test/nbt_size_helpers: Implement tests for valid input

I stumbled over this when writing the unit test. Previously, it would return
an error code but explicitly mark it as not being an error. This was intended
behavior but I decided to change it because I didn’t anticipate it when writing
the test.

Technically `ErrorOr<T>` can be used to pass any message alongside `T`,
but practically, it is reasonable to assume that the error code is
`ErrorCodes::SUCCESS` when `isError` is false. Therefore, this feature
should be really only used in the weirdest edge cases - if at all.
Even then, it is most likely still preferable to flag it as an error and
just hand the resulting `T` back using the long constructor
`ErrorOr<T>(bool, uint8_t, T)`.

scripts/build.sh

@@ -33,7 +33,7 @@ fi
 
 # `.cpp` files in src/lib will be automatically picked up and compiled into
 # dynamically linked libraries.
-echo "Building libs..."
+echo ">>> Building libs..."
 create_directory bin/lib
 for lib in $(find ./src/lib -name "*.cpp"); do
     COMPILE_COMMAND="$CXX_WITH_FLAGS -I ./include -fPIC -shared -o $(sed -e 's/^.\/src/.\/bin/;s/cpp$/so/' <<< $lib) $lib"
@@ -55,7 +55,7 @@ wait
 # How to run a tool: specify the library path to use for the dynamic linker
 #   when running a program
 # Example: LD_LIBRARY_PATH=bin/lib bin/tools/dumpnbt
-echo "Building tools..."
+echo ">>> Building tools..."
 create_directory bin/tools
 # add compile commands to this array
 COMPILE_COMMANDS=(

scripts/clean.sh

@@ -15,6 +15,8 @@
 # version 3 along with this program.
 # If not, see https://www.gnu.org/licenses/agpl-3.0.en.html
 
+echo ">>> Cleaning build files..."
+
 source scripts/lib.sh
 
 remove ./bin

scripts/clean_dependencies.sh

@@ -17,7 +17,7 @@
 
 source scripts/lib.sh
 
-echo "Checking download cache for unneeded or corrupted files..."
+echo ">>> Checking download cache for unneeded or corrupted files..."
 for file in $(ls .download_cache); do
     #TODO: remove if unknown shasum
     if grep $file scripts/setup_project.sh >/dev/null 2>&1; then
@@ -32,7 +32,8 @@ for file in $(ls .download_cache); do
         rm ".download_cache/$file"
     fi
 done
-echo ""
+echo "
+>>> Cleaning dependencies..."
 
 remove ./dependencies
 create_directory ./dependencies

scripts/setup_project.sh

@@ -72,9 +72,7 @@ function download {
     fi
 }
 
-echo "Cleaning build files..."
 scripts/clean.sh
-echo "Cleaning dependencies..."
 scripts/clean_dependencies.sh
 
 set -e # failures are not acceptable here
@@ -82,20 +80,21 @@ create_directory dependencies/tmp
 download https://github.com/DuffsDevice/tiny-utf8/archive/refs/tags/v4.4.3.tar.gz dependencies/tmp/tiny-utf8.tar.gz 8e3f61651909c9f3105d3501932a96aa65733127fb6e7cf94cb1b0a2dff42c8f
 download https://github.com/fpagliughi/sockpp/archive/refs/tags/v0.7.1.tar.gz dependencies/tmp/sockpp.tar.gz 2e023528bebbd2ac083fc91fbe6d5c4158c3336bedbcff48f594f3b28f53b940
 
-echo -n "Extracting tiny-utf8... "
+echo -n ">>> Extracting tiny-utf8... "
 gzip -d dependencies/tmp/tiny-utf8.tar.gz
 tar -xf dependencies/tmp/tiny-utf8.tar -C dependencies
-echo "done."
+echo "done"
 
-echo -n "Extracting sockpp... "
+echo -n ">>> Extracting sockpp... "
 gzip -d dependencies/tmp/sockpp.tar.gz
 tar -xf dependencies/tmp/sockpp.tar -C dependencies
-echo "done."
-echo -n "Building sockpp... "
+echo "done"
+
+echo ">>> Building sockpp... "
 pushd dependencies/sockpp-0.7.1/ >/dev/null 2>&1
 cmake -Bbuild .
 cmake --build build
 popd >/dev/null 2>&1
-echo "done."
 
+echo ">>> Cleaning up..."
 remove dependencies/tmp

scripts/test.sh

@@ -25,16 +25,20 @@ else
 fi
 echo "$LD_LIBRARY_PATH"
 
+echo ">>> Cleaning tests..."
+remove bin/test
 create_directory bin/test
 
-echo "Building tests..."
+echo ">>> Building tests..."
 
 # add compile commands to this array
 COMPILE_COMMANDS=(
-    "$CXX_WITH_FLAGS src/test/nbt_helpers.cpp -I./include -Lbin/lib -l:nbt.so -l:javacompat.so -o bin/test/nbt_helpers"
+    "$CXX_WITH_FLAGS src/test/nbt_read_write_helpers.cpp -I./include -Lbin/lib -l:nbt.so -l:javacompat.so -o bin/test/nbt_read_write_helpers"
     "$CXX_WITH_FLAGS src/test/cli_argument_parser.cpp -Lbin/lib -l:cli.so -o bin/test/cli_argument_parser"
     "$CXX_WITH_FLAGS src/test/javacompat.cpp -I./include -Lbin/lib -l:javacompat.so -o bin/test/javacompat"
-    "$CXX_WITH_FLAGS src/test/nbt_writestring_failure_mode.cpp -I./include -Lbin/lib -l:nbt.so -l:javacompat.so -o bin/test/nbt_writestring_failure_mode"
+    "$CXX_WITH_FLAGS src/test/nbt_write_string_failure_mode.cpp -I./include -Lbin/lib -l:nbt.so -l:javacompat.so -o bin/test/nbt_write_string_failure_mode"
+    "$CXX_WITH_FLAGS src/test/nbt_tags.cpp -I./include -Lbin/lib -l:nbt.so -l:javacompat.so -o bin/test/nbt_tags"
+    "$CXX_WITH_FLAGS src/test/nbt_size_helpers.cpp -I./include -Lbin/lib -l:nbt.so -l:javacompat.so -o bin/test/nbt_size_helpers"
 )
 for command in ${!COMPILE_COMMANDS[@]}; do
     echo "${COMPILE_COMMANDS[command]}"
@@ -44,9 +48,15 @@ done
 
 wait
 
-echo "Running tests..."
+echo ">>> Running tests..."
 
+# explicitly allow commands to fail at this stage
 set +e
+
 for test in $(ls bin/test); do
     bin/test/$test
 done
+
+for test in $(ls scripts/test); do
+    scripts/test/$test
+done

scripts/test/hexnet.sh

@@ -0,0 +1,23 @@
+#!/usr/bin/env bash
+
+# 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
+
+echo "################################################################################
+Testing hexnet
+################################################################################"
+
+echo "Test not yet implemented."
+#TODO: implement unit test after merging back with master

setupenv.bashrc

@@ -44,6 +44,4 @@ if [ -f "$PROJECT_BASE_DIR/.localenv.bashrc" ]; then
     source "$PROJECT_BASE_DIR/.localenv.bashrc"
 fi
 
-unset PROJECT_BASE_DIR
-
 echo "done."

