CRC32 implementation

openVulkanoCpp/Math/CRC32.hpp

@@ -0,0 +1,52 @@
+/*
+ * This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at https://mozilla.org/MPL/2.0/.
+ */
+
+#pragma once
+
+#include <stdint.h>
+
+class CRC32
+{
+	uint32_t m_table[256];
+	uint32_t m_currentValue = 0;
+
+public:
+	CRC32()
+	{
+		uint32_t polynomial = 0xEDB88320;
+		for (uint32_t i = 0; i < 256; i++)
+		{
+			uint32_t c = i;
+			for (size_t j = 0; j < 8; j++)
+			{
+				if (c & 1)
+				{
+					c = polynomial ^ (c >> 1);
+				}
+				else
+				{
+					c >>= 1;
+				}
+			}
+			m_table[i] = c;
+		}
+	}
+
+	void Update(size_t len, const uint8_t* buf)
+	{
+		uint32_t c = m_currentValue ^ 0xFFFFFFFF;
+		for (size_t i = 0; i < len; ++i)
+		{
+			c = m_table[(c ^ buf[i]) & 0xFF] ^ (c >> 8);
+		}
+		m_currentValue = c ^ 0xFFFFFFFF;
+	}
+
+	uint32_t GetValue() const
+	{
+		return m_currentValue;
+	}
+};