From 137e04eda0b0beec85c7580bfa2a08e0e9b08552 Mon Sep 17 00:00:00 2001
From: Hatter Jiang <jht5945@gmail.com>
Date: Thu, 19 Jan 2023 22:19:54 +0800
Subject: [PATCH] feat: add __internal/memory

---
 README.md                     |  4 +++-
 __internal/memory/Cargo.lock  |  7 +++++++
 __internal/memory/Cargo.toml  |  8 +++++++
 __internal/memory/README.md   |  3 +++
 __internal/memory/src/main.rs | 39 +++++++++++++++++++++++++++++++++++
 5 files changed, 60 insertions(+), 1 deletion(-)
 create mode 100644 __internal/memory/Cargo.lock
 create mode 100644 __internal/memory/Cargo.toml
 create mode 100644 __internal/memory/README.md
 create mode 100644 __internal/memory/src/main.rs

diff --git a/README.md b/README.md
index 6fcec52..bc1623e 100644
--- a/README.md
+++ b/README.md
@@ -90,6 +90,8 @@ Project or files:
 ├── __image
 │   ├── plotters
 │   └── svg
+├── __internal
+│   └── memory
 ├── __lang
 │   ├── boa
 │   ├── java
@@ -261,6 +263,6 @@ Project or files:
     ├── vec.rs
     └── while.rs
 
-230 directories, 39 files
+232 directories, 39 files
 ```
 
diff --git a/__internal/memory/Cargo.lock b/__internal/memory/Cargo.lock
new file mode 100644
index 0000000..1fad482
--- /dev/null
+++ b/__internal/memory/Cargo.lock
@@ -0,0 +1,7 @@
+# This file is automatically @generated by Cargo.
+# It is not intended for manual editing.
+version = 3
+
+[[package]]
+name = "memory"
+version = "0.1.0"
diff --git a/__internal/memory/Cargo.toml b/__internal/memory/Cargo.toml
new file mode 100644
index 0000000..db4f6ef
--- /dev/null
+++ b/__internal/memory/Cargo.toml
@@ -0,0 +1,8 @@
+[package]
+name = "memory"
+version = "0.1.0"
+edition = "2021"
+
+# See more keys and their definitions at https://doc.rust-lang.org/cargo/reference/manifest.html
+
+[dependencies]
diff --git a/__internal/memory/README.md b/__internal/memory/README.md
new file mode 100644
index 0000000..4b0aca5
--- /dev/null
+++ b/__internal/memory/README.md
@@ -0,0 +1,3 @@
+
+Reference:
+* https://radu-matei.com/blog/practical-guide-to-wasm-memory/
diff --git a/__internal/memory/src/main.rs b/__internal/memory/src/main.rs
new file mode 100644
index 0000000..858506e
--- /dev/null
+++ b/__internal/memory/src/main.rs
@@ -0,0 +1,39 @@
+#[no_mangle]
+pub fn malloc_1(len: usize) -> *mut u8 {
+    let mut buf = Vec::with_capacity(len);
+    let ptr = buf.as_mut_ptr();
+    std::mem::forget(buf);
+    return ptr;
+}
+
+#[no_mangle]
+pub fn free_1(ptr: *mut u8, len: usize) {
+    let data = unsafe { Vec::from_raw_parts(ptr, len, len) };
+    std::mem::drop(data);
+}
+
+#[no_mangle]
+pub fn malloc_2(len: usize) -> *mut u8 {
+    let align = std::mem::align_of::<usize>();
+    let layout = unsafe { std::alloc::Layout::from_size_align_unchecked(len, align) };
+    unsafe { std::alloc::alloc(layout) }
+}
+
+#[no_mangle]
+pub fn free_2(ptr: *mut u8, len: usize) {
+    let align = std::mem::align_of::<usize>();
+    let layout = unsafe { std::alloc::Layout::from_size_align_unchecked(len, align) };
+    unsafe { std::alloc::dealloc(ptr, layout) }
+}
+
+fn main() {
+    println!("Malloc-1");
+    let p = malloc_1(1024);
+    println!("Free-1");
+    free_1(p, 1024);
+
+    println!("Malloc-2");
+    let p = malloc_2(1024);
+    println!("Free-2");
+    free_2(p, 1024);
+}