Implement set 1 challenge 2.

src/main.rs

@@ -1,7 +1,11 @@
 mod set1;
 
 use crate::set1::challenge1;
+use crate::set1::challenge2;
+use crate::set1::challenge3;
 
 fn main() {
     challenge1();
+    challenge2();
+    challenge3();
 }

src/set1.rs

@@ -1,6 +1,8 @@
+use std::fmt::Write;
 use std::num::ParseIntError;
 use std::str;
 
+#[derive(PartialEq, PartialOrd, Debug)]
 pub struct HexBytes(Vec<u8>);
 pub struct Base64Bytes(Vec<u8>);
 
@@ -88,9 +90,9 @@ impl HexBytes {
         )
     }
 
-    pub fn from_str(s: &str) -> Result<HexBytes, String> {
+    pub fn from_str(s: &str) -> HexBytes {
         if s.len() % 2 != 0 {
-            return Err(String::from("Input string has uneven number of characters"));
+            panic!("Input string has uneven number of characters");
         }
 
         let bytes_result: Result<Vec<u8>, ParseIntError> = (0..s.len())
@@ -99,24 +101,55 @@ impl HexBytes {
             .collect();
 
         match bytes_result {
-            Ok(b) => Ok(HexBytes(b)),
-            Err(_) => Err(String::from("Could not convert all digit pairs to hex.")),
+            Ok(b) => HexBytes(b),
+            Err(_) => panic!("Could not convert all digit pairs to hex."),
         }
     }
+
+    pub fn to_utf8_string(&self) -> String {
+        let HexBytes(v) = self;
+        String::from(str::from_utf8(&v).unwrap())
+    }
+
+    pub fn to_hex_string(&self) -> String {
+        let HexBytes(v) = self;
+        let mut r = String::new();
+        for e in v.iter() {
+            write!(r, "{:02x}", e);
+        }
+        r
+    }
+
+    fn xor(HexBytes(a): &HexBytes, HexBytes(b): &HexBytes) -> HexBytes {
+        HexBytes(
+            Iterator::zip(a.iter(), b.iter())
+                .map(|z| *(z.0) ^ *(z.1))
+                .collect(),
+        )
+    }
 }
 
 pub fn challenge1() {
     let input = HexBytes::from_str("49276d206b696c6c696e6720796f757220627261696e206c696b65206120706f69736f6e6f7573206d757368726f6f6d");
     let expected = String::from("SSdtIGtpbGxpbmcgeW91ciBicmFpbiBsaWtlIGEgcG9pc29ub3VzIG11c2hyb29t");
-    match input {
-        Ok(bytes) => {
-            let output = bytes.to_base64();
-            if output.to_string() != expected {
-                println!("HexBytes.to_base64 failed.")
-            } else {
-                println!("[okay] Challenge 1: {}", output);
-            }
-        }
-        Err(e) => println!("Error: {}", e),
-    };
+    let result = input.to_base64();
+    if result.to_string() == expected {
+        println!("[okay] Challenge 1: {}", result);
+    } else {
+        println!("[fail] Challenge 1")
+    }
 }
+
+pub fn challenge2() {
+    let a = HexBytes::from_str("1c0111001f010100061a024b53535009181c");
+    let b = HexBytes::from_str("686974207468652062756c6c277320657965");
+    let r = HexBytes::xor(&a, &b);
+    let e = HexBytes::from_str("746865206b696420646f6e277420706c6179");
+    if r == e {
+        println!("[okay] Challenge 2: {}", r.to_hex_string());
+    } else {
+        println!("[fail] Challenge 2")
+    }
+}
+
+pub fn challenge3() {}