feat: support no_std

Cargo.toml

@@ -22,6 +22,6 @@ name = "bench"
 harness = false
 
 [features]
-# depcrecated, will be removed in a future release
-array_chunks = []
+default = ["std"]
+std = []
 unsafe = []

src/decode.rs

@@ -1,24 +1,27 @@
 use crate::alphabet::{self, SIZE, SIZE_SIZE};
-use std::error::Error;
-use std::fmt::{Display, Formatter};
+
+#[cfg(not(feature = "std"))]
+use alloc::vec::Vec;
+
+use core::fmt::{Display, Formatter};
 /// The error type returned when the input is not a valid base45 string
 #[derive(Eq, PartialEq, Copy, Clone, Debug)]
 pub struct DecodeError;
 
 impl Display for DecodeError {
-    fn fmt(&self, f: &mut Formatter<'_>) -> std::fmt::Result {
+    fn fmt(&self, f: &mut Formatter<'_>) -> core::fmt::Result {
         f.write_str("Invalid base45 string")
     }
 }
 
-impl Error for DecodeError {}
+impl core::error::Error for DecodeError {}
 
 /// Decode a string from base45
 ///
 /// Takes a base45 encoded string and returns a UTF-8 string on success
 ///
 /// ```rust,no_run
-/// # fn main() -> Result<(), Box<dyn std::error::Error>> {
+/// # fn main() -> Result<(), Box<dyn core::error::Error>> {
 /// let decoded = String::from_utf8(base45::decode("%69 VD92EX0")?)?;
 /// assert_eq!(decoded, "Hello!!");
 /// # Ok(())

src/encode.rs

@@ -1,6 +1,8 @@
 use crate::alphabet::{self, SIZE, SIZE_SIZE};
 
-#[inline(always)]
+#[cfg(not(feature = "std"))]
+use alloc::{string::String, vec::Vec};
+
 fn divmod<const N: u32>(x: u32) -> (u32, u32) {
     (x / N, x % N)
 }

src/lib.rs

@@ -1,3 +1,4 @@
+#![cfg_attr(not(feature = "std"), no_std)]
 //! Encoder/decoder for base45 that is fully compatible with
 //! [`draft-faltstrom-base45-07.txt`](https://www.ietf.org/archive/id/draft-faltstrom-base45-07.txt)
 //!
@@ -14,6 +15,9 @@
 //!   [`core::slice::ChunksExact`](https://doc.rust-lang.org/core/slice/struct.ChunksExact.html).
 //!   Ideally, there is no performance penalty using this means.
 
+#[cfg(not(feature = "std"))]
+extern crate alloc;
+
 pub mod alphabet;
 mod decode;
 mod encode;

src/tests.rs

@@ -1,4 +1,6 @@
 use crate::*;
+#[cfg(not(feature = "std"))]
+use alloc::{string::String, vec};
 
 #[test]
 fn encode_ab() {