// 
// JoolzCheat
// Copyright (c)2003 [JAPS]Joolz
// 
// 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., 675 Mass Ave, Cambridge, MA 02139, USA.
// 
// NOTE:
// GNU license doesn't cover Engine, Misc or Common directory.
// Content of Engine directory is copyrighted (c) 1999, 2000, by Valve LLC
// and it is licensed under Valve's proprietary license (see original HL SDK).
// 
#include <windows.h>
#include "Crc32Static.h"

// Static CRC table
DWORD CCrc32Static::s_arrdwCrc32Table[256] =
{
	0x00000000, 0x77073096, 0xEE0E612C, 0x990951BA,
	0x076DC419, 0x706AF48F, 0xE963A535, 0x9E6495A3,
	0x0EDB8832, 0x79DCB8A4, 0xE0D5E91E, 0x97D2D988,
	0x09B64C2B, 0x7EB17CBD, 0xE7B82D07, 0x90BF1D91,
	0x1DB71064, 0x6AB020F2, 0xF3B97148, 0x84BE41DE,
	0x1ADAD47D, 0x6DDDE4EB, 0xF4D4B551, 0x83D385C7,
	0x136C9856, 0x646BA8C0, 0xFD62F97A, 0x8A65C9EC,
	0x14015C4F, 0x63066CD9, 0xFA0F3D63, 0x8D080DF5,
	0x3B6E20C8, 0x4C69105E, 0xD56041E4, 0xA2677172,
	0x3C03E4D1, 0x4B04D447, 0xD20D85FD, 0xA50AB56B,
	0x35B5A8FA, 0x42B2986C, 0xDBBBC9D6, 0xACBCF940,
	0x32D86CE3, 0x45DF5C75, 0xDCD60DCF, 0xABD13D59,
	0x26D930AC, 0x51DE003A, 0xC8D75180, 0xBFD06116,
	0x21B4F4B5, 0x56B3C423, 0xCFBA9599, 0xB8BDA50F,
	0x2802B89E, 0x5F058808, 0xC60CD9B2, 0xB10BE924,
	0x2F6F7C87, 0x58684C11, 0xC1611DAB, 0xB6662D3D,

	0x76DC4190, 0x01DB7106, 0x98D220BC, 0xEFD5102A,
	0x71B18589, 0x06B6B51F, 0x9FBFE4A5, 0xE8B8D433,
	0x7807C9A2, 0x0F00F934, 0x9609A88E, 0xE10E9818,
	0x7F6A0DBB, 0x086D3D2D, 0x91646C97, 0xE6635C01,
	0x6B6B51F4, 0x1C6C6162, 0x856530D8, 0xF262004E,
	0x6C0695ED, 0x1B01A57B, 0x8208F4C1, 0xF50FC457,
	0x65B0D9C6, 0x12B7E950, 0x8BBEB8EA, 0xFCB9887C,
	0x62DD1DDF, 0x15DA2D49, 0x8CD37CF3, 0xFBD44C65,
	0x4DB26158, 0x3AB551CE, 0xA3BC0074, 0xD4BB30E2,
	0x4ADFA541, 0x3DD895D7, 0xA4D1C46D, 0xD3D6F4FB,
	0x4369E96A, 0x346ED9FC, 0xAD678846, 0xDA60B8D0,
	0x44042D73, 0x33031DE5, 0xAA0A4C5F, 0xDD0D7CC9,
	0x5005713C, 0x270241AA, 0xBE0B1010, 0xC90C2086,
	0x5768B525, 0x206F85B3, 0xB966D409, 0xCE61E49F,
	0x5EDEF90E, 0x29D9C998, 0xB0D09822, 0xC7D7A8B4,
	0x59B33D17, 0x2EB40D81, 0xB7BD5C3B, 0xC0BA6CAD,

