暗号化コード

ゲームで使われる独自スクリプトやテキスト型データはよくfgets()で一行ずつ読み込んでなんたらやるように書かれます。
そのfgets()の書き方を流用できる暗号版MyFGetS()を作りました。
最終コカラゲ暗号システムとはまた別です。
すきにつかってね！！

//KAngo.h

#ifndef __KANGO_H_INCLUDED__
#define __KANGO_H_INCLUDED__

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

class CKAngo
{
private:
	int N_TESTS;
	char ttable[27];
	int counter;
	
	char CKAngo::Char2Char_Enc(char ch);
	char CKAngo::Char2Char_Dec(char ch);
	int CKAngo::MyFGetCh(char *buf, FILE *f);
public:
	CKAngo()
	{
		N_TESTS = 27;
		counter = 0;
		const char ttable_b[27] = {
			91, 87, 49, 23, 74, 77, 41, 33, 66, 61,
			97, 10,  9, 24, 91, 53, 87, 62, 93, 63,
			49, 14, 28, 10, 78, 69, 62,
		};
		for(int i=0;i<N_TESTS;i++)
		{
			ttable[i] = ttable_b[i];
		}
	}
	void ResetCounter();
	int MyFGetStr(char *buf, FILE *f);
	void FileToGetAngo(char *filename);
	void FileToPutAngo(char *filename, char *outfilename);
};

#endif //__KANGO_H_INCLUDED__

KAngo.cpp

#include "KAngo.h"

char CKAngo::Char2Char_Enc(char ch)
{
	char rval;
	rval = ch ^ ttable[counter];
	counter++;
	if (counter >= N_TESTS) counter = 0;
	return rval;
}

char CKAngo::Char2Char_Dec(char ch)
{
	char rval;
	rval = ch ^ ttable[counter];
	counter++;
	if (counter >= N_TESTS) counter = 0;
	return rval;
}

int CKAngo::MyFGetCh(char *buf, FILE *f)
{
	int nreaded;
	char ch, dch;
	nreaded = fread(&ch, sizeof(char), 1, f);
	if (nreaded < 1)
	{
		return 0;
	}
	dch = Char2Char_Dec(ch);
	if (dch == '\n' || dch == '\r')
	{
		return -1;
	}
	*buf = dch;
	return 1;
}

int CKAngo::MyFGetStr(char *buf, FILE *f)
{
	int readed = 0; // ok the word must be "read", I know;
	while(1)
	{
		int v;
		char ch;
		v = MyFGetCh(&ch, f);
		if (v == -1)//Return
		{
			*buf = 0;
			break;
		}
		if (v == 0)//EOF
		{
			*buf = 0;
			if (!readed)
			{
				return 0;
			}
			else
			{
				break;
			}
		}
		*buf = ch;
		readed++;
		buf++;
	}
	return 1;
}

void CKAngo::ResetCounter()
{
	counter = 0;
}

void CKAngo::FileToGetAngo(char *filename)
{
	char buf[4096];
	FILE *f;
	
	counter = 0;
	
	f = fopen(filename, "rb");
	if (!f) return;
	
	while(MyFGetStr(buf, f))
	{
		puts(buf);
	}

	fclose(f);
}

void CKAngo::FileToPutAngo(char *filename, char *outfilename)
{
	FILE *f;
	FILE *fdest;
	char buf[1024];

	counter = 0;

	f = fopen(filename, "rt");
	if (f == 0) return;
	fdest = fopen(outfilename, "wb");
	if (fdest == 0) return;

	while(fgets(buf, 1024, f))
	{
		if (!buf[0]) continue;
		
		char *str = buf;

		while(*str)
		{
			char ch = Char2Char_Enc(*str);
			fwrite(&ch, sizeof(char), 1, fdest);
			str++;
		}
	}

	fclose(f);
	fclose(fdest);
	return;
}

使い方の例。
テキストファイルzzz.txtを暗号化してzzza.txtに書き込み、
そのあとzzza.txtを読み込んで表示します。

//Test.cpp
#include "KAngo.h"

void main()
{
	CKAngo angob;
	angob.FileToPutAngo("zzz.txt", "zzza.txt");
	angob.ResetCounter();
	angob.FileToGetAngo("zzza.txt");
}