Data Types - Revision history

imported>Fenhl: Fenhl moved page Data Types to Data types over redirect: case

2015-12-07T07:39:38Z

Fenhl moved page Data Types to Data types over redirect: case

← Older revision	Revision as of 07:39, 7 December 2015
(No difference)

imported>Fenhl: Fenhl moved page Data Types to Data types over redirect: case

2015-12-07T07:39:38Z

Fenhl moved page Data Types to Data types over redirect: case

← Older revision	Revision as of 07:39, 7 December 2015
(No difference)

imported>Fenhl: Fenhl moved page Data Types to Data types over redirect: case

2015-12-07T07:39:38Z

Fenhl moved page Data Types to Data types over redirect: case

← Older revision	Revision as of 07:39, 7 December 2015
(No difference)

imported>Fenhl: Fenhl moved page Data Types to Data types over redirect: case

2015-12-07T07:39:38Z

Fenhl moved page Data Types to Data types over redirect: case

← Older revision	Revision as of 07:39, 7 December 2015
(No difference)

imported>Fenhl: Fenhl moved page Data Types to Data types over redirect: case

2015-12-07T07:39:38Z

Fenhl moved page Data Types to Data types over redirect: case

← Older revision	Revision as of 07:39, 7 December 2015
(No difference)

imported>Fenhl: Fenhl moved page Data Types to Data types over redirect: case

2015-12-07T07:39:38Z

Fenhl moved page Data Types to Data types over redirect: case

← Older revision		Revision as of 07:39, 7 December 2015
Line 1:		Line 1:
	~~All data sent over the network is [http://en.wikipedia.org/wiki/Endianness~~#Big-endian big-endian], that is the bytes are sent from most significant byte to least significant byte. The majority of everyday computers are little-endian, therefore it may be necessary to change the endianness before sending data over the network.		#REDIRECT [[Data types]]

	Other than 'String' and 'Metadata', which are decoded with a custom function, these data formats are identical to those provided by the Java classes [http://download.oracle.com/javase/1.4.2/docs/api/java/io/DataInputStream.html DataInputStream] and [http://download.oracle.com/javase/1.4.2/docs/api/java/io/DataOutputStream.html DataOutputStream].

	~~{\| class="wikitable"~~
	~~\|- class="row0"~~
	~~\| class="col0" \|~~
	~~! class="col1" \| Size~~
	~~! class="col2" \| Range~~
	~~! class="col3" \| Notes~~
	~~\|- class="row1"~~
	~~! class="col0 centeralign" \| bool~~
	~~\| class="col1 centeralign" \| 1~~
	~~\| class="col2" \| 0 or 1~~
	~~\| class="col3" \| Value can be either true (0x01) or false (0x00)~~
	~~\|- class="row2"~~
	~~! class="col0 centeralign" \| byte~~
	~~\| class="col1 centeralign" \| 1~~
	~~\| class="col2" \| -128 to 127~~
	~~\| class="col3" \| Signed, two's complement~~
	~~\|- class="row3"~~
	~~! class="col0 centeralign" \| short~~
	~~\| class="col1 centeralign" \| 2~~
	~~\| class="col2" \| -32768 to 32767~~
	~~\| class="col3" \| Signed, two's complement~~
	~~\|- class="row4"~~
	~~! class="col0 centeralign" \| int~~
	~~\| class="col1 centeralign" \| 4~~
	~~\| class="col2" \| -2147483648 to 2147483647~~
	~~\| class="col3" \| Signed, two's complement~~
	~~\|- class="row5"~~
	~~! class="col0 centeralign" \| long~~
	~~\| class="col1 centeralign" \| 8~~
	~~\| class="col2" \| -9223372036854775808 to 9223372036854775807~~
	~~\| class="col3" \| Signed, two's complement~~
	~~\|- class="row8"~~
	~~! class="col0 centeralign" \| 128-bit integer~~
	~~\| class="col1 centeralign" \| 16~~
	~~\| class="col2" \| 0 to 340282366920938463463374607431768211455~~
	~~\| class="col3" \| Unsigned, two's complement~~

	~~Used in [http://wiki.vg/Protocol#Entity_Properties_.280x2C.29 0x2C] to transmit UUIDs.~~

