// Public domain / CC0. Use freely for any purpose. RoyR 2026
// strings.cm - String manipulation
// Demonstrates: string literals, character arrays, string functions

void printf(uint8 *fmt);

int32 str_len(uint8 *s) {
    int32 len = 0;
    while (s[len]) {
        len = len + 1;
    }
    return len;
}

void str_copy(uint8 *dest, uint8 *src) {
    int32 i = 0;
    while (src[i]) {
        dest[i] = src[i];
        i = i + 1;
    }
    dest[i] = 0;
}

int32 str_cmp(uint8 *s1, uint8 *s2) {
    int32 i = 0;
    while (s1[i] && s2[i]) {
        if (s1[i] != s2[i]) {
            return s1[i] - s2[i];
        }
        i = i + 1;
    }
    return s1[i] - s2[i];
}

void str_reverse(uint8 *s) {
    int32 len = str_len(s);
    int32 i = 0;
    int32 j = len - 1;
    while (i < j) {
        uint8 temp = s[i];
        s[i] = s[j];
        s[j] = temp;
        i = i + 1;
        j = j - 1;
    }
}

int32 main(void) {
    uint8 *msg = "Hello, World!";
    printf("Original string: %s\n", msg);
    printf("Length: %d\n", str_len(msg));
    
    uint8 buffer[100];
    str_copy(buffer, msg);
    printf("Copied string: %s\n", buffer);
    
    str_reverse(buffer);
    printf("Reversed: %s\n", buffer);
    
    uint8 *s1 = "apple";
    uint8 *s2 = "banana";
    uint8 *s3 = "apple";
    
    printf("\nString comparison:\n");
    printf("  '%s' vs '%s': %d\n", s1, s2, str_cmp(s1, s2));
    printf("  '%s' vs '%s': %d\n", s1, s3, str_cmp(s1, s3));
    printf("  '%s' vs '%s': %d\n", s2, s1, str_cmp(s2, s1));
    
    return 0;
}