serata losca

src/lib.rs

@@ -1,8 +1,106 @@
-pub const BASE64_ALPHABET : &str = "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/=-_";
-pub const HEX_ALPHABET : &str = "ABCDEFabcdef0123456789";
 
-// Calculate the shannon entropy of a given byte slice
-pub fn shannon_entropy(bytes: &[u8]) -> f32 {
+// Calculate the shannon entropy of a given string for a given alphabeth
+pub fn shannon_entropy(s: &str) -> f32 {
+    let mut entropy = 0f32;
+
+    if s.is_empty() {
+        return entropy;
+    }
+
+    for c in 0..=255 {
+        let count = s.matches(char::from(c)).count() as f32;
+        let slen = s.len() as f32;
+        let p : f32 = count / slen;
+        println!("{}, {:?} {:?} {:?}", c, count, slen, p);
+        if p > 0.0 {
+            entropy += - p * p.log2();
+        }
+    }
+
+    entropy
+}
+
+// Calculate the shannon entropy of a given string detecting the used alphabeth
+pub fn str_shannon_entropy(s: &str) -> f32 {
+    let mut entropy = 0f32;
+
+    if s.is_empty() {
+        return entropy;
+    }
+    entropy = 1f32;
+
+    entropy
+}
+
+
+// Tests
+#[cfg(test)]
+mod tests {
+    use super::shannon_entropy;
+
+    #[test]
+    fn it_works() {
+        let test_strings = vec![
+            ("hello world", 2.8453512),
+            ("hello worldd", 2.8553884),
+            ("a", 0.0),
+            ("", 0.0),
+        ];
+
+        for (test, answer) in test_strings {
+            let entropy: f32 = shannon_entropy(test);
+            assert_eq!(entropy, answer);
+        }
+    }
+
+    #[test]
+    fn test_entropy_empty() {
+        let h = shannon_entropy("");
+        assert_eq!(h, 0.0);
+    }
+
+    #[test]
+    fn test_entropy_a() {
+        let h = shannon_entropy("a");
+        assert_eq!(h, 0.0);
+    }
+
+    #[test]
+    fn test_entropy_aaaaa() {
+        let h = shannon_entropy("aaaaa");
+        assert_eq!(h, 0.0);
+    }
+
+    #[test]
+    fn test_entropy_ab() {
+        let h = shannon_entropy("ab");
+        assert_eq!(h, 1.0);
+    }
+
+    #[test]
+    fn test_entropy_aab() {
+        let h = shannon_entropy("aab");
+        assert_eq!(h, 0.9182958);
+    }
+
+    #[test]
+    fn test_entropy_equal_distribution1() {
+        let mut stringmerda = String::new();
+
+        for _ in 0..2 {
+            for i in 0..=255 {
+                stringmerda.push(char::from(i));
+            }
+        }
+
+        // println!("{:#?}", stringmerda.as_bytes());
+        println!("{}", stringmerda.len());
+        // let h = shannon_entropy(&stringmerda);
+
+        // assert_eq!(h, 8.0);
+    }
+
+    pub fn shannon_entropy2(bytes: &[u8]) -> f32 {
         let mut entropy = 0.0;
         let mut counts = [0; 256];
 
@@ -20,112 +118,25 @@ pub fn shannon_entropy(bytes: &[u8]) -> f32 {
         entropy
     }
 
-// Calculate the shannon entropy of a given byte slice for a specific charset
-pub fn shannon_entropy_charset(bytes: &[u8], charset: &str) -> f32 {
-    let mut entropy = 0.0;
+    // #[test]
+    // fn test_entropy_equal_distribution2() {
+    //     let mut bytes = [0u8; 256*2];
+    //     for i in 0..bytes.len() {
+    //         bytes[i] = (i % 256) as u8;
+    //     }
 
-    for single_char in charset.chars() {
-        let count = bytes.iter().filter(|&&n| n as char == single_char).count();
-        if count == 0 { continue }
-        let p: f32 = (count as f32) / (bytes.len() as f32);
-        entropy -= p * p.log(2.0);
-    }
-
-    entropy
-}
-
-// Determine if a string is made up only of hexdigits
-pub fn is_hex_str(s: &str) -> bool {
-    s.chars().filter(|&n| !(n.is_digit(16))).count() == 0
-}
-
-// Determine if a string is made up only of base64/base64url digits
-pub fn is_base64_str(s: &str) -> bool {
-    let alphabet: Vec<_> = BASE64_ALPHABET.chars().collect();
-    s.chars().filter(|n| !(alphabet.contains(n))).count() == 0
-}
-
-// Calculate the shannon entropy of a given string
-pub fn str_entropy(s: &str) -> f32 {
-    if is_hex_str(s) {
-        return shannon_entropy_charset(s.as_bytes(), HEX_ALPHABET);
-    }
-
-    if is_base64_str(s) {
-        return shannon_entropy_charset(s.as_bytes(), BASE64_ALPHABET);
-    }
-
-    shannon_entropy(s.as_bytes())
-}
-
-// Tests
-#[cfg(test)]
-mod tests {
-    use super::{shannon_entropy, str_entropy, is_hex_str, is_base64_str};
-
-    #[test]
-    fn test_entropy() {
-        let test_strings = vec![
-            ("hello world", 2.8453512),
-            ("hello worldd", 2.8553884),
-            ("a", 0.0),
-            ("aaaaa", 0.0),
-            ("ab", 1.0),
-            ("aab", 0.9182958),
-            ("", 0.0),
-        ];
-
-        for (test, answer) in test_strings {
-            let entropy: f32 = str_entropy(test);
-            assert_eq!(entropy, answer);
-        }  
-    }
-
-    #[test]
-    fn test_entropy_equal_distribution1() {
-        let mut bytes = [0u8; 256];
-        for i in 0..256 {
-            bytes[i] = i as u8;
-        }
-
-        let h = shannon_entropy(&bytes);
-        assert_eq!(h, 8.0);
-    }
-
-    #[test]
-    fn test_entropy_equal_distribution2() {
-        let mut bytes = [0u8; 256*2];
-        for i in 0..bytes.len() {
-            bytes[i] = (i % 256) as u8;
-        }
-
-        let h = shannon_entropy(&bytes);
-        assert_eq!(h, 8.0);
-    }
+    //     println!("{}", bytes.len());
+    //     let pippo = String::from_utf8_lossy(&bytes);
+    //     println!("{}", pippo.len());
+    //     let h = shannon_entropy(&pippo);
+    //     assert_eq!(h, 8.0);
+    // }
 
     #[test]
     fn test_entropy_helloworld() {
-        let h = str_entropy("hello, world");
+        let h = shannon_entropy("hello, world");
         assert_eq!(h, 3.0220551);
-        let h = str_entropy("hello world");
+        let h = shannon_entropy("hello world");
         assert_eq!(h, 2.8453512);
     }
-
-    #[test]
-    fn test_hex_str_reconizer() {
-        let s = is_hex_str("0123456789abcdef0123456789abcdef");
-        assert_eq!(s, true);
-        let s = is_hex_str("68656c6c6f20776f726c64");
-        assert_eq!(s, true);
-        let s = is_hex_str("g");
-        assert_eq!(s, false);
-    }
-
-    #[test]
-    fn test_base64_str_reconizer() {
-        let s = is_base64_str("aGVsbG8gd29ybGQ=");
-        assert_eq!(s, true);
-        let s = is_base64_str("#@$");
-        assert_eq!(s, false);
-    }
 }