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Introduction

Tom and Nathan have written an excellent "Perl Cookbook" holding many solutions to common problems. It has solved many problems for me the last years, but... I very often run into problems for which there is no solution in the cookbook. I decided to organize my own engineered solutions into a web Perl cookbook. This page is not to be seen as an alternative to Tom's and Nathan's book, but rather as a complement.

This is to be considered work-in-progress, which is why there might not be to many entries here initially.

Converting a Hex String to Values

Recipes

Converting a Hex String to Values

Problem

You want to convert a string of hexadecimal characters to a list of their byte-values.

Solution

Use a combination of pack and unpack to (1) pack the hex string into a binary structure and then (2) unpack the binary structure into a list of unsigned char values:

$hex_string = "000102031F";
$STRING = pack("H*", $hex_string);      # (1)
@VALUE = unpack("C*", $STRING);         # (2)

Discussion

The problem occured when I was writing a program to read and parse Motorola S-records in a file. The data part of each S-record consists of a hex-string which is then to be interpreted as data bytes.

Last modified: Wed May 30 10:31:29 2001