Add "alloc" feature

.github/workflows/rust.yml

@@ -3,7 +3,7 @@ on: [pull_request]
 name: Continuous Integration
 
 jobs:
-  test:
+  Test:
     name: Test Suite
     runs-on: ubuntu-latest
     strategy:
@@ -13,16 +13,17 @@ jobs:
           - stable
           - nightly
     steps:
+      - name: Checkout Crate
       - uses: actions/checkout@v2
+      - name: Checkout Toolchain
       - uses: actions-rs/toolchain@v1
         with:
           profile: minimal
           toolchain: ${{ matrix.rust }}
           override: true
-      - uses: actions-rs/cargo@v1
-        with:
-          command: test
-          args: --verbose --features strict
+      - name: Run Test Script
+        env: ${{ matrix.rust }}
+        run: ./contrib/test.sh
 
   fmt:
     name: Rustfmt
@@ -60,7 +61,8 @@ jobs:
           command: clippy
           args: -- -D warnings
 
-  Embedded:
+  EmbeddedWithAlloc:
+    name: no_std with alloc
     runs-on: ubuntu-latest
     steps:
       - name: Checkout
@@ -79,4 +81,20 @@ jobs:
         env:
           RUSTFLAGS: "-C link-arg=-Tlink.x"
           CARGO_TARGET_THUMBV7M_NONE_EABI_RUNNER: "qemu-system-arm -cpu cortex-m3 -machine mps2-an385 -nographic -semihosting-config enable=on,target=native -kernel"
-        run: cd embedded && cargo run --target thumbv7m-none-eabi
+        run: cd embedded/with-allocator && cargo run --target thumbv7m-none-eabi
+
+  EmbeddedNoAlloc:
+    name: no_std no alloc
+    runs-on: ubuntu-latest
+    strategy:
+    steps:
+      - uses: actions/checkout@v2
+      - uses: actions-rs/toolchain@v1
+        with:
+          profile: minimal
+          toolchain: stable
+          override: true
+      - uses: actions-rs/cargo@v1
+        with:
+          command: rustc
+          args: -- -C link-arg=-nostartfiles

.gitignore

@@ -2,5 +2,7 @@
 *.o
 /Cargo.lock
 
-/embedded/Cargo.lock
-/embedded/.cargo
+/embedded/no-allocator/Cargo.lock
+/embedded/no-allocator/.cargo
+/embedded/with-allocator/Cargo.lock
+/embedded/with-allocator/.cargo

Cargo.toml

@@ -13,7 +13,9 @@ edition = "2018"
 
 [features]
 default = ["std"]
-std = []
+std = ["alloc"]
+alloc = []
+
 # Only for CI to make all warnings errors, do not activate otherwise (may break forward compatibility)
 strict = []
 

contrib/test.sh

@@ -0,0 +1,25 @@
+#!/bin/sh
+#
+# CI test script for rust-bech32.
+#
+# The "strict" feature is used to configure cargo to deny all warnings, always use it in test runs.
+
+set -ex
+
+# Sanity, check tools exist.
+cargo --version
+rustc --version
+
+# Check without features ("strict" is a CI feature only, see above).
+cargo build --no-default-features --features="strict"
+cargo test --no-default-features --features="strict"
+
+# Check "std" feature (implies "alloc").
+cargo build --no-default-features --features="strict std"
+cargo test --no-default-features --features="strict std"
+
+# Check "alloc" feature alone.
+cargo build --no-default-features --features="strict alloc"
+cargo test --no-default-features --features="strict alloc"
+
+exit 0

embedded/no-allocator/Cargo.toml

@@ -0,0 +1,15 @@
+[package]
+authors = ["Tobin C. Harding <me@tobin.cc>"]
+edition = "2018"
+readme = "README.md"
+name = "no-allocator"
+version = "0.1.0"
+
+[profile.dev]
+panic = "abort"
+
+[profile.release]
+panic = "abort"
+
+[dependencies]
+bech32 = { path = "../../", default_features = false }

embedded/no-allocator/README.md

@@ -0,0 +1,10 @@
+# no_std test crate without an allocator
+
+This crate is based on the blog post found at:
+
+ https://blog.dbrgn.ch/2019/12/24/testing-for-no-std-compatibility/
+
+Its purpose is to test that the `rust-bech32` library can be built in a `no_std` environment without
+a global allocator.
+
+Build with: `cargo rustc -- -C link-arg=-nostartfiles`.

