How to read information from a byte[]

Question

0.00/5 (No votes)

See more:

Hi I need help on how to read information from the byte[] in C++. I know the header information about the array like how many bits to be read at a time(for example 4 bits for integer )and the order.

Thanks

Posted 16-Oct-12 1:14am

Chirma

Updated 21-Oct-12 23:42pm

v2

Add a Solution

Comments

OriginalGriff 16-Oct-12 7:26am

This is not a good question - we cannot work out from that little what you are trying to do.
Remember that we can't see your screen, access your HDD, or read your mind.
Use the "Improve question" widget to edit your question and provide better information.

BTW: I suspect you mean "Bytes" not "Bits": please try to be accurate, as it can make a big difference to the answer!

2 solutions

Solution 2

You have edited this question, but not added any more information. If you want to read blocks of data (from where?) in C++ then look at the fstream[^] class, or the fread()[^] CRT function.

Posted 22-Oct-12 1:49am

Richard MacCutchan

Add a Solution

Add your solution here

Treat my content as plain text, not as HTML

Preview 0

…

Existing Members

Sign in to your account

...or Join us

Download, Vote, Comment, Publish.

Your Email
Password
Forgot your password?

Your Email
This email is in use. Do you need your password?
Optional Password

I have read and agree to the Terms of Service and Privacy Policy
Please subscribe me to the CodeProject newsletters

When answering a question please:

Read the question carefully.
Understand that English isn't everyone's first language so be lenient of bad spelling and grammar.
If a question is poorly phrased then either ask for clarification, ignore it, or edit the question and fix the problem. Insults are not welcome.
Don't tell someone to read the manual. Chances are they have and don't get it. Provide an answer or move on to the next question.

Let's work to help developers, not make them feel stupid.

This content, along with any associated source code and files, is licensed under The Code Project Open License (CPOL)

Marius Bancila · Accepted Answer · 2012-10-16T01:29:00

You're not making too much sense. I think you make a confusion between bits and bytes. I guess what you want is to extract data from an array of bytes. Notice there is no byte type in C++, that is probably a typedef (for unsigned char). I also guess what you are looking for is something like this:

C++

int extract_int(unsigned char[] array, size_t offset)
{
    int n = 0;
    memcpy(&n, array + offset, sizeof(n));
    return n;
}

However, this does not address some issues:
- the endianess: little endian vs. big endian, and how your data is stored in the array; my sample assume it's little endian
- validation: you need to do some extra validation, like that offset + sizeof the extracted data type is not beyond the boundaries of the array.