From 5789f5372177d0ff4190b45641eecf51d9b34bc5 Mon Sep 17 00:00:00 2001
From: Dan Cojocaru <dancojocaru2010@hotmail.com>
Date: Sun, 21 Nov 2021 00:38:43 +0200
Subject: [PATCH] First commit

---
 .gitignore   |   2 +
 Makefile     |  22 +++++++
 README.md    |  29 ++++++++++
 dynarray.hpp | 160 +++++++++++++++++++++++++++++++++++++++++++++++++++
 example.cpp  |  38 ++++++++++++
 5 files changed, 251 insertions(+)
 create mode 100644 .gitignore
 create mode 100644 Makefile
 create mode 100644 README.md
 create mode 100644 dynarray.hpp
 create mode 100644 example.cpp

diff --git a/.gitignore b/.gitignore
new file mode 100644
index 0000000..39e99c7
--- /dev/null
+++ b/.gitignore
@@ -0,0 +1,2 @@
+obj
+example
diff --git a/Makefile b/Makefile
new file mode 100644
index 0000000..825a31c
--- /dev/null
+++ b/Makefile
@@ -0,0 +1,22 @@
+CXX?=g++
+
+.PHONY: debug run clean
+
+example: obj/example.o
+	${CXX} $^ -o $@
+
+run: example
+	./example
+
+debug:
+	COMPILE_FLAGS="-D DEBUG" make -B example
+
+obj:
+	@if [ ! -d obj ]; then mkdir obj; fi
+
+obj/%.o: %.cpp | obj
+	${CXX} ${COMPILE_FLAGS} -c $^ -o $@
+
+clean:
+	@if [ -d obj ]; then echo rm -r obj; rm -r obj; fi
+	@if [ -f example ]; then echo rm example; rm example; fi
diff --git a/README.md b/README.md
new file mode 100644
index 0000000..532aa86
--- /dev/null
+++ b/README.md
@@ -0,0 +1,29 @@
+# DynArray: basic dynamic array (list/vector) implementation
+
+Why? Why not.
+
+## How to run?
+
+### Got make?
+
+```shell
+make run
+```
+
+### No make?
+
+```shell
+g++ example.cpp -o example
+./example
+```
+
+### Windows?
+
+```powershell
+g++ example.cpp -o example.exe
+.\example.exe
+```
+
+### Windows without `g++`?
+
+I never compiled something using `msvc` from the terminal. I guess make a new Visual Studio project, copy-paste the files in there and have fun, idk.
diff --git a/dynarray.hpp b/dynarray.hpp
new file mode 100644
index 0000000..81de0cc
--- /dev/null
+++ b/dynarray.hpp
@@ -0,0 +1,160 @@
+#pragma once
+
+#ifdef DEBUG
+#define TMP_DEBUG_12345 DEBUG
+#undef DEBUG
+#include <iostream>
+using std::cerr;
+#define DEBUG (cerr << "[DynArray " << this << "] ")
+#endif
+
+template <class T>
+class DynArray {
+private:
+	T* _buffer;
+	size_t _length;
+	size_t _capacity;
+
+public:
+	explicit DynArray(size_t capacity = 64)
+		: _buffer(new T[capacity])
+		, _length(0) 
+		, _capacity(capacity) {
+			#ifdef DEBUG
+			DEBUG << "New array with capacity " << capacity << '\n';
+			#endif
+		}
+
+	~DynArray() {
+		#ifdef DEBUG
+		DEBUG << "Destroyed" << '\n';
+		#endif
+		delete[] _buffer;
+	}
+
+	size_t size() const {
+		return _length;
+	}
+
+	size_t length() const {
+		return _length;
+	}
+
+	operator bool() const {
+		return length() > 0;
+	}
+
+	size_t capacity() const {
+		return _capacity;
+	}
+
+	void push_back(T element) {
+		if (_length + 1 > _capacity) {
+			#ifdef DEBUG
+			DEBUG << "Push attempt when length and capacity are " << _capacity << ", reallocating" << '\n';
+			#endif
+			T *new_buffer = new T[_capacity * 2];
+			for (size_t i = 0; i < _capacity; ++i) {
+				new_buffer[i] = _buffer[i];
+			}
+			delete[] _buffer;
+			_buffer = new_buffer;
+			_capacity *= 2;
+		}
+		_buffer[_length++] = element;
+	}
+
+	DynArray<T>& operator<<(T element) {
+		push_back(element);
+		return *this;
+	}
+
+	void pop_back() {
+		_length--;
+	}
+
+	T& operator[](size_t index) {
+		return _buffer[index];
+	}
+
+	const T& operator[](size_t index) const {
+		return _buffer[index];
+	}
+
+	// Iterator bullshit
+	class iterator {
+	private:
+		DynArray<T>* _arr;
+		size_t _index;
+	public:
+		// Default constructible
+		iterator() : _arr(nullptr), _index(-1) {}
+		iterator(DynArray<T> &arr, size_t index = 0) : _arr(&arr), _index(index) {}
+		// Copy constructible
+		iterator(const iterator &it) : _arr(it._arr), _index(it._index) {}
+
+		// Copy assignable
+		iterator& operator=(const iterator& it) {
+			_arr = it._arr;
+			_index = it._index;
+		}
+
+		// Comparable
+		bool operator==(const iterator& it) const {
+			return _arr == it._arr && _index == it._index;
+		}
+
+		bool operator!=(const iterator& it) const {
+			return !(*this == it);
+		}
+
+		// Dereferencable
+		T& operator*() {
+			return (*_arr)[_index];
+		}
+		const T& operator*() const {
+			return (*_arr)[_index];
+		}
+
+		T* operator->() {
+			return &((*_arr)[_index]);
+		}
+		const T* operator->() const {
+			return &((*_arr)[_index]);
+		}
+
+		// Can be incremented
+		iterator& operator++() {
+			_index++;
+			return *this;
+		}
+
+		iterator operator++(int) {
+			auto copy = *this;
+			++*this;
+			return copy;
+		}
+	};
+
+	iterator begin() {
+		return iterator(*this);
+	}
+	const iterator begin() const {
+		return iterator(*this);
+	}
+
+	iterator end() {
+		return iterator(*this, size());
+	}
+	const iterator end() const {
+		return iterator(*this, size());
+	}
+};
+
+#ifdef TMP_DEBUG_12345
+#ifdef DEBUG
+#undef DEBUG
+#endif
+#define DEBUG TMP_DEBUG_12345
+#undef TMP_DEBUG_12345
+#endif
diff --git a/example.cpp b/example.cpp
new file mode 100644
index 0000000..67790f0
--- /dev/null
+++ b/example.cpp
@@ -0,0 +1,38 @@
+#include <iostream>
+#include <random>
+using std::cout;
+using std::cin;
+
+#include "dynarray.hpp"
+
+int main() {
+	size_t n;
+	cout << "How many numbers to generate? ";
+	cin >> n;
+
+	std::default_random_engine r_eng;
+	DynArray<std::default_random_engine::result_type> arr;
+	for (auto i = 0; i < n; i++)
+	{
+		arr << r_eng();
+	}
+	cout << '\n';
+
+	cout << "Size: " << arr.size() << '\n';
+	cout << "Capacity: " << arr.capacity() << '\n';
+	cout << "Elements: [";
+	bool first = true;
+	for (auto elem : arr)
+	{
+		if (!first) {
+			cout << ", ";
+		}
+		else {
+			first = false;
+		}
+		cout << elem;
+	}
+	cout << "]\n";
+
+	return 0;
+}
\ No newline at end of file