Make alphabet use bytes instead of characters

src/decode.rs

@@ -65,7 +65,7 @@ impl<R: Read, W: Write> Decoder<R, W> {
             for (i, &c) in in_buf.iter().enumerate() {
                 let c = c.into();
                 num <<= 6;
-                if c == self.alphabet.pad() {
+                if c == char::from(self.alphabet.pad()) {
                     continue;
                 }
                 if i != bytes {

src/encode.rs

@@ -68,14 +68,21 @@ impl<R: Read, W: Write> Encoder<R, W> {
             }
             if let Some(wrap) = self.wrap {
                 for idx in 0..=3 {
-                    write!(self.writer, "{}", obuf[idx])?;
+                    write!(self.writer, "{}", char::from(obuf[idx]))?;
                     total += 1;
                     if total % wrap == 0 {
                         writeln!(self.writer)?;
                     }
                 }
             } else {
-                write!(self.writer, "{}{}{}{}", obuf[0], obuf[1], obuf[2], obuf[3])?;
+                write!(
+                    self.writer,
+                    "{}{}{}{}",
+                    char::from(obuf[0]),
+                    char::from(obuf[1]),
+                    char::from(obuf[2]),
+                    char::from(obuf[3])
+                )?;
             }
             if outlen < 4 {
                 break;

src/lib.rs

@@ -10,19 +10,20 @@ pub use {decode::Decoder, encode::Encoder, error::Error as B64Error};
 #[derive(Clone, Copy)]
 /// Defines the character set used for encoding and decoding
 pub struct B64Alphabet {
-    items: [char; 64],
-    pad: char,
+    items: [u8; 64],
+    pad: u8,
 }
 
 /// The most common Base64 alphabet as defined in [RFC4648](https://www.rfc-editor.org/rfc/rfc4648)
 pub static B64_RFC4648_ALPHABET: B64Alphabet = B64Alphabet {
     items: [
-        'A', 'B', 'C', 'D', 'E', 'F', 'G', 'H', 'I', 'J', 'K', 'L', 'M', 'N', 'O', 'P', 'Q', 'R',
-        'S', 'T', 'U', 'V', 'W', 'X', 'Y', 'Z', 'a', 'b', 'c', 'd', 'e', 'f', 'g', 'h', 'i', 'j',
-        'k', 'l', 'm', 'n', 'o', 'p', 'q', 'r', 's', 't', 'u', 'v', 'w', 'x', 'y', 'z', '0', '1',
-        '2', '3', '4', '5', '6', '7', '8', '9', '+', '/',
+        b'A', b'B', b'C', b'D', b'E', b'F', b'G', b'H', b'I', b'J', b'K', b'L', b'M', b'N', b'O',
+        b'P', b'Q', b'R', b'S', b'T', b'U', b'V', b'W', b'X', b'Y', b'Z', b'a', b'b', b'c', b'd',
+        b'e', b'f', b'g', b'h', b'i', b'j', b'k', b'l', b'm', b'n', b'o', b'p', b'q', b'r', b's',
+        b't', b'u', b'v', b'w', b'x', b'y', b'z', b'0', b'1', b'2', b'3', b'4', b'5', b'6', b'7',
+        b'8', b'9', b'+', b'/',
     ],
-    pad: '=',
+    pad: b'=',
 };
 
 impl Default for B64Alphabet {
@@ -34,14 +35,14 @@ impl Default for B64Alphabet {
 impl B64Alphabet {
     pub(crate) fn get(&self, c: char) -> Option<usize> {
         for (idx, x) in self.items.iter().enumerate() {
-            if *x == c {
+            if char::from(*x) == c {
                 return Some(idx);
             }
         }
         None
     }
 
-    pub(crate) fn pad(&self) -> char {
+    pub(crate) fn pad(&self) -> u8 {
         self.pad
     }
 }