	0xEDB88320, 0x9ABFB3B6, 0x03B6E20C, 0x74B1D29A,
	0xEAD54739, 0x9DD277AF, 0x04DB2615, 0x73DC1683,
	0xE3630B12, 0x94643B84, 0x0D6D6A3E, 0x7A6A5AA8,
	0xE40ECF0B, 0x9309FF9D, 0x0A00AE27, 0x7D079EB1,
	0xF00F9344, 0x8708A3D2, 0x1E01F268, 0x6906C2FE,
	0xF762575D, 0x806567CB, 0x196C3671, 0x6E6B06E7,
	0xFED41B76, 0x89D32BE0, 0x10DA7A5A, 0x67DD4ACC,
	0xF9B9DF6F, 0x8EBEEFF9, 0x17B7BE43, 0x60B08ED5,
	0xD6D6A3E8, 0xA1D1937E, 0x38D8C2C4, 0x4FDFF252,
	0xD1BB67F1, 0xA6BC5767, 0x3FB506DD, 0x48B2364B,
	0xD80D2BDA, 0xAF0A1B4C, 0x36034AF6, 0x41047A60,
	0xDF60EFC3, 0xA867DF55, 0x316E8EEF, 0x4669BE79,
	0xCB61B38C, 0xBC66831A, 0x256FD2A0, 0x5268E236,
	0xCC0C7795, 0xBB0B4703, 0x220216B9, 0x5505262F,
	0xC5BA3BBE, 0xB2BD0B28, 0x2BB45A92, 0x5CB36A04,
	0xC2D7FFA7, 0xB5D0CF31, 0x2CD99E8B, 0x5BDEAE1D,

	0x9B64C2B0, 0xEC63F226, 0x756AA39C, 0x026D930A,
	0x9C0906A9, 0xEB0E363F, 0x72076785, 0x05005713,
	0x95BF4A82, 0xE2B87A14, 0x7BB12BAE, 0x0CB61B38,
	0x92D28E9B, 0xE5D5BE0D, 0x7CDCEFB7, 0x0BDBDF21,
	0x86D3D2D4, 0xF1D4E242, 0x68DDB3F8, 0x1FDA836E,
	0x81BE16CD, 0xF6B9265B, 0x6FB077E1, 0x18B74777,
	0x88085AE6, 0xFF0F6A70, 0x66063BCA, 0x11010B5C,
	0x8F659EFF, 0xF862AE69, 0x616BFFD3, 0x166CCF45,
	0xA00AE278, 0xD70DD2EE, 0x4E048354, 0x3903B3C2,
	0xA7672661, 0xD06016F7, 0x4969474D, 0x3E6E77DB,
	0xAED16A4A, 0xD9D65ADC, 0x40DF0B66, 0x37D83BF0,
	0xA9BCAE53, 0xDEBB9EC5, 0x47B2CF7F, 0x30B5FFE9,
	0xBDBDF21C, 0xCABAC28A, 0x53B39330, 0x24B4A3A6,
	0xBAD03605, 0xCDD70693, 0x54DE5729, 0x23D967BF,
	0xB3667A2E, 0xC4614AB8, 0x5D681B02, 0x2A6F2B94,
	0xB40BBE37, 0xC30C8EA1, 0x5A05DF1B, 0x2D02EF8D,
};

//***********************************************
CCrc32Static::CCrc32Static()
{
}

//***********************************************
CCrc32Static::~CCrc32Static()
{
}

//***********************************************
inline void CCrc32Static::CalcCrc32(const BYTE byte, DWORD &dwCrc32)
{
	dwCrc32 = ((dwCrc32) >> 8) ^ s_arrdwCrc32Table[(byte) ^ ((dwCrc32) & 0x000000FF)];
}

//***********************************************
bool CCrc32Static::GetFileSizeQW(const HANDLE hFile, QWORD &qwSize)
{
	bool bSuccess = true;

	try
	{
		DWORD dwLo = 0, dwHi = 0;
		dwLo = GetFileSize(hFile, &dwHi);

		if(dwLo == INVALID_FILE_SIZE && GetLastError() != NO_ERROR)
		{
			bSuccess = false;
			qwSize = 0;
		}
		else
		{
			qwSize = MAKEQWORD(dwHi, dwLo);
		}
	}
	catch(...)
	{
		bSuccess = false;
	}