src/lib/cli.cpp

@@ -258,5 +258,66 @@ namespace CLI {
         // argument is not present, but this is not an error -> false, NOT_PRESENT, ""
         else return ErrorOr<std::string>(false, ErrorCodes::NOT_PRESENT, std::string(""));
     }
-    //std::string ArgumentsParser::getUsage();
+
+    std::string ArgumentsParser::getUsage(){
+        std::string usageString = "";
+        if (this->description != "") {
+            usageString += "Help: " + this->programName + "\n\n\t" + this->description + "\n\n";
+        }
+        usageString += "Usage: " + this->programName + " ";
+
+        if(!this->flagsByShortName.empty()){
+            usageString += "[-";
+        }
+
+        for(const auto& [key, value]: this->flagsByShortName){
+            usageString.push_back(key);
+        }
+
+        if(!this->flagsByShortName.empty()){
+            usageString += "] ";
+        }
+
+        for(const auto& [key, value]: this->optionsByShortName){
+            usageString += "[-";
+            usageString.push_back(key);
+            usageString += " " + value->placeholder + "] ";
+        }
+
+        for(const auto& argument: this->arguments){
+            usageString += argument.placeholder + " ";
+        }
+
+        usageString.push_back('\n');
+
+        if(!this->flagsByShortName.empty()){
+            usageString += "\nFlags:\n";
+
+            for(const auto& [key, value]: this->flagsByShortName){
+                usageString += "\t-";
+                usageString.push_back(key);
+                usageString += ", --" + value->longName + "\n\t\t" + value->description + "\n";
+            }
+        }
+
+        if(!this->optionsByShortName.empty()){
+            usageString += "\nOptions:\n";
+
+            for(const auto& [key, value]: this->optionsByShortName){
+                usageString += "\t-";
+                usageString.push_back(key);
+                usageString += " " + value->placeholder + ", --" + value->longName + "=" + value->placeholder + "\n\t\t" + value->description + "\n";
+            }
+        }
+
+        if(!this->arguments.empty()){
+            usageString += "\nArguments:\n";
+
+            for(const auto& argument: this->arguments){
+                usageString += "\t" + argument.placeholder + "\n\t\t" + argument.description + "\n";
+            }
+        }
+
+        return usageString;
+    }
 }

src/lib/cli.h++

@@ -1,94 +0,0 @@
-// 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
-
-#pragma once
-
-#include <string>
-#include <vector>
-#include <map>
-
-#include "error.hpp"
-
-namespace CLI {
-
-    struct Flag {
-        char shortName;
-        std::string longName;
-        // used for automatic usage generation
-        std::string description;
-
-        bool present;
-
-        Flag();
-        Flag(char shortName, std::string longName, std::string description);
-    };
-
-    struct Option {
-        char shortName;
-        std::string longName;
-        // used for automatic usage generation
-        std::string description;
-        std::string placeholder; // the "COUNT" in "ping [-c <COUNT>] <HOST>"
-
-        bool present;
-        std::string value;
-
-        Option();
-        Option(char shortName, std::string longName, std::string placeholder, std::string description);
-    };
-
-    struct Argument {
-        // used for automatic usage generation
-        std::string description;
-        std::string placeholder; // the "HOST" in "ping [-c <COUNT>] <HOST>"
-
-        bool present;
-        std::string value;
-
-        Argument();
-        Argument(std::string placeholder, std::string description);
-    };
-
-    class ArgumentsParser {
-        private:
-            std::map<char, Flag*> flagsByShortName;
-            std::map<std::string, Flag*> flagsByLongName;
-            std::map<char, Option*> optionsByShortName;
-            std::map<std::string, Option*> optionsByLongName;
-            std::vector<Argument> arguments;
-            std::string description;
-            std::string additionalInfo;
-
-        public:
-            std::string programName;
-            bool wrongUsage;
-            std::vector<std::string> wrongUsageMessages;
-
-            // using int here bc that's how main() is defined
-            ArgumentsParser(int argc, const char* const argv[], std::vector<Flag> flags, std::vector<Option> options, std::vector<Argument> arguments);
-            ArgumentsParser(int argc, const char* const argv[], std::vector<Flag> flags, std::vector<Option> options, std::vector<Argument> arguments, std::string description);
-            ArgumentsParser(int argc, const char* const argv[], std::vector<Flag> flags, std::vector<Option> options, std::vector<Argument> arguments, std::string description, std::string additionalInfo);
-            ~ArgumentsParser();
-
-            ErrorOr<bool> getFlag(char shortName);
-            ErrorOr<bool> getFlag(std::string longName);
-            ErrorOr<std::string> getArgument(std::vector<CLI::Argument>::size_type position);
-            ErrorOr<std::string> getOption(char shortName);
-            ErrorOr<std::string> getOption(std::string longName);
-
-            std::string getUsage();
-    };
-
-}

src/lib/error.hpp

@@ -78,10 +78,12 @@ namespace ErrorCodes {
     // when dealing with maps
     const uint8_t UNKNOWN_KEY = 5;
 
+    //mismatched size in java strings
+    const uint8_t MISMATCHEDSIZE = 6;
+
+    const uint8_t NOT_YET_KNOWN = 7;
+
     const uint8_t UNIMPLEMENTED = 254;
 
     const uint8_t UNKNOWN = 255;
-
-    //mismatched size in java strings
-    const uint8_t MISMATCHEDSIZE = 6;
 }

