From 920120bbcec9f91df3336f62970b3e010a4fa6c2 Mon Sep 17 00:00:00 2001
From: Stefan Boberg <stefan.boberg@epicgames.com>
Date: Thu, 6 Mar 2025 16:18:32 +0100
Subject: reduced memory churn using fixed_xxx containers (#236)

* Added EASTL to help with eliminating memory allocations
* Applied EASTL to eliminate memory allocations, primarily by using `fixed_vector` et al to use stack allocations / inline struct allocations

Reduces memory events in traces by close to a factor of 10 in test scenario (starting editor for project F)
---
 src/zencore/compactbinary.cpp | 10 ++++++----
 1 file changed, 6 insertions(+), 4 deletions(-)

(limited to 'src/zencore/compactbinary.cpp')

diff --git a/src/zencore/compactbinary.cpp b/src/zencore/compactbinary.cpp
index adccaba70..b43cc18f1 100644
--- a/src/zencore/compactbinary.cpp
+++ b/src/zencore/compactbinary.cpp
@@ -15,6 +15,8 @@
 #include <zencore/testing.h>
 #include <zencore/uid.h>
 
+#include <EASTL/fixed_vector.h>
+
 #include <fmt/format.h>
 #include <string_view>
 
@@ -1376,9 +1378,9 @@ TryMeasureCompactBinary(MemoryView View, CbFieldType& OutType, uint64_t& OutSize
 CbField
 LoadCompactBinary(BinaryReader& Ar, BufferAllocator Allocator)
 {
-	std::vector<uint8_t> HeaderBytes;
-	CbFieldType			 FieldType;
-	uint64_t			 FieldSize = 1;
+	eastl::fixed_vector<uint8_t, 32> HeaderBytes;
+	CbFieldType						 FieldType;
+	uint64_t						 FieldSize = 1;
 
 	for (const int64_t StartPos = Ar.CurrentOffset(); FieldSize > 0;)
 	{
@@ -1393,7 +1395,7 @@ LoadCompactBinary(BinaryReader& Ar, BufferAllocator Allocator)
 		HeaderBytes.resize(ReadOffset + ReadSize);
 
 		Ar.Read(HeaderBytes.data() + ReadOffset, ReadSize);
-		if (TryMeasureCompactBinary(MakeMemoryView(HeaderBytes), FieldType, FieldSize))
+		if (TryMeasureCompactBinary(MakeMemoryView(HeaderBytes.data(), HeaderBytes.size()), FieldType, FieldSize))
 		{
 			if (FieldSize <= uint64_t(Ar.Size() - StartPos))
 			{
-- 
cgit v1.2.3