SkMD5: cleanup header and minor refactor

src/core/SkMD5.h

 /*
  * Copyright 2012 Google Inc.
  *
  * Use of this source code is governed by a BSD-style license that can be
  * found in the LICENSE file.
  */
 
 #ifndef SkMD5_DEFINED
 #define SkMD5_DEFINED
 
-#include "SkTypes.h"
-#include "SkEndian.h"
 #include "SkStream.h"
 
-//The following macros can be defined to affect the MD5 code generated.
-//SK_MD5_CLEAR_DATA causes all intermediate state to be overwritten with 0's.
-//SK_CPU_LENDIAN allows 32 bit <=> 8 bit conversions without copies (if alligned).
-//SK_CPU_FAST_UNALIGNED_ACCESS allows 32 bit <=> 8 bit conversions without copies if SK_CPU_LENDIAN.
-
+/* Calculate a 128-bit MD5 message-digest of the bytes sent to this stream. */
 class SkMD5 : public SkWStream {
 public:
     SkMD5();
 
     /** Processes input, adding it to the digest.
-     *  Note that this treats the buffer as a series of uint8_t values.
-     */
-    bool write(const void* buffer, size_t size) override {
-        this->update(reinterpret_cast<const uint8_t*>(buffer), size);
-        return true;
-    }
+        Calling this after finish is undefined.  */
+    bool write(const void* buffer, size_t size) final;
 
-    size_t bytesWritten() const override { return SkToSizeT(this->byteCount); }
+    size_t bytesWritten() const final { return SkToSizeT(this->byteCount); }
 
-    /** Processes input, adding it to the digest. Calling this after finish is undefined. */
-    void update(const uint8_t* input, size_t length);
+    /** Alias for write() */
+    void update(const uint8_t* b, size_t l) { (void)this->write(b, l); }
 
     struct Digest {
         uint8_t data[16];
         bool operator ==(Digest const& other) const {
             return 0 == memcmp(data, other.data, sizeof(data));
         }
-        bool operator !=(Digest const& other) const {
-            return 0 != memcmp(data, other.data, sizeof(data));
-        }
+        bool operator !=(Digest const& other) const { return !(*this == other); }
     };
 
     /** Computes and returns the digest. */
     void finish(Digest& digest);
 
 private:
-    // number of bytes, modulo 2^64
-    uint64_t byteCount;
-
-    // state (ABCD)
-    uint32_t state[4];
-
-    // input buffer
-    uint8_t buffer[64];
+    uint64_t byteCount;  // number of bytes, modulo 2^64
+    uint32_t state[4];   // state (ABCD)
+    uint8_t buffer[64];  // input buffer
 };
 
 #endif