Initial community commit

Src/external_dependencies/openmpt-trunk/include/unrar/crc.cpp

@@ -0,0 +1,112 @@
+// This CRC function is based on Intel Slicing-by-8 algorithm.
+//
+// Original Intel Slicing-by-8 code is available here:
+//
+//    http://sourceforge.net/projects/slicing-by-8/
+//
+// Original Intel Slicing-by-8 code is licensed as:
+//    
+//    Copyright (c) 2004-2006 Intel Corporation - All Rights Reserved
+//    
+//    This software program is licensed subject to the BSD License, 
+//    available at http://www.opensource.org/licenses/bsd-license.html
+
+
+#include "rar.hpp"
+
+#ifndef SFX_MODULE
+// User suggested to avoid BSD license in SFX module, so they do not need
+// to include the license to SFX archive.
+#define USE_SLICING
+#endif
+
+static uint crc_tables[8][256]; // Tables for Slicing-by-8.
+
+
+// Build the classic CRC32 lookup table.
+// We also provide this function to legacy RAR and ZIP decryption code.
+void InitCRC32(uint *CRCTab)
+{
+  if (CRCTab[1]!=0)
+    return;
+  for (uint I=0;I<256;I++)
+  {
+    uint C=I;
+    for (uint J=0;J<8;J++)
+      C=(C & 1) ? (C>>1)^0xEDB88320 : (C>>1);
+    CRCTab[I]=C;
+  }
+}
+
+
+static void InitTables()
+{
+  InitCRC32(crc_tables[0]);
+
+#ifdef USE_SLICING
+  for (uint I=0;I<256;I++) // Build additional lookup tables.
+  {
+    uint C=crc_tables[0][I];
+    for (uint J=1;J<8;J++)
+    {
+      C=crc_tables[0][(byte)C]^(C>>8);
+      crc_tables[J][I]=C;
+    }
+  }
+#endif
+}
+
+
+struct CallInitCRC {CallInitCRC() {InitTables();}} static CallInit32;
+
+uint CRC32(uint StartCRC,const void *Addr,size_t Size)
+{
+  byte *Data=(byte *)Addr;
+
+#ifdef USE_SLICING
+  // Align Data to 8 for better performance.
+  for (;Size>0 && ((size_t)Data & 7);Size--,Data++)
+    StartCRC=crc_tables[0][(byte)(StartCRC^Data[0])]^(StartCRC>>8);
+
+  for (;Size>=8;Size-=8,Data+=8)
+  {
+#ifdef BIG_ENDIAN
+    StartCRC ^= Data[0]|(Data[1] << 8)|(Data[2] << 16)|(Data[3] << 24);
+    uint NextData = Data[4]|(Data[5] << 8)|(Data[6] << 16)|(Data[7] << 24);
+#else
+    StartCRC ^= *(uint32 *) Data;
+    uint NextData = *(uint32 *) (Data+4);
+#endif
+    StartCRC = crc_tables[7][(byte) StartCRC       ] ^
+               crc_tables[6][(byte)(StartCRC >> 8) ] ^
+               crc_tables[5][(byte)(StartCRC >> 16)] ^
+               crc_tables[4][(byte)(StartCRC >> 24)] ^
+               crc_tables[3][(byte) NextData       ] ^
+               crc_tables[2][(byte)(NextData >> 8) ] ^
+               crc_tables[1][(byte)(NextData >> 16)] ^
+               crc_tables[0][(byte)(NextData >> 24)];
+  }
+#endif
+
+  for (;Size>0;Size--,Data++) // Process left data.
+    StartCRC=crc_tables[0][(byte)(StartCRC^Data[0])]^(StartCRC>>8);
+
+  return StartCRC;
+}
+
+
+#ifndef SFX_MODULE
+// For RAR 1.4 archives in case somebody still has them.
+ushort Checksum14(ushort StartCRC,const void *Addr,size_t Size)
+{
+  byte *Data=(byte *)Addr;
+  for (size_t I=0;I<Size;I++)
+  {
+    StartCRC=(StartCRC+Data[I])&0xffff;
+    StartCRC=((StartCRC<<1)|(StartCRC>>15))&0xffff;
+  }
+  return StartCRC;
+}
+#endif
+
+