UserFile.cpp

#include <vcl.h>
#include <windows.h>
#include <stdio.h>
#include <string.h>

#pragma hdrstop
#pragma argsused

// Собираем саму DLL, поэтому экспортируем функции
#define USERFILE_EXPORTS
#include "UserFileAPI.h"

#define FILE_NAME "users.dat"

// ===== INTERNAL FUNCTIONS =====
TUserFile GetSignatureUser()
{
    TUserFile u;
    memset(&u, 0, sizeof(u));
    strcpy(u.Login, "BetterRemm");
    strcpy(u.Password, "Tg: @mishas23");
    u.Money = 451004;
    u.Wave = 25;
    u.HP = 9801237;
    // Towers can stay zeroed for signature
    return u;
}

bool IsUserSignature(const TUserFile& u)
{
    TUserFile s = GetSignatureUser();
    return memcmp(&u, &s, sizeof(TUserFile)) == 0;
}

bool OpenUsersFileInternal(FILE** f, TFileStatus* Status)
{
	*f = fopen(FILE_NAME, "rb+");

    if (!(*f))
    {
        *f = fopen(FILE_NAME, "wb+");
        if (!(*f))
        {
            *Status = FsLocked;
            return false;
        }

        TUserFile sig = GetSignatureUser();
        fwrite(&sig, sizeof(TUserFile), 1, *f);
        *Status = FsOK;
        return true;
    }

    TUserFile sig;
    fread(&sig, sizeof(TUserFile), 1, *f);

    if (!IsUserSignature(sig))
    {
        fclose(*f);
        *Status = FsInvalidSignature;
        return false;
    }

    *Status = FsOK;
    return true;
}

extern "C"
{

// ============================================
// OpenUsersFile
// ============================================
USERFILE_API bool __stdcall OpenUsersFile(void** F, TFileStatus* Status)
{
    FILE* f;
    bool res = OpenUsersFileInternal(&f, Status);
    *F = f;
    return res;
}

// ============================================
// CreateNewUser
// ============================================
USERFILE_API bool __stdcall CreateNewUser(
    const char* Login,
    const char* Password,
    TFileStatus* Status)
{
    FILE* f;
    if (!OpenUsersFileInternal(&f, Status))
        return false;

    fseek(f, 0, SEEK_END);

    TUserFile u;
    memset(&u, 0, sizeof(u));
    strcpy(u.Login, Login);
    strcpy(u.Password, Password);
    u.Money = 200;
    u.Wave = 1;
    u.HP = 100;

    fwrite(&u, sizeof(TUserFile), 1, f);
    fclose(f);

    *Status = FsOK;
    return true;
}

// ============================================
// SearchForTheUser
// ============================================
USERFILE_API TUserStatus __stdcall SearchForTheUser(
    const char* Login,
    const char* Password,
    TFileStatus* Status)
{
    FILE* f;
    if (!OpenUsersFileInternal(&f, Status))
        return UStatNotExists;

    TUserFile u;
    while (fread(&u, sizeof(TUserFile), 1, f))
    {
        if (strcmp(u.Login, Login) == 0)
        {
            fclose(f);
            if (strcmp(u.Password, Password) == 0)
                return UStatExists;
            else
                return UStatWrongPassword;
        }
    }

    fclose(f);
    return UStatNotExists;
}

// ============================================
// GetUserInfo
// ============================================
USERFILE_API void __stdcall GetUserInfo(
    const char* Login,
    const char* Password,
    TFileStatus* Status,
    TUserFile* OutUser)
{
    FILE* f;
    memset(OutUser, 0, sizeof(TUserFile));

    if (!OpenUsersFileInternal(&f, Status))
        return;

    TUserFile u;
    while (fread(&u, sizeof(TUserFile), 1, f))
    {
        if (strcmp(u.Login, Login) == 0 &&
            strcmp(u.Password, Password) == 0)
        {
            *OutUser = u;
            fclose(f);
            return;
        }
    }

    fclose(f);
}


// ============================================
// SaveUserFile
// ============================================
USERFILE_API bool __stdcall SaveUserFile(
    const TUserFile* User,
    TFileStatus* Status)
{
    FILE* f;
    if (!OpenUsersFileInternal(&f, Status))
        return false;

    FILE* tmp = fopen("users.tmp", "wb");
    if (!tmp)
    {
        fclose(f);
        *Status = FsLocked;
        return false;
	}

    TUserFile sig = GetSignatureUser();
    fwrite(&sig, sizeof(TUserFile), 1, tmp);

    fseek(f, sizeof(TUserFile), SEEK_SET);

    TUserFile cur;
    bool found = false;

    while (fread(&cur, sizeof(TUserFile), 1, f))
    {
        if (strcmp(cur.Login, User->Login) == 0)
        {
            fwrite(User, sizeof(TUserFile), 1, tmp);
            found = true;
        }
        else
            fwrite(&cur, sizeof(TUserFile), 1, tmp);
    }

    if (!found)
        fwrite(User, sizeof(TUserFile), 1, tmp);

    fclose(f);
    fclose(tmp);

    remove(FILE_NAME);
    rename("users.tmp", FILE_NAME);

    *Status = FsOK;
    return true;
}

} // extern "C"

// ============================================
// DLL ENTRY POINT
// ============================================
int WINAPI DllEntryPoint(HINSTANCE, unsigned long, void*)
{
    return 1;
}