Data Type Education Document

[Joe[x86]]

Poke.

I got bored, so I decided to write up a document on data types. Yeah, its rather dry, but I wanted to get it across with no nonsence. If you want to spice it up a bit, feel free to do so. I have a codeheader and code style in my stylesheet, so you can add code blocks if you want (see test.html for example).

If you'd like to host a copy on your server, do something like this.

Code Select Expand

cd ~/public_html
mkdir datatypes
wget http://www.javaop.com/~joe/datatypes/index.html
wget http://www.javaop.com/~joe/datatypes/test.html
wget http://www.javaop.com/~joe/datatypes/stylesheet.css

[Yegg]

You should include Half-word and QuadWord. According to answers.com these are actual Word forms. I think by their name you will know what their value is to be.

[Arta]

nybble*

What about strings?

[R.a.B.B.i.T]

Obviously strings are a series of bytes.  Silly Arta ^^

[MyndFyre]

Obviously strings are a series of bytes.  Silly Arta ^^

Yeah, but different types of strings are different kinds of sequences of bytes. 

[dxoigmn]

From the document:

The Nibble
I am not aware of a nibble being used in Battle.net programming, but for completeness I will discuss it here. A nibble is four bits, half a byte. The biggest nibble is 2^4, or 16.

The large value of a nibble (nybble, however you want to spell it) is 15, not 16. There are, however, 16 possible values for a nibble.

The Byte
The byte is a single character, 8 bits. Any character is a single byte. The biggest byte possible is 2^8, or 256.

Same as above. The largest value of a byte is 255. There are 256 possible values though. It is not always true that any character is a single byte. That highly depends upon the type of encoding used, unless you're talking about 7-bit ASCII which should be noted then.


Actually, as I look more and more through the document, a lot of the information is wrong about sizes of datatypes.

[MyndFyre]

Generally, the largest value of data is 2^{number-of-bits} - 1

[edit]Corrected the rather egregious error.  Thanks, Arta![/edit]

[Arta]

2^{number-of-bits}-1, you mean

[Joe[x86]]

Thanks everyone. Its been fixed and you've all been credited.

Yegg, I have no experience with a HWORD. I'll look it up later. Seems as if it would be no different than a byte.

[dxoigmn]

x86] link=topic=12613.msg125433#msg125433 date=1125002871]
Thanks everyone. Its been fixed and you've all been credited.

Yegg, I have no experience with a HWORD. I'll look it up later. Seems as if it would be no different than a byte.

The size of your WORD and DWORDS are still wrong. The number of values they can represent are be 2^16 and 2^32, respectively. Subtract one to get the maximum value they can present (if they're unsigned, that is).

[R.a.B.B.i.T]

Byte booleans aren't seen in the BNCS protocol, and WORD booleans aren't either, only DWORD Booleans are (at least by the common BotDev definitions, where the sizes are all wrong).  A more accurate term for "DWORD Boolean" would be "32-Bit Boolean", however.  Nybble is in there for no reason; it is not used by the BNCS protocol nor by any future definition you present.  A more accurate list:
Unsigned Byte: 7 (ANSI) or 8 (ASCII) bits; value range from 0 - 255 inclusive
HWORD: One half of the WORD-size of the CPU; on a 32-bit system a HWORD is 2 bytes, and on a 64-bit system a HWORD is 4 bytes.
WORD: The standard data size of the CPU; on a 32-bit system a WORD is 4 bytes, and on a 64-bit system a WORD is 8 bytes.
32-Bit Boolean: A 32-bit represenation of 0 or 1.
DWORD: Double the WORD-size of the CPU; on a 32-bit system a DWORD is 8 bytes, and on a 64-bit system a DWORD is 16 bytes.
QWORD: Quadruple the WORD-size of the CPU; on a 32-bit system a QWORD is 16 bytes, and on a 64-bit system it is 64 bytes.

I still say Arta and his crew need to update BnetDocs with the correct information.

[Arta]

I've never heard 'HWORD' before. That looks like a SHORT to me.

[Newby]

Nor have I. I have heard of QWORDS, though.

[iago]

x86] link=topic=12613.msg125433#msg125433 date=1125002871]
Thanks everyone. Its been fixed and you've all been credited.

Yegg, I have no experience with a HWORD. I'll look it up later. Seems as if it would be no different than a byte.

The size of your WORD and DWORDS are still wrong. The number of values they can represent are be 2^16 and 2^32, respectively. Subtract one to get the maximum value they can present (if they're unsigned, that is).

The above is correct

A WORD is not always the same size on all systems, but for the purpose of Battle.net bot development, we will consider it to always be 16 bits, or two bytes. A WORD can be up to 255^2, and coresponds with the BASIC data type Integer, and the C data type short.

A word can be up to 256²-1, or 65525.  It has 256², or 65536 possible values. 

You'd be better off using the 2^x notation. 

[dxoigmn]

Nor have I. I have heard of QWORDS, though.

QWORDS are quad-words, 64-bits typically. Pertaining to Battle.net, the only place I have seen them used was for a character's experience in Diablo II.