Merge #166: Introduce crate level decoding functions

97222f2 Introduce crate level decoding functions (Tobin C. Harding)

Pull request description:

  We would like to release a bare-bones 1.0 version of this crate that excludes the `FromHex` trait. So that users can still decode vectors and arrays without the trait introduced two new decoding functions.

  Intentionally do not use `decode` as the name incase we later want to add a more general `decode` function.

ACKs for top commit:
  Kixunil:
    ACK 97222f2
  apoelstra:
    ACK 97222f2; successfully ran local tests

Tree-SHA512: 64faf6f8b617a69c74e46cf6d967525ca691559aa7c2993025298fd8d6eb88c0058cdec09d395c1418dde6571ac9cbf0793a90688661b7a33afb6f316f66b20c

src/lib.rs

@@ -66,6 +66,9 @@ pub mod prelude {
     pub use crate::{display::DisplayHex, parse::FromHex};
 }
 
+#[cfg(feature = "alloc")]
+use alloc::vec::Vec;
+
 pub(crate) use table::Table;
 
 #[rustfmt::skip]                // Keep public re-exports separate.
@@ -80,6 +83,23 @@ pub use self::{
     parse::FromHex,
 };
 
+/// Decodes a hex string into a vector of bytes.
+///
+/// # Errors
+///
+/// Errors if `s` is not a valid hex string.
+#[cfg(feature = "alloc")]
+pub fn decode_vec(s: &str) -> Result<Vec<u8>, HexToBytesError> { Vec::from_hex(s) }
+
+/// Decodes a hex string into an array of bytes.
+///
+/// # Errors
+///
+/// Errors if `s` is not a valid hex string or the correct length.
+pub fn decode_array<const N: usize>(s: &str) -> Result<[u8; N], HexToArrayError> {
+    <[u8; N]>::from_hex(s)
+}
+
 /// Possible case of hex.
 #[derive(Debug, Copy, Clone, Eq, PartialEq, Hash)]
 pub enum Case {