From 2473736979b829e09130a7261b38eb8c1367a06d Mon Sep 17 00:00:00 2001
From: jbzdarkid <jbzdarkid@gmail.com>
Date: Wed, 24 Oct 2018 18:44:37 -0700
Subject: Perf: Cache memory offsets

---
 WitnessRandomizer/Memory.cpp | 10 ++++++++--
 WitnessRandomizer/Memory.h   |  2 ++
 2 files changed, 10 insertions(+), 2 deletions(-)

(limited to 'WitnessRandomizer')

diff --git a/WitnessRandomizer/Memory.cpp b/WitnessRandomizer/Memory.cpp
index c5852ac..f2bd8f1 100644
--- a/WitnessRandomizer/Memory.cpp
+++ b/WitnessRandomizer/Memory.cpp
@@ -58,16 +58,22 @@ void Memory::ThrowError() {
 
 uintptr_t Memory::ComputeOffset(std::vector<int> offsets)
 {
-	uintptr_t cumulativeAddress = _baseAddress;
-
 	// Leave off the last offset, since it will be either read/write, and may not be of type unitptr_t.
 	int final_offset = offsets.back();
 	offsets.pop_back();
+
+	auto search = _computedOffsets.find(offsets);
+	if (search != std::end(_computedOffsets)) {
+		return search->second + final_offset;
+	}
+
+	uintptr_t cumulativeAddress = _baseAddress;
 	for (int offset : offsets) {
 		cumulativeAddress += offset;
 		if (!ReadProcessMemory(_handle, (LPVOID)cumulativeAddress, &cumulativeAddress, sizeof(uintptr_t), NULL)) {
 			ThrowError();
 		}
 	}
+	_computedOffsets[offsets] = cumulativeAddress;
 	return cumulativeAddress + final_offset;
 }
diff --git a/WitnessRandomizer/Memory.h b/WitnessRandomizer/Memory.h
index 6882c9c..dc92349 100644
--- a/WitnessRandomizer/Memory.h
+++ b/WitnessRandomizer/Memory.h
@@ -40,6 +40,8 @@ private:
 	void ThrowError();
 
 	uintptr_t ComputeOffset(std::vector<int> offsets);
+
+	std::map<std::vector<int>, uintptr_t> _computedOffsets;
 	uintptr_t _baseAddress;
 	HANDLE _handle;
 };
\ No newline at end of file
-- 
cgit 1.4.1