Data types

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Revision as of 04:40, 18 July 2013 by Drainedsoul (talk | contribs) (Terminology clean up)
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All data sent over the network is 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.

Other than 'String' and 'Metadata', which are decoded with a custom function, these data formats are identical to those provided by the Java classes DataInputStream and DataOutputStream.

Size Range Notes
byte 1 -128 to 127 Signed, two's complement
short 2 -32768 to 32767 Signed, two's complement
int 4 -2147483648 to 2147483647 Signed, two's complement
long 8 -9223372036854775808 to 9223372036854775807 Signed, two's complement
float 4

See this

Single-precision 32-bit IEEE 754 floating point
double 8

See this

Double-precision 64-bit IEEE 754 floating point
string ≥ 2
≤ 240
N/A UCS-2 big-endian string prefixed by a short containing the length of the string in code points. UCS-2 is a fixed-width encoding with each code point represented by a 16-bit code unit. As it is limited to 16 bits it can only represent code points in the Basic Multilangual Plane (U+0000 through U+FFFF inclusive).
bool 1 0 or 1 Value can be either true (0x01) or false (0x00)
metadata Varies See this

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:

abs_int = (int)double * 32;

And back again:

double = (double)abs_int / 32;