src/lib/nbt.cpp

@@ -370,6 +370,151 @@ namespace NBT {
                 writeInt64(destination, data[i]);
             }
         }
+
+        //FIXME: instead of blindly passing the error code upwards, choose
+        // one that is applicable to the situation (for example replace
+        // OUT_OF_RANGE with OVERRUN where appropriate)
+        //
+        // The total size in bytes
+        //
+        // Does not work for compound tags and lists. This is an intended
+        // feature as compound tags and lists need to be dealt with
+        // separately to avoid unnecessarily long and complex code.
+        //
+        // Regardinng lists specifically: The size of some lists can can
+        // be determined easily by looking at the contained data type and
+        // size information but cases like string lists or compound lists
+        // are significantly more difficult to deal with. Parsing their
+        // contents requires special attention anyway due the tag headers
+        // of contained tags being absent so they may as well get their
+        // own function for this as well.
+        ErrorOr<uint64_t> totalTagSize(uint8_t data[], uint64_t dataSize, uint64_t currentPosition) {
+            uint8_t nextTag;
+            if (dataSize <= currentPosition) {
+                return ErrorOr<uint64_t>(true, ErrorCodes::OVERRUN);
+            } else {
+                nextTag = data[currentPosition];
+            }
+            // deal with compound tags and lists separately
+            if (nextTag == TagType::COMPOUND || nextTag == TagType::LIST) return ErrorOr<uint64_t>(true, ErrorCodes::NOT_YET_KNOWN);
+            // deal with end tag before trying to access the name
+            if (nextTag == TagType::END) return ErrorOr<uint64_t>(1);
+
+            ErrorOr<int16_t> nameSize = helper::readInt16(data, dataSize, currentPosition+1);
+            if (nameSize.isError) {
+                return ErrorOr<uint64_t>(true, nameSize.errorCode);
+            }
+            // add type byte and name size bytes
+            uint64_t prefixSize = (uint64_t) nameSize.value + 3;
+            switch (nextTag) {
+                case TagType::INT8:
+                    return ErrorOr<uint64_t>(prefixSize+1);
+                case TagType::INT16:
+                    return ErrorOr<uint64_t>(prefixSize+2);
+                case TagType::INT32:
+                    return ErrorOr<uint64_t>(prefixSize+4);
+                case TagType::INT64:
+                    return ErrorOr<uint64_t>(prefixSize+8);
+                case TagType::FLOAT:
+                    return ErrorOr<uint64_t>(prefixSize+4);
+                case TagType::DOUBLE:
+                    return ErrorOr<uint64_t>(prefixSize+8);
+                case TagType::INT8_ARRAY: {
+                    ErrorOr<int32_t> arrayLength = helper::readInt32(data, dataSize, currentPosition+prefixSize);
+                    if (arrayLength.isError) {
+                        return ErrorOr<uint64_t>(true, arrayLength.errorCode);
+                    }
+                    return ErrorOr<uint64_t>((uint64_t) arrayLength.value + prefixSize + 4);
+                }
+                case TagType::STRING: {
+                    ErrorOr<int16_t> stringSize = helper::readInt16(data, dataSize, currentPosition+prefixSize);
+                    if (stringSize.isError) {
+                        return ErrorOr<uint64_t>(true, stringSize.errorCode);
+                    }
+                    return ErrorOr<uint64_t>((uint64_t) stringSize.value + prefixSize + 2);
+                }
+                case TagType::INT32_ARRAY: {
+                    ErrorOr<int32_t> arrayLength = helper::readInt32(data, dataSize, currentPosition+prefixSize);
+                    if (arrayLength.isError) {
+                        return ErrorOr<uint64_t>(true, arrayLength.errorCode);
+                    }
+                    return ErrorOr<uint64_t>((uint64_t) arrayLength.value*4 + prefixSize + 4);
+                }
+                case TagType::INT64_ARRAY: {
+                    ErrorOr<int32_t> arrayLength = helper::readInt32(data, dataSize, currentPosition+prefixSize);
+                    if (arrayLength.isError) {
+                        return ErrorOr<uint64_t>(true, arrayLength.errorCode);
+                    }
+                    return ErrorOr<uint64_t>((uint64_t) arrayLength.value*8 + prefixSize + 4);
+                }
+                // unknown tag or parsing error
+                default:
+                    return ErrorOr<uint64_t>(true, ErrorCodes::UNKNOWN);
+            }
+        }
+
+        //FIXME: instead of blindly passing the error code upwards, choose
+        // one that is applicable to the situation (for example replace
+        // OUT_OF_RANGE with OVERRUN where appropriate)
+        //
+        // Length is the number of stored elements, not to be confused with size
+        // which is the size in bytes.
+        ErrorOr<int32_t> containedDataLength(uint8_t data[], uint64_t dataSize, uint64_t currentPosition){
+
+            uint8_t nextTag;
+            if (dataSize <= currentPosition) {
+                return ErrorOr<int32_t>(true, ErrorCodes::OVERRUN);
+            } else {
+                nextTag = data[currentPosition];
+            }
+
+            // deal with compound tags separately
+            if (nextTag == TagType::COMPOUND) {
+                return ErrorOr<int32_t>(true, ErrorCodes::NOT_YET_KNOWN);
+            }
+
+            // deal with end tag before trying to access the name
+            if (nextTag == TagType::END) {
+                return ErrorOr<int32_t>(0);
+            }
+
+            // tags that only ever hold one value
+            if (nextTag == TagType::INT8 || nextTag == TagType::INT16 || nextTag == TagType::INT32 || nextTag == TagType::INT64 || nextTag == TagType::FLOAT || nextTag == TagType::DOUBLE) {
+                return ErrorOr<int32_t>(1);
+            }
+
+            ErrorOr<int16_t> nameSize = helper::readInt16(data, dataSize, currentPosition+1);
+            if (nameSize.isError) {
+                return ErrorOr<int32_t>(true, nameSize.errorCode);
+            }
+            // add type byte and name size bytes
+            uint64_t prefixSize = (uint64_t) nameSize.value + 3;
+            switch (nextTag) {
+                case TagType::INT8_ARRAY: {
+                    return helper::readInt32(data, dataSize, currentPosition+prefixSize);
+                }
+                case TagType::STRING: {
+                    ErrorOr<int16_t> stringSize = helper::readInt16(data, dataSize, currentPosition+prefixSize);
+                    if (stringSize.isError) {
+                        return ErrorOr<int32_t>(true, stringSize.errorCode);
+                    }
+                    return ErrorOr<int32_t>((int32_t) stringSize.value);
+                }
+                case TagType::LIST: {
+                    // add an additional byte for the contained data type
+                    return helper::readInt32(data, dataSize, currentPosition+prefixSize+1);
+                }
+                case TagType::INT32_ARRAY: {
+                    return helper::readInt32(data, dataSize, currentPosition+prefixSize);
+                }
+                case TagType::INT64_ARRAY: {
+                    return helper::readInt32(data, dataSize, currentPosition+prefixSize);
+                }
+                default:
+                    // unknown tag or parsing error
+                    return ErrorOr<int32_t>(true, ErrorCodes::UNKNOWN);
+            }
+        }
     }
 
     //Tag constructors
@@ -424,9 +569,10 @@ namespace NBT {
         }
     }
 
-    bool validateRawNBTData(uint8_t data[], uint64_t dataSize){
-        //state machine?
-        //TODO: implement
+    bool validateRawNBTData(uint8_t data[], uint64_t dataSize, uint64_t initialPosition){
+        //TODO: find out the size of the next tag
+        //TODO: consume tag
+        //TODO: recurse if tag compound and return if tag end
         return false;
     }
 }

src/lib/nbt.hpp

@@ -66,6 +66,25 @@ namespace NBT {
         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;
     }
 
     //Generic parent class to make declaration easier
@@ -94,5 +113,5 @@ namespace NBT {
         bool validate(uint8_t data[]);
     };
 
-    bool validateRawNBTData(uint8_t data[], int length);
+    bool validateRawNBTData(uint8_t data[], int length, uint64_t initialPosition=0);
 }

src/test/assert.hpp

@@ -15,4 +15,4 @@
 
 #include <iostream>
 
-#define ASSERT(truth) if ((truth)); else { std::cout << "Assertion failed: " << #truth << std::endl; return 1; }
+#define ASSERT(truth) if ((truth)); else { std::cout << "On line " << __LINE__ << ": Assertion failed: " << #truth << std::endl; return 1; }

src/test/cli_argument_parser.cpp

@@ -23,7 +23,7 @@
 
 int main() {
     std::cout << "################################################################################" << std::endl;
-    std::cout << "CLI argument parser tests" << std::endl;
+    std::cout << "CLI argument parsing tests" << std::endl;
     std::cout << "################################################################################" << std::endl;
 
     // Valid parameter test ############################################
@@ -636,5 +636,115 @@ int main() {
     delete[] tooManyArgumentsTestParameterList;
     std::cout << "Passed too many arguments test." << std::endl;
 
