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Contents
# encoding: UTF-8
module JSON
module Stream
# A character buffer that expects a UTF-8 encoded stream of bytes.
# This handles truncated multi-byte characters properly so we can just
# feed it binary data and receive a properly formatted UTF-8 String as
# output. See here for UTF-8 parsing details:
# http://en.wikipedia.org/wiki/UTF-8
# http://tools.ietf.org/html/rfc3629#section-3
class Buffer
def initialize
@state, @buf, @need = :start, [], 0
end
# Fill the buffer with a String of binary UTF-8 encoded bytes. Returns
# as much of the data in a UTF-8 String as we have. Truncated multi-byte
# characters are saved in the buffer until the next call to this method
# where we expect to receive the rest of the multi-byte character.
def <<(data)
bytes = []
data.bytes.each do |b|
case @state
when :start
if b < 128
bytes << b
elsif b >= 192
@state = :multi_byte
@buf << b
@need = case
when b >= 240 then 4
when b >= 224 then 3
when b >= 192 then 2 end
else
error('Expected start of multi-byte or single byte char')
end
when :multi_byte
if b > 127 && b < 192
@buf << b
if @buf.size == @need
bytes += @buf.slice!(0, @buf.size)
@state = :start
end
else
error('Expected continuation byte')
end
end
end
bytes.pack('C*').force_encoding(Encoding::UTF_8).tap do |str|
error('Invalid UTF-8 byte sequence') unless str.valid_encoding?
end
end
private
def error(message)
raise ParserError, message
end
end
end
end
Version data entries
7 entries across 7 versions & 2 rubygems