X-Git-Url: https://notaz.gp2x.de/cgi-bin/gitweb.cgi?a=blobdiff_plain;f=source%2Fmupen64plus-video-arachnoid%2Fsrc%2Fhash%2FCRCCalculator.cpp;fp=source%2Fmupen64plus-video-arachnoid%2Fsrc%2Fhash%2FCRCCalculator.cpp;h=57a18061fe9dbcab41cfa1410c4ea1783764e6a0;hb=22726e4d55be26faa48b57b22689cbedde27ae44;hp=0000000000000000000000000000000000000000;hpb=fc5d46b49a19d41f9f2da5a9336daec452900475;p=mupen64plus-pandora.git

diff --git a/source/mupen64plus-video-arachnoid/src/hash/CRCCalculator.cpp b/source/mupen64plus-video-arachnoid/src/hash/CRCCalculator.cpp
new file mode 100755
index 0000000..57a1806
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+/******************************************************************************
+ * Arachnoid Graphics Plugin for Mupen64Plus
+ * http://bitbucket.org/wahrhaft/mupen64plus-video-arachnoid/
+ *
+ * Copyright (C) 2007 Kristofer Karlsson, Rickard Niklasson
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License
+ * as published by the Free Software Foundation; either version 2
+ * of the License, or (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301, USA.
+ *****************************************************************************/
+
+#include "CRCCalculator.h"
+
+#define CRC32_POLYNOMIAL    0xedb88320L    //0x04C11DB7
+typedef unsigned char byte;
+
+//-----------------------------------------------------------------------------
+// Static Variabels
+//-----------------------------------------------------------------------------
+unsigned int CRCCalculator::m_crcTable[256] = {0};   
+
+static unsigned int crc_table[256];
+
+//-----------------------------------------------------------------------------
+//! Constructor
+//-----------------------------------------------------------------------------
+CRCCalculator::CRCCalculator()
+{
+    static bool hashTableInitialized = false;
+
+    //Build hash table
+    //http://www.gamedev.net/reference/articles/article1941.asp
+    if ( !hashTableInitialized )
+    {
+     //   unsigned int crc;
+
+     //   //For each value 
+     //   for (int i=0; i<256; i++)
+        //{
+     //       crc = _reflect( i, 8 ) << 24;
+
+     //       for (int j = 0; j < 8; j++) 
+     //       {
+              //  crc = (crc << 1) ^ (crc & (1 << 31) ? CRC32_POLYNOMIAL : 0);
+     //       }
+     //       
+     //       m_crcTable[i] = _reflect( crc, 32 );
+     //   }
+
+        unsigned int crc;
+        unsigned int poly;  // polynomial exclusive-or pattern 
+        // terms of polynomial defining this crc (except x^32): 
+        static const unsigned char p[] = {0,1,2,4,5,7,8,10,11,12,16,22,23,26};
+
+        /* make exclusive-or pattern from polynomial (0xedb88320L) */
+        poly = 0L;
+        for (unsigned int n = 0; n < sizeof(p)/sizeof(unsigned char); n++)
+        {
+            poly |= 1L << (31 - p[n]);
+        }
+         
+        for (int n=0; n<256; ++n)
+        {
+            crc = (unsigned int)n;
+
+            for (int k = 0; k < 8; k++)
+            {
+                crc = (crc & 1) ? (poly ^ (crc >> 1)) : crc >> 1;
+            }
+            crc_table[n] = crc;
+        }
+
+        hashTableInitialized = true;
+    }
+}
+
+//-----------------------------------------------------------------------------
+// CalculateCRC
+//-----------------------------------------------------------------------------
+#define DO1(buf) crc = crc_table[((int)crc ^ (*buf++)) & 0xff] ^ (crc >> 8);
+#define DO1b(buf) crc = (crc >> 8) ^ crc_table[(crc & 0xFF) ^ *buf++]
+unsigned int CRCCalculator::calcCRC(unsigned int crc, void *buffer, unsigned int count)
+{
+    byte* p = (byte*) buffer; 
+    //unsigned int orig = crc;
+
+ //   p = (byte*) buffer;
+ //   while (count--) 
+ //   {
+    //    crc = (crc >> 8) ^ m_crcTable[(crc & 0xFF) ^ *p++];
+ //   }
+
+ //   return crc ^ orig;
+
+    if (buffer == 0) return 0L;
+
+    crc = crc ^ 0xffffffffL;
+    while (count--)
+    {
+        crc = crc_table[((int)crc ^ (*p++)) & 0xff] ^ (crc >> 8);
+    }
+   // if (len) do {
+   //   DO1(buf);
+   // } while (--len);
+    return crc ^ 0xffffffffL;
+}
+
+//-----------------------------------------------------------------------------
+// CalculatePaletteCRC
+//-----------------------------------------------------------------------------
+unsigned int CRCCalculator::calcPaletteCRC(unsigned int crc, void *buffer, unsigned int count)
+{
+    byte *p;
+    unsigned int orig = crc;
+
+    p = (byte*) buffer;
+    while (count--)
+    {
+        crc = (crc >> 8) ^ m_crcTable[(crc & 0xFF) ^ *p++];
+        crc = (crc >> 8) ^ m_crcTable[(crc & 0xFF) ^ *p++];
+
+        p += 6;
+    }
+
+    return crc ^ orig;
+}
+
+//*****************************************************************************
+// Private Functions
+//*****************************************************************************
+
+//-----------------------------------------------------------------------------
+//* Reflect
+//! Help function when creating the CRC Table
+//! Swaps bit 0 for bit 7
+//!       bit 1 for bit 6
+//!       bit 2 for bit 5 ...
+//-----------------------------------------------------------------------------
+unsigned int CRCCalculator::_reflect(unsigned int ref, char ch)
+{
+    unsigned int value = 0;
+    for (int i=1; i<(ch + 1); ++i)
+    {
+        if(ref & 1) 
+        {
+            value |= 1 << (ch - i);
+        }
+        ref >>= 1;
+    }
+    return value;
+}