+    std::cout << "################################################################################" << std::endl;
+    std::cout << "CLI argument parser help tests" << std::endl;
+    std::cout << "################################################################################" << std::endl;
+
+    // normal usage with all types of CLI input ########################
+    std::vector<CLI::Flag> helpTestFlags;
+    helpTestFlags.push_back(CLI::Flag('a', "apple", "throws an apple on Newton's head."));
+    helpTestFlags.push_back(CLI::Flag('y', "yapple", "throws an yapple on Newton's head."));
+
+    std::vector<CLI::Option> helpTestOptions;
+    helpTestOptions.push_back(CLI::Option('b', "banana", "BANANA", "smack someone with a ripe banana."));
+    helpTestOptions.push_back(CLI::Option('c', "corn", "CORNHUBBBBB", "visit cornhub."));
+
+    std::vector<CLI::Argument> helpTestArguments;
+    helpTestArguments.push_back(CLI::Argument("WASH", "Number of times to wash my shark."));
+    helpTestArguments.push_back(CLI::Argument("SHAKE", "Number of times to shake fist at cloud."));
+
+    const char** helpTestCommand = new const char*[1];
+    helpTestCommand[0] = "universecreator";
+    CLI::ArgumentsParser helpTestParser = CLI::ArgumentsParser(1, helpTestCommand, helpTestFlags, helpTestOptions, helpTestArguments, "Create a universe with a banana and an apple.");
+
+    ASSERT(helpTestParser.getUsage() == "Help: universecreator\n\n\tCreate a universe with a banana and an apple.\n\nUsage: universecreator [-ay] [-b BANANA] [-c CORNHUBBBBB] WASH SHAKE \n\nFlags:\n\t-a, --apple\n\t\tthrows an apple on Newton's head.\n\t-y, --yapple\n\t\tthrows an yapple on Newton's head.\n\nOptions:\n\t-b BANANA, --banana=BANANA\n\t\tsmack someone with a ripe banana.\n\t-c CORNHUBBBBB, --corn=CORNHUBBBBB\n\t\tvisit cornhub.\n\nArguments:\n\tWASH\n\t\tNumber of times to wash my shark.\n\tSHAKE\n\t\tNumber of times to shake fist at cloud.\n");
+    std::cout << "Passed normal usage test." << std::endl;
+
+    // no description ##################################################
+    std::vector<CLI::Flag> usageOnlyTestFlags;
+    usageOnlyTestFlags.push_back(CLI::Flag('a', "apple", "throws an apple on Newton's head."));
+    usageOnlyTestFlags.push_back(CLI::Flag('y', "yapple", "throws an yapple on Newton's head."));
+
+    std::vector<CLI::Option> usageOnlyTestOptions;
+    usageOnlyTestOptions.push_back(CLI::Option('b', "banana", "BANANA", "smack someone with a ripe banana."));
+    usageOnlyTestOptions.push_back(CLI::Option('c', "corn", "CORNHUBBBBB", "visit cornhub."));
+
+    std::vector<CLI::Argument> usageOnlyTestArguments;
+    usageOnlyTestArguments.push_back(CLI::Argument("WASH", "Number of times to wash my shark."));
+    usageOnlyTestArguments.push_back(CLI::Argument("SHAKE", "Number of times to shake fist at cloud."));
+
+    const char** usageOnlyTestCommand = new const char*[1];
+    usageOnlyTestCommand[0] = "universecreator";
+    CLI::ArgumentsParser usageOnlyTestParser = CLI::ArgumentsParser(1, usageOnlyTestCommand, usageOnlyTestFlags, usageOnlyTestOptions, usageOnlyTestArguments);
+
+    ASSERT(usageOnlyTestParser.getUsage() == "Usage: universecreator [-ay] [-b BANANA] [-c CORNHUBBBBB] WASH SHAKE \n\nFlags:\n\t-a, --apple\n\t\tthrows an apple on Newton's head.\n\t-y, --yapple\n\t\tthrows an yapple on Newton's head.\n\nOptions:\n\t-b BANANA, --banana=BANANA\n\t\tsmack someone with a ripe banana.\n\t-c CORNHUBBBBB, --corn=CORNHUBBBBB\n\t\tvisit cornhub.\n\nArguments:\n\tWASH\n\t\tNumber of times to wash my shark.\n\tSHAKE\n\t\tNumber of times to shake fist at cloud.\n");
+    std::cout << "Passed normal usage without description test." << std::endl;
+
+    // no flags ########################################################
+    std::vector<CLI::Flag> noFlagsFlags;
+
+    std::vector<CLI::Option> noFlagsOptions;
+    noFlagsOptions.push_back(CLI::Option('b', "banana", "BANANA", "smack someone with a ripe banana."));
+    noFlagsOptions.push_back(CLI::Option('c', "corn", "CORNHUBBBBB", "visit cornhub."));
+
+    std::vector<CLI::Argument> noFlagsArguments;
+    noFlagsArguments.push_back(CLI::Argument("WASH", "Number of times to wash my shark."));
+    noFlagsArguments.push_back(CLI::Argument("SHAKE", "Number of times to shake fist at cloud."));
+
+    const char** noFlagsCommand = new const char*[1];
+    noFlagsCommand[0] = "universecreator";
+    CLI::ArgumentsParser noFlagsParser = CLI::ArgumentsParser(1, noFlagsCommand, noFlagsFlags, noFlagsOptions, noFlagsArguments, "Create a universe with a banana and an apple.");
+
+    ASSERT(noFlagsParser.getUsage() == "Help: universecreator\n\n\tCreate a universe with a banana and an apple.\n\nUsage: universecreator [-b BANANA] [-c CORNHUBBBBB] WASH SHAKE \n\nOptions:\n\t-b BANANA, --banana=BANANA\n\t\tsmack someone with a ripe banana.\n\t-c CORNHUBBBBB, --corn=CORNHUBBBBB\n\t\tvisit cornhub.\n\nArguments:\n\tWASH\n\t\tNumber of times to wash my shark.\n\tSHAKE\n\t\tNumber of times to shake fist at cloud.\n");
+
+    // no options ######################################################
+    std::vector<CLI::Flag> noOptionsFlags;
+    noOptionsFlags.push_back(CLI::Flag('a', "apple", "throws an apple on Newton's head."));
+    noOptionsFlags.push_back(CLI::Flag('y', "yapple", "throws an yapple on Newton's head."));
+
+    std::vector<CLI::Option> noOptionsOptions;
+
+    std::vector<CLI::Argument> noOptionsArguments;
+    noOptionsArguments.push_back(CLI::Argument("WASH", "Number of times to wash my shark."));
+    noOptionsArguments.push_back(CLI::Argument("SHAKE", "Number of times to shake fist at cloud."));
+
+    const char** noOptionsCommand = new const char*[1];
+    noOptionsCommand[0] = "universecreator";
+    CLI::ArgumentsParser noOptionsParser = CLI::ArgumentsParser(1, noOptionsCommand, noOptionsFlags, noOptionsOptions, noOptionsArguments, "Create a universe with a banana and an apple.");
+
+    ASSERT(noOptionsParser.getUsage() == "Help: universecreator\n\n\tCreate a universe with a banana and an apple.\n\nUsage: universecreator [-ay] WASH SHAKE \n\nFlags:\n\t-a, --apple\n\t\tthrows an apple on Newton's head.\n\t-y, --yapple\n\t\tthrows an yapple on Newton's head.\n\nArguments:\n\tWASH\n\t\tNumber of times to wash my shark.\n\tSHAKE\n\t\tNumber of times to shake fist at cloud.\n");
+
+    // no arguments ####################################################
+    std::vector<CLI::Flag> noArgumentsFlags;
+    noArgumentsFlags.push_back(CLI::Flag('a', "apple", "throws an apple on Newton's head."));
+    noArgumentsFlags.push_back(CLI::Flag('y', "yapple", "throws an yapple on Newton's head."));
+
+    std::vector<CLI::Option> noArgumentsOptions;
+    noArgumentsOptions.push_back(CLI::Option('b', "banana", "BANANA", "smack someone with a ripe banana."));
+    noArgumentsOptions.push_back(CLI::Option('c', "corn", "CORNHUBBBBB", "visit cornhub."));
+
+    std::vector<CLI::Argument> noArgumentsArguments;
+
+    const char** noArgumentsCommand = new const char*[1];
+    noArgumentsCommand[0] = "universecreator";
+    CLI::ArgumentsParser noArgumentsParser = CLI::ArgumentsParser(1, noArgumentsCommand, noArgumentsFlags, noArgumentsOptions, noArgumentsArguments, "Create a universe with a banana and an apple.");
+
+    ASSERT(noArgumentsParser.getUsage() == "Help: universecreator\n\n\tCreate a universe with a banana and an apple.\n\nUsage: universecreator [-ay] [-b BANANA] [-c CORNHUBBBBB] \n\nFlags:\n\t-a, --apple\n\t\tthrows an apple on Newton's head.\n\t-y, --yapple\n\t\tthrows an yapple on Newton's head.\n\nOptions:\n\t-b BANANA, --banana=BANANA\n\t\tsmack someone with a ripe banana.\n\t-c CORNHUBBBBB, --corn=CORNHUBBBBB\n\t\tvisit cornhub.\n");
+    std::cout << "Passed absent section usage test." << std::endl;
+
+    // no CLI input ####################################################
+    std::vector<CLI::Flag> noCLIFlags;
+
+    std::vector<CLI::Option> noCLIOptions;
+
+    std::vector<CLI::Argument> noCLIArguments;
+
+    const char** noCLICommand = new const char*[1];
+    noCLICommand[0] = "universecreator";
+    CLI::ArgumentsParser noCLIParser = CLI::ArgumentsParser(1, noCLICommand, noCLIFlags, noCLIOptions, noCLIArguments, "Create a universe with a banana and an apple.");
+
+    ASSERT(noCLIParser.getUsage() == "Help: universecreator\n\n\tCreate a universe with a banana and an apple.\n\nUsage: universecreator \n");
+    std::cout << "Passed no CLI input usage test." << std::endl;
+
     return 0;
 }

src/test/nbt_read_write_helpers.cpp

@@ -26,7 +26,7 @@
 
 int main(){
     std::cout << "################################################################################" << std::endl;
-    std::cout << "NBT helper tests" << std::endl;
+    std::cout << "NBT read/write helper tests" << std::endl;
     std::cout << "################################################################################" << std::endl;
 
