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#include "wtf8.h"

/*
 * Check if first two bits of the character are "10", meaning it's a UTF-8
 * continuation character
 */
int is_utf8_cont(unsigned char c) {
    return (c & 0xC0) == 0x80;
}

/*
 * Print each octet of a string of characters as lowercase hex followed by a
 * trailing space, ending with a newline
 */
void print_octets(char *s) {
    unsigned char c;

    /*
     * Iterate through the string, printing each octet, ending with a newline
     */
    while ((c = *s++))
        printf("%c%02x", (is_utf8_cont(c) ? '-' : ' '), c);
    putchar('\n');

    return;
}

/*
 * Print each of the UTF-8 characters to align with the output of
 * print_octets(), with each character in line with the end of the octet that
 * terminates it, ending with a newline
 */
void print_characters(char *s) {

    /*
     * We need a short counter to find how long each character is
     */
    int c;

    /*
     * Iterate through the string
     */
    while (*s) {

        /*
         * Print blanks and increment a counter until we find how long this
         * character is
         */
        for (c = 1; is_utf8_cont(s[c]); c++)
            printf("   ");

        /*
         * Print two spaces, and then the full character
         */
        printf("  ");
        while (c--)
            putchar(*s++);
    }

    /*
     * End with a newline
     */
    putchar('\n');
    return;
}

/*
 * Main function
 */
int main(int argc, char **argv) {

    /*
     * Check we have one and only one argument
     */
    if (argc != 2)
        exit(EXIT_FAILURE);

    /*
     * Print the sole argument first as hex octets, then as characters, spaced
     * accordingly
     */
    print_octets(argv[1]);
    print_characters(argv[1]);

    /*
     * Done!
     */
    exit(EXIT_SUCCESS);
}