Data types: Difference between revisions
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All | 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. | ||
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]. | 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]. | ||
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| 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/UCS-2 UCS-2] | | class="col3" | [http://en.wikipedia.org/wiki/UTF-16/UCS-2 UCS-2] big-endian string prefixed by a short containing the length of the string in [http://en.wikipedia.org/wiki/Code_point 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 [https://en.wikipedia.org/wiki/Plane_(Unicode)#Basic_Multilingual_Plane Basic Multilangual Plane] (U+0000 through U+FFFF inclusive). | ||
|- class="row8" | |- class="row8" | ||
! class="col0 centeralign" | bool | ! class="col0 centeralign" | bool | ||
| class="col1 centeralign" | 1 | | class="col1 centeralign" | 1 | ||
| class="col2" | 0 or 1 | | class="col2" | 0 or 1 | ||
| class="col3" | Value can be either | | class="col3" | Value can be either true (0x01) or false (0x00) | ||
|- class="row9" | |- class="row9" | ||
! class="col0 centeralign" | metadata | ! class="col0 centeralign" | metadata | ||
Revision as of 04:40, 18 July 2013
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;