conversion to/from bytes and data buffer modules

res/modules/bit_converter.lua

@@ -4,8 +4,6 @@ local MAX_UINT16 = 65535
 local MIN_UINT16 = 0
 local MAX_UINT32 = 4294967295
 local MIN_UINT32 = 0
-local MAX_UINT64 = 18446744073709551615
-local MIN_UINT64 = 0
 
 local MAX_INT16 = 32767
 local MIN_INT16 = -32768
@@ -30,7 +28,7 @@ function bit_converter.string_to_bytes(str)
 
 	local len = string.len(str)
 
-	local lenBytes = bit_converter.int32_to_bytes(len)
+	local lenBytes = bit_converter.uint16_to_bytes(len)
 
 	for i = 1, #lenBytes do
 		bytes[i] = lenBytes[i]
@@ -127,23 +125,6 @@ function bit_converter.double_to_bytes(double)
 	return floatOrDoubleToBytes(double, 'd')
 end
 
-function bit_converter.int64_to_bytes(int)
-	if int > MAX_INT64 or int < MIN_INT64 then
-		error("invalid int64")
-	end
-
-	return {
-		intToByte(bit.rshift(int, 56)),
-		intToByte(bit.rshift(int, 48)),
-		intToByte(bit.rshift(int, 40)),
-		intToByte(bit.rshift(int, 32)),
-		intToByte(bit.rshift(int, 24)),
-		intToByte(bit.rshift(int, 16)),
-		intToByte(bit.rshift(int, 8)),
-		intToByte(int)
-	}
-end
-
 function bit_converter.uint32_to_bytes(int)
 	if int > MAX_UINT32 or int < MIN_UINT32 then
 		error("invalid uint32")
@@ -168,6 +149,23 @@ function bit_converter.uint16_to_bytes(int)
 	}
 end
 
+function bit_converter.int64_to_bytes(int)
+	if int > MAX_INT64 or int < MIN_INT64 then
+		error("invalid int64")
+	end
+
+	return {
+		intToByte(bit.rshift(int, 56)),
+		intToByte(bit.rshift(int, 48)),
+		intToByte(bit.rshift(int, 40)),
+		intToByte(bit.rshift(int, 32)),
+		intToByte(bit.rshift(int, 24)),
+		intToByte(bit.rshift(int, 16)),
+		intToByte(bit.rshift(int, 8)),
+		intToByte(int)
+	}
+end
+
 function bit_converter.int32_to_bytes(int)
 	if int > MAX_INT32 or int < MIN_INT32 then
 		error("invalid int32")
@@ -193,7 +191,7 @@ function bit_converter.bytes_to_double(bytes)
 end
 
 function bit_converter.bytes_to_string(bytes)
-	local len = bit_converter.bytes_to_int32({ bytes[1], bytes[2], bytes[3], bytes[4]})
+	local len = bit_converter.bytes_to_uint16({ bytes[1], bytes[2] })
 
 	local str = ""
 
@@ -215,27 +213,6 @@ function bit_converter.bytes_to_float(bytes)
 	error("unsupported operation")
 end
 
-function bit_converter.bytes_to_int64(bytes)
-	if #bytes < 8 then
-		error("eof")
-	end
-     return
-     bit.bor(
-     bit.bor(
-     bit.bor(
-     bit.bor(
-     bit.bor(
-     bit.bor(
-     bit.bor(
-     bit.lshift(bytes[1], 56),
-     bit.lshift(bytes[2], 48)),
-     bit.lshift(bytes[3], 40)),
-     bit.lshift(bytes[4], 32)),
-     bit.lshift(bytes[5], 24)),
-     bit.lshift(bit.band(bytes[6], 0xFF), 16)),
-     bit.lshift(bit.band(bytes[7], 0xFF), 8)),bit.band(bytes[8], 0xFF))
-end
-
 function bit_converter.bytes_to_uint32(bytes)
 	if #bytes < 4 then
 		error("eof")
@@ -259,6 +236,27 @@ function bit_converter.bytes_to_uint16(bytes)
      bytes[2], 0)
 end
 
+function bit_converter.bytes_to_int64(bytes)
+	if #bytes < 8 then
+		error("eof")
+	end
+     return
+     bit.bor(
+     bit.bor(
+     bit.bor(
+     bit.bor(
+     bit.bor(
+     bit.bor(
+     bit.bor(
+     bit.lshift(bytes[1], 56),
+     bit.lshift(bytes[2], 48)),
+     bit.lshift(bytes[3], 40)),
+     bit.lshift(bytes[4], 32)),
+     bit.lshift(bytes[5], 24)),
+     bit.lshift(bit.band(bytes[6], 0xFF), 16)),
+     bit.lshift(bit.band(bytes[7], 0xFF), 8)),bit.band(bytes[8], 0xFF))
+end
+
 function bit_converter.bytes_to_int32(bytes)
 	return bit_converter.bytes_to_uint32(bytes) - MAX_INT32
 end

res/modules/data_buffer.lua

@@ -1,5 +1,25 @@
 local bit_converter = require "core:bit_converter"
 