	~~The vanilla Minecraft server internally sends this as two longs.~~
	~~\|- class="row7"~~
	~~! class="col0 centeralign" \| float~~
	~~\| class="col1 centeralign" \| 4~~
	~~\| class="col2" \|~~
	~~See [http://java.sun.com/docs/books/jls/third_edition/html/typesValues.html#4.2.3 this]~~
	~~\| class="col3" \| Single-precision 32-bit IEEE 754 floating point~~
	~~\|- class="row8"~~
	~~! class="col0 centeralign" \| double~~
	~~\| class="col1 centeralign" \| 8~~
	~~\| class="col2" \|~~
	~~See [http://java.sun.com/docs/books/jls/third_edition/html/typesValues.html#4.2.3 this]~~
	~~\| class="col3" \| Double-precision 64-bit IEEE 754 floating point~~
	~~\|- class="row9"~~
	~~! class="col0 centeralign" \| string~~
	~~\| class="col1 centeralign" \| ≥ 2 <br />≤ 240~~
	~~\| class="col2" \| N/A~~
	~~\| class="col3" \| UTF-8 String length prefixed with a VarInt~~
	\|-
	~~! class="centeralign" \| varInt~~
	~~\| class="centeralign" \| Varies~~
	~~\| [http://developers.google.com/protocol-buffers/docs/encoding#varints Protocol Buffer 32-bit Varint]~~
	\|
	~~\|- class="row9"~~
	~~! class="col0 centeralign" \| metadata~~
	~~\| class="col1 centeralign" \| Varies~~
	~~\| class="col2" \| See [[Entities#Entity_Metadata_Format\|this]]~~
	~~\| class="Col3" \|~~
	\|}

	~~=== Fixed-point numbers ===~~

	Some fields may be stored as [https://en.wikipedia.org/wiki/Fixed-point_arithmetic fixed-point numbers], where a certain number of bits represents the signed integer part (number to the left of the decimal point) and the rest represents the fractional part (to the right). Floating points (float and double9, in contrast, keep the number itself (mantissa) in one chunk, while the location of the decimal point (exponent) is stored beside it.

	Essentially, while fixed-point numbers have lower range than floating points, their fractional precision is greater for higher values. This makes them ideal for representing global coordinates of an entity in Minecraft, as it's more important to store the integer part accurately than position them more precisely within a single block (or meter).

	~~Coordinates are often represented as a 32-bit integer, where 5 of the least-significant bits are dedicated to the fractional part, and the rest store the integer part.~~

	~~Java lacks support for fractional integers directly, but you can represent them as integers. To convert from a double to this integer representation, use the following formulas:~~
	~~abs_int = (int)double * 32;~~
	~~And back again:~~

	~~double = (double)abs_int / 32;~~

	~~[[Category:Protocol Details]]~~
	[[~~Category:Minecraft Modern~~]]

imported>Thinkofdeath at 13:25, 25 October 2013

2013-10-25T13:25:49Z

← Older revision		Revision as of 13:25, 25 October 2013
Line 59:		Line 59:
	\| class="col1 centeralign" \| ≥ 2 <br />≤ 240		\| class="col1 centeralign" \| ≥ 2 <br />≤ 240
	\| class="col2" \| N/A		\| class="col2" \| N/A
	\| class="col3" \| ~~[http://en.wikipedia.org/wiki/~~UTF-~~16 UTF-16] big-endian string~~ prefixed by a ~~short containing the length of the string in code units.~~		\| class="col3" \| UTF-8 String length prefixed with a VarInt
			\|-
	~~UTF-16 is a variable-length encoding, which means that a single Unicode code point (what most programmers think of as a~~ "~~character~~"~~) may be encoded by a variable number of code units.~~		! class="centeralign" \| varInt
			\| class="centeralign" \| Varies
	~~UTF-16 encodes code points as either one or two 16 bit code units.~~		\| [http://developers.google.com/protocol-buffers/docs/encoding#varints Protocol Buffer 32-bit Varint]
			\|
	~~Characters in the Basic Multilingual Plane (U+0000 through U+FFFF inclusive) are encoded as one 16 bit code unit.~~

	~~Characters in the other Unicode planes (U+10000 through U+10FFFF inclusive) are encoded as two 16 bit code units (a high/low~~ "~~surrogate pair~~").

	~~Therefore, the length in bytes of a string may be obtained by multiplying the number of code units by two, and the opposite operation may be performed by dividing by two.~~

	~~However, since UTF-16 is variable-length, the number of code units is totally unrelated to the number of code points (i~~.e. ~~"characters"), and you will actually have to decode the string to obtain this information.~~

	~~It was historically believed that the Minecraft~~ protocol ~~used the fixed~~-~~width~~ encoding ~~UCS~~-~~2, however this has since been proven to be incorrect.~~
	\|- class="row9"		\|- class="row9"
	! class="col0 centeralign" \| metadata		! class="col0 centeralign" \| metadata

imported>Aadnk: I believe the term "absolute integer" is confusing. It sounds too much like the absolute value of an integer. Better to call them by their more formal name - fixed-point integers.

