Add no_std support (#52)

Add `no_std` support

Author: dongcarl

.gitignore

@@ -7,3 +7,5 @@ Cargo.lock
 #fuzz
 fuzz/hfuzz_target
 fuzz/hfuzz_workspace
+
+*~

.travis.yml

@@ -14,5 +14,6 @@ script:
   - cargo test --verbose
   - cargo test --verbose --features "serde"
   - cargo build --verbose --features "fuzztarget"
+  - cargo build --verbose --no-default-features
   - if [ "$(rustup show | grep default | grep beta)" != "" ]; then cargo install --force cargo-web && cargo web build --target=asmjs-unknown-emscripten && cargo web test --target=asmjs-unknown-emscripten --nodejs; fi
   - if [ "$(rustup show | grep default | grep stable)" != "" ]; then cd fuzz && cargo test --verbose && ./travis-fuzz.sh; fi

CHANGELOG.md

@@ -1,3 +1,7 @@
+# 0.6.0 - 2019-07-10
+
+* Add `no_std` support, rearrange traits to not depend on `io::Write`
+
 # 0.5.0 - 2019-06-28
 
 * Fix panic when parsing hashes that contain multibyte characters

Cargo.toml

@@ -1,6 +1,6 @@
 [package]
 name = "bitcoin_hashes"
-version = "0.5.0"
+version = "0.6.0"
 authors = ["Andrew Poelstra <[email protected]>"]
 license = "CC0-1.0"
 description = "Hash functions used by rust-bitcoin which support rustc 1.14.0"
@@ -13,17 +13,18 @@ name = "bitcoin_hashes"
 path = "src/lib.rs"
 
 [features]
-default = []
+default = [ "std" ]
+std = ["byteorder/std", "serde/std"]
 unstable = []  # for benchmarking
 fuzztarget = [] # used by other rust-bitcoin projects to make hashes almost-noops, DON'T USE THIS
 
 [dev-dependencies]
 serde_test = "1.0"
 
 [dependencies]
-byteorder = "1.2"
+byteorder = { version = "1.2", default-features = false }
 
 [dependencies.serde]
 version = "1.0"
 optional = true
-
+default-features = false

src/cmp.rs

@@ -20,26 +20,26 @@ pub fn fixed_time_eq(a: &[u8], b: &[u8]) -> bool {
 
     let mut r: u8 = 0;
     for i in 0..count {
-        let mut rs = unsafe { ::std::ptr::read_volatile(&r) };
+        let mut rs = unsafe { ::core::ptr::read_volatile(&r) };
         rs |= lhs[i] ^ rhs[i];
-        unsafe { ::std::ptr::write_volatile(&mut r, rs); }
+        unsafe { ::core::ptr::write_volatile(&mut r, rs); }
     }
     {
-        let mut t = unsafe { ::std::ptr::read_volatile(&r) };
+        let mut t = unsafe { ::core::ptr::read_volatile(&r) };
         t |= t >> 4;
-        unsafe { ::std::ptr::write_volatile(&mut r, t); }
+        unsafe { ::core::ptr::write_volatile(&mut r, t); }
     }
     {
-        let mut t = unsafe { ::std::ptr::read_volatile(&r) };
+        let mut t = unsafe { ::core::ptr::read_volatile(&r) };
         t |= t >> 2;
-        unsafe { ::std::ptr::write_volatile(&mut r, t); }
+        unsafe { ::core::ptr::write_volatile(&mut r, t); }
     }
     {
-        let mut t = unsafe { ::std::ptr::read_volatile(&r) };
+        let mut t = unsafe { ::core::ptr::read_volatile(&r) };
         t |= t >> 1;
-        unsafe { ::std::ptr::write_volatile(&mut r, t); }
+        unsafe { ::core::ptr::write_volatile(&mut r, t); }
     }
-    unsafe { (::std::ptr::read_volatile(&r) & 1) == 0 }
+    unsafe { (::core::ptr::read_volatile(&r) & 1) == 0 }
 }
 
 #[test]

src/error.rs

@@ -15,7 +15,7 @@
 //! # Error Type
 //!
 
