/* ** Command & Conquer Generals Zero Hour(tm) ** Copyright 2025 Electronic Arts Inc. ** ** 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 3 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, see . */ //////////////////////////////////////////////////////////////////////////////// // // // (c) 2001-2003 Electronic Arts Inc. // // // //////////////////////////////////////////////////////////////////////////////// // CRC.h /////////////////////////////////////////////////////////////// // A class encapsulating CRC calculation // Author: Matthew D. Campbell, October 2001 #pragma once #ifndef _CRC_H_ #define _CRC_H_ #include "Lib/BaseType.h" #include "winsock2.h" // for htonl #ifdef _DEBUG class CRC { public: CRC() { crc = 0; } void computeCRC( const void *buf, Int len ); ///< Compute the CRC for a buffer, added into current CRC void clear( void ) { crc = 0; } ///< Clears the CRC to 0 // UnsignedInt get( void ) { return htonl(crc); } ///< Get the combined CRC UnsignedInt get( void ); private: void addCRC( UnsignedByte val ); ///< CRC a 4-byte block UnsignedInt crc; }; #else // optimized inline only version class CRC { public: CRC(void) { crc=0; } /// Compute the CRC for a buffer, added into current CRC __forceinline void computeCRC( const void *buf, Int len ) { if (!buf||len<1) return; /* C++ version left in for reference purposes for (UnsignedByte *uintPtr=(UnsignedByte *)buf;len>0;len--,uintPtr++) { int hibit; if (crc & 0x80000000) { hibit = 1; } else { hibit = 0; } crc <<= 1; crc += *uintPtr; crc += hibit; } */ // ASM version, verified by comparing resulting data with C++ version data unsigned *crcPtr=&crc; _asm { mov esi,[buf] mov ecx,[len] dec ecx mov edi,[crcPtr] mov ebx,dword ptr [edi] xor eax,eax lp: mov al,byte ptr [esi] shl ebx,1 inc esi adc ebx,eax dec ecx jns lp mov dword ptr [edi],ebx }; } /// Clears the CRC to 0 void clear( void ) { crc = 0; } ///< Get the combined CRC UnsignedInt get( void ) const { return crc; } private: UnsignedInt crc; }; #endif #endif // _CRC_H_