memory/string support cleanup and additions (#220)

* removed unused memory classes
* added align.h alignment helpers used in upcoming changes
* added char16_t StringLength
* avoid memory alloc in SetCurrentThreadName
* added command line parsing helpers to zencore/commandline.h
* removed IoBuffer direct VirtualAlloc path

5 files changed, 112 insertions, 42 deletions

diff --git a/src/zencore/include/zencore/commandline.h b/src/zencore/include/zencore/commandline.h
new file mode 100644
index 000000000..a4ce6b27d
--- /dev/null
+++ b/src/zencore/include/zencore/commandline.h
@@ -0,0 +1,39 @@
+// Copyright Epic Games, Inc. All Rights Reserved.
+
+#pragma once
+
+#include <zenbase/zenbase.h>
+
+#include <functional>
+#include <string_view>
+
+namespace zen {
+
+void IterateCommandlineArgs(std::function<void(const std::string_view& Arg)>& ProcessArg);
+
+template<typename Func>
+void
+IterateCommaSeparatedValue(std::string_view OptionArgs, Func&& ProcessArg)
+{
+	while (OptionArgs.size())
+	{
+		const auto		 CommaPos = OptionArgs.find_first_of(',');
+		std::string_view OptionArg;
+
+		if (CommaPos == std::string_view::npos)
+		{
+			// No comma or final argument
+			OptionArg  = OptionArgs;
+			OptionArgs = {};
+		}
+		else
+		{
+			OptionArg  = OptionArgs.substr(0, CommaPos);
+			OptionArgs = OptionArgs.substr(CommaPos + 1);
+		}
+
+		ProcessArg(OptionArg);
+	}
+}
+
+}  // namespace zen
diff --git a/src/zencore/include/zencore/iobuffer.h b/src/zencore/include/zencore/iobuffer.h
index 15455dbaa..493b7375e 100644
--- a/src/zencore/include/zencore/iobuffer.h
+++ b/src/zencore/include/zencore/iobuffer.h
@@ -243,7 +243,6 @@ protected:
 		kIsMutable		= 1 << 1,
 		kIsExtended		= 1 << 2,  // Is actually a SharedBufferExtendedCore
 		kIsMaterialized = 1 << 3,  // Data pointers are valid
-		kLowLevelAlloc	= 1 << 4,  // Using direct memory allocation
 		kIsWholeFile	= 1 << 5,  // References an entire file
 		kIoBufferAlloc	= 1 << 6,  // Using IoBuffer allocator
 		kIsOwnedByThis	= 1 << 7,
diff --git a/src/zencore/include/zencore/memory.h b/src/zencore/include/zencore/memory.h
index 7a893d3ab..fdea1a5f1 100644
--- a/src/zencore/include/zencore/memory.h
+++ b/src/zencore/include/zencore/memory.h
@@ -24,18 +24,6 @@ concept ContiguousRange = true;
 
 struct MemoryView;
 
-class MemoryArena
-{
-public:
-	ZENCORE_API MemoryArena();
-	ZENCORE_API ~MemoryArena();
-
-	ZENCORE_API void* Alloc(size_t Size, size_t Alignment);
-	ZENCORE_API void  Free(void* Ptr);
-
-private:
-};
-
 class Memory
 {
 public:
@@ -43,35 +31,6 @@ public:
 	ZENCORE_API static void	 Free(void* Ptr);
 };
 
-/** Allocator which claims fixed-size blocks from the underlying allocator.
-
-	There is no way to free individual memory blocks.
-
-	\note This is not thread-safe, you will need to provide synchronization yourself
-*/
-
-class ChunkingLinearAllocator
-{
-public:
-	explicit ChunkingLinearAllocator(uint64_t ChunkSize, uint64_t ChunkAlignment = sizeof(std::max_align_t));
-	~ChunkingLinearAllocator();
-
-	ZENCORE_API void Reset();
-
-	ZENCORE_API void* Alloc(size_t Size, size_t Alignment = sizeof(void*));
-	inline void		  Free(void* Ptr) { ZEN_UNUSED(Ptr); /* no-op */ }
-
-	ChunkingLinearAllocator(const ChunkingLinearAllocator&) = delete;
-	ChunkingLinearAllocator& operator=(const ChunkingLinearAllocator&) = delete;
-
-private:
-	uint8_t*		   m_ChunkCursor	  = nullptr;
-	uint64_t		   m_ChunkBytesRemain = 0;
-	const uint64_t	   m_ChunkSize		  = 0;
-	const uint64_t	   m_ChunkAlignment	  = 0;
-	std::vector<void*> m_ChunkList;
-};
-
 //////////////////////////////////////////////////////////////////////////
 
 struct MutableMemoryView
diff --git a/src/zencore/include/zencore/memory/align.h b/src/zencore/include/zencore/memory/align.h
new file mode 100644
index 000000000..acf4157c4
--- /dev/null
+++ b/src/zencore/include/zencore/memory/align.h
@@ -0,0 +1,67 @@
+// Copyright Epic Games, Inc. All Rights Reserved.
+
+#include <zenbase/zenbase.h>
+
+namespace zen {
+
+/**
+ * Aligns a value to the nearest higher multiple of 'Alignment', which must be a power of two.
+ *
+ * @param  Val        The value to align.
+ * @param  Alignment  The alignment value, must be a power of two.
+ *
+ * @return The value aligned up to the specified alignment.
+ */
+template<typename T>
+constexpr T
+Align(T Val, uint64_t Alignment)
+{
+	return (T)(((uint64_t)Val + Alignment - 1) & ~(Alignment - 1));
+}
+
+/**
+ * Aligns a value to the nearest lower multiple of 'Alignment', which must be a power of two.
+ *
+ * @param  Val        The value to align.
+ * @param  Alignment  The alignment value, must be a power of two.
+ *
+ * @return The value aligned down to the specified alignment.
+ */
+template<typename T>
+constexpr T
+AlignDown(T Val, uint64_t Alignment)
+{
+	return (T)(((uint64_t)Val) & ~(Alignment - 1));
+}
+
+/**
+ * Checks if a pointer is aligned to the specified alignment.
+ *
+ * @param  Val        The value to align.
+ * @param  Alignment  The alignment value, must be a power of two.
+ *
+ * @return true if the pointer is aligned to the specified alignment, false otherwise.
+ */
+template<typename T>
+constexpr bool
+IsAligned(T Val, uint64_t Alignment)
+{
+	return !((uint64_t)Val & (Alignment - 1));
+}
+
+/**
+ * Aligns a value to the nearest higher multiple of 'Alignment'.
+ *
+ * @param  Val        The value to align.
+ * @param  Alignment  The alignment value, can be any arbitrary value.
+ *
+ * @return The value aligned up to the specified alignment.
+ */
+template<typename T>
+constexpr T
+AlignArbitrary(T Val, uint64_t Alignment)
+{
+	return (T)((((uint64_t)Val + Alignment - 1) / Alignment) * Alignment);
+}
+
+}  // namespace zen
diff --git a/src/zencore/include/zencore/string.h b/src/zencore/include/zencore/string.h
index b0232d883..b10b6a2ba 100644
--- a/src/zencore/include/zencore/string.h
+++ b/src/zencore/include/zencore/string.h
@@ -51,6 +51,12 @@ StringLength(const wchar_t* str)
 	return wcslen(str);
 }
 
+inline size_t
+StringLength(const char16_t* str)
+{
+	return std::char_traits<char16_t>::length(str);
+}
+
 //////////////////////////////////////////////////////////////////////////
 // File name helpers
 //