Downloading extensions from Github Repo. (#1101)

Downloading extensions from Github Repo.

app/src/main/java/eu/kanade/tachiyomi/util/Hash.kt

@@ -0,0 +1,42 @@
+package eu.kanade.tachiyomi.util
+
+import java.security.MessageDigest
+
+object Hash {
+
+    private val chars = charArrayOf('0', '1', '2', '3', '4', '5', '6', '7', '8', '9',
+            'a', 'b', 'c', 'd', 'e', 'f')
+
+    private val MD5 get() = MessageDigest.getInstance("MD5")
+
+    private val SHA256 get() = MessageDigest.getInstance("SHA-256")
+
+    fun sha256(bytes: ByteArray): String {
+        return encodeHex(SHA256.digest(bytes))
+    }
+
+    fun sha256(string: String): String {
+        return sha256(string.toByteArray())
+    }
+
+    fun md5(bytes: ByteArray): String {
+        return encodeHex(MD5.digest(bytes))
+    }
+
+    fun md5(string: String): String {
+        return md5(string.toByteArray())
+    }
+
+    private fun encodeHex(data: ByteArray): String {
+        val l = data.size
+        val out = CharArray(l shl 1)
+        var i = 0
+        var j = 0
+        while (i < l) {
+            out[j++] = chars[(240 and data[i].toInt()).ushr(4)]
+            out[j++] = chars[15 and data[i].toInt()]
+            i++
+        }
+        return String(out)
+    }
+}