	return bSuccess;
}

//***********************************************
DWORD CCrc32Static::StringCrc32(LPCTSTR szString, DWORD &dwCrc32)
{
	DWORD dwErrorCode = NO_ERROR;

	dwCrc32 = 0xFFFFFFFF;

	try
	{
		while(*szString != '\0')
		{
			CalcCrc32((BYTE)*szString, dwCrc32);
			szString++;
		}
	}
	catch(...)
	{
		// An unknown exception happened
		dwErrorCode = ERROR_CRC;
	}

	dwCrc32 = ~dwCrc32;

	return dwErrorCode;
}

//***********************************************
DWORD CCrc32Static::FileCrc32Win32(LPCTSTR szFilename, DWORD &dwCrc32)
{
	DWORD dwErrorCode = NO_ERROR;
	HANDLE hFile = NULL;

	dwCrc32 = 0xFFFFFFFF;

	try
	{
		// Open the file
		hFile = CreateFile(szFilename,
			GENERIC_READ,
			FILE_SHARE_READ,
			NULL,
			OPEN_EXISTING,
			FILE_ATTRIBUTE_ARCHIVE | FILE_ATTRIBUTE_HIDDEN | FILE_ATTRIBUTE_READONLY | FILE_ATTRIBUTE_SYSTEM | FILE_FLAG_SEQUENTIAL_SCAN,
			NULL);
		if(hFile == INVALID_HANDLE_VALUE)
			dwErrorCode = GetLastError();
		else
		{
			BYTE buffer[MAX_BUFFER_SIZE];
			DWORD dwBytesRead, dwLoop;
			BOOL bSuccess = ReadFile(hFile, buffer, sizeof(buffer), &dwBytesRead, NULL);
			while(bSuccess && dwBytesRead)
			{
				for(dwLoop = 0; dwLoop < dwBytesRead; dwLoop++)
					CalcCrc32(buffer[dwLoop], dwCrc32);
				bSuccess = ReadFile(hFile, buffer, sizeof(buffer), &dwBytesRead, NULL);
			}
		}
	}
	catch(...)
	{
		// An unknown exception happened
		dwErrorCode = ERROR_CRC;
	}

	if(hFile != NULL) CloseHandle(hFile);

	dwCrc32 = ~dwCrc32;

	return dwErrorCode;
}

//***********************************************
DWORD CCrc32Static::FileCrc32Filemap(LPCTSTR szFilename, DWORD &dwCrc32)
{
	DWORD dwErrorCode = NO_ERROR;
	HANDLE hFile = NULL, hFilemap = NULL;

	dwCrc32 = 0xFFFFFFFF;

	try
	{
		// Open the file
		hFile = CreateFile(szFilename,
			GENERIC_READ,
			FILE_SHARE_READ,
			NULL,
			OPEN_EXISTING,
			FILE_ATTRIBUTE_ARCHIVE | FILE_ATTRIBUTE_HIDDEN | FILE_ATTRIBUTE_READONLY | FILE_ATTRIBUTE_SYSTEM | FILE_FLAG_SEQUENTIAL_SCAN,
			NULL);
		if(hFile == INVALID_HANDLE_VALUE)
			dwErrorCode = GetLastError();
		else
		{
			QWORD qwFileSize = 0, qwFileOffset = 0;
			DWORD dwByteCount, dwViewSize;
			DWORD dwBaseAddress;

			// Get the file size
			if(!GetFileSizeQW(hFile, qwFileSize))
				dwErrorCode = ERROR_BAD_LENGTH;
			else if(qwFileSize != 0)	// We cannot CRC zero byte files
			{
				// Create the file mapping
				hFilemap = CreateFileMapping(hFile,
					NULL,
					PAGE_READONLY,
					0,
					0,
					NULL);
				if(hFilemap == NULL)
					dwErrorCode = GetLastError();
				else
				{
					LPBYTE pByte;