-use std::{error, fmt};
+use core::fmt;
 
 /// Hex decoding error
 #[derive(Copy, Clone, PartialEq, Eq)]
@@ -44,17 +44,3 @@ impl fmt::Display for Error {
     }
 }
 
-impl error::Error for Error {
-    fn cause(&self) -> Option<&error::Error> {
-        None
-    }
-
-    fn description(&self) -> &str {
-        match *self {
-            Error::InvalidChar(_) => "invalid hex character",
-            Error::OddLengthString(_) => "odd hex string length",
-            Error::InvalidLength(_, _) => "bad hex string length",
-        }
-    }
-}
-

src/hash160.rs

@@ -19,7 +19,7 @@
 
 //! # HASH160 (SHA256 then RIPEMD160)
 
-use std::str;
+use core::str;
 
 use sha256;
 use ripemd160;
@@ -84,11 +84,10 @@ impl HashTrait for Hash {
 
 #[cfg(test)]
 mod tests {
-    use std::io::Write;
-
     use hash160;
     use hex::{FromHex, ToHex};
     use Hash;
+    use HashEngine;
 
     #[derive(Clone)]
     struct Test {
@@ -110,12 +109,12 @@ mod tests {
                     0xb8, 0x5d, 0xf1, 0x69, 0xc1, 0x8a, 0x3c, 0x69, 0x7f,
                     0xbb, 0x2d, 0xc4, 0xec, 0xef, 0x94, 0xac, 0x55, 0xfe,
                     0x81, 0x64, 0xcc, 0xf9, 0x82, 0xa1, 0x38, 0x69, 0x1a,
-                    0x55, 0x19, 
+                    0x55, 0x19,
                 ],
                 output: vec![
                     0xda, 0x0b, 0x34, 0x52, 0xb0, 0x6f, 0xe3, 0x41,
                     0x62, 0x6a, 0xd0, 0x94, 0x9c, 0x18, 0x3f, 0xbd,
-                    0xa5, 0x67, 0x68, 0x26, 
+                    0xa5, 0x67, 0x68, 0x26,
                 ],
                 output_str: "da0b3452b06fe341626ad0949c183fbda5676826",
             },
@@ -131,7 +130,7 @@ mod tests {
             // Hash through engine, checking that we can input byte by byte
             let mut engine = hash160::Hash::engine();
             for ch in test.input {
-                engine.write_all(&[ch]).expect("write to engine");
+                engine.input(&[ch]);
             }
             let manual_hash = Hash::from_engine(engine);
             assert_eq!(hash, manual_hash);
@@ -160,18 +159,18 @@ mod tests {
 
 #[cfg(all(test, feature="unstable"))]
 mod benches {
-    use std::io::Write;
     use test::Bencher;
 
     use hash160;
     use Hash;
+    use HashEngine;
 
     #[bench]
     pub fn hash160_10(bh: & mut Bencher) {
         let mut engine = hash160::Hash::engine();
         let bytes = [1u8; 10];
         bh.iter( || {
-            engine.write_all(&bytes).expect("write");
+            engine.input(&bytes);
         });
         bh.bytes = bytes.len() as u64;
     }
@@ -181,7 +180,7 @@ mod benches {
         let mut engine = hash160::Hash::engine();
         let bytes = [1u8; 1024];
         bh.iter( || {
-            engine.write_all(&bytes).expect("write");
+            engine.input(&bytes);
         });
         bh.bytes = bytes.len() as u64;
     }
@@ -191,7 +190,7 @@ mod benches {
         let mut engine = hash160::Hash::engine();
         let bytes = [1u8; 65536];
         bh.iter( || {
-            engine.write_all(&bytes).expect("write");
+            engine.input(&bytes);
         });
         bh.bytes = bytes.len() as u64;
     }

src/hex.rs

@@ -15,11 +15,11 @@
 //! # Hex encoding and decoding
 //!
 
-use std::fmt;
-use std::str;
+use core::{fmt, str};
 use {Error, Hash};
 
 /// Trait for objects that can be serialized as hex strings
+#[cfg(any(test, feature = "std"))]
 pub trait ToHex {
     /// Hex representation of the object
     fn to_hex(&self) -> String;
@@ -39,6 +39,7 @@ pub trait FromHex: Sized {
     }
 }
 
+#[cfg(any(test, feature = "std"))]
 impl<T: fmt::LowerHex> ToHex for T {
     /// Outputs the hash in hexadecimal form
     fn to_hex(&self) -> String {
@@ -152,9 +153,10 @@ pub fn format_hex_reverse(data: &[u8], f: &mut fmt::Formatter) -> fmt::Result {
     Ok(())
 }
 
+#[cfg(any(test, feature = "std"))]
 impl ToHex for [u8] {
     fn to_hex(&self) -> String {
-        use std::fmt::Write;
+        use core::fmt::Write;
         let mut ret = String::with_capacity(2 * self.len());
         for ch in self {
             write!(ret, "{:02x}", ch).expect("writing to string");
@@ -163,6 +165,7 @@ impl ToHex for [u8] {
     }
 }
 
