From bc765534ed59e23036bf0e6fecea576e90a2dc29 Mon Sep 17 00:00:00 2001
From: Kjetil <kjetil@muybridge.xyz>
Date: Wed, 16 Feb 2022 15:03:57 +0100
Subject: [PATCH] feat: Add memcpy_dtoh in cust

to allow users of cust to also copy memory from device to host
---
 crates/cust/CHANGELOG.md      |  4 ++++
 crates/cust/src/memory/mod.rs | 11 +++++++++++
 2 files changed, 15 insertions(+)

diff --git a/crates/cust/CHANGELOG.md b/crates/cust/CHANGELOG.md
index 540182a8..af5aa2b9 100644
--- a/crates/cust/CHANGELOG.md
+++ b/crates/cust/CHANGELOG.md
@@ -2,6 +2,10 @@
 
 Notable changes to this project will be documented in this file.
 
+## Unreleased
+
+ - Add `memory::memcpy_dtoh` to allow copying from device to host.
+
 ## 0.3.2 - 2/16/22
 
 - Fixed `ModuleJitOptions` not working (due to cursed reasons).
diff --git a/crates/cust/src/memory/mod.rs b/crates/cust/src/memory/mod.rs
index 43fa2dd7..c0639e13 100644
--- a/crates/cust/src/memory/mod.rs
+++ b/crates/cust/src/memory/mod.rs
@@ -214,6 +214,17 @@ pub unsafe fn memcpy_htod(
     Ok(())
 }
 
+/// Simple wrapper over cuMemcpyDtoH_v2
+#[allow(clippy::missing_safety_doc)]
+pub unsafe fn memcpy_dtoh(
+    d_ptr: *mut c_void,
+    src_ptr: cust_raw::CUdeviceptr,
+    size: usize,
+) -> CudaResult<()> {
+    crate::sys::cuMemcpyDtoH_v2(d_ptr, src_ptr, size).to_result()?;
+    Ok(())
+}
+
 /// Get the current free and total memory.
 ///
 /// Returns in `.1` the total amount of memory available to the the current context.