From df22fef24fa8aea64a43e6342b6c0999bf923153 Mon Sep 17 00:00:00 2001
From: Alex Beregszaszi <alex@rtfs.hu>
Date: Fri, 21 Dec 2018 21:49:08 +0000
Subject: [PATCH] Add sha1 precompile

---
 Cargo.toml      |  1 +
 Makefile        |  2 +-
 sha1/Cargo.toml | 15 +++++++++++++++
 sha1/README.md  |  3 +++
 sha1/src/lib.rs | 21 +++++++++++++++++++++
 5 files changed, 41 insertions(+), 1 deletion(-)
 create mode 100644 sha1/Cargo.toml
 create mode 100644 sha1/README.md
 create mode 100644 sha1/src/lib.rs

diff --git a/Cargo.toml b/Cargo.toml
index c733c31..9a50699 100644
--- a/Cargo.toml
+++ b/Cargo.toml
@@ -9,6 +9,7 @@ members = [
     "identity",
     "keccak256",
     "ripemd160",
+    "sha1",
     "sha256",
 ]
 
diff --git a/Makefile b/Makefile
index a501986..26075c1 100644
--- a/Makefile
+++ b/Makefile
@@ -1,4 +1,4 @@
-TARGETS=bls12pairing ecadd ecmul ecpairing ed25519 identity keccak256 ripemd160 sha256
+TARGETS=bls12pairing ecadd ecmul ecpairing ed25519 identity keccak256 ripemd160 sha1 sha256
 
 all:
 	@cargo build --release --target wasm32-unknown-unknown
diff --git a/sha1/Cargo.toml b/sha1/Cargo.toml
new file mode 100644
index 0000000..40e3839
--- /dev/null
+++ b/sha1/Cargo.toml
@@ -0,0 +1,15 @@
+[package]
+name = "ewasm-precompile-sha1"
+version = "0.1.0"
+authors = ["Alex Beregszaszi <alex@rtfs.hu>"]
+license = "Apache-2.0"
+repository = "https://github.com/ewasm/ewasm-precompiles"
+description = "Ethereum SHA1 precompile in Rust"
+publish = false
+
+[dependencies]
+sha1 = "0.6"
+ewasm_api = "0.5"
+
+[lib]
+crate-type = ["cdylib"]
diff --git a/sha1/README.md b/sha1/README.md
new file mode 100644
index 0000000..2f1a9cc
--- /dev/null
+++ b/sha1/README.md
@@ -0,0 +1,3 @@
+# sha1
+
+This is the precompile for enabling SHA-1 hashing according to [EIP-180](https://github.com/ethereum/EIPs/issues/180)
diff --git a/sha1/src/lib.rs b/sha1/src/lib.rs
new file mode 100644
index 0000000..55399f0
--- /dev/null
+++ b/sha1/src/lib.rs
@@ -0,0 +1,21 @@
+extern crate ewasm_api;
+extern crate sha1;
+
+#[cfg(not(test))]
+#[no_mangle]
+pub extern "C" fn main() {
+    let length = ewasm_api::calldata_size();
+
+    // charge a base fee plus a word fee for every 256-bit word
+    let base_fee = 62;
+    let word_fee = 8;
+    let total_cost = base_fee + ((length + 31) / 32) * word_fee;
+
+    ewasm_api::consume_gas(total_cost as u64);
+
+    let data = ewasm_api::unsafe_calldata_copy(0, length);
+
+    let hash = sha1::Sha1::from(data).digest().bytes();
+
+    ewasm_api::finish_data(&hash)
+}