emud64.h

////////////////////////////////////////////////////////////////////////////////
//
// emud64.h - Class EmuD64
//   1541 Disk Image Driver - access files, directory from disk image
//
// MIT License
//
// Copyright (c) 2024 by David R. Van Wagner
// davevw.com
//
// Permission is hereby granted, free of charge, to any person obtaining a copy
// of this software and associated documentation files (the "Software"), to deal
// in the Software without restriction, including without limitation the rights
// to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
// copies of the Software, and to permit persons to whom the Software is
// furnished to do so, subject to the following conditions:
//
// The above copyright notice and this permission notice shall be included in all
// copies or substantial portions of the Software.
//
// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
// IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
// FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
// AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
// LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
// OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
// SOFTWARE.
//
////////////////////////////////////////////////////////////////////////////////

#pragma once

class EmuD64
{
private:
    unsigned char* bytes;
    char* filename_d64;
    bool* track_dirty;

public:
    EmuD64(const char* filename_d64); // tested
    ~EmuD64(); // TODO: TEST

    class DirStruct;
    
    void InitializeData(unsigned char* disk_name, unsigned char* id); // TODO: TEST
    int GetSectorOffset(int track, int sector); // tested
    void WalkDirectory(bool (*dirFn)(EmuD64* d64, DirStruct* dir, int n, bool last, void*& context), void*& context); // tested
    int GetDirectoryCount(); // tested
    int GetDeletedCount();
    DirStruct* DirectoryEntry(int i); // tested
    void DiskBAMField(int field_offset, int size, unsigned char* field); // tested
    void DiskBAMPrintable(int field_offset, int size, char* field); // tested
    void DiskName(char* disk_name, int size); // tested
    void DiskId(char* disk_id, int size); // tested
    void DiskDosType(char* disk_dos_type, int size); // tested
    int BlocksFree(); // tested
    void ReadFileByIndex(int i, unsigned char* data, int& length); // tested
    void ReadFileByName(unsigned char* filename, unsigned char* bytes, int &length); // TODO: TEST
    void StoreFileByName(char* filename, unsigned char* data, int data_len); // TODO: TEST
    const char* GetDirectoryFormatted(); // tested
    bool GetDirectoryProgram(unsigned char* data, int& data_size); // TODO: TEST

private:
    struct BlockStruct
    {
        int track;
        int sector;
    };

    void WriteBlock(BlockStruct block, BlockStruct next_block, unsigned char* data, int data_len, int data_offset);
    BlockStruct AllocBlock(bool directory);
    void StoreFileByStruct(DirStruct* dir, unsigned char* data, int data_len);
    bool FindOrAllocDirectoryEntry(DirStruct* dir, int& track, int& sector, int& entry);
    void LoadFromFilenameOrCreate();
    void FlushDisk();

public:
    static const int sectors_per_disk =
    (
        21 + 21 + 21 + 21 + 21 + 21 + 21 + 21 + 21 + 21 + 21 + 21 + 21 + 21 + 21 + 21 + 21 +
        19 + 19 + 19 + 19 + 19 + 19 + 19 +
        18 + 18 + 18 + 18 + 18 + 18 +
        17 + 17 + 17 + 17 + 17
    );
    static const int bytes_per_disk = 256 * sectors_per_disk;
    static const int dir_track = 18;
    static const int dir_sector = 1;
    static const int dir_entry_size = 32;
    static const int n_tracks = 35;
    static const int bytes_per_sector = 256;
    static const int dir_entries_per_sector = bytes_per_sector / dir_entry_size;
    static const int dir_entries_max = (19/*sectors_per_track[dir_track]*/ - 1) * dir_entries_per_sector;
    static const int bam_track = dir_track;
    static const int bam_sector = 0;
    static const int disk_name_offset = 0x90;
    static const int disk_name_size = 16;
    static const int disk_id_offset = 0xA2;
    static const int disk_id_size = 2;
    static const int disk_dos_type_offset = 0xA5;
    static const int disk_dos_type_size = 2;

    class DirStruct
    {
    public:
        static const int dir_name_size = 16;
        const int dir_unused_size = 6;
        enum FileType { DEL = 0, SEQ = 1, PRG = 2, USR = 3, REL = 4 };

        int next_track;
        int next_sector;
        int file_type; // lower 4 bits, 4 unused, 5 for @SAVE, 6 for > Locked, 7 Closed otherwise *
        int file_track;
        int file_sector;
        unsigned char filename[16]; // 16 character, PETSCII, $A0 right padded
        int rel_track;
        int rel_sector;
        int rel_length;
        unsigned char unused[6]; // 6 bytes unused except GEOS disks
        unsigned short n_sectors; // 16-bit

        DirStruct(); // tested

        void Read(EmuD64* d64, int track, int sector, int n); // tested
        void ReadData(EmuD64* d64, unsigned char* data, int offset); // tested
        int Store(EmuD64* d64, int dir_track, int dir_sector, int dir_sector_entry);
        static char PrintableChar(unsigned char c); // tested
        void getName(unsigned char* name, int size);
        const char* FileTypeString(); // tested
        const char* toString(); // tested
    }; // class DirStruct 

}; // class EmuD64