Hex to char array in C

Question

Given a string of hex values i.e. e.g. \"0011223344\" so that\'s 0x00, 0x11 etc.

How do I add these values to a char array?

Equivalent to say:

<

Answer 1

Below are my hex2bin and bin2hex implementations.

These functions:

• Are public domain (feel free to copy and paste)
• Are simple
• Are correct (i.e., tested)
• Perform error handling (-1 means invalid hex string)

hex2bin

static char h2b(char c) {
    return '0'<=c && c<='9' ? c - '0'      :
           'A'<=c && c<='F' ? c - 'A' + 10 :
           'a'<=c && c<='f' ? c - 'a' + 10 :
           /* else */         -1;
}

int hex2bin(unsigned char* bin,  unsigned int bin_len, const char* hex) {
    for(unsigned int i=0; i

bin2hex

static char b2h(unsigned char b, int upper) {
    return b<10 ? '0'+b : (upper?'A':'a')+b-10;
}

void bin2hex(char* hex, const unsigned char* bin, unsigned int bin_len, int upper) {
    for(unsigned int i=0; i>4,   upper);
        hex[2*i+1] = b2h(bin[i]&0x0F, upper);
    }
}