+#[cfg(any(test, feature = "std"))]
 impl FromHex for Vec<u8> {
     fn from_byte_iter<I>(iter: I) -> Result<Self, Error>
         where I: Iterator<Item=Result<u8, Error>> +
@@ -217,9 +220,9 @@ impl_fromhex_array!(512);
 
 #[cfg(test)]
 mod tests {
-    use std::fmt;
+    use core::fmt;
 
-    use super::{format_hex, format_hex_reverse, ToHex, FromHex};
+    use super::{format_hex, format_hex_reverse, FromHex, ToHex};
     use Error;
 
     #[test]

src/hmac.rs

@@ -19,7 +19,7 @@
 
 //! # HMAC support
 
-use std::{borrow, fmt, io, ops, str};
+use core::{borrow, fmt, ops, str};
 #[cfg(feature="serde")]
 use serde::{Serialize, Serializer, Deserialize, Deserializer};
 
@@ -99,15 +99,9 @@ impl<T: Hash> HashEngine for HmacEngine<T> {
     }
 
     const BLOCK_SIZE: usize = T::Engine::BLOCK_SIZE;
-}
-
-impl<T: Hash> io::Write for HmacEngine<T> {
-    fn write(&mut self, buf: &[u8]) -> io::Result<usize> {
-        self.iengine.write(buf)
-    }
-
-    fn flush(&mut self) -> io::Result<()> {
-        self.iengine.flush()
+    
+    fn input(&mut self, buf: &[u8]) {
+        self.iengine.input(buf)
     }
 }
 

src/lib.rs

@@ -27,15 +27,18 @@
 #![deny(unused_mut)]
 #![deny(missing_docs)]
 
+#![cfg_attr(all(not(test), not(feature = "std")), no_std)]
 #![cfg_attr(all(test, feature = "unstable"), feature(test))]
 #[cfg(all(test, feature = "unstable"))] extern crate test;
 
+#[cfg(any(test, feature="std"))] extern crate core;
 #[cfg(feature="serde")] extern crate serde;
 #[cfg(all(test,feature="serde"))] extern crate serde_test;
 extern crate byteorder;
 
 #[macro_use] mod util;
 #[macro_use] mod serde_macros;
+#[cfg(any(test, feature = "std"))] mod std_impls;
 pub mod error;
 pub mod hex;
 pub mod hash160;
@@ -48,15 +51,15 @@ pub mod sha256d;
 pub mod siphash24;
 pub mod cmp;
 
-use std::{borrow, fmt, hash, io, ops};
+use core::{borrow, fmt, hash, ops};
 
 pub use hmac::{Hmac, HmacEngine};
 pub use error::Error;
 
 /// A hashing engine which bytes can be serialized into. It is expected
 /// to implement the `io::Write` trait, but to never return errors under
 /// any conditions.
-pub trait HashEngine: Clone + io::Write {
+pub trait HashEngine: Clone {
     /// Byte array representing the internal state of the hash engine
     type MidState;
 
@@ -67,11 +70,8 @@ pub trait HashEngine: Clone + io::Write {
     /// Length of the hash's internal block size, in bytes
     const BLOCK_SIZE: usize;
 
-    /// Add data to the hash engine without any error return type to deal with
-    #[inline(always)]
-    fn input(&mut self, data: &[u8]) {
-        self.write_all(data).expect("hash returned error");
-    }
+    /// Add data to the hash engine
+    fn input(&mut self, data: &[u8]);
 }
 
 /// Trait which applies to hashes of all types
@@ -82,7 +82,7 @@ pub trait Hash: Copy + Clone + PartialEq + Eq + Default + PartialOrd + Ord +
     ops::Index<ops::RangeTo<usize>, Output = [u8]> +
     ops::Index<ops::Range<usize>, Output = [u8]> +
     ops::Index<usize, Output = u8> +
-    hex::ToHex + borrow::Borrow<[u8]>
+    borrow::Borrow<[u8]>
 {
     /// A hashing engine which bytes can be serialized into. It is expected
     /// to implement the `io::Write` trait, and to never return errors under
@@ -106,10 +106,8 @@ pub trait Hash: Copy + Clone + PartialEq + Eq + Default + PartialOrd + Ord +
 
     /// Hashes some bytes
     fn hash(data: &[u8]) -> Self {
-        use std::io::Write;
-
         let mut engine = Self::engine();
-        engine.write_all(data).unwrap();
+        engine.input(data);
         Self::from_engine(engine)
     }