Refactor code based on clippy suggestions

src/bytes.rs

@@ -11,13 +11,16 @@ impl Bytes {
     }
 
     pub fn from_utf8(s: &str) -> Bytes {
-        Bytes(s.as_bytes().iter().map(|c| c.clone()).collect())
+        Bytes(s.as_bytes().to_vec())
     }
 
-    #[allow(dead_code)]
     pub fn to_utf8(&self) -> String {
         let Bytes(v) = self;
-        String::from(std::str::from_utf8(&v).unwrap())
+        String::from(std::str::from_utf8(v).unwrap())
+    }
+
+    pub fn to_sub_utf8(&self, length: usize) -> String {
+        Bytes(self.0[..length].to_vec()).to_utf8()
     }
 
     pub fn len(&self) -> usize {
@@ -69,7 +72,7 @@ impl Bytes {
     pub fn is_ascii(&self) -> bool {
         let Bytes(v) = self;
         for &c in v.iter() {
-            if c < 32 || c > 127 {
+            if !(32..=127).contains(&c) {
                 return false;
             }
         }
@@ -103,7 +106,7 @@ impl Bytes {
         h.last().unwrap().1
     }
 
-    pub fn pad_pkcs7(&mut self, block_size: usize) -> () {
+    pub fn pad_pkcs7(&mut self, block_size: usize) {
         let Bytes(v) = self;
         let padding_value = (block_size - v.len() % block_size) as u8;
         for _ in 0..padding_value {
@@ -118,7 +121,7 @@ impl Bytes {
         let last_block_index = self.len() / block_size - 1;
         let last_block = self.get_block(last_block_index, block_size).0;
         let pad_byte = last_block[block_size - 1];
-        if pad_byte < 1 || pad_byte > 16 {
+        if !(1..=16).contains(&pad_byte) {
             return false;
         }
         for i in 0..(pad_byte as usize) {
@@ -127,10 +130,10 @@ impl Bytes {
                 return false;
             }
         }
-        return true;
+        true
     }
 
-    pub fn remove_pkcs7(&mut self, block_size: usize) -> () {
+    pub fn remove_pkcs7(&mut self, block_size: usize) {
         if !self.has_valid_pkcs7(block_size) {
             return;
         }
@@ -141,7 +144,7 @@ impl Bytes {
         }
     }
 
-    pub fn flip_bit(&mut self, byte_index: usize, bit_index: usize) -> () {
+    pub fn flip_bit(&mut self, byte_index: usize, bit_index: usize) {
         let Bytes(v) = self;
         let flip_mask: u8 = 0b1 << bit_index;
         v[byte_index] ^= flip_mask;