start implementation of NBT parser

build.sh

@@ -13,7 +13,7 @@ CXX_WITH_FLAGS="$CXX $CXXFLAGS"
 echo "Building libs..."
 mkdir -pv bin/lib
 for lib in $(find ./src/lib -name "*.cpp"); do
-    COMPILE_COMMAND="$CXX_WITH_FLAGS -shared -o $(sed -e 's/^.\/src/.\/bin/;s/cpp$/so/' <<< $lib) $lib"
+    COMPILE_COMMAND="$CXX_WITH_FLAGS -fPIC -shared -o $(sed -e 's/^.\/src/.\/bin/;s/cpp$/so/' <<< $lib) $lib"
     echo $COMPILE_COMMAND
     $COMPILE_COMMAND &
 done
@@ -33,9 +33,13 @@ wait
 # Example: LD_LIBRARY_PATH=bin/lib bin/tools/dumpnbt
 echo "Building tools..."
 mkdir -pv bin/tools
-# add compile commands to this variable
-COMPILE_COMMANDS="
-set -v
-$CXX_WITH_FLAGS src/tools/dumpnbt.cpp -Lbin/lib -l:nbt.so -o bin/tools/dumpnbt &
-"
-sh <<< $COMPILE_COMMANDS
+# add compile commands to this array
+COMPILE_COMMANDS=(
+"$CXX_WITH_FLAGS src/tools/dumpnbt.cpp -Lbin/lib -l:nbt.so -o bin/tools/dumpnbt"
+)
+for command in ${!COMPILE_COMMANDS[@]}; do
+    echo "${COMPILE_COMMANDS[command]}"
+    ${COMPILE_COMMANDS[command]} &
+done
+
+wait

src/lib/error.cpp

@@ -0,0 +1 @@
+#include "error.h++"

src/lib/error.h++

@@ -0,0 +1,21 @@
+#pragma once
+
+template <typename T>
+struct ErrorOr {
+    bool isError;
+    T value;
+
+    ErrorOr<T>();
+    ErrorOr<T>(T);
+};
+
+template <typename T>
+ErrorOr<T>::ErrorOr() {
+    this->isError = false;
+}
+
+template <typename T>
+ErrorOr<T>::ErrorOr(T value) {
+    this->isError = false;
+    this->value = value;
+}

src/lib/nbt.cpp

@@ -1,6 +1,12 @@
 #include <bit>
+#include <cstdint>
+#include <vector>
 
-// This is just an example for how to find out if the system is big endian or little endian. Do not use this.
+#include "nbt.h++"
+#include "error.h++"
+
+// This is just an example for how to find out if the system is big endian
+// or little endian. Do not use this.
 int endianness_example() {
     if constexpr (std::endian::native == std::endian::big)
     {
@@ -20,3 +26,74 @@ int endianness_example() {
     }
 }
 
