ultra fast dump function in C (output like hexdump -C)

hexdump.c

// ultra fast dump function (output like hexdump -C)
void hexdump(const void *data, size_t size)
{
    static const char digits[] = "0123456789abcdef";
    char line[80]; // we use 79 chars at most
    size_t i;
    int j;

    for (i = 0; i < size; i += 16)
    {
        // offset in hex (8 digits)
        line[0] = digits[(i >> 28) & 0x0f];
        line[1] = digits[(i >> 24) & 0x0f];
        line[2] = digits[(i >> 20) & 0x0f];
        line[3] = digits[(i >> 16) & 0x0f];
        line[4] = digits[(i >> 12) & 0x0f];
        line[5] = digits[(i >> 8) & 0x0f];
        line[6] = digits[(i >> 4) & 0x0f];
        line[7] = digits[i & 0x0f];

        // placeholder for hex dump
        memset(line + 8, ' ', 52);

        for (j = 0; (j < 16) && (i + j < size); j += 1)
        {
            uint8_t byte = ((const uint8_t *)data)[i + j];

            // byte as hex digits
            size_t o = j * 3 + ((j >= 8) ? 11 : 10);
            line[o] = digits[(byte >> 4) & 0xf];
            line[o + 1] = digits[byte & 0xf];

            // byte as printable char
            line[61 + j] = ((byte >= 32) && (byte <= 126)) ? (char)byte : '.';
        }

        line[60] = '|';      // opening delimiter for ascii dump
        line[61 + j] = '|';  // closing delimiter
        line[62 + j] = '\n'; // newline

        fwrite(line, 1, 63 + j, stdout);
    }

    printf("%08zx\n", size);
}