hex2bin.c File Reference

Converts hexadecimal input strings to binary. More...

#include "sysdefs.h"
#include <stdio.h>
#include <ctype.h>

Go to the source code of this file.

Functions
static int	getbin (int x)
int	main (void)

Detailed Description

Converts hexadecimal input strings to binary.

Definition in file hex2bin.c.

Function Documentation

getbin()

static int getbin ( int  x )

static

Definition at line 19 of file hex2bin.c.

{
    if (x >= '0' && x <= '9')
        return x - '0';
 
    if (x >= 'A' && x <= 'F')
        return x - 'A' + 10;
 
    return x - 'a' + 10;
}

References x.

Referenced by main().

main()

int main

(

void

)

Definition at line 32 of file hex2bin.c.

{
    while (true) {
        int byte = getchar();
        if (byte == EOF)
            return 0;
        if (!isxdigit(byte))
            continue;
 
        const int digit = getchar();
        if (digit == EOF || !isxdigit(digit)) {
            fprintf(stderr, "Invalid input\n");
            return 1;
        }
 
        byte = (getbin(byte) << 4) | getbin(digit);
        if (putchar(byte) == EOF) {
            perror(NULL);
            return 1;
        }
    }
}

References getbin(), isxdigit, and NULL.