+namespace NBT {
+    namespace helpers {
+        ErrorOr<int8_t> readByte(uint8_t* data[], uint64_t dataSize, uint64_t currentPosition) {
+            //TODO: implement
+            return ErrorOr<int8_t>(0);
+        }
+
+        ErrorOr<int16_t> readInt16(uint8_t* data[], uint64_t dataSize, uint64_t currentPosition) {
+            //TODO: implement
+            return ErrorOr<int16_t>(0);
+        }
+
+        ErrorOr<int32_t> readInt32(uint8_t* data[], uint64_t dataSize, uint64_t currentPosition) {
+            //TODO: implement
+            return ErrorOr<int32_t>(0);
+        }
+
+        ErrorOr<int64_t> readInt64(uint8_t* data[], uint64_t dataSize, uint64_t currentPosition) {
+            //TODO: implement
+            return ErrorOr<int64_t>(0);
+        }
+
+        //FIXME: we just assume that float is a single-precision IEEE754
+        // floating point number
+        ErrorOr<float> readFloat32(uint8_t* data[], uint64_t dataSize, uint64_t currentPosition) {
+            //TODO: implement assuming standard single-precision IEEE754 float
+            // Alternatively, maybe calculate a floating point number by using
+            // the stored value as math instructions?
+            return ErrorOr<float>(0.0f);
+        }
+
+        //FIXME: we just assume that double is a double-precision IEEE754
+        // floating point number
+        ErrorOr<double> readFloat64(uint8_t* data[], uint64_t dataSize, uint64_t currentPosition) {
+            //TODO: implement assuming standard double-precision IEEE754 float
+            // Alternatively, maybe calculate a floating point number by using
+            // the stored value as math instructions?
+            return ErrorOr<double>(0.0);
+        }
+
+        ErrorOr<std::vector<int8_t>> readByteArray(uint8_t* data[], uint64_t dataSize, uint64_t currentPosition) {
+            //TODO: implement
+            return ErrorOr<std::vector<int8_t>>({0});
+        }
+
+        //TODO: find suitable string type
+        // Maybe use a struct that holds decoded (de-Java-fied) string
+        // data, decoded size, and original size? Original size is needed
+        // so the parser knows where to continue.
+        //ErrorOr<> readString(uint8_t* data[], uint64_t dataSize, uint64_t currentPosition) {
+            //TODO: implement
+            // return ErrorOr<>("");
+        //}
+
+        ErrorOr<std::vector<int32_t>> readInt32Array(uint8_t* data[], uint64_t dataSize, uint64_t currentPosition) {
+            //TODO: implement
+            return ErrorOr<std::vector<int32_t>>({0});
+        }
+
+        ErrorOr<std::vector<int64_t>> readInt64Array(uint8_t* data[], uint64_t dataSize, uint64_t currentPosition) {
+            //TODO: implement
+            return ErrorOr<std::vector<int64_t>>({0});
+        }
+    }
+
+    bool validateRawNBTData(uint8_t* data[], uint64_t dataSize){
+        //state machine?
+        //TODO: implement
+        return false;
+    }
+}

src/lib/nbt.h++

@@ -6,15 +6,24 @@
 // All tag types:
 // generic representation:  Tag(Byte: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
-// byte:                    Tag( 1, String:name, uint16:name_size, byte:content,   1) => a single signed byte, size and content type not stored
-// int16:                   Tag( 2, String:name, uint16:name_size, int16:content,  2) => 16 bit signed integer, size and content type not stored
-// int32:                   Tag( 3, String:name, uint16:name_size, int32:content,  4) => 32 bit signed integer, size and content type not stored
-// int64:                   Tag( 4, String:name, uint16:name_size, int64:content,  8) => 64 bit signed integer, size and content type not stored
-// float32:                 Tag( 5, String:name, uint16:name_size, float32:content,4) => 32 bit IEEE754 floating point number, size and content type not stored
-// float64:                 Tag( 6, String:name, uint16:name_size, float64:content,8) => 64 bit IEEE754 floating point number, size and content type not stored
-// byte[]:                  Tag( 7, String:name, uint16:name_size, byte[]:content, int32:size) => content stored prefixed with size, content type not stored
-// String:                  Tag( 8, String:name, uint16:name_size, byte[]:content, uint16:size) => Java style modified UTF-8 string, content stored prefixed with size, content type not stored
+// byte:                    Tag( 1, String:name, uint16:name_size, byte: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
+// float32:                 Tag( 5, String:name, uint16:name_size, float32:content,4) => 32 bit IEEE754 floating point number, size not stored
+// float64:                 Tag( 6, String:name, uint16:name_size, float64:content,8) => 64 bit IEEE754 floating point number, size not stored
+// byte[]:                  Tag( 7, String:name, uint16:name_size, byte[]:content, int32:size) => content stored prefixed with size
+// String:                  Tag( 8, String:name, uint16:name_size, byte[]: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 and content type not stored
-// int32[]:                 Tag(11, String:name, uint16:name_size, int32[]:content,int32:size) => list of 32 bit signed integers prefixed with its size, content type not stored, endianness unknown 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, content type not stored, endianness unknown at this point
+// 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 "error.h++"
+
+namespace NBT {
+    bool validateRawNBTData(uint8_t* data[], int length);
+}