From 53878c3e2b6805034ed12490f72493a0f8f8e2c5 Mon Sep 17 00:00:00 2001
From: BodgeMaster <>
Date: Thu, 15 Sep 2022 06:06:47 +0200
Subject: [PATCH] lib/nbt: Start implementing the in-memory data structure for
 NBT

---
 src/lib/error.hpp |  2 ++
 src/lib/nbt.cpp   | 51 ++++------------------------------------
 src/lib/nbt.hpp   | 59 +++++++++++++++++++----------------------------
 3 files changed, 31 insertions(+), 81 deletions(-)

diff --git a/src/lib/error.hpp b/src/lib/error.hpp
index 2cc55ef..58c44eb 100644
--- a/src/lib/error.hpp
+++ b/src/lib/error.hpp
@@ -89,6 +89,8 @@ namespace ErrorCodes {
 
     const uint8_t NOT_YET_KNOWN = 7;
 
+    const uint8_t INVALID_TYPE = 8;
+
     const uint8_t UNIMPLEMENTED = 254;
 
     const uint8_t UNKNOWN = 255;
diff --git a/src/lib/nbt.cpp b/src/lib/nbt.cpp
index 4782ad9..17e5352 100644
--- a/src/lib/nbt.cpp
+++ b/src/lib/nbt.cpp
@@ -543,56 +543,15 @@ namespace NBT {
         }
     }
 
-    //Tag constructors
-
+    // generic class that all tag types are derived from
     template <typename T>
-    Tag<T>::Tag(uint8_t tagType, tiny_utf8::string name, uint16_t nameSize, T content, uint32_t size)
-        : tagType(tagType), name(name), nameSize(nameSize), content(content) ,size(size)
-    {}
+    Tag<T>::Tag() {
 
-    End::End() : Tag::Tag(0, "", 0, 0, 0) {}
-
-    Byte::Byte(tiny_utf8::string name, uint16_t nameSize, int8_t content)
-        : Tag::Tag(1, name, nameSize, content, 1)
-    {}
-
-    Byte::Byte(uint8_t data[]){
-        if(validate(data)){
-            this->tagType = 1;
-
-            uint8_t nameSizeSlice[] = {data[1], data[2]};
-
-            ErrorOr<int16_t> readIntResult = Helper::readInt16(nameSizeSlice, 2, 0);
-            if(!readIntResult.isError){
-                this->nameSize = readIntResult.value;
-            }else{
-                throw readIntResult.errorCode;
-            }
-
-            uint8_t nameSlice[this->nameSize+2];
-            for(int i=0; i<this->nameSize+2; i++){
-                nameSlice[i] = data[i+1];
-            }
-
-            ErrorOr<tiny_utf8::string> readStringResult = Helper::readString(nameSlice, this->nameSize, 0);
-            if(!readStringResult.isError){
-                this->name = readStringResult.value;
-            }else{
-                throw readStringResult.errorCode;
-            }
-
-            //int8 needs only one byte
-            this->content = data[this->nameSize+4];
-        }
     }
 
-    //more conditions will be added
-    bool Byte::validate(uint8_t data[]){
-        if(data[0] == 0x01){
-            return true;
-        }else{
-            return false;
-        }
+    template <typename T>
+    ErrorOr<std::vector<uint8_t>> Tag<T>::toRawData() {
+        return ErrorOr<std::vector<uint8_t>>(true, ErrorCodes::INVALID_TYPE);
     }
 
     bool validateRawListContents(uint8_t data[], uint64_t dataSize, uint64_t initialPosition, uint64_t* processedDataSize) {
diff --git a/src/lib/nbt.hpp b/src/lib/nbt.hpp
index e1ade91..eae5ed9 100644
--- a/src/lib/nbt.hpp
+++ b/src/lib/nbt.hpp
@@ -72,45 +72,34 @@ namespace NBT {
     }
 
     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;
+        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 parent class to make declaration easier
+    // generic class that all tag types are derived from
     template <typename T>
-    class Tag{
-        public:
-        uint8_t tagType;
-        tiny_utf8::string name;
-        uint16_t nameSize;
-        T content;
-        int32_t size;
+    struct Tag {
+        const uint8_t type = TagType::INVALID;
+        T* containedData;
 
-        Tag(){}
-        Tag(uint8_t tagType, tiny_utf8::string name, uint16_t nameSize, T content, uint32_t size);
-    };
-
-    class End: public Tag<uint8_t>{
-        public:
-        End();
-    };
-
-    class Byte: public Tag<int8_t>{
-        public:
-        Byte(tiny_utf8::string name, uint16_t nameSize, int8_t content);
-        Byte(uint8_t data[]);
-        bool validate(uint8_t data[]);
+        Tag();
+        ErrorOr<std::vector<uint8_t>> toRawData();
     };
 
     bool validateRawNBTData(uint8_t data[], uint64_t dataSize, uint64_t initialPosition=0, uint64_t* processedDataSize=nullptr);