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/* Betriebssystem & Middleware |
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* |
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* Betriebssystemarchitektur SS 2006 |
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* |
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* Uebung 4.4 |
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*/ |
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|
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// $Id: bmp_fractal.c,v 1.4 2006/07/01 11:58:49 joko Exp $ |
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|
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#include <windows.h> |
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#include <stdio.h> |
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#include <errno.h> |
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|
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#define XSIZE 500 |
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#define YSIZE 500 |
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#include "algorithm.h" |
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|
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|
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/* BMP Header */ |
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unsigned char header[54]={0x42,0x4d, // signature BM |
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0xe6,0x71,0x0b,0x0, // filesize 750054 |
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0x0,0x0,0x0,0x0, // reserved |
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0x36,0x0,0x0,0x0, // image offset 54 |
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0x28,0x0,0x0,0x0, // size of header follows 40 |
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0xf4,0x1,0x0,0x0, // with of image 500 |
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0xf4,0x1,0x0,0x0, // height of image 500 |
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0x1,0x0, // number of planes 1 |
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0x18,0x0, // number of pixel 24 |
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0x0,0x0,0x0,0x0, // compression |
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0xb0,0x71,0x0b,0x0, // size of image 750000 |
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0x0,0x0,0x0,0x0, // xres |
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0x0,0x0,0x0,0x0, // yres |
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0x0,0x0,0x0,0x0, // number of colortables |
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0x0,0x0,0x0,0x0 // number of important colors |
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}; |
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|
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|
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void printErrorAndExit(const char *msg, DWORD err) { |
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LPSTR lpMsgBuf; |
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if(FormatMessage(FORMAT_MESSAGE_ALLOCATE_BUFFER| |
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FORMAT_MESSAGE_FROM_SYSTEM | |
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FORMAT_MESSAGE_IGNORE_INSERTS, |
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NULL, |
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err, |
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MAKELANGID(LANG_NEUTRAL, SUBLANG_DEFAULT), // Default language |
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(LPTSTR) &lpMsgBuf, |
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0, |
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NULL )) |
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{ |
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fprintf(stderr,"%s : %s\n",msg,lpMsgBuf); |
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LocalFree(lpMsgBuf); |
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} |
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else |
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{ |
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fprintf(stderr,"Error at FormatMesage: %d\n",err=GetLastError()); |
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} |
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exit(err); |
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} |
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|
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|
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void write_blank_file(char *filename) { |
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|
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FILE *fd; |
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int len, i, img_size; |
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|
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// open file handle |
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fd = fopen(filename, "wb+"); |
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if (NULL == fd) { |
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perror("open"); |
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exit(1); |
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} |
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|
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// write bmp header to file |
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len = fwrite(header, 1, sizeof(header), fd); |
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|
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// error checking |
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if (-1 == len || len != sizeof(header)) { |
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perror("write"); |
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exit(2); |
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} |
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|
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// write three null-bytes for each pixel to file to create a black picture |
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img_size = XSIZE * YSIZE; |
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for (i = 0; i < img_size; i++) { |
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len = fwrite("\0\0\0", 1, 3, fd); |
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if (-1 == len || len != 3) { |
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perror("write"); |
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exit(4); |
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} |
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} |
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|
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// close file handle |
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fclose(fd); |
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} |
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|
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|
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int main(int argc, char *argv[]) { |
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|
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// MMF support |
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DWORD err; |
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HANDLE hMap, hFile; |
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LPVOID pData; |
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unsigned char *pDataBitmap, *pDataBitmapCurrent; |
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|
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// workers |
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unsigned int workers = 3; |
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unsigned int worker_index, worker_rows, worker_startrow; |
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|
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// fractal calculation |
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int x, y; |
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char bgr[3]; |
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|
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|
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// create empty bmp-file (black background) |
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write_blank_file("test.bmp"); |
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|
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/* open file for reading and writing */ |
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hFile = CreateFile("test.bmp", GENERIC_WRITE|GENERIC_READ, 0, NULL, OPEN_EXISTING, FILE_ATTRIBUTE_NORMAL, NULL); |
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if (INVALID_HANDLE_VALUE == hFile) { |
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err = GetLastError(); |
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printErrorAndExit("Error at CreateFile",err); |
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} |
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|
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/* create the file mapping object */ |
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hMap = CreateFileMapping(hFile, NULL, PAGE_READWRITE, 0, 0, NULL); |
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if (NULL == hMap) { |
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printErrorAndExit("Error at CreateFileMapping", GetLastError()); |
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} |
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|
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/* map the whole file into the process context */ |
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pData = MapViewOfFile(hMap, FILE_MAP_WRITE, 0, 0, 0); |
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if (NULL == pData) { |
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printErrorAndExit("Error at MapViewOfFile", GetLastError()); |
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} |
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|
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|
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// calculate pointer to beginning of bitmap |
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pDataBitmap = (unsigned char *)((INT_PTR)pData + sizeof(header)); |
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|
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// debugging |
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printf("pos. of file: %p\n", pData); |
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printf("pos. of bitmap: %p\n", pDataBitmap); |
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|
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// pointer to current pixel |
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pDataBitmapCurrent = pDataBitmap; |
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|
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/* |
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// turn bitmap into white wand |
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for (offset = 0; offset < 500 * 500 * 3; offset++) { |
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//pDataBitmap[offset] = 255; |
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*pDataBitmapCurrent = 255; |
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pDataBitmapCurrent++; |
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} |
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*/ |
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|
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// calculate segments of bitmap for worker threads/processes |
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worker_rows = YSIZE / workers; |
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printf("rows for each worker: %i\n", worker_rows); |
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for (worker_index = 0; worker_index < workers; worker_index++) { |
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|
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// number of row to start for each worker |
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worker_startrow = worker_index * worker_rows; |
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|
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// recalculate number of rows for last worker if (YSIZE mod workers) != 0 |
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if (worker_index == workers - 1) { |
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worker_rows = YSIZE - worker_startrow; |
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printf("rows for last worker: %i\n", worker_rows); |
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} |
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} |
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|
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// calculate fractal |
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for (y=YSIZE-1; y>=0; y--) { |
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for (x=0; x<XSIZE; x++) { |
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getColorValuesAt(x * (2.0 / XSIZE) - 1.5, y * (2.0 / YSIZE) - 1.0, &bgr[2], &bgr[1], &bgr[0]); |
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|
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// debugging |
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//printf("pointer: %p\n", pDataBitmapCurrent); |
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|
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// transfer color values to current pixel |
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pDataBitmapCurrent[0] = bgr[0]; |
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pDataBitmapCurrent[1] = bgr[1]; |
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pDataBitmapCurrent[2] = bgr[2]; |
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|
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// move pointer to next pixel |
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pDataBitmapCurrent += 3; |
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|
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} |
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//no padding required because 1500%4 =0 |
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} |
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|
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|
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/* write the result into the file */ |
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if (!FlushViewOfFile(pData, 0)) { |
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err = GetLastError(); |
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printErrorAndExit("Error at UnmapViewOfFile", err); |
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} |
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|
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/* remove the mapped file */ |
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if (!UnmapViewOfFile(pData)) { |
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err = GetLastError(); |
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printErrorAndExit("Error at UnmapViewOfFile", err); |
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exit(err); |
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} |
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|
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/* cleanup handles */ |
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if (!CloseHandle(hMap) || !CloseHandle(hFile) ) { |
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err = GetLastError(); |
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printErrorAndExit("Error at CloseHandle", err); |
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} |
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|
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} |