#include <stdio.h>
#include <time.h>
#include <windows.h>

void test(char* fname)
{
	printf("open file %s ... ", fname);
	HANDLE f = CreateFile(fname, GENERIC_READ, FILE_SHARE_READ, NULL, OPEN_EXISTING, FILE_ATTRIBUTE_NORMAL, NULL);
	if( f == INVALID_HANDLE_VALUE) {
		printf("error %d\n", GetLastError());
		return;
	}
	unsigned int size = SetFilePointer(f, 0, 0, FILE_END);
	SetFilePointer(f, 0, 0, FILE_BEGIN);
	printf("Ok\nsize %u Mb\n", size / 1048576);

	printf("map create ... ");
	HANDLE fm = CreateFileMapping(f, NULL, PAGE_READONLY, 0, size, NULL);
	if(!fm) {
		printf("error %d\n", GetLastError());
		CloseHandle(f);
		return;
	}
	printf("Ok\n");

	printf("map to memory ... ");
	char* mem = (char*) MapViewOfFile(fm, FILE_MAP_READ, 0, 0, size);
	if(!mem) {
		printf("error %d\n", GetLastError());
	} else {
		printf("Ok\n");
		char* end = mem + size;
		// Расчет контрольной суммы файла 10 раз
		for(int i = 0; i < 10; i++) {
			char res = 0;
			char* ptr = mem;
			while(ptr < end) {
				res ^= *ptr;
				ptr++;
			}
			printf("%5d msec checksum %d\n", clock(), res);
			Sleep(1000); // Чтобы успеть что-нибудь увидеть в диспетчере
		}
		UnmapViewOfFile((void*) mem);
	}
	CloseHandle(fm);
	CloseHandle(f);
}

int main(int argc,char **argv) {
	if(argv[1]) {
		test(argv[1]);
	} else {
		printf("test.exe filename\n");
	}
	system("pause");
}

open file C:\Download\ubuntu-13.10-desktop-i386.iso ... Ok
size 895 Mb
map create ... Ok
map to memory ... Ok
 8283 msec checksum 59
10062 msec checksum 59
11653 msec checksum 59
13291 msec checksum 59
14898 msec checksum 59
16504 msec checksum 59
18127 msec checksum 59
19734 msec checksum 59
21325 msec checksum 59
22932 msec checksum 59

open file C:\Download\ubuntu-13.10-desktop-i386.iso ... Ok
size 895 Mb
map create ... Ok
map to memory ... Ok
  733 msec checksum 59
 2511 msec checksum 59
 4134 msec checksum 59
 5740 msec checksum 59
 7363 msec checksum 59
 8985 msec checksum 59
10608 msec checksum 59
12261 msec checksum 59
13884 msec checksum 59
15506 msec checksum 59