我有一个带有十六进制地址（char）的文件，将它们转换为unsigned long的最佳方法是什么？

I got a file full with hexadecimal addresses, I've managed to parse the file and fetch them yet I must convert them back to unsigned long, what's the best algorithm or fast way to do so considering the file is very long (a few megs) ?I got a file full with hexadecimal addresses, I