     // used for all integer tests
@@ -524,15 +524,5 @@ int main(){
 
     std::cout << "Passed writeString NBT helper test." << std::endl;
 
-    //Byte tag constructor test
-    uint8_t bytetest[] = {0x01, 0x00, 0x02, 0x68, 0x69, 0x32};
-    NBT::Byte byte = NBT::Byte(bytetest);
-
-    ASSERT(byte.tagType == 1);
-    ASSERT(byte.nameSize == 2);
-    ASSERT(byte.content = 0x32);
-    ASSERT(byte.name == tiny_utf8::string("hi"));
-
-    std::cout << "Passed Byte Tag constructor test." << std::endl;
     return 0;
 }

src/test/nbt_size_helpers.cpp

@@ -0,0 +1,257 @@
+// 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
+
+#include <iostream>
+#include <cstdint>
+
+#include "assert.hpp"
+
+#include "../lib/nbt.hpp"
+#include "../lib/error.hpp"
+
+int main() {
+    std::cout
+        << "################################################################################\n"
+        << "NBT size helper tests\n"
+        << "################################################################################"
+        << std::endl;
+
+    // a full copy of /resources/NBT_data/simple_nbt
+    //
+    // This contains all tag types. It is most likely not suitable for
+    // tests chasing edge cases as it is - as the name says - really
+    // basic NBT data.
+    uint8_t simpleNBTData[] = {
+        0x0a, 0x00, 0x00, 0x08, 0x00, 0x3e, 0x53, 0x70,
+        0x61, 0x63, 0x65, 0x73, 0x20, 0x61, 0x6e, 0x64,
+        0x20, 0x73, 0x70, 0x65, 0x63, 0x69, 0x61, 0x6c,
+        0x20, 0x63, 0x68, 0x61, 0x72, 0x61, 0x63, 0x74,
+        0x65, 0x72, 0x73, 0x20, 0x61, 0x72, 0x65, 0x20,
+        0x61, 0x6c, 0x6c, 0x6f, 0x77, 0x65, 0x64, 0x20,
+        0x69, 0x6e, 0x20, 0x74, 0x61, 0x67, 0x20, 0x6e,
+        0x61, 0x6d, 0x65, 0x73, 0x2c, 0x20, 0x72, 0x69,
+        0x67, 0x68, 0x74, 0x3f, 0x00, 0x16, 0x49, 0x64,
+        0x6b, 0x2e, 0x20, 0x4c, 0x65, 0x74, 0xe2, 0x80,
+        0x99, 0x73, 0x20, 0x66, 0x69, 0x6e, 0x64, 0x20,
+        0x6f, 0x75, 0x74, 0x2e, 0x0a, 0x00, 0x08, 0x63,
+        0x6f, 0x6d, 0x70, 0x6f, 0x75, 0x6e, 0x64, 0x03,
+        0x00, 0x0b, 0x73, 0x6f, 0x6d, 0x65, 0x5f, 0x6e,
+        0x75, 0x6d, 0x62, 0x65, 0x72, 0xd3, 0x07, 0x23,
+        0x41, 0x08, 0x00, 0x09, 0x73, 0x6f, 0x6d, 0x65,
+        0x5f, 0x74, 0x65, 0x78, 0x74, 0x00, 0x0c, 0x65,
+        0x61, 0x74, 0x20, 0x61, 0x20, 0x63, 0x6f, 0x6f,
+        0x6b, 0x69, 0x65, 0x00, 0x06, 0x00, 0x06, 0x64,
+        0x6f, 0x75, 0x62, 0x6c, 0x65, 0x41, 0x23, 0x07,
+        0xd3, 0x4e, 0xfd, 0x07, 0xf1, 0x05, 0x00, 0x05,
+        0x66, 0x6c, 0x6f, 0x61, 0x74, 0x42, 0x0d, 0x12,
+        0x43, 0x02, 0x00, 0x05, 0x69, 0x6e, 0x74, 0x31,
+        0x36, 0x07, 0xd0, 0x03, 0x00, 0x05, 0x69, 0x6e,
+        0x74, 0x33, 0x32, 0x00, 0x9a, 0x21, 0x12, 0x0b,
+        0x00, 0x0b, 0x69, 0x6e, 0x74, 0x33, 0x32, 0x5f,
+        0x61, 0x72, 0x72, 0x61, 0x79, 0x00, 0x00, 0x00,
+        0x04, 0x17, 0xbf, 0xe8, 0x3c, 0x00, 0x00, 0xa8,
+        0xfb, 0x7f, 0xff, 0xff, 0xff, 0x61, 0x72, 0x72,
+        0x61, 0x04, 0x00, 0x05, 0x69, 0x6e, 0x74, 0x36,
+        0x34, 0x00, 0x00, 0x00, 0xbc, 0x97, 0xde, 0x9e,
+        0x3e, 0x0c, 0x00, 0x0b, 0x69, 0x6e, 0x74, 0x36,
+        0x34, 0x5f, 0x61, 0x72, 0x72, 0x61, 0x79, 0x00,
+        0x00, 0x00, 0x05, 0x00, 0x00, 0x00, 0x00, 0x00,
+        0x03, 0xa8, 0xf9, 0x00, 0x00, 0x00, 0x00, 0x01,
+        0x67, 0xe7, 0xbd, 0x7f, 0xff, 0xff, 0xff, 0xff,
+        0xff, 0xff, 0xff, 0x00, 0x00, 0xab, 0xd8, 0x00,
+        0x00, 0xab, 0xd8, 0x00, 0x0b, 0x12, 0x21, 0x00,
+        0x79, 0x61, 0x72, 0x01, 0x00, 0x04, 0x69, 0x6e,
+        0x74, 0x38, 0x64, 0x07, 0x00, 0x0a, 0x69, 0x6e,
+        0x74, 0x38, 0x5f, 0x61, 0x72, 0x72, 0x61, 0x79,
+        0x00, 0x00, 0x00, 0x08, 0x71, 0x35, 0x77, 0x62,
+        0x54, 0x64, 0xf5, 0x32, 0x09, 0x00, 0x09, 0x6c,
+        0x69, 0x73, 0x74, 0x5f, 0x69, 0x6e, 0x74, 0x38,
+        0x01, 0x00, 0x00, 0x00, 0x05, 0x41, 0x60, 0x4e,
+        0x7f, 0xfa, 0x09, 0x00, 0x0c, 0x6c, 0x69, 0x73,
+        0x74, 0x5f, 0x73, 0x74, 0x72, 0x69, 0x6e, 0x67,
+        0x73, 0x08, 0x00, 0x00, 0x00, 0x0c, 0x00, 0x06,
+        0x50, 0x61, 0x63, 0x6d, 0x61, 0x6e, 0x00, 0x03,
+        0x61, 0x74, 0x65, 0x00, 0x03, 0x61, 0x6c, 0x6c,
+        0x00, 0x03, 0x74, 0x68, 0x65, 0x00, 0x04, 0x64,
+        0x6f, 0x74, 0x73, 0x00, 0x02, 0x73, 0x6f, 0x00,
+        0x03, 0x6e, 0x6f, 0x77, 0x00, 0x06, 0x68, 0x65,
+        0xe2, 0x80, 0x99, 0x73, 0x00, 0x06, 0x63, 0x6f,
+        0x6d, 0x69, 0x6e, 0x67, 0x00, 0x03, 0x66, 0x6f,
+        0x72, 0x00, 0x03, 0x74, 0x68, 0x65, 0x00, 0x06,
+        0x77, 0x6f, 0x72, 0x64, 0x73, 0x2e, 0x08, 0x00,
+        0x06, 0x73, 0x74, 0x72, 0x69, 0x6e, 0x67, 0x00,
+        0x0c, 0x48, 0x65, 0x6c, 0x6c, 0x6f, 0x20, 0x57,
+        0x6f, 0x72, 0x6c, 0x64, 0x21, 0x00
+    };
+    uint64_t simpleNBTDataSize = 478;
+
+    //##################################################################
+    // Basic valid data tests
+    //##################################################################
+    // const uint8_t END        =  0;
+    ErrorOr<uint64_t> totalSize = NBT::helper::totalTagSize(simpleNBTData, simpleNBTDataSize, 0x93);
+    ErrorOr<int32_t> dataLength = NBT::helper::containedDataLength(simpleNBTData, simpleNBTDataSize, 0x93);
+
+    ASSERT(!totalSize.isError);
+    ASSERT(totalSize.value == 1);
+    ASSERT(!dataLength.isError);
+    ASSERT(dataLength.value == 0);
+
+    totalSize = NBT::helper::totalTagSize(simpleNBTData, simpleNBTDataSize, 477);
+    dataLength = NBT::helper::containedDataLength(simpleNBTData, simpleNBTDataSize, 477);
+
+    ASSERT(!totalSize.isError);
+    ASSERT(totalSize.value == 1);
