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

#define MAX_LEN 512
#define READIN_FILE "readin.txt"
#define OUTFILE "xefs.dat"

typedef struct _RULE {
	ULONG Policy;
	WCHAR Pattern[MAX_LEN];
} RULE, *PRULE;

RULE gRule;

BOOLEAN IsFileExist(char *filename);//檢查文件是否存在
BOOLEAN CheckReadinFile(char *filename);//檢查讀入的文件。合法的文件第一行是Policy，第二行是Pattern


int main()
{
	FILE *pReadinFile;
	FILE *pOutFile;
	WCHAR wbuffer[MAX_LEN];
	ULONG Policy;			//讀出的策略
	ULONG ByteWritten = 0;	//已經寫了的字節數
	ULONG ByteWrittenSum = 0;//前面數據的和，用來校驗
	ULONG i, len;
	PULONG Data;

	system("cls");

	if(!IsFileExist(READIN_FILE))
	{
		printf("文件%s不存在！\n", READIN_FILE);
		exit(1);
	}

	if (!CheckReadinFile(READIN_FILE))
	{
		printf("文件%s不符合格式要求：第一行Policy；第二行Pattern\n", READIN_FILE);
		exit(1);
	}

	pReadinFile = fopen("readin.txt", "r");
	pOutFile = fopen("xefs.dat", "w");

	fscanf(pReadinFile, "%d", &Policy);//讀第一行
	fwrite(&Policy, sizeof(ULONG), 1, pOutFile);//寫頭4個字節（Policy）
	ByteWritten += sizeof(ULONG);	//此時寫了幾個字節
	ByteWrittenSum += Policy;		//累加校驗和

	fscanf(pReadinFile, "%S", &wbuffer);//讀第二行
	len = wcslen(wbuffer);				//讀出的長度（按WCHAR算）
	fwrite(wbuffer, sizeof(WCHAR), len, pOutFile);//將讀出的Pattern按WCHAR寫進文件
	ByteWritten += len * sizeof(WCHAR);	//寫了多少個字節

	Data = (PULONG)wbuffer;
	for(i = 0; i < len / sizeof(WCHAR); i++)	//這里循環條件按ULONG算，sizeof(ULONG) = sizeof(WCHAR) * 2
		ByteWrittenSum += Data[i];	//累加校驗和

	//將剩余部分寫空
	memset(wbuffer, 0, MAX_LEN * sizeof(WCHAR));
	fwrite(wbuffer, sizeof(WCHAR), (sizeof(RULE) - ByteWritten) / sizeof(WCHAR), pOutFile);

	//最后4個字節寫CRC校驗和
	fwrite(&ByteWrittenSum, sizeof(ULONG), 1, pOutFile);

	fclose(pReadinFile);
	fclose(pOutFile);
	
	return 0;
}

BOOLEAN IsFileExist(char *filename)
{
	FILE *fp;

	fp = fopen(filename, "r");

	if (fp)
	{
		fclose(fp);
		return TRUE;
	}
	return FALSE;
}

BOOLEAN CheckReadinFile(char *filename)
{
	FILE *fp;
	ULONG linenum = 0;
	CHAR buf[MAX_LEN * 2];

	fp = fopen(filename, "r");
	while (fscanf(fp, "%s", buf) > 0) {
		linenum ++;
	}

	fclose(fp);

	if(linenum != 2)
		return FALSE;
	return TRUE;
}