From 4c559f50a4b7009d7ddb862f6553b399a5b0dfb4 Mon Sep 17 00:00:00 2001
From: Bananymous <bananymousosq@gmail.com>
Date: Tue, 20 Dec 2022 11:37:28 +0200
Subject: [PATCH] BAN: StringView::Split() now precomputes number of elements

We dont have to resize vector on PushBack()'s if we reserve required size
---
 BAN/BAN/StringView.cpp       | 20 +++++++++++++++++++-
 BAN/include/BAN/Errors.h     |  1 +
 BAN/include/BAN/StringView.h |  2 +-
 kernel/kernel/Shell.cpp      |  2 +-
 4 files changed, 22 insertions(+), 3 deletions(-)

diff --git a/BAN/BAN/StringView.cpp b/BAN/BAN/StringView.cpp
index 2881d2e9b..760933319 100644
--- a/BAN/BAN/StringView.cpp
+++ b/BAN/BAN/StringView.cpp
@@ -62,9 +62,27 @@ namespace BAN
 		return result;
 	}
 
-	Vector<StringView> StringView::Split(char delim, bool allow_empties)
+	ErrorOr<Vector<StringView>> StringView::Split(char delim, bool allow_empties)
 	{
+		size_type count = 0;
+		{
+			size_type start = 0;
+			for (size_type i = 0; i < m_size; i++)
+			{
+				if (m_data[i] == delim)
+				{
+					if (allow_empties || start != i)
+						count++;
+					start = i + 1;
+				}
+			}
+			if (start != m_size)
+				count++;
+		}
+
 		Vector<StringView> result;
+		TRY(result.Reserve(count));
+
 		size_type start = 0;
 		for (size_type i = 0; i < m_size; i++)
 		{
diff --git a/BAN/include/BAN/Errors.h b/BAN/include/BAN/Errors.h
index 6ed44afa9..bc89e3bc9 100644
--- a/BAN/include/BAN/Errors.h
+++ b/BAN/include/BAN/Errors.h
@@ -40,6 +40,7 @@ class ErrorOr
 public:
 	ErrorOr(const T& value)		: m_has_error(false)	{ m_data = (void*)new T(value); }
 	ErrorOr(const Error& error) : m_has_error(true)		{ m_data = (void*)new Error(error); }
+	template<typename S> ErrorOr(const ErrorOr<S>& other) : ErrorOr(other.GetError()) {}
 	~ErrorOr()											{ IsError() ? (delete reinterpret_cast<Error*>(m_data)) : (delete reinterpret_cast<T*>(m_data)); }
 
 	bool IsError() const			{ return m_has_error; }
diff --git a/BAN/include/BAN/StringView.h b/BAN/include/BAN/StringView.h
index 0bc531a56..3db5c8e2f 100644
--- a/BAN/include/BAN/StringView.h
+++ b/BAN/include/BAN/StringView.h
@@ -24,7 +24,7 @@ namespace BAN
 
 		StringView Substring(size_type, size_type = -1) const;
 
-		Vector<StringView> Split(char, bool = false);
+		ErrorOr<Vector<StringView>> Split(char, bool = false);
 
 		size_type Count(char) const;
 
diff --git a/kernel/kernel/Shell.cpp b/kernel/kernel/Shell.cpp
index b79902765..b6978314f 100644
--- a/kernel/kernel/Shell.cpp
+++ b/kernel/kernel/Shell.cpp
@@ -228,7 +228,7 @@ namespace Kernel
 			case Keyboard::Key::NumpadEnter:
 			{
 				kprint("\n");
-				ProcessCommand(m_buffer.SV().Split(' '));
+				ProcessCommand(MUST(m_buffer.SV().Split(' ')));
 				m_buffer.Clear();
 				PrintPrompt();
 				break;