2013-09-25T16:31:35Z

I believe the term "absolute integer" is confusing. It sounds too much like the absolute value of an integer. Better to call them by their more formal name - fixed-point integers.

← Older revision		Revision as of 16:31, 25 September 2013
Line 81:		Line 81:
	\|}		\|}

	~~Some data may be stored as an "absolute integer", which is a more precise kind of integer, and a less precise kind of double. The conversion from double to absolute integer is like so:~~		=== Fixed-point numbers ===

	~~abs_int =~~ (~~int~~)~~double * 32;~~		Some fields may be stored as [https://en.wikipedia.org/wiki/Fixed-point_arithmetic fixed-point numbers], where a certain number of bits represents the signed integer part (number to the left of the decimal point) and the rest represents the fractional part (to the right). Floating points (float and double9, in contrast, keep the number itself (mantissa) in one chunk, while the location of the decimal point (exponent) is stored beside it.

			Essentially, while fixed-point numbers have lower range than floating points, their fractional precision is greater for higher values. This makes them ideal for representing global coordinates of an entity in Minecraft, as it's more important to store the integer part accurately than position them more precisely within a single block (or meter).

			Coordinates are often represented as a 32-bit integer, where 5 of the least-significant bits are dedicated to the fractional part, and the rest store the integer part.

			Java lacks support for fractional integers directly, but you can represent them as integers. To convert from a double to this integer representation, use the following formulas:
			abs_int = (int)double * 32;
	And back again:		And back again:

	double = (double)abs_int / 32;		double = (double)abs_int / 32;

	[[Category:Protocol Details]]		[[Category:Protocol Details]]
	[[Category:Minecraft Modern]]		[[Category:Minecraft Modern]]

imported>Drainedsoul: Add 128-bit integer

2013-08-28T00:15:24Z

Add 128-bit integer

← Older revision		Revision as of 00:15, 28 August 2013
Line 34:		Line 34:
	\| class="col2" \| -9223372036854775808 to 9223372036854775807		\| class="col2" \| -9223372036854775808 to 9223372036854775807
	\| class="col3" \| Signed, two's complement		\| class="col3" \| Signed, two's complement
	\|- class="~~row6~~"		\|- class="row8"
			! class="col0 centeralign" \| 128-bit integer
			\| class="col1 centeralign" \| 16
			\| class="col2" \| 0 to 340282366920938463463374607431768211455
			\| class="col3" \| Unsigned, two's complement

			Used in [http://wiki.vg/Protocol#Entity_Properties_.280x2C.29 0x2C] to transmit UUIDs.

			The vanilla Minecraft server internally sends this as two longs.
			\|- class="row7"
	! class="col0 centeralign" \| float		! class="col0 centeralign" \| float
	\| class="col1 centeralign" \| 4		\| class="col1 centeralign" \| 4
Line 40:		Line 49:
	See [http://java.sun.com/docs/books/jls/third_edition/html/typesValues.html#4.2.3 this]		See [http://java.sun.com/docs/books/jls/third_edition/html/typesValues.html#4.2.3 this]
	\| class="col3" \| Single-precision 32-bit IEEE 754 floating point		\| class="col3" \| Single-precision 32-bit IEEE 754 floating point
	\|- class="~~row7~~"		\|- class="row8"
	! class="col0 centeralign" \| double		! class="col0 centeralign" \| double
	\| class="col1 centeralign" \| 8		\| class="col1 centeralign" \| 8
Line 46:		Line 55:
	See [http://java.sun.com/docs/books/jls/third_edition/html/typesValues.html#4.2.3 this]		See [http://java.sun.com/docs/books/jls/third_edition/html/typesValues.html#4.2.3 this]
	\| class="col3" \| Double-precision 64-bit IEEE 754 floating point		\| class="col3" \| Double-precision 64-bit IEEE 754 floating point
	\|- class="~~row8~~"		\|- class="row9"
	! class="col0 centeralign" \| string		! class="col0 centeralign" \| string
	\| class="col1 centeralign" \| ≥ 2 <br />≤ 240		\| class="col1 centeralign" \| ≥ 2 <br />≤ 240

imported>Drainedsoul: Fix typo

2013-08-26T19:49:34Z

Fix typo

← Older revision		Revision as of 19:49, 26 August 2013
Line 60:		Line 60:
	Characters in the other Unicode planes (U+10000 through U+10FFFF inclusive) are encoded as two 16 bit code units (a high/low "surrogate pair").		Characters in the other Unicode planes (U+10000 through U+10FFFF inclusive) are encoded as two 16 bit code units (a high/low "surrogate pair").

