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|
# encoding: binary
# frozen_string_literal: true
require "amq/protocol/type_constants"
require "amq/protocol/float_32bit"
module AMQ
module Protocol
class TableValueDecoder
#
# Behaviors
#
include TypeConstants
# Pack format strings use explicit endianness (available as of Ruby 1.9.3)
PACK_UINT32_BE = 'N'.freeze
PACK_INT64_BE = 'q>'.freeze
PACK_INT16_BE = 's>'.freeze
PACK_UINT64_BE = 'Q>'.freeze
PACK_FLOAT32 = 'f'.freeze # single precision float (native endian, matches encoder)
PACK_FLOAT64 = 'G'.freeze # big-endian double precision float
PACK_UCHAR_UINT32 = 'CN'.freeze
#
# API
#
def self.decode_array(data, initial_offset)
array_length = data.byteslice(initial_offset, 4).unpack1(PACK_UINT32_BE)
ary = []
offset = initial_offset + 4
while offset <= (initial_offset + array_length)
type, offset = decode_value_type(data, offset)
i = case type
when TYPE_STRING
v, offset = decode_string(data, offset)
v
when TYPE_BYTE_ARRAY
# Ruby doesn't have a direct counterpart to
# ByteBuffer or byte[], so using a string feels
# more appropriate than an array of fixnums
v, offset = decode_string(data, offset)
v
when TYPE_INTEGER
v, offset = decode_integer(data, offset)
v
when TYPE_DECIMAL
v, offset = decode_big_decimal(data, offset)
v
when TYPE_TIME
v, offset = decode_time(data, offset)
v
when TYPE_HASH
v, offset = decode_hash(data, offset)
v
when TYPE_BOOLEAN
v, offset = decode_boolean(data, offset)
v
when TYPE_BYTE
v, offset = decode_byte(data, offset)
v
when TYPE_SIGNED_16BIT
v, offset = decode_short(data, offset)
v
when TYPE_SIGNED_64BIT
v, offset = decode_long(data, offset)
v
when TYPE_32BIT_FLOAT
v, offset = decode_32bit_float(data, offset)
v
when TYPE_64BIT_FLOAT
v, offset = decode_64bit_float(data, offset)
v
when TYPE_VOID
nil
when TYPE_ARRAY
v, offset = decode_array(data, offset)
v
else
raise ArgumentError.new("unsupported type in a table value: #{type.inspect}, do not know how to decode!")
end
ary << i
end
[ary, initial_offset + array_length + 4]
end
def self.decode_string(data, offset)
length = data.byteslice(offset, 4).unpack1(PACK_UINT32_BE)
offset += 4
v = data.byteslice(offset, length)
offset += length
[v, offset]
end
def self.decode_integer(data, offset)
v = data.byteslice(offset, 4).unpack1(PACK_UINT32_BE)
offset += 4
[v, offset]
end
def self.decode_long(data, offset)
v = data.byteslice(offset, 8).unpack1(PACK_INT64_BE)
offset += 8
[v, offset]
end
def self.decode_big_decimal(data, offset)
decimals, raw = data.byteslice(offset, 5).unpack(PACK_UCHAR_UINT32)
offset += 5
v = BigDecimal(raw.to_s) * (BigDecimal(TEN) ** -decimals)
[v, offset]
end
def self.decode_time(data, offset)
timestamp = data.byteslice(offset, 8).unpack1(PACK_UINT64_BE)
v = Time.at(timestamp)
offset += 8
[v, offset]
end
def self.decode_boolean(data, offset)
byte = data.getbyte(offset)
offset += 1
[(byte == 1), offset]
end
def self.decode_32bit_float(data, offset)
v = data.byteslice(offset, 4).unpack1(PACK_FLOAT32)
offset += 4
[v, offset]
end
def self.decode_64bit_float(data, offset)
v = data.byteslice(offset, 8).unpack1(PACK_FLOAT64)
offset += 8
[v, offset]
end
def self.decode_value_type(data, offset)
[data.byteslice(offset, 1), offset + 1]
end
def self.decode_hash(data, offset)
length = data.byteslice(offset, 4).unpack1(PACK_UINT32_BE)
v = Table.decode(data.byteslice(offset, length + 4))
offset += 4 + length
[v, offset]
end
# Decodes/Converts a byte value from the data at the provided offset.
#
# @param [String] data - Binary data string
# @param [Integer] offset - The offset from which to read the byte
# @return [Array] - The Integer value and new offset pair
def self.decode_byte(data, offset)
[data.getbyte(offset), offset + 1]
end
def self.decode_short(data, offset)
v = data.byteslice(offset, 2).unpack1(PACK_INT16_BE)
offset += 2
[v, offset]
end
end # TableValueDecoder
end # Protocol
end # AMQ
|
