Adding new class to compute CRC32 of a char array

Algorithms/CRC32.cpp

@@ -0,0 +1,89 @@
+/*
+ open source routing machine
+ Copyright (C) Dennis Luxen, others 2010
+
+ This program is free software; you can redistribute it and/or modify
+ it under the terms of the GNU AFFERO General Public License as published by
+ the Free Software Foundation; either version 3 of the License, or
+ 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 Affero General Public License
+ along with this program; if not, write to the Free Software
+ Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
+ or see http://www.gnu.org/licenses/agpl.txt.
+ */
+
+#include "CRC32.h"
+
+CRC32::CRC32() : crc(0) {
+    crcFunction = detectBestCRC32C();
+}
+
+unsigned CRC32::SoftwareBasedCRC32(char *str, unsigned len, unsigned crc) {
+    boost::crc_optimal<32, 0x1EDC6F41, 0x0, 0x0, true, true> CRC32_Processor;
+    CRC32_Processor.process_bytes( str, 100000000);
+    return CRC32_Processor.checksum();
+}
+
+unsigned CRC32::SSEBasedCRC32( char *str, unsigned len, unsigned crc) {
+    unsigned q=len/sizeof(unsigned),
+            r=len%sizeof(unsigned),
+            *p=(unsigned*)str/*, crc*/;
+
+    //crc=0;
+    while (q--) {
+        __asm__ __volatile__(
+                ".byte 0xf2, 0xf, 0x38, 0xf1, 0xf1;"
+                :"=S"(crc)
+                 :"0"(crc), "c"(*p)
+        );
+        ++p;
+    }
+
+    str=(char*)p;
+    while (r--) {
+        __asm__ __volatile__(
+                ".byte 0xf2, 0xf, 0x38, 0xf1, 0xf1;"
+                :"=S"(crc)
+                 :"0"(crc), "c"(*str)
+        );
+        ++str;
+    }
+    return crc;
+}
+
+CRC32::CRC32CFunctionPtr CRC32::detectBestCRC32C() {
+    static const int SSE42_BIT = 20;
+    unsigned ecx = cpuid(1);
+    bool hasSSE42 = ecx & (1 << SSE42_BIT);
+    if (hasSSE42) {
+        return &CRC32::SSEBasedCRC32; //crc32 hardware accelarated;
+    } else {
+        return &CRC32::SoftwareBasedCRC32; //crc32cSlicingBy8;
+    }
+}
+
+unsigned CRC32::cpuid(unsigned functionInput) {
+    unsigned eax;
+    unsigned ebx;
+    unsigned ecx;
+    unsigned edx;
+    asm("cpuid" : "=a" (eax), "=b" (ebx), "=c" (ecx), "=d" (edx) : "a" (functionInput));
+    return ecx;
+}
+
+unsigned CRC32::operator()(char *str, unsigned len){
+    crc =((*this).*(crcFunction))(str, len, crc);
+    return crc;
+}
+
+
+CRC32::~CRC32() {
+    // TODO Auto-generated destructor stub
+}
+

Algorithms/CRC32.h

@@ -0,0 +1,45 @@
+/*
+ open source routing machine
+ Copyright (C) Dennis Luxen, others 2010
+
+ This program is free software; you can redistribute it and/or modify
+ it under the terms of the GNU AFFERO General Public License as published by
+ the Free Software Foundation; either version 3 of the License, or
+ 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 Affero General Public License
+ along with this program; if not, write to the Free Software
+ Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
+ or see http://www.gnu.org/licenses/agpl.txt.
+ */
+
+#ifndef CRC32_H_
+#define CRC32_H_
+
+#include <boost/crc.hpp>  // for boost::crc_32_type
+
+class CRC32 {
+private:
+    unsigned crc;
+    unsigned slowcrc_table[1<<8];
+
+    typedef boost::crc_optimal<32, 0x1EDC6F41, 0x0, 0x0, true, true> my_crc_32_type;
+    typedef unsigned (CRC32::*CRC32CFunctionPtr)(char *str, unsigned len, unsigned crc);
+
+    unsigned SoftwareBasedCRC32(char *str, unsigned len, unsigned crc);
+    unsigned SSEBasedCRC32( char *str, unsigned len, unsigned crc);
+    unsigned cpuid(unsigned functionInput);
+    CRC32CFunctionPtr detectBestCRC32C();
+    CRC32CFunctionPtr crcFunction;
+public:
+    CRC32();
+    unsigned operator()(char *str, unsigned len);
+    virtual ~CRC32();
+};
+
+#endif /* CRC32_H_ */