FOSS-VG/src/lib/nbt.hpp

// Copyright 2022, FOSS-VG Developers and Contributers
//
// This program is free software: you can redistribute it and/or modify it
// under the terms of the GNU Affero General Public License as published
// by the Free Software Foundation, version 3.
//
// 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 Affero General Public License for more details.
//
// You should have received a copy of the GNU Affero General Public License
// version 3 along with this program.
// If not, see https://www.gnu.org/licenses/agpl-3.0.en.html

// information taken from https://wiki.vg/NBT
// This is an attempt at creating a uniform model for all NBT tags to allow for a uniform interface based on subclassing a single NBT tag super class.

// NBT tags have a type, optionally a name which consists of the name size and the name string, optionally content type, and optionally a payload which can consist of optionally content type, optionally a content size,
// and the stored content. The format in which they are stored is as follows: <type><name size><name><payload>. All numbers are stored in big endian representation.
// All tag types:
// generic representation:  Tag(uint8:tag_type, String:name, uint16:name_size, byte[]:content, int32:size)
// None (compound end):     Tag( 0, "",          0,                None,           0) => used to determine the end of a compound tag, only the type gets stored
// int8:                    Tag( 1, String:name, uint16:name_size, int8:content,   1) => a single signed byte, size not stored
// int16:                   Tag( 2, String:name, uint16:name_size, int16:content,  2) => 16 bit signed integer, size not stored
// int32:                   Tag( 3, String:name, uint16:name_size, int32:content,  4) => 32 bit signed integer, size not stored
// int64:                   Tag( 4, String:name, uint16:name_size, int64:content,  8) => 64 bit signed integer, size not stored
// float:                   Tag( 5, String:name, uint16:name_size, float:content,  4) => 32 bit IEEE754 floating point number, size not stored
// double:                  Tag( 6, String:name, uint16:name_size, double:content, 8) => 64 bit IEEE754 floating point number, size not stored
// int8[]:                  Tag( 7, String:name, uint16:name_size, int8[]:content, int32:size) => content stored prefixed with size
// String:                  Tag( 8, String:name, uint16:name_size, String:content, uint16:size) => Java style modified UTF-8 string, content stored prefixed with size
// Tag[] (list):            Tag<Tag:type>( 9, String:name, uint16:name_size, Tag[]:content, int32:size) => list of tags of the same type with tag type and name information omitted prefixed by (in order) content type and size
// Tag[] (compound):        Tag(10, String:name, uint16:name_size, Tag[]:content,  int32:size) => list of tags, last tag is always an end tag, size not stored
// int32[]:                 Tag(11, String:name, uint16:name_size, int32[]:content,int32:size) => list of 32 bit signed integers prefixed with its size, endianness not verified at this point
// int64[]:                 Tag(12, String:name, uint16:name_size, int64[]:content,int32:size) => list of 64 bit signed integers prefixed with its size, endianness not verified at this point

#pragma once
#include <cstdint>
#include <vector>
#include <tinyutf8/tinyutf8.h>
#include "error.hpp"

namespace NBT {
    namespace Helper {
        ErrorOr<int8_t> readInt8(uint8_t data[], uint64_t dataSize, uint64_t currentPosition);
        ErrorOr<int16_t> readInt16(uint8_t data[], uint64_t dataSize, uint64_t currentPosition);
        ErrorOr<int32_t> readInt32(uint8_t data[], uint64_t dataSize, uint64_t currentPosition);
        ErrorOr<int64_t> readInt64(uint8_t data[], uint64_t dataSize, uint64_t currentPosition);
        ErrorOr<float> readFloat(uint8_t data[], uint64_t dataSize, uint64_t currentPosition);
        ErrorOr<double> readDouble(uint8_t data[], uint64_t dataSize, uint64_t currentPosition);
        ErrorOr<std::vector<int8_t>> readInt8Array(uint8_t data[], uint64_t dataSize, uint64_t currentPosition);
        ErrorOr<tiny_utf8::string> readString(uint8_t data[], uint64_t dataSize, uint64_t currentPosition);
        ErrorOr<std::vector<int32_t>> readInt32Array(uint8_t data[], uint64_t dataSize, uint64_t currentPosition);
        ErrorOr<std::vector<int64_t>> readInt64Array(uint8_t data[], uint64_t dataSize, uint64_t currentPosition);

        void writeInt8(std::vector<uint8_t>* destination, int8_t data);
        void writeInt16(std::vector<uint8_t>* destination, int16_t data);
        void writeInt32(std::vector<uint8_t>* destination, int32_t data);
        void writeInt64(std::vector<uint8_t>* destination, int64_t data);
        void writeFloat(std::vector<uint8_t>* destination, float data);
        void writeDouble(std::vector<uint8_t>* destination, double data);
        void writeInt8Array(std::vector<uint8_t>* destination, std::vector<int8_t> data);
        void writeInt8Array(std::vector<uint8_t>* destination, int8_t data[], uint32_t dataSize);
        void writeString(std::vector<uint8_t>* destination, tiny_utf8::string data);
        void writeInt32Array(std::vector<uint8_t>* destination, std::vector<int32_t> data);
        void writeInt32Array(std::vector<uint8_t>* destination, int32_t data[], uint32_t dataSize);
        void writeInt64Array(std::vector<uint8_t>* destination, std::vector<int64_t> data);
        void writeInt64Array(std::vector<uint8_t>* destination, int64_t data[], uint32_t dataSize);

        ErrorOr<uint64_t> totalTagSize(uint8_t data[], uint64_t dataSize, uint64_t currentPosition);
        ErrorOr<int32_t> containedDataLength(uint8_t data[], uint64_t dataSize, uint64_t currentPosition);
    }

    namespace TagType {
        const uint8_t END        =   0;
        const uint8_t INT8       =   1;
        const uint8_t INT16      =   2;
        const uint8_t INT32      =   3;
        const uint8_t INT64      =   4;
        const uint8_t FLOAT      =   5;
        const uint8_t DOUBLE     =   6;
        const uint8_t INT8_ARRAY =   7;
        const uint8_t STRING     =   8;
        const uint8_t LIST       =   9;
        const uint8_t COMPOUND   =  10;
        const uint8_t INT32_ARRAY=  11;
        const uint8_t INT64_ARRAY=  12;
        // This is a workaround that's not part of the spec.
        const uint8_t INVALID    = 255;

        // This class is used as a placeholder for implementing the end tag.
        class End {};
    }

    // generic class that all tag types are derived from
    template <typename T>
    struct Tag {
        const uint8_t type = TagType::INVALID;
        T* containedData;

        Tag();
        ErrorOr<std::vector<uint8_t>> toRawData();
    };

    bool validateRawNBTData(uint8_t data[], uint64_t dataSize, uint64_t initialPosition=0, uint64_t* processedDataSize=nullptr);
}