primitives - remove eth_checksum and move the code to the crate instead

Author: elpiel

Cargo.lock

@@ -25,7 +25,7 @@ time = "0.1.42"
 hex = "0.3.2"
 merkletree = "0.10.0"
 tiny-keccak = "1.5"
-eth_checksum = { version = "0.1.1", git = "https://github.com/elpiel/rust-eth-checksum", branch = "clean-up-and-performance" }
+rust-crypto = "0.2"
 # Numbers - BigNum, Numbers, Traits and Derives
 num-bigint = { version = "0.2", features = ["serde"] }
 num = "0.2.0"

primitives/Cargo.toml

@@ -1,5 +1,4 @@
 use std::convert::TryFrom;
-use std::error::Error;
 use std::iter::Sum;
 use std::ops::{Add, AddAssign, Div, Mul, Sub};
 use std::str::FromStr;

primitives/src/big_num.rs

@@ -0,0 +1,28 @@
+use crypto::{digest::Digest, sha3::Sha3};
+
+pub fn checksum(address: &str) -> String {
+    let address = address.trim_start_matches("0x").to_lowercase();
+
+    let address_hash = {
+        let mut hasher = Sha3::keccak256();
+        hasher.input(address.as_bytes());
+        hasher.result_str()
+    };
+
+    address
+        .char_indices()
+        .fold(String::from("0x"), |mut acc, (index, address_char)| {
+            // this cannot fail since it's Keccak256 hashed
+            let n = u16::from_str_radix(&address_hash[index..index + 1], 16).unwrap();
+
+            if n > 7 {
+                // make char uppercase if ith character is 9..f
+                acc.push_str(&address_char.to_uppercase().to_string())
+            } else {
+                // already lowercased
+                acc.push(address_char)
+            }
+
+            acc
+        })
+}

primitives/src/eth_checksum.rs

@@ -24,6 +24,7 @@ pub mod util {
     pub mod logging;
 }
 pub mod analytics;
+mod eth_checksum;
 pub mod validator;
 
 pub use self::ad_unit::AdUnit;