+local MAX_UINT16 = 65535
+local MIN_UINT16 = 0
+local MAX_UINT32 = 4294967295
+local MIN_UINT32 = 0
+
+local MAX_INT16 = 32767
+local MIN_INT16 = -32768
+local MAX_INT32 = 2147483647
+local MIN_INT32 = -2147483648
+local MAX_INT64 = 9223372036854775807
+local MIN_INT64 = -9223372036854775808
+
+local TYPE_ZERO = 0
+local TYPE_UINT16 = 1
+local TYPE_UINT32 = 2
+local TYPE_INT16 = 3
+local TYPE_INT32 = 4
+local TYPE_INT64 = 5
+local TYPE_DOUBLE = 6
+
 -- Data buffer
 
 local data_buffer = { }
@@ -62,6 +82,44 @@ function data_buffer:put_int64(int64)
 	self:put_bytes(bit_converter.int64_to_bytes(int64))
 end
 
+function data_buffer:put_number(num)
+	local bytes
+	local type
+
+	if math.floor(num) ~= num then
+		type = TYPE_DOUBLE
+		bytes = bit_converter.double_to_bytes(num)
+	elseif num == 0 then
+		type = TYPE_ZERO
+		bytes = { }
+	elseif num > 0 then
+		if num <= MAX_UINT16 then
+			type = TYPE_UINT16
+			bytes = bit_converter.uint16_to_bytes(num)
+		elseif num <= MAX_UINT32 then
+			type = TYPE_UINT32
+			bytes = bit_converter.uint32_to_bytes(num)
+		elseif num <= MAX_INT64 then
+			type = TYPE_INT64
+			bytes = bit_converter.int64_to_bytes(num)
+		end
+	elseif num < 0 then
+		if num >= MIN_INT16 then
+			type = TYPE_INT16
+			bytes = bit_converter.int16_to_bytes(num)
+		elseif num >= MIN_INT32 then
+			type = TYPE_INT32
+			bytes = bit_converter.int32_to_bytes(num)
+		elseif num >= MIN_INT64 then
+			type = TYPE_INT64
+			bytes = bit_converter.int64_to_bytes(num)
+		end
+	end
+
+	self:put_byte(type)
+	self:put_bytes(bytes)
+end
+
 -- Get functions
 
 function data_buffer:get_byte()
@@ -70,6 +128,28 @@ function data_buffer:get_byte()
 	return byte
 end
 
+function data_buffer:get_number()
+	local type = self:get_byte()
+
+	if type == TYPE_ZERO then
+		return 0
+	elseif type == TYPE_UINT16 then
+		return self:get_uint16()
+	elseif type == TYPE_UINT32 then
+		return self:get_uint32()
+	elseif type == TYPE_INT16 then 
+		return self:get_int16()
+	elseif type == TYPE_INT32 then 
+		return self:get_int32()
+	elseif type == TYPE_INT64 then 
+		return self:get_int64()
+	elseif type == TYPE_DOUBLE then
+		return self:get_double()
+	else
+		error("unknown lua number type: "..type)
+	end
+end
+
 function data_buffer:get_single()
 	return bit_converter.bytes_to_single(self:get_bytes(4))
 end
@@ -79,8 +159,8 @@ function data_buffer:get_double()
 end
 
 function data_buffer:get_string()
-	local len = self:get_bytes(4)
+	local len = self:get_bytes(2)
-	local str = self:get_bytes(bit_converter.bytes_to_int32(len))
+	local str = self:get_bytes(bit_converter.bytes_to_uint16(len))
 	local bytes = { }
 
 	for i = 1, #len do
@@ -98,6 +178,14 @@ function data_buffer:get_bool()
 	return bit_converter.byte_to_bool(self:get_byte())
 end
 
+function data_buffer:get_uint16()
+	return bit_converter.bytes_to_uint16(self:get_bytes(2))
+end
+
+function data_buffer:get_uint32()
+	return bit_converter.bytes_to_uint32(self:get_bytes(4))
+end
+
 function data_buffer:get_int16()
 	return bit_converter.bytes_to_int16(self:get_bytes(2))
 end
@@ -114,8 +202,8 @@ function data_buffer:size()
 	return #self.bytes
 end
 
-function data_buffer:get_bytes(len)
+function data_buffer:get_bytes(n)
-	if len == nil then
+	if n == nil then
 		return self.bytes
 	else
 		local bytes = { }