embedded/no-allocator/src/main.rs

@@ -0,0 +1,26 @@
+//! Test `no_std` build of `bech32`.
+//!
+//! Build with: `cargo rustc -- -C link-arg=-nostartfiles`.
+//!
+
+#![no_std]
+#![no_main]
+
+use core::panic::PanicInfo;
+
+// Note: `#[global_allocator]` is NOT set.
+
+#[allow(unused_imports)]
+use bech32;
+
+/// This function is called on panic, defining this ensures build will fail if `std` is enabled
+/// because `panic` will be defined twice.
+#[panic_handler]
+fn panic(_info: &PanicInfo) -> ! {
+    loop {}
+}
+
+#[no_mangle]
+pub extern "C" fn _start() -> ! {
+    loop {}
+}

embedded/Cargo.toml → embedded/with-allocator/Cargo.toml

@@ -2,7 +2,7 @@
 authors = ["Riccardo Casatta <riccardo@casatta.it>"]
 edition = "2018"
 readme = "README.md"
-name = "embedded"
+name = "with-allocator"
 version = "0.1.0"
 
 [dependencies]
@@ -11,10 +11,10 @@ cortex-m-rt = "0.6.10"
 cortex-m-semihosting = "0.3.3"
 panic-halt = "0.2.0"
 alloc-cortex-m = "0.4.1"
-bech32 = { path="../", default-features = false }
+bech32 = { path="../../", default-features = false }
 
 [[bin]]
-name = "embedded"
+name = "with-allocator"
 test = false
 bench = false
 

src/lib.rs

@@ -57,19 +57,21 @@ assert_eq!(variant, Variant::Bech32);
 #![cfg_attr(feature = "strict", deny(warnings))]
 #![cfg_attr(all(not(feature = "std"), not(test)), no_std)]
 
-#[cfg(all(not(feature = "std"), not(test)))]
+#[cfg(feature = "alloc")]
 extern crate alloc;
 
 #[cfg(any(test, feature = "std"))]
 extern crate core;
 
-#[cfg(all(not(feature = "std"), not(test)))]
+#[cfg(all(feature = "alloc", not(feature = "std")))]
 use alloc::borrow::Cow;
-#[cfg(all(not(feature = "std"), not(test)))]
+#[cfg(all(feature = "alloc", not(feature = "std")))]
 use alloc::{string::String, vec::Vec};
-use core::convert::{Infallible, TryFrom};
+#[cfg(feature = "alloc")]
+use core::convert::Infallible;
+use core::convert::TryFrom;
 use core::{fmt, mem};
-#[cfg(any(feature = "std", test))]
+#[cfg(feature = "std")]
 use std::borrow::Cow;
 
 /// Integer in the range `0..32`
@@ -220,6 +222,7 @@ pub trait FromBase32: Sized {
     fn from_base32(b32: &[u5]) -> Result<Self, Self::Err>;
 }
 
+#[cfg(feature = "alloc")]
 impl WriteBase32 for Vec<u5> {
     type Err = Infallible;
 
@@ -234,6 +237,7 @@ impl WriteBase32 for Vec<u5> {
     }
 }
 
+#[cfg(feature = "alloc")]
 impl FromBase32 for Vec<u8> {
     type Err = Error;
 