	Therefore, the length in bytes of a string may be obtained by multiplying the number of code ~~points~~ by two, and the opposite operation may be performed by dividing by two.		Therefore, the length in bytes of a string may be obtained by multiplying the number of code units by two, and the opposite operation may be performed by dividing by two.

	However, since UTF-16 is variable-length, the number of code units is totally unrelated to the number of code points (i.e. "characters"), and you will actually have to decode the string to obtain this information.		However, since UTF-16 is variable-length, the number of code units is totally unrelated to the number of code points (i.e. "characters"), and you will actually have to decode the string to obtain this information.

← Older revision		Revision as of 07:39, 7 December 2015
Line 1:		Line 1:
	~~All data sent over the network is [http://en.wikipedia.org/wiki/Endianness~~#Big-endian big-endian], that is the bytes are sent from most significant byte to least significant byte. The majority of everyday computers are little-endian, therefore it may be necessary to change the endianness before sending data over the network.		#REDIRECT [[Data types]]

	Other than 'String' and 'Metadata', which are decoded with a custom function, these data formats are identical to those provided by the Java classes [http://download.oracle.com/javase/1.4.2/docs/api/java/io/DataInputStream.html DataInputStream] and [http://download.oracle.com/javase/1.4.2/docs/api/java/io/DataOutputStream.html DataOutputStream].

	~~{\| class="wikitable"~~
	~~\|- class="row0"~~
	~~\| class="col0" \|~~
	~~! class="col1" \| Size~~
	~~! class="col2" \| Range~~
	~~! class="col3" \| Notes~~
	~~\|- class="row1"~~
	~~! class="col0 centeralign" \| bool~~
	~~\| class="col1 centeralign" \| 1~~
	~~\| class="col2" \| 0 or 1~~
	~~\| class="col3" \| Value can be either true (0x01) or false (0x00)~~
	~~\|- class="row2"~~
	~~! class="col0 centeralign" \| byte~~
	~~\| class="col1 centeralign" \| 1~~
	~~\| class="col2" \| -128 to 127~~
	~~\| class="col3" \| Signed, two's complement~~
	~~\|- class="row3"~~
	~~! class="col0 centeralign" \| short~~
	~~\| class="col1 centeralign" \| 2~~
	~~\| class="col2" \| -32768 to 32767~~
	~~\| class="col3" \| Signed, two's complement~~
	~~\|- class="row4"~~
	~~! class="col0 centeralign" \| int~~
	~~\| class="col1 centeralign" \| 4~~
	~~\| class="col2" \| -2147483648 to 2147483647~~
	~~\| class="col3" \| Signed, two's complement~~
	~~\|- class="row5"~~
	~~! class="col0 centeralign" \| long~~
	~~\| class="col1 centeralign" \| 8~~
	~~\| class="col2" \| -9223372036854775808 to 9223372036854775807~~
	~~\| class="col3" \| Signed, two's complement~~
	~~\|- class="row8"~~
	~~! class="col0 centeralign" \| 128-bit integer~~
	~~\| class="col1 centeralign" \| 16~~
	~~\| class="col2" \| 0 to 340282366920938463463374607431768211455~~
	~~\| class="col3" \| Unsigned, two's complement~~

	~~Used in [http://wiki.vg/Protocol#Entity_Properties_.280x2C.29 0x2C] to transmit UUIDs.~~