					// Loop while we map a section of the file and CRC it
					while(qwFileSize > 0)
					{
						if(qwFileSize < MAX_VIEW_SIZE)
							dwViewSize = LODWORD(qwFileSize);
						else
							dwViewSize = MAX_VIEW_SIZE;

						dwBaseAddress = (DWORD)MapViewOfFile(hFilemap,
							FILE_MAP_READ,
							HIDWORD(qwFileOffset),
							LODWORD(qwFileOffset),
							dwViewSize);

						dwByteCount = dwViewSize;
						pByte = (LPBYTE)dwBaseAddress;
						while(dwByteCount-- > 0)
						{
							CalcCrc32(*pByte, dwCrc32);
							pByte++;
						}

						UnmapViewOfFile((LPVOID)dwBaseAddress);
						qwFileOffset += dwViewSize;
						qwFileSize -= dwViewSize;
					}
				}
			}
		}
	}
	catch(...)
	{
		// An unknown exception happened
		dwErrorCode = ERROR_CRC;
	}

	if(hFile != NULL) CloseHandle(hFile);
	if(hFilemap != NULL) CloseHandle(hFilemap);

	dwCrc32 = ~dwCrc32;

	return dwErrorCode;
}

//***********************************************
DWORD CCrc32Static::FileCrc32Assembly(LPCTSTR szFilename, DWORD &dwCrc32)
{
	DWORD dwErrorCode = NO_ERROR;
	HANDLE hFile = NULL;

	dwCrc32 = 0xFFFFFFFF;

	try
	{
		// Open the file
		hFile = CreateFile(szFilename,
			GENERIC_READ,
			FILE_SHARE_READ,
			NULL,
			OPEN_EXISTING,
			FILE_ATTRIBUTE_ARCHIVE | FILE_ATTRIBUTE_HIDDEN | FILE_ATTRIBUTE_READONLY | FILE_ATTRIBUTE_SYSTEM | FILE_FLAG_SEQUENTIAL_SCAN,
			NULL);
		if(hFile == INVALID_HANDLE_VALUE)
			dwErrorCode = GetLastError();
		else
		{
			// There is a bug in the Microsoft compilers where inline assembly
			// code cannot access static member variables.  This is a work around
			// for that bug.  For more info see Knowledgebase article Q88092
			LPVOID ptrCrc32Table = &s_arrdwCrc32Table;

			BYTE buffer[MAX_BUFFER_SIZE];
			DWORD dwBytesRead;
			BOOL bSuccess = ReadFile(hFile, buffer, sizeof(buffer), &dwBytesRead, NULL);
			while(bSuccess && dwBytesRead)
			{
				// Register use:
				//		eax - CRC32 value
				//		ebx - a lot of things
				//		ecx - CRC32 value
				//		edx - address of end of buffer
				//		esi - address of start of buffer
				//		edi - CRC32 table
				__asm
				{
					// Save the esi and edi registers
					push esi
					push edi

					mov eax, dwCrc32			// Load the pointer to dwCrc32
					mov ecx, [eax]				// Dereference the pointer to load dwCrc32

					mov edi, ptrCrc32Table		// Load the CRC32 table

					lea esi, buffer				// Load buffer
					mov ebx, dwBytesRead		// Load dwBytesRead
					lea edx, [esi + ebx]		// Calculate the end of the buffer

				crc32loop:
					xor eax, eax				// Clear the eax register
					mov bl, byte ptr [esi]		// Load the current source byte
					
					mov al, cl					// Copy crc value into eax
					inc esi						// Advance the source pointer

					xor al, bl					// Create the index into the CRC32 table
					shr ecx, 8

					mov ebx, [edi + eax * 4]	// Get the value out of the table
					xor ecx, ebx				// xor with the current byte

					cmp edx, esi				// Have we reached the end of the buffer?
					jne crc32loop

					// Restore the edi and esi registers
					pop edi
					pop esi

					mov eax, dwCrc32			// Load the pointer to dwCrc32
					mov [eax], ecx				// Write the result
				}
				bSuccess = ReadFile(hFile, buffer, sizeof(buffer), &dwBytesRead, NULL);
			}
		}
	}
	catch(...)
	{
		// An unknown exception happened
		dwErrorCode = ERROR_CRC;
	}

	if(hFile != NULL) CloseHandle(hFile);

	dwCrc32 = ~dwCrc32;

	return dwErrorCode;
}