@@ -243,6 +247,7 @@ impl FromBase32 for Vec<u8> {
 }
 
 /// A trait for converting a value to a type `T` that represents a `u5` slice.
+#[cfg(feature = "alloc")]
 pub trait ToBase32 {
     /// Convert `Self` to base32 vector
     fn to_base32(&self) -> Vec<u5> {
@@ -257,11 +262,13 @@ pub trait ToBase32 {
 }
 
 /// Interface to calculate the length of the base32 representation before actually serializing
+#[cfg(feature = "alloc")]
 pub trait Base32Len: ToBase32 {
     /// Calculate the base32 serialized length
     fn base32_len(&self) -> usize;
 }
 
+#[cfg(feature = "alloc")]
 impl<T: AsRef<[u8]>> 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.
@@ -306,6 +313,7 @@ impl<T: AsRef<[u8]>> ToBase32 for T {
     }
 }
 
+#[cfg(feature = "alloc")]
 impl<T: AsRef<[u8]>> Base32Len for T {
     fn base32_len(&self) -> usize {
         let bits = self.as_ref().len() * 8;
@@ -327,6 +335,7 @@ pub trait CheckBase32<T: AsRef<[u5]>> {
     fn check_base32(self) -> Result<T, Self::Err>;
 }
 
+#[cfg(feature = "alloc")]
 impl<T: AsRef<[u8]>> CheckBase32<Vec<u5>> for T {
     type Err = Error;
 
@@ -336,6 +345,7 @@ impl<T: AsRef<[u8]>> CheckBase32<Vec<u5>> for T {
 }
 
 #[derive(Clone, Copy, PartialEq, Eq)]
+#[cfg(feature = "alloc")]
 enum Case {
     Upper,
     Lower,
@@ -348,6 +358,7 @@ enum Case {
 /// * **MixedCase**: If the HRP contains both uppercase and lowercase characters.
 /// * **InvalidChar**: If the HRP contains any non-ASCII characters (outside 33..=126).
 /// * **InvalidLength**: If the HRP is outside 1..83 characters long.
+#[cfg(feature = "alloc")]
 fn check_hrp(hrp: &str) -> Result<Case, Error> {
     if hrp.is_empty() || hrp.len() > 83 {
         return Err(Error::InvalidLength);
@@ -387,6 +398,7 @@ fn check_hrp(hrp: &str) -> Result<Case, Error> {
 /// * If [check_hrp] returns an error for the given HRP.
 /// # Deviations from standard
 /// * No length limits are enforced for the data part
+#[cfg(feature = "alloc")]
 pub fn encode_to_fmt<T: AsRef<[u5]>>(
     fmt: &mut fmt::Write,
     hrp: &str,
@@ -416,6 +428,7 @@ pub fn encode_to_fmt<T: AsRef<[u5]>>(
 /// * If [check_hrp] returns an error for the given HRP.
 /// # Deviations from standard
 /// * No length limits are enforced for the data part
+#[cfg(feature = "alloc")]
 pub fn encode_without_checksum_to_fmt<T: AsRef<[u5]>>(
     fmt: &mut fmt::Write,
     hrp: &str,
@@ -454,6 +467,7 @@ const BECH32M_CONST: u32 = 0x2bc8_30a3;
 