	~~The vanilla Minecraft server internally sends this as two longs.~~
	~~\|- class="row7"~~
	~~! class="col0 centeralign" \| float~~
	~~\| class="col1 centeralign" \| 4~~
	~~\| class="col2" \|~~
	~~See [http://java.sun.com/docs/books/jls/third_edition/html/typesValues.html#4.2.3 this]~~
	~~\| class="col3" \| Single-precision 32-bit IEEE 754 floating point~~
	~~\|- class="row8"~~
	~~! class="col0 centeralign" \| double~~
	~~\| class="col1 centeralign" \| 8~~
	~~\| class="col2" \|~~
	~~See [http://java.sun.com/docs/books/jls/third_edition/html/typesValues.html#4.2.3 this]~~
	~~\| class="col3" \| Double-precision 64-bit IEEE 754 floating point~~
	~~\|- class="row9"~~
	~~! class="col0 centeralign" \| string~~
	~~\| class="col1 centeralign" \| ≥ 2 <br />≤ 240~~
	~~\| class="col2" \| N/A~~
	~~\| class="col3" \| UTF-8 String length prefixed with a VarInt~~
	\|-
	~~! class="centeralign" \| varInt~~
	~~\| class="centeralign" \| Varies~~
	~~\| [http://developers.google.com/protocol-buffers/docs/encoding#varints Protocol Buffer 32-bit Varint]~~
	\|
	~~\|- class="row9"~~
	~~! class="col0 centeralign" \| metadata~~
	~~\| class="col1 centeralign" \| Varies~~
	~~\| class="col2" \| See [[Entities#Entity_Metadata_Format\|this]]~~
	~~\| class="Col3" \|~~
	\|}

	~~=== Fixed-point numbers ===~~

	Some fields may be stored as [https://en.wikipedia.org/wiki/Fixed-point_arithmetic fixed-point numbers], where a certain number of bits represents the signed integer part (number to the left of the decimal point) and the rest represents the fractional part (to the right). Floating points (float and double9, in contrast, keep the number itself (mantissa) in one chunk, while the location of the decimal point (exponent) is stored beside it.

	Essentially, while fixed-point numbers have lower range than floating points, their fractional precision is greater for higher values. This makes them ideal for representing global coordinates of an entity in Minecraft, as it's more important to store the integer part accurately than position them more precisely within a single block (or meter).

	~~Coordinates are often represented as a 32-bit integer, where 5 of the least-significant bits are dedicated to the fractional part, and the rest store the integer part.~~

	~~Java lacks support for fractional integers directly, but you can represent them as integers. To convert from a double to this integer representation, use the following formulas:~~
	~~abs_int = (int)double * 32;~~
	~~And back again:~~

	~~double = (double)abs_int / 32;~~

	~~[[Category:Protocol Details]]~~
	[[~~Category:Minecraft Modern~~]]

← Older revision		Revision as of 00:15, 28 August 2013
Line 34:		Line 34:
	\| class="col2" \| -9223372036854775808 to 9223372036854775807		\| class="col2" \| -9223372036854775808 to 9223372036854775807
	\| class="col3" \| Signed, two's complement		\| class="col3" \| Signed, two's complement
	\|- class="~~row6~~"		\|- class="row8"
			! class="col0 centeralign" \| 128-bit integer
			\| class="col1 centeralign" \| 16
			\| class="col2" \| 0 to 340282366920938463463374607431768211455
			\| class="col3" \| Unsigned, two's complement

			Used in [http://wiki.vg/Protocol#Entity_Properties_.280x2C.29 0x2C] to transmit UUIDs.

			The vanilla Minecraft server internally sends this as two longs.
			\|- class="row7"
	! class="col0 centeralign" \| float		! class="col0 centeralign" \| float
	\| class="col1 centeralign" \| 4		\| class="col1 centeralign" \| 4
Line 40:		Line 49:
	See [http://java.sun.com/docs/books/jls/third_edition/html/typesValues.html#4.2.3 this]		See [http://java.sun.com/docs/books/jls/third_edition/html/typesValues.html#4.2.3 this]
	\| class="col3" \| Single-precision 32-bit IEEE 754 floating point		\| class="col3" \| Single-precision 32-bit IEEE 754 floating point
	\|- class="~~row7~~"		\|- class="row8"
	! class="col0 centeralign" \| double		! class="col0 centeralign" \| double
	\| class="col1 centeralign" \| 8		\| class="col1 centeralign" \| 8
Line 46:		Line 55:
	See [http://java.sun.com/docs/books/jls/third_edition/html/typesValues.html#4.2.3 this]		See [http://java.sun.com/docs/books/jls/third_edition/html/typesValues.html#4.2.3 this]
	\| class="col3" \| Double-precision 64-bit IEEE 754 floating point		\| class="col3" \| Double-precision 64-bit IEEE 754 floating point
	\|- class="~~row8~~"		\|- class="row9"
	! class="col0 centeralign" \| string		! class="col0 centeralign" \| string
	\| class="col1 centeralign" \| ≥ 2 <br />≤ 240		\| class="col1 centeralign" \| ≥ 2 <br />≤ 240