Merge #90: Do not require know size at compile time

060ef26 Do not require know size at compile time (Tobin C. Harding)

Pull request description:

  The `Base32Len` and `ToBase32` traits currently require the implementing type to have a known size at compile time. This is an unnecessary restriction.

  Fix: #82

  FTR I did not know at first which functions this reasoning could by applied to so I added `+ ?Sized` to every generic that was `AsRef<[u8]>` and let the compiler tell me which ones were correct.

ACKs for top commit:
  apoelstra:
    ACK 060ef26

Tree-SHA512: ad03db3244203e7d3f74dda2ec46bdde5395e9bfc37e7ccf5a2886a16c4ad16710473b616a944699babc111f61fdca80cf2e9f5f448d219b335a5057ec5cec38

Author: apoelstra

src/lib.rs

@@ -309,7 +309,7 @@ pub trait Base32Len: ToBase32 {
 }
 
 #[cfg(feature = "alloc")]
-impl<T: AsRef<[u8]>> ToBase32 for T {
+impl<T: AsRef<[u8]> + ?Sized> ToBase32 for T {
     fn write_base32<W: WriteBase32>(&self, writer: &mut W) -> Result<(), <W as WriteBase32>::Err> {
         // Amount of bits left over from last round, stored in buffer.
         let mut buffer_bits = 0u32;
@@ -354,7 +354,7 @@ impl<T: AsRef<[u8]>> ToBase32 for T {
 }
 
 #[cfg(feature = "alloc")]
-impl<T: AsRef<[u8]>> Base32Len for T {
+impl<T: AsRef<[u8]> + ?Sized> Base32Len for T {
     fn base32_len(&self) -> usize {
         let bits = self.as_ref().len() * 8;
         if bits % 5 == 0 {