Thread: Print hexadecimal strings from binary

Hello to all in forum,

I'm newbie in C/C++, I would like to have some help from you experts.

May you give some example in how to search in C or C++ a hexadecimal patterns within a binary file.

For example:
String1:

Code:

0x44 0x65 0x07

Then, once found, extract those 3 bytes and the next 11 bytes (14 bytes in total).
Finally, from those 14 bytes, print without spaces "bytes 1 to 6", "bytes 6 to 12", and byte "13 to 14".
Then I would like to print last 2 bytes (13 to 14) joined in decimal format.

The output without any conversion would be:

Code:

446507c90688 888000800005 0015
4465072ec918 059173495269 002C
44650700cc01 01811bc90b00 00AB

But the output converting to decimal the last 2 bytes would be:

Code:

446507c90688 888000800005 21
4465072ec918 059173495269 44
44650700cc01 01811bc90b00 171

The sample file is attached, and looks like this:

Code:

06    00    00    80    00    00    00    80    09    3c    c9    06    88    88    80    00
80    00    44    65    07    c9    06    88    88    80    00    80    00    05    00    15
37    06    01    00    00    01    00    65    00    00    00    02    00    00    02    00
18    00    00    00    03    00    00    03    00    17    00    00    00    04    00    00
04    00    01    00    00    00    05    00    00    05    00    15    00    00    00    0a
00    ff    ff    00    65    00    00    44    65    07    2e    c9    18    05    91    73
49    52    69    00    2C    ff    ff    ff    00    cb    41    04    72    23    01    ff
ff    ff    00    01    03    ca    03    08    08    fe    cb    0a    00    00    00    00
00    44    65    07    00    cc    01    01    81    1b    c9    0b    00    00    AB    55
01    11    04    b1    7f    ff    ff    ff    ca    06    00    00    00    00    00    00

Thanks for any help or suggestion.

Your hex-dump program has a bug. The hex view of your file that you posted in code tags is not an exact representation of the file you attached. For example, starting at line 8 in the code tags, your actual file does not have two FF's in a row.

At any rate, you should post your attempt at solving your problem.

(And your binary file should probably have an extension other than .txt since it's definitely not a text file. You can give it no extension, or .bin, or one you invent.)

Hello oogabooga,

I'm asking for some help in this because I don't know how to begin to make an attempt. I have the idea to use regular expression but I don't know how to apply it and if it is a good option.

I'm attaching again the file and now I've verified the hexdump is correct representation of code tags.

PD: I've put "txt" extension because without extension or using another extension the forum application doesn't let me upload the file.

Code:

06 00 00 80 00 00 00 80  09 3c c9 06 88 88 80 00
80 00 44 65 07 c9 06 88  88 80 00 80 00 05 00 15
37 06 01 00 00 01 00 65  00 00 00 02 00 00 02 00
18 00 00 00 03 00 00 03  00 17 00 00 00 04 00 00
04 00 01 00 00 00 05 00  00 05 00 15 00 00 00 0a
00 ff ff 00 65 00 00 44  65 07 2e c9 18 05 91 73
49 52 69 00 2c ff ff ff  00 cb 41 04 72 23 01 ff
ff 00 01 03 ca 03 08 08  fe cb 0a 00 00 00 00 00
44 65 07 00 cc 01 01 81  1b c9 0b 00 00 ab 55 33
01 11 04 b1 7f ff ff ca  06 00 00 00 00 00 00 00

Thanks for any help.

As a first attempt, try creating a program that reads the file a byte at a time and when it reads a 0x44 byte, prints out that byte and the next 13 bytes. Post the program.

Input iterators may be helpful.
Other than that, there are a lot of algorithms that work with iterations and there are also output formatting for writing to file/console (ostream).

Have you tried? If so, post your code.
Make a small program from scratch that applies these techniques to practice them. Once you've got that down, you can apply it to your big problem.

If you don't know the C++ language, then you should probably read a beginner's book (such as this).
But let's start with you do know. Do you know what iterators are? Do you know what algorithms there are or where to find them? Do you know how to format output?