+    ASSERT(!dataLength.isError);
+    ASSERT(dataLength.value == 0);
+
+    //const uint8_t INT8       =  1;
+    totalSize = NBT::helper::totalTagSize(simpleNBTData, simpleNBTDataSize, 0x133);
+    dataLength = NBT::helper::containedDataLength(simpleNBTData, simpleNBTDataSize, 0x133);
+
+    ASSERT(!totalSize.isError);
+    ASSERT(totalSize.value == 8);
+    ASSERT(!dataLength.isError);
+    ASSERT(dataLength.value == 1);
+
+    //const uint8_t INT16      =  2;
+    totalSize = NBT::helper::totalTagSize(simpleNBTData, simpleNBTDataSize, 0xb1);
+    dataLength = NBT::helper::containedDataLength(simpleNBTData, simpleNBTDataSize, 0xb1);
+
+    ASSERT(!totalSize.isError);
+    ASSERT(totalSize.value == 10);
+    ASSERT(!dataLength.isError);
+    ASSERT(dataLength.value == 1);
+
+    //const uint8_t INT32      =  3;
+    totalSize = NBT::helper::totalTagSize(simpleNBTData, simpleNBTDataSize, 0xbb);
+    dataLength = NBT::helper::containedDataLength(simpleNBTData, simpleNBTDataSize, 0xbb);
+
+    ASSERT(!totalSize.isError);
+    ASSERT(totalSize.value == 12);
+    ASSERT(!dataLength.isError);
+    ASSERT(dataLength.value == 1);
+
+    totalSize = NBT::helper::totalTagSize(simpleNBTData, simpleNBTDataSize, 0x67);
+    dataLength = NBT::helper::containedDataLength(simpleNBTData, simpleNBTDataSize, 0x67);
+
+    ASSERT(!totalSize.isError);
+    ASSERT(totalSize.value == 18);
+    ASSERT(!dataLength.isError);
+    ASSERT(dataLength.value == 1);
+
+    //const uint8_t INT64      =  4;
+    totalSize = NBT::helper::totalTagSize(simpleNBTData, simpleNBTDataSize, 0xe9);
+    dataLength = NBT::helper::containedDataLength(simpleNBTData, simpleNBTDataSize, 0xe9);
+
+    ASSERT(!totalSize.isError);
+    ASSERT(totalSize.value == 16);
+    ASSERT(!dataLength.isError);
+    ASSERT(dataLength.value == 1);
+
+    //const uint8_t FLOAT      =  5;
+    totalSize = NBT::helper::totalTagSize(simpleNBTData, simpleNBTDataSize, 0xa5);
+    dataLength = NBT::helper::containedDataLength(simpleNBTData, simpleNBTDataSize, 0xa5);
+
+    ASSERT(!totalSize.isError);
+    ASSERT(totalSize.value == 12);
+    ASSERT(!dataLength.isError);
+    ASSERT(dataLength.value == 1);
+
+    //const uint8_t DOUBLE     =  6;
+    totalSize = NBT::helper::totalTagSize(simpleNBTData, simpleNBTDataSize, 0x94);
+    dataLength = NBT::helper::containedDataLength(simpleNBTData, simpleNBTDataSize, 0x94);
+
+    ASSERT(!totalSize.isError);
+    ASSERT(totalSize.value == 17);
+    ASSERT(!dataLength.isError);
+    ASSERT(dataLength.value == 1);
+
+    //const uint8_t INT8_ARRAY =  7;
+    totalSize = NBT::helper::totalTagSize(simpleNBTData, simpleNBTDataSize, 0x13b);
+    dataLength = NBT::helper::containedDataLength(simpleNBTData, simpleNBTDataSize, 0x13b);
+
+    ASSERT(!totalSize.isError);
+    ASSERT(totalSize.value == 25);
+    ASSERT(!dataLength.isError);
+    ASSERT(dataLength.value == 8);
+
+    //const uint8_t STRING     =  8;
+    totalSize = NBT::helper::totalTagSize(simpleNBTData, simpleNBTDataSize, 0x1c6);
+    dataLength = NBT::helper::containedDataLength(simpleNBTData, simpleNBTDataSize, 0x1c6);
+
+    ASSERT(!totalSize.isError);
+    ASSERT(totalSize.value == 23);
+    ASSERT(!dataLength.isError);
+    ASSERT(dataLength.value == 12);
+
+    totalSize = NBT::helper::totalTagSize(simpleNBTData, simpleNBTDataSize, 0x79);
+    dataLength = NBT::helper::containedDataLength(simpleNBTData, simpleNBTDataSize, 0x79);
+
+    ASSERT(!totalSize.isError);
+    ASSERT(totalSize.value == 26);
+    ASSERT(!dataLength.isError);
+    ASSERT(dataLength.value == 12);
+
+    //const uint8_t LIST       =  9;
+    totalSize = NBT::helper::totalTagSize(simpleNBTData, simpleNBTDataSize, 0x154);
+    dataLength = NBT::helper::containedDataLength(simpleNBTData, simpleNBTDataSize, 0x154);
+
+    ASSERT(totalSize.isError);
+    ASSERT(totalSize.errorCode == ErrorCodes::NOT_YET_KNOWN);
+    ASSERT(!dataLength.isError);
+    ASSERT(dataLength.value == 5);
+
+    totalSize = NBT::helper::totalTagSize(simpleNBTData, simpleNBTDataSize, 0x16a);
+    dataLength = NBT::helper::containedDataLength(simpleNBTData, simpleNBTDataSize, 0x16a);
+
+    ASSERT(totalSize.isError);
+    ASSERT(totalSize.errorCode == ErrorCodes::NOT_YET_KNOWN);
+    ASSERT(!dataLength.isError);
+    ASSERT(dataLength.value == 12);
+
+    //const uint8_t COMPOUND   = 10;
+    totalSize = NBT::helper::totalTagSize(simpleNBTData, simpleNBTDataSize, 0x5c);
+    dataLength = NBT::helper::containedDataLength(simpleNBTData, simpleNBTDataSize, 0x5c);
+
+    ASSERT(totalSize.isError);
+    ASSERT(totalSize.errorCode == ErrorCodes::NOT_YET_KNOWN);
+    ASSERT(dataLength.isError);
+    ASSERT(dataLength.errorCode == ErrorCodes::NOT_YET_KNOWN);
+
+    //const uint8_t INT32_ARRAY= 11;
+    totalSize = NBT::helper::totalTagSize(simpleNBTData, simpleNBTDataSize, 0xc7);
+    dataLength = NBT::helper::containedDataLength(simpleNBTData, simpleNBTDataSize, 0xc7);
+
+    ASSERT(!totalSize.isError);
+    ASSERT(totalSize.value == 34);
+    ASSERT(!dataLength.isError);
+    ASSERT(dataLength.value == 4);
+
+    //const uint8_t INT64_ARRAY= 12;
+    totalSize = NBT::helper::totalTagSize(simpleNBTData, simpleNBTDataSize, 0xf9);
+    dataLength = NBT::helper::containedDataLength(simpleNBTData, simpleNBTDataSize, 0xf9);
+
+    ASSERT(!totalSize.isError);
+    ASSERT(totalSize.value == 58);
+    ASSERT(!dataLength.isError);
+    ASSERT(dataLength.value == 5);
+
+    std::cout << "Passed simple valid data test." << std::endl;
+
+    //TODO: add tests for errors and edge cases
+
+    return 0;
+}

