File reverser usando le win32api

win32api-reverse.c

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

int main(int argc, char **argv)
{
	char s; //buffer

	HANDLE file; //Handle del file

	DWORD fileSize; //La dimensione del file

	LPDWORD lpFileSizeHigh; //In caso la dimensione sia > 2gb

	file = CreateFile(argv[1], GENERIC_READ, FILE_SHARE_READ, NULL,
			OPEN_EXISTING, FILE_ATTRIBUTE_NORMAL, NULL);

	if (file == INVALID_HANDLE_VALUE)
	{
		printf("Error opening the file: %x", GetLastError());
		return 1;
	}

	fileSize = GetFileSize(file, &lpFileSizeHigh);

	LPVOID lpBuffer = &s;

	DWORD nBytesToRead, lpnBytesToRead;
	nBytesToRead = 1;

	SetFilePointer(file, -1L, NULL, SEEK_END);

	while (fileSize > 0)
	{
		fileSize--;

		if (!ReadFile(file, &lpBuffer, nBytesToRead, &lpnBytesToRead, NULL)) {
			printf("Error on the Read: %d", GetLastError());
			return 2;
		}

		printf("%c", lpBuffer);

		SetFilePointer(file, -2L, NULL, SEEK_CUR);
	}

	if (!CloseHandle(file))
	{
		printf("Error, can't close the file: %x", GetLastError());
	}

	return 0;
}