Initial commit - version 1.31

crc32.cpp

@@ -0,0 +1,26 @@
+//Module name: crc32
+//Author: Alcaro
+//Date: June 3, 2015
+//Licence: GPL v3.0 or higher
+
+#include "crc32.h"
+
+static const uint32_t crctable_4bits[]={
+	0x00000000, 0x1DB71064, 0x3B6E20C8, 0x26D930AC, 0x76DC4190, 0x6B6B51F4, 0x4DB26158, 0x5005713C,
+	0xEDB88320, 0xF00F9344, 0xD6D6A3E8, 0xCB61B38C, 0x9B64C2B0, 0x86D3D2D4, 0xA00AE278, 0xBDBDF21C,
+};
+uint32_t crc32_update(const uint8_t* data, size_t len, uint32_t crc)
+{
+	crc = ~crc;
+	for (size_t i=0;i<len;i++)
+	{
+		crc = crctable_4bits[(crc^ data[i]    )&0x0F] ^ (crc>>4);
+		crc = crctable_4bits[(crc^(data[i]>>4))&0x0F] ^ (crc>>4);
+	}
+	return ~crc;
+}
+
+uint32_t crc32(const uint8_t* data, size_t len)
+{
+	return crc32_update(data, len, 0);
+}