hash/adler: convert to object style accumulator

Makefile.am

@@ -115,6 +115,7 @@ UTIL_FILES   =			\
     hash/crc.hpp		\
     hash/fasthash.cpp		\
     hash/fasthash.hpp		\
+    hash/fletcher.cpp		\
     hash/fletcher.hpp		\
     hash/fnv1a.cpp		\
     hash/fnv1a.hpp		\

hash/adler.cpp

@@ -19,23 +19,31 @@
 #include "./fletcher.hpp"
 #include "../debug.hpp"
 
-static const unsigned MODULUS = 65521;
+static constexpr unsigned MODULUS = 65521;
+
+using util::hash::adler32;
 
 
 ///////////////////////////////////////////////////////////////////////////////
-uint32_t
-util::hash::adler32 (const void* restrict _data, size_t _size) noexcept
-{
-    return adler32 (
-        static_cast<const uint8_t*> (_data),
-        static_cast<const uint8_t*> (_data) + _size
-    );
-}
+adler32::adler32 ():
+    fletcher (MODULUS, 1, 0)
+{ ; }
 
 
-//-----------------------------------------------------------------------------
-uint32_t
-util::hash::adler32 (const uint8_t *restrict first, const uint8_t *restrict last) noexcept
-{
-    return fletcher<32, MODULUS, 1, 0> (first, last - first);
-}
+/////////////////////////////////////////////////////////////////////////////////
+//uint32_t
+//util::hash::adler32 (const void* restrict _data, size_t _size) noexcept
+//{
+//    return adler32 (
+//        static_cast<const uint8_t*> (_data),
+//        static_cast<const uint8_t*> (_data) + _size
+//    );
+//}
+//
+//
+////-----------------------------------------------------------------------------
+//uint32_t
+//util::hash::adler32 (const uint8_t *restrict first, const uint8_t *restrict last) noexcept
+//{
+//    return fletcher<32, MODULUS, 1, 0> (first, last - first);
+//}

hash/adler.hpp

@@ -14,8 +14,10 @@
  * Copyright 2010-2014 Danny Robson <danny@nerdcruft.net>
  */
 
-#ifndef __UTIL_ADLER_HPP
-#define __UTIL_ADLER_HPP
+#ifndef __UTIL_HASH_ADLER_HPP
+#define __UTIL_HASH_ADLER_HPP
+
+#include "./fletcher.hpp"
 
 #include <cstdint>
 #include <cstdlib>
@@ -23,8 +25,10 @@
 
 ///////////////////////////////////////////////////////////////////////////////
 namespace util { namespace hash {
-    uint32_t adler32 (const void* restrict, size_t) noexcept;
-    uint32_t adler32 (const uint8_t *restrict first, const uint8_t *restrict last) noexcept;
+    class adler32 : public fletcher<uint32_t> {
+    public:
+        adler32 ();
+    };
 } }
 
 #endif

hash/fletcher.cpp

@@ -0,0 +1,89 @@
+/*
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ *
+ * Copyright 2010 Danny Robson <danny@nerdcruft.net>
+ */
+
+
+#include "./fletcher.hpp"
+
+#include "../debug.hpp"
+
+
+using util::hash::fletcher;
+
+
+///////////////////////////////////////////////////////////////////////////////
+template <typename T>
+fletcher<T>::fletcher (part_t _modulus, part_t _a, part_t _b):
+    m_modulus { _modulus },
+    m_initial { _a, _b },
+    m_state   { m_initial }
+{ ; }
+
+
+//-----------------------------------------------------------------------------
+template <typename T>
+void
+fletcher<T>::reset (void)
+{
+    m_state = m_initial;
+}
+
+
+///////////////////////////////////////////////////////////////////////////////
+template <typename T>
+void
+fletcher<T>::update (const void *restrict data, size_t size) noexcept
+{
+    CHECK (data);
+
+    auto first = static_cast<const uint8_t *restrict> (data);
+    update (first, first + size);
+}
+
+
+//-----------------------------------------------------------------------------
+template <typename T>
+void
+fletcher<T>::update (const uint8_t *restrict first, const uint8_t *restrict last) noexcept
+{
+    CHECK (first);
+    CHECK (last);
+    CHECK_LE (first, last);
+
+    for (auto cursor = first; cursor < last; ++cursor) {
+        m_state.a = (m_state.a + *cursor  ) % m_modulus;
+        m_state.b = (m_state.a + m_state.b) % m_modulus;
+    }
+}
+
+
+//-----------------------------------------------------------------------------
+template <typename T>
+void
+fletcher<T>::finish (void)
+{ ; }
+
+
+///////////////////////////////////////////////////////////////////////////////
+template <typename T>
+typename fletcher<T>::digest_t
+fletcher<T>::digest (void) const
+{
+    return (m_state.b << (sizeof (part_t) * 8)) + m_state.a;
+}
+
+
+///////////////////////////////////////////////////////////////////////////////
+template class util::hash::fletcher<uint32_t>;

hash/fletcher.hpp

@@ -11,11 +11,11 @@
  * See the License for the specific language governing permissions and
  * limitations under the License.
  *
- * Copyright 2010 Danny Robson <danny@nerdcruft.net>
+ * Copyright 2010-2016 Danny Robson <danny@nerdcruft.net>
  */
 
-#ifndef __UTIL_FLETCHER_HPP
-#define __UTIL_FLETCHER_HPP
+#ifndef __UTIL_HASH_FLETCHER_HPP
+#define __UTIL_HASH_FLETCHER_HPP
 
 #include "../types/bits.hpp"
 
@@ -24,28 +24,35 @@
 
 
 ///////////////////////////////////////////////////////////////////////////////
-template <
-    unsigned OUTPUT,
-    unsigned MODULUS,
-    unsigned INITIAL_A,
-    unsigned INITIAL_B
->
-typename bits_type<OUTPUT>::uint
-fletcher (const void *restrict _data,
-          size_t size)
-{
-    typedef typename bits_type<OUTPUT / 2>::uint temp_t;
+namespace util { namespace hash {
+    template <typename DIGEST>
+    class fletcher {
+    public:
+        using digest_t = DIGEST;
+        using part_t = typename bytes_type<sizeof (digest_t) / 2>::uint;
 
-    auto data = static_cast<const uint8_t*> (_data);
-    temp_t A = INITIAL_A, B = INITIAL_B;
+        fletcher (part_t modulus, part_t a, part_t b);
 
-    for (size_t i = 0; i < size; ++i) {
-        A = (A + data[i]) % MODULUS;
-        B = (A +       B) % MODULUS;
-    }
+        void update (const void *restrict, size_t) noexcept;
+        void update (const uint8_t *restrict first, const uint8_t *restrict last) noexcept;
+
+        void finish (void);
+        digest_t digest (void) const;
+
+        void reset (void);
+
+    private:
+        const digest_t m_modulus;
+
+        struct state_t {
+            part_t a, b;
+        };
+
+        const state_t m_initial;
+        state_t m_state;
+    };
+} }
 
-    return (B << (OUTPUT / 2u)) + A;
-}
 
 #endif