From ca16919063cf34bc7d02ec41bceace2bbc2b180e Mon Sep 17 00:00:00 2001
From: lganzzzo <lganzzzo@gmail.com>
Date: Sun, 5 Aug 2018 02:28:31 +0300
Subject: [PATCH] algorithm CRC32 added

---
 algorithm/CRC32.cpp | 77 +++++++++++++++++++++++++++++++++++++++++++++
 algorithm/CRC32.hpp | 52 ++++++++++++++++++++++++++++++
 2 files changed, 129 insertions(+)
 create mode 100644 algorithm/CRC32.cpp
 create mode 100644 algorithm/CRC32.hpp

diff --git a/algorithm/CRC32.cpp b/algorithm/CRC32.cpp
new file mode 100644
index 00000000..b868128d
--- /dev/null
+++ b/algorithm/CRC32.cpp
@@ -0,0 +1,77 @@
+/***************************************************************************
+ *
+ * Project         _____    __   ____   _      _
+ *                (  _  )  /__\ (_  _)_| |_  _| |_
+ *                 )(_)(  /(__)\  )( (_   _)(_   _)
+ *                (_____)(__)(__)(__)  |_|    |_|
+ *
+ *
+ * Copyright 2018-present, Leonid Stryzhevskyi, <lganzzzo@gmail.com>
+ *
+ * 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.
+ *
+ ***************************************************************************/
+
+#include "CRC32.hpp"
+
+namespace oatpp { namespace algorithm {
+  
+const p_word32 CRC32::TABLE_04C11DB7 = generateTable(0x04C11DB7);
+  
+v_word32 CRC32::bitReverse(v_word32 poly) {
+  v_word32 result = 0;
+  for(v_int32 i = 0; i < 32; i ++) {
+    if((poly & (1 << i)) > 0) {
+      result |= 1 << (31 - i);
+    }
+  }
+  return result;
+}
+  
+p_word32 CRC32::generateTable(v_word32 poly) {
+  
+  p_word32 result = new v_word32[256];
+  v_word32 polyReverse = bitReverse(poly);
+  v_word32 value;
+  
+  for(v_int32 i = 0; i < 256; i++) {
+    value = i;
+    for (v_int32 bit = 0; bit < 8; bit++) {
+      if (value & 1) {
+        value = (value >> 1) ^ polyReverse;
+      } else {
+        value = (value >> 1);
+      }
+    }
+    
+    result[i] = value;
+    
+  }
+  
+  return result;
+  
+}
+  
+v_word32 CRC32::calc(const void *buffer, v_int32 size, v_word32 crc, v_word32 initValue, v_word32 xorOut, p_word32 table) {
+  
+  p_word8 data = (p_word8) buffer;
+  crc = crc ^ initValue;
+  
+  for(v_int32 i = 0; i < size; i++) {
+    crc = table[(crc & 0xFF) ^ data[i]] ^ (crc >> 8);
+  }
+  
+  return crc ^ xorOut;
+}
+  
+}}
diff --git a/algorithm/CRC32.hpp b/algorithm/CRC32.hpp
new file mode 100644
index 00000000..b962a92a
--- /dev/null
+++ b/algorithm/CRC32.hpp
@@ -0,0 +1,52 @@
+/***************************************************************************
+ *
+ * Project         _____    __   ____   _      _
+ *                (  _  )  /__\ (_  _)_| |_  _| |_
+ *                 )(_)(  /(__)\  )( (_   _)(_   _)
+ *                (_____)(__)(__)(__)  |_|    |_|
+ *
+ *
+ * Copyright 2018-present, Leonid Stryzhevskyi, <lganzzzo@gmail.com>
+ *
+ * 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.
+ *
+ ***************************************************************************/
+
+#ifndef oatpp_algorithm_CRC32_hpp
+#define oatpp_algorithm_CRC32_hpp
+
+#include "oatpp/core/base/Environment.hpp"
+
+#include "oatpp/encoding/Hex.hpp"
+
+namespace oatpp { namespace algorithm {
+  
+class CRC32 {
+public:
+  static const p_word32 TABLE_04C11DB7;
+public:
+
+  static v_word32 bitReverse(v_word32 poly);
+  
+  /**
+   *  Generates v_word32 table[256] for polynomial
+   */
+  static p_word32 generateTable(v_word32 poly);
+  
+  static v_word32 calc(const void *buffer, v_int32 size, v_word32 crc = 0, v_word32 initValue = 0xFFFFFFFF, v_word32 xorOut = 0xFFFFFFFF, p_word32 table = TABLE_04C11DB7);
+  
+};
+    
+}}
+
+#endif /* oatpp_algorithm_CRC32_hpp */