fileio.h

/* ScummVM - Graphic Adventure Engine
 *
 * ScummVM is the legal property of its developers, whose names
 * are too numerous to list here. Please refer to the COPYRIGHT
 * file distributed with this source distribution.
 *
 * This program is free software: you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation, either version 3 of the License, or
 * (at your option) any later version.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program.  If not, see <http://www.gnu.org/licenses/>.
 *
 */
 
/*
 * This code is based on original Sfinx source code
 * Copyright (c) 1994-1997 Janusz B. Wisniewski and L.K. Avalon
 */
 
#ifndef CGE2_FILEIO_H
#define CGE2_FILEIO_H
 
#include "common/file.h"
 
namespace CGE2 {
 
#define kBtSize       2048
#define kBtKeySize    13
#define kBtLevel      2
#define kBtInnerCount ((kBtSize - 4 /*sizeof(Header) */) / (kBtKeySize + 2 /*sizeof(Inner) */))
#define kBtLeafCount  ((kBtSize - 4 /*sizeof(Header) */) / (kBtKeySize + 4 + 4 /*sizeof(BtKeypack) */))
#define kBtValNone    0xFFFF
#define kBtValRoot    0
#define kCatName      "VOL.CAT"
#define kDatName      "VOL.DAT"
#define kCryptSeed    0xA5
 
enum ID {
    kIdNear, kIdMTake, kIdFTake, kIdPhase, kIdSeq,
    kIdName, kIdType, kIdFront, kIdEast,
    kIdPortable, kIdTransparent,
    kIdNone = -1
};
 
struct BtKeypack {
    char _key[kBtKeySize];
    uint32 _pos;
    uint32 _size;
};
 
struct Inner {
    uint8  _key[kBtKeySize];
    uint16 _down;
};
 
struct Header {
    uint16 _count;
    uint16 _down;
};
 
struct BtPage {
    Header _header;
    union {
        // dummy filler to make proper size of union
        uint8 _data[kBtSize - 4]; /* 4 is the size of struct Header */
        // inner version of data: key + word-sized page link
        Inner _inner[kBtInnerCount];
        // leaf version of data: key + all user data
        BtKeypack _leaf[kBtLeafCount];
    };
 
    void readBTree(Common::ReadStream &s);
};
 
class ResourceManager {
private:
    struct {
        BtPage *_page;
        uint16 _pageNo;
        int _index;
    } _buff[kBtLevel];
 
    BtPage *getPage(int level, uint16 pageId);
    uint16 catRead(byte *buf, uint16 length);
    Common::File *_catFile;
    Common::File *_datFile;
    void xCrypt(byte *buf, uint16 length);
public:
    ResourceManager();
    ~ResourceManager();
    uint16 read(byte *buf, uint16 length);
    bool seek(int32 offs, int whence = SEEK_SET);
 
    BtKeypack *find(const char *key);
    bool exist(const char *name);
};
 
class EncryptedStream {
private:
    Common::SeekableReadStream *_readStream;
    int _lineCount;
    bool _error;
public:
    EncryptedStream(ResourceManager *resman, const char *name);
    ~EncryptedStream();
    bool err();
    bool eos();
    bool seek(int32 offset);
    int32 pos();
    int32 size();
    uint32 read(byte *dataPtr, uint32 dataSize);
    int16 readSint16LE();
    uint32 readUint32LE();
    Common::String readLine();
    int getLineCount() { return _lineCount; }
 
    static const char *const kIdTab[];
};
 
} // End of namespace CGE2
 
#endif // CGE2_FILEIO_H