#{@encoding}' codec can't decode byte #x%02x: #{@reason}\n  in \"#{@name}\", position #{@position}" % @character.to_i
 121       else
 122         "unacceptable character #x%04x: #{@reason}\n  in \"#{@name}\", position #{@position}" % @character.to_i
 123       end
 124     end
 125   end
 126 end
 127