src/test/nbt_tags.cpp

@@ -0,0 +1,44 @@
+// 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
+
+#include <iostream>
+#include <cstdint>
+#include <vector>
+#include <fstream>
+
+#include "assert.hpp"
+
+#include "../lib/nbt.hpp"
+#include "../lib/error.hpp"
+#include "../lib/javacompat.hpp"
+
+int main(){
+    std::cout << "################################################################################" << std::endl;
+    std::cout << "NBT object tests" << std::endl;
+    std::cout << "################################################################################" << std::endl;
+
+    //Byte tag constructor test
+    uint8_t bytetest[] = {0x01, 0x00, 0x02, 0x68, 0x69, 0x32};
+    NBT::Byte byte = NBT::Byte(bytetest);
+
+    ASSERT(byte.tagType == 1);
+    ASSERT(byte.nameSize == 2);
+    ASSERT(byte.content = 0x32);
+    ASSERT(byte.name == tiny_utf8::string("hi"));
+
+    std::cout << "Passed Byte Tag constructor test." << std::endl;
+
+    return 0;
+}

src/tools/hexnet.cpp

@@ -19,6 +19,7 @@
 #include <cstdint>
 #include <cctype>
 #include <sockpp/tcp_acceptor.h>
+#include <sockpp/tcp6_acceptor.h>
 #include <thread>
 #include <mutex>
 #include <csignal>
@@ -40,8 +41,11 @@ int64_t mtu = 1500;
 std::string host;
 in_port_t port;
 sockpp::tcp_socket* tcpSocket;
+sockpp::tcp6_socket* tcp6Socket;
 sockpp::tcp_acceptor tcpAcceptor;
+sockpp::tcp6_acceptor tcp6Acceptor;
 std::mutex tcpSocketMutex;
+std::mutex tcp6SocketMutex;
 std::mutex consoleMutex;
 // used for coordinated graceful exit across threads
 bool exitProgram = false;
@@ -50,12 +54,20 @@ void signalHandler(int signal) {
     exitProgram = true;
     // if still waiting for incoming connection, stop waiting
     tcpAcceptor.shutdown();
+    tcp6Acceptor.shutdown();
     // tell sockpp to close TCP socket if open because it blocks when trying
     // to read and there is no data
-    if (*tcpSocket) {
+
+    if (tcpSocket != nullptr && *tcpSocket) {
         // Intentionally not using the mutex here
+        std::cout << "test\n";
         tcpSocket->shutdown(SHUT_RD);
     }
+
+    if (tcp6Socket != nullptr && *tcp6Socket) {
+        // Intentionally not using the mutex here
+        tcp6Socket->shutdown(SHUT_RD);
+    }
     //TODO: figure out if - and how - this applies to UDP
 
     // Priority is to finish up all unfinished business that can be finished up.
@@ -64,32 +76,71 @@ void signalHandler(int signal) {
     consoleMutex.lock();
     std::cerr << "Received signal " << signal << ", shutting down." << std::endl;
     consoleMutex.unlock();
+    std::exit(signal);
 }
 
 void readFromTCPSocket(sockpp::tcp_socket* socket, int64_t mtu) {
-        ssize_t numBytes;
-        uint8_t buffer[mtu];
-        tcpSocketMutex.lock();
-        while (!exitProgram && (numBytes = socket->read(buffer, sizeof(buffer))) > 0) {
-            tcpSocketMutex.unlock();
-            consoleMutex.lock();
-            for (ssize_t i=0; i<numBytes; i++) {
-                std::cout << std::hex << std::setfill('0') << std::setw(2) << (short) buffer[i];
-            }
-            std::cout.flush();
-            consoleMutex.unlock();
-            tcpSocketMutex.lock();
-        }
+    ssize_t numBytes;
+    uint8_t buffer[mtu];
+    tcpSocketMutex.lock();
+    while (!exitProgram && (numBytes = socket->read(buffer, sizeof(buffer))) > 0) {
         tcpSocketMutex.unlock();
         consoleMutex.lock();
-        std::cerr << std::endl << "Connection closed." << std::endl;
+        for (ssize_t i=0; i<numBytes; i++) {
+            std::cout << std::hex << std::setfill('0') << std::setw(2) << (short) buffer[i];
+        }
+        std::cout.flush();
         consoleMutex.unlock();
+        tcpSocketMutex.lock();
+    }
+    tcpSocketMutex.unlock();
+    consoleMutex.lock();
+    std::cerr << std::endl << "Connection closed." << std::endl;
+    consoleMutex.unlock();
+}
+
+void readFromTCP6Socket(sockpp::tcp6_socket* socket, int64_t mtu){
+    ssize_t numBytes;
+    uint8_t buffer[mtu];
+    tcp6SocketMutex.lock();
+    while (!exitProgram && (numBytes = socket->read(buffer, sizeof(buffer))) > 0) {
+        tcp6SocketMutex.unlock();
+        consoleMutex.lock();
+        for (ssize_t i=0; i<numBytes; i++) {
+            std::cout << std::hex << std::setfill('0') << std::setw(2) << (short) buffer[i];
+        }
+        std::cout.flush();
+        consoleMutex.unlock();
+        tcp6SocketMutex.lock();
+    }
+    tcp6SocketMutex.unlock();
+    consoleMutex.lock();
+    std::cerr << std::endl << "Connection closed." << std::endl;
+    consoleMutex.unlock();
+}
+
+void writeToTCPSocket(sockpp::tcp_socket* socket){
+    while (!exitProgram) {
+       //TODO: Implement locking/unlocking/threading shenanigans
+    }
+    consoleMutex.lock();
+    std::cerr << std::endl << "Connection closed." << std::endl;
+    consoleMutex.unlock();
+}
+
+void writeToTCP6Socket(sockpp::tcp6_socket* socket){
+    while (!exitProgram) {
+       //TODO: Implement locking/unlocking/threading shenanigans
+    }
+    consoleMutex.lock();
+    std::cerr << std::endl << "Connection closed." << std::endl;
+    consoleMutex.unlock();
 }
 
 int main(int argc, char* argv[]){
 
-    signal(SIGINT, signalHandler);
-    signal(SIGTERM, signalHandler);
+    std::signal(SIGINT, signalHandler);
+    std::signal(SIGTERM, signalHandler);
 
     std::vector<CLI::Flag> flags;
     flags.push_back(CLI::Flag('4', "ipv4", "use IPv4, defaults to both when -4 and -6 are omitted, otherwise uses what is specified"));
@@ -98,84 +149,142 @@ int main(int argc, char* argv[]){
     flags.push_back(CLI::Flag('u', "udp", "use UDP, defaults to both when -t and -u are omitted, otherwise uses what is specified"));
     flags.push_back(CLI::Flag('n', "no-color", "disable coloring the output (intended for terminals that don't work well with color escape sequences)"));
     flags.push_back(CLI::Flag('e', "echo-back", "echo input back to stdout"));
+    flags.push_back(CLI::Flag('h', "help", "print this information and exit"));
+    flags.push_back(CLI::Flag('l', "license", "print license information and exit"));
 
     std::vector<CLI::Option> options;
     options.push_back(CLI::Option('c', "connect", "HOST", "connect to HOST, listen for incoming connections if omitted"));
     options.push_back(CLI::Option('m', "mtu-optimize", "MTU", "Optimize for a specific maximum transfer unit by reading MTU bytes at a time."));
     options.push_back(CLI::Option(
-        'p', "print-prefixes", "TCPv4i:UDPv4i:TCPv6i:UDPv6i:TCPv4o:UDPv4o:TCPv6o:UDPv6o",
-        "override default prefixes for output (defaults to spaces + coloring the output or \"t4:u4:t6:u6:T4:U4:T6:U6\" in no-color mode)"
+        'p', "print-prefixes", "TCPin:UDPin:TCPout:UDPout",
+        "override default prefixes for output (defaults to spaces + coloring the output or \"t:u:T:U\" in no-color mode)"
     ));
     options.push_back(CLI::Option(
-        'i', "input-prefixes", "TCP:UDP:IPv4:IPv6",
-        "override default prefixes for input (defaults to \"t:u:4:6\")"
+        'i', "input-prefixes", "TCP:UDP",
+        "override default prefixes for input (defaults to \"t:u\")"
     ));
 
     std::vector<CLI::Argument> arguments;
     arguments.push_back(CLI::Argument("PORT", "the port to use"));
 