 impl Variant {
     // Produce the variant based on the remainder of the polymod operation
+    #[cfg(feature = "alloc")]
     fn from_remainder(c: u32) -> Option<Self> {
         match c {
             BECH32_CONST => Some(Variant::Bech32),
@@ -476,6 +490,7 @@ impl Variant {
 /// * If [check_hrp] returns an error for the given HRP.
 /// # Deviations from standard
 /// * No length limits are enforced for the data part
+#[cfg(feature = "alloc")]
 pub fn encode<T: AsRef<[u5]>>(hrp: &str, data: T, variant: Variant) -> Result<String, Error> {
     let mut buf = String::new();
     encode_to_fmt(&mut buf, hrp, data, variant)?.unwrap();
@@ -488,6 +503,7 @@ pub fn encode<T: AsRef<[u5]>>(hrp: &str, data: T, variant: Variant) -> Result<St
 /// * If [check_hrp] returns an error for the given HRP.
 /// # Deviations from standard
 /// * No length limits are enforced for the data part
+#[cfg(feature = "alloc")]
 pub fn encode_without_checksum<T: AsRef<[u5]>>(hrp: &str, data: T) -> Result<String, Error> {
     let mut buf = String::new();
     encode_without_checksum_to_fmt(&mut buf, hrp, data)?.unwrap();
@@ -497,6 +513,7 @@ pub fn encode_without_checksum<T: AsRef<[u5]>>(hrp: &str, data: T) -> Result<Str
 /// Decode a bech32 string into the raw HRP and the data bytes.
 ///
 /// Returns the HRP in lowercase, the data with the checksum removed, and the encoding.
+#[cfg(feature = "alloc")]
 pub fn decode(s: &str) -> Result<(String, Vec<u5>, Variant), Error> {
     let (hrp_lower, mut data) = split_and_decode(s)?;
     if data.len() < CHECKSUM_LENGTH {
@@ -518,9 +535,11 @@ pub fn decode(s: &str) -> Result<(String, Vec<u5>, Variant), Error> {
 /// Decode a bech32 string into the raw HRP and the data bytes, assuming no checksum.
 ///
 /// Returns the HRP in lowercase and the data.
+#[cfg(feature = "alloc")]
 pub fn decode_without_checksum(s: &str) -> Result<(String, Vec<u5>), Error> { split_and_decode(s) }
 
 /// Decode a bech32 string into the raw HRP and the `u5` data.
+#[cfg(feature = "alloc")]
 fn split_and_decode(s: &str) -> Result<(String, Vec<u5>), Error> {
     // Split at separator and check for two pieces
     let (raw_hrp, raw_data) = match s.rfind(SEP) {
@@ -577,12 +596,14 @@ fn split_and_decode(s: &str) -> Result<(String, Vec<u5>), Error> {
     Ok((hrp_lower, data))
 }
 
+#[cfg(feature = "alloc")]
 fn verify_checksum(hrp: &[u8], data: &[u5]) -> Option<Variant> {
     let mut exp = hrp_expand(hrp);
     exp.extend_from_slice(data);
     Variant::from_remainder(polymod(&exp))
 }
 
+#[cfg(feature = "alloc")]
 fn hrp_expand(hrp: &[u8]) -> Vec<u5> {
     let mut v: Vec<u5> = Vec::new();
     for b in hrp {
@@ -595,6 +616,7 @@ fn hrp_expand(hrp: &[u8]) -> Vec<u5> {
     v
 }
 
+#[cfg(feature = "alloc")]
 fn polymod(values: &[u5]) -> u32 {
     let mut chk: u32 = 1;
     let mut b: u8;
@@ -623,6 +645,7 @@ const CHARSET: [char; 32] = [
 ];
 
 /// Reverse character set. Maps ASCII byte -> CHARSET index on [0,31]
+#[cfg(feature = "alloc")]
 const CHARSET_REV: [i8; 128] = [
     -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1,
     -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1,
@@ -697,6 +720,7 @@ impl std::error::Error for Error {
 /// let base5 = convert_bits(&[0xff], 8, 5, true);
 /// assert_eq!(base5.unwrap(), vec![0x1f, 0x1c]);
 /// ```
+#[cfg(feature = "alloc")]
 pub fn convert_bits<T>(data: &[T], from: u32, to: u32, pad: bool) -> Result<Vec<u8>, Error>
 where
     T: Into<u8> + Copy,
@@ -732,6 +756,7 @@ where
 }
 
 #[cfg(test)]
+#[cfg(feature = "alloc")] // Note, all the unit tests currently require an allocator.
 mod tests {
     use super::*;