From d5c50fca6c56645e925a33468600fe765743fbda Mon Sep 17 00:00:00 2001
From: Kiran Kulkarni <kiran@helpshift.com>
Date: Mon, 16 Nov 2015 18:22:39 +0530
Subject: [PATCH] Use native Java MessageDigest for SHA-1

This change enables Ketamine to function without Apache Commons codec
---
 project.clj           |  3 +--
 src/ketamine/util.clj | 27 +++++++++++++++++++++++++--
 2 files changed, 26 insertions(+), 4 deletions(-)

diff --git a/project.clj b/project.clj
index 77a8729..d53d739 100644
--- a/project.clj
+++ b/project.clj
@@ -3,5 +3,4 @@
   :url "https://github.com/ghoseb/ketamine/"
   :license {:name "Eclipse Public License"
             :url "http://www.eclipse.org/legal/epl-v10.html"}
-  :dependencies [[org.clojure/clojure "1.5.1"]
-                 [commons-codec "1.8"]])
+  :dependencies [[org.clojure/clojure "1.5.1"]])
diff --git a/src/ketamine/util.clj b/src/ketamine/util.clj
index 3d1c547..2918f7c 100644
--- a/src/ketamine/util.clj
+++ b/src/ketamine/util.clj
@@ -1,14 +1,37 @@
 (ns ^{:doc "Ketamine utility functions."
       :author "Baishampayan Ghose <b.ghose@helpshift.com>"}
   ketamine.util
-  (:import org.apache.commons.codec.digest.DigestUtils))
+  (:require [clojure.string :as cs])
+  (:import java.security.MessageDigest))
+
+
+(def ^:private hex [\0 \1 \2 \3 \4 \5 \6 \7 \8 \9 \a \b \c \d \e \f])
+
+(defn ^:private hexify-byte
+  [b]
+  (let [v (bit-and b 0xFF)]
+    [(hex (bit-shift-right v 4)) (hex (bit-and v 0x0F))]))
+
+(defn hexify
+  "Convert byte-array to hex string"
+  [ba]
+  (cs/join (mapcat hexify-byte ba)))
+
+
+(defn sha1sum
+  [^String s]
+  {:pre [(string? s)]}
+  (let  [digest ^MessageDigest (MessageDigest/getInstance "SHA-1")]
+    (.reset digest)
+    (hexify (.digest digest
+                     (.getBytes ^String s "UTF-8")))))
 
 
 (defn hash-code
   "Hash a string and convert the hash code into a number in 64 bit address space."
   [^String x]
   (-> x
-      DigestUtils/sha1Hex
+      sha1sum
       (subs 0 8)
       (Long/parseLong 16)))