-    CLI::ArgumentsParser cliParser = CLI::ArgumentsParser(argc, argv, flags, options, arguments);
+    CLI::ArgumentsParser cliParser = CLI::ArgumentsParser(argc, argv, flags, options, arguments, "Arbitrary tcp/udp connections in hex format.");
+
+    if (cliParser.getFlag("help").value){
+        std::cout << cliParser.getUsage() << std::endl;
+        return EXIT_SUCCESS;
+    }
+    if (cliParser.getFlag("license").value){
+        std::cout
+            << "Copyright 2022, FOSS-VG Developers and Contributers\n"
+            << "\n"
+            << "Hexnet is part of the FOSS-VG development tool suite.\n"
+            << "\n"
+            << "This program is free software: you can redistribute it and/or modify it\n"
+            << "under the terms of the GNU Affero General Public License as published\n"
+            << "by the Free Software Foundation, version 3.\n"
+            << "\n"
+            << "This program is distributed in the hope that it will be useful,\n"
+            << "but WITHOUT ANY WARRANTY; without even the implied\n"
+            << "warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.\n"
+            << "See the GNU Affero General Public License for more details.\n"
+            << "\n"
+            << "You should have received a copy of the GNU Affero General Public License\n"
+            << "version 3 along with this program.\n"
+            << "If not, see https://www.gnu.org/licenses/agpl-3.0.en.html"
+            << std::endl;
+        return EXIT_SUCCESS;
+    }
 
     if (cliParser.wrongUsage) {
-        //TODO: spit out usage information generated by the parser
+        std::cout << cliParser.getUsage() << std::endl;
         return EXIT_USAGE;
     }
-    if (cliParser.getFlag('4').value || cliParser.getFlag('6').value) {
-        ipv4 = cliParser.getFlag('4').value;
-        ipv6 = cliParser.getFlag('6').value;
+    if (cliParser.getFlag("ipv4").value || cliParser.getFlag("ipv6").value) {
+        ipv4 = cliParser.getFlag("ipv4").value;
+        ipv6 = cliParser.getFlag("ipv4").value;
     }
-    if (cliParser.getFlag('t').value || cliParser.getFlag('u').value) {
-        tcp = cliParser.getFlag('t').value;
-        udp = cliParser.getFlag('u').value;
+    if (cliParser.getFlag("tcp").value || cliParser.getFlag("udp").value) {
+        tcp = cliParser.getFlag("tcp").value;
+        udp = cliParser.getFlag("udp").value;
     }
     if (cliParser.getOption('c').errorCode == ErrorCodes::NOT_PRESENT) {
         listenMode = true;
     }
-    if (cliParser.getOption('m').errorCode == ErrorCodes::SUCCESS) {
-        mtu = std::stol(cliParser.getOption('m').value);
+    if (cliParser.getOption("mtu-optimize").errorCode == ErrorCodes::SUCCESS) {
+        mtu = std::stol(cliParser.getOption("mtu-optimize").value);
     }
-    host = cliParser.getOption('c').value;
+    host = cliParser.getOption("connect").value;
     //FIXME: use a function that returns a fixed-width data type instead,
     //       ensure that the given value is a valid port
     port = (in_port_t) std::stoi(cliParser.getArgument(0).value);
 
     if (listenMode) {
-        if (ipv6) {
-            std::cerr << "IPv6 support is not implented yet." << std::endl;
-            return EXIT_UNIMPLEMENTED;
-        }
         if (udp) {
             std::cerr << "UDP support is not implemented yet." << std::endl;
             return EXIT_UNIMPLEMENTED;
         }
-        std::cerr << "Listening on port " << port << "." << std::endl;
 
-        sockpp::socket_initializer socketInitializer;
-        tcpAcceptor = sockpp::tcp_acceptor(port);
+        if (ipv6) {
+            //std::cerr << "IPv6 support is not implented yet." << std::endl;
+            //return EXIT_UNIMPLEMENTED;
+            std::cerr << "Listening on port " << port << "." << std::endl;
+            sockpp::socket_initializer socketInitializer;
+            tcp6Acceptor = sockpp::tcp6_acceptor(port);
 
-        if (!tcpAcceptor) {
-            std::cerr << "Error while creating TCP acceptor: " << tcpAcceptor.last_error_str() << std::endl;
-            return EXIT_RUNTIME;
+            if(!tcp6Acceptor){
+                std::cerr << "Error while creating TCP6 acceptor: " << tcp6Acceptor.last_error_str() << std::endl;
+                return EXIT_RUNTIME;
+            }
+
+            sockpp::inet6_address peer;
+            tcp6Socket = new sockpp::tcp6_socket();
+            *tcp6Socket = tcp6Acceptor.accept(&peer);
+
+            std::cerr << "Incoming connection from " << peer << std::endl;
+
+            if (!(*tcp6Socket)) {
+                std::cerr << "Error on incoming connection: " << tcp6Acceptor.last_error_str() << std::endl;
+                delete tcp6Socket;
+                return EXIT_RUNTIME;
+            }
+
+            std::thread threadReadFromTCP6 = std::thread(readFromTCP6Socket, tcp6Socket, mtu);
+            threadReadFromTCP6.join();
+
+            delete tcp6Socket;
+            return EXIT_SUCCESS;
         }
 
-        sockpp::inet_address peer;
-        tcpSocket = new sockpp::tcp_socket();
-        *tcpSocket = tcpAcceptor.accept(&peer);
+        if(ipv4){
+            std::cerr << "Listening on port " << port << "." << std::endl;
 
-        std::cerr << "Incoming connection from " << peer << std::endl;
+            sockpp::socket_initializer socketInitializer;
+            tcpAcceptor = sockpp::tcp_acceptor(port);
+
+            if (!tcpAcceptor) {
+                std::cerr << "Error while creating TCP acceptor: " << tcpAcceptor.last_error_str() << std::endl;
+                return EXIT_RUNTIME;
+            }
+
+            sockpp::inet_address peer;
+            tcpSocket = new sockpp::tcp_socket();
+            *tcpSocket = tcpAcceptor.accept(&peer);
+
+            std::cerr << "Incoming connection from " << peer << std::endl;
+
+            if (!(*tcpSocket)) {
+                std::cerr << "Error on incoming connection: " << tcpAcceptor.last_error_str() << std::endl;
+                delete tcpSocket;
+                return EXIT_RUNTIME;
+            }
+
+            std::thread threadReadFromTCP = std::thread(readFromTCPSocket, tcpSocket, mtu);
+            threadReadFromTCP.join();
 
-        if (!(*tcpSocket)) {
-            std::cerr << "Error on incoming connection: " << tcpAcceptor.last_error_str() << std::endl;
             delete tcpSocket;
-            return EXIT_RUNTIME;
+            return EXIT_SUCCESS;
         }
 
-        std::thread threadReadTCP = std::thread(readFromTCPSocket, tcpSocket, mtu);
-        threadReadTCP.join();
-
-        delete tcpSocket;
-        return EXIT_SUCCESS;
-
     } else {
         std::cerr << "Client mode is not implemented yet." << std::endl;
         return EXIT_UNIMPLEMENTED;