hex to decimal binary cli tool

[DebianJoe]

Well, you guys are always sharing your nice little quality of life things, and since I had to do this for a class, I thought I'd share it.

It's a simple tool that allows you to launch it from command line with a hexadecimal number after it (like "htoi FFF" or "htoi 0xF1F" or "htoi 0XFF1"), and it converts the hex number into an integer for you. Since we were supposed to allow upper or lowercase letter, catch overflows, or allow prefixing with '0x', this one took me a bit. Seems to work well, so why not share:

Code: Select all

#include <stdio.h>
#include <stdlib.h>
#include <limits.h>

unsigned int htoi(char s[])
{
    unsigned int val = 0;
    int x = 0;

    if(s[x] == '0' && (s[x+1]=='x' || s[x+1]=='X')) x+=2;

    while(s[x] != '\0'){
        if(val > UINT_MAX) return 0;
        else if(s[x]>='0' && s[x]<='9'){
            val = val * 16 + s[x] - '0';
        }
        else if(s[x]>='A' && s[x] <='F'){
            val = val * 16 + s[x] - 'A' + 10;
        }
        else if(s[x]>='a' && s[x]<='f'){
            val = val * 16 + s[x] - 'a' + 10;
        }
        else return 0;
        x++;
    }
    return val;
}

int main(int argc, char *argv[])
{
    char *hexalpha;
    if((argc > 1) && (argc < 3))
        hexalpha=argv[1];
    else{
        printf("Must be ran as 'htoi <hexnumber>'\n");
        exit(0);
    }
    if(htoi(hexalpha)==0)
        printf("Hex string overflow or non-valid entry\n");
    else
        printf("%u\n", htoi(hexalpha));

    return 0;
}

Compile with gcc (or your favorite C compiler) and output to a file called "htoi". Copy or move to /usr/bin/ or wherever you want it, and enjoy never having to convert a hex to a decimal again.

Guess I should explain the choice of name: Hex TO Interger == htoi

[wuxmedia]

neat.
look forward to 'itoh'
mucho gusto.

[xaos52]

htoi

Code: Select all

#!/bin/sh
printf '%d\n' 0x"$1"

[DebianJoe]

^^ cute.

...../bin/sh
http://heirloom.cvs.sourceforge.net/hei ... irloom-sh/

[xaos52]

Code: Select all

#!/bin/sh
printf '%d\n' 0x"${1#0[xX]}"

This one allows 0x or 0X prefix.

It still works without the !

Yes, I know /bin/sh hides a lot of coding. But it is there ready for use on any linux system.

[DebianJoe]

It still works without the !

I honestly didn't know that. I was trying it out while you replied.

hmmm..

Code: Select all

#!/usr/bin/env python
from sys import argv
script, first = argv
i = int(first, 16)
print i

....should work too, but WAY more overhead than any of the supplied.

Edit: I think it's probably reasonable to point out that Xaos's answer is by far the simplest way for a user who just wants a cli option for entering in a hex number and getting out a decimal one. You're already in a shell, just make the call. The only advantage to doing it in a lower level language is if it serves as a system process that is forked elsewhere as a sub-process, and you use the IO stream for some purpose. This is mostly just me joking at this point. Also, don't call python if there's a shell/bash option, ever. It's bloated and pointless. /disclaimer

2nd Edit: (because I just can't help myself.)

Code: Select all

#!/bin/sh
htoi $1

[Titan]

Just tried this Joe and its great!

Going to go through the code and comment it to see if i understand it all, which will hopefully compliment my progress so far with the C book.

[GekkoP]

^ same here.
I'm still on learncodethehardway (both C and Python, guess why I'm going mad lately...), and I'll go through this C script to see what I can understand by my own.