From 5e7a4907ec8f8a4fc6c08fc4f5432ff132338399 Mon Sep 17 00:00:00 2001
From: Bas Schoenmaeckers <b.schoenmaeckers@zandersgroup.com>
Date: Thu, 25 Jun 2026 12:56:41 +0200
Subject: [PATCH] Add allocator functions to c-api

---
 .cspell.dict/cpython.txt |  1 +
 Cargo.lock               |  1 +
 crates/capi/Cargo.toml   |  1 +
 crates/capi/src/lib.rs   |  1 +
 crates/capi/src/pymem.rs | 46 ++++++++++++++++++++++++++++++++++++++++
 5 files changed, 50 insertions(+)
 create mode 100644 crates/capi/src/pymem.rs

diff --git a/.cspell.dict/cpython.txt b/.cspell.dict/cpython.txt
index 84265bda609..e5b31b57f15 100644
--- a/.cspell.dict/cpython.txt
+++ b/.cspell.dict/cpython.txt
@@ -192,6 +192,7 @@ pyerrors
 Pyfunc
 pylifecycle
 pymain
+pymem
 pyrepl
 pystate
 PYTHONTRACEMALLOC
diff --git a/Cargo.lock b/Cargo.lock
index 743e293f161..bd10622e601 100644
--- a/Cargo.lock
+++ b/Cargo.lock
@@ -3447,6 +3447,7 @@ version = "0.5.0"
 dependencies = [
  "bitflags 2.13.0",
  "itertools 0.14.0",
+ "libc",
  "num-complex",
  "pyo3",
  "rustpython-pylib",
diff --git a/crates/capi/Cargo.toml b/crates/capi/Cargo.toml
index 601989faa1d..878620ebe23 100644
--- a/crates/capi/Cargo.toml
+++ b/crates/capi/Cargo.toml
@@ -14,6 +14,7 @@ crate-type = ["cdylib", "rlib"]
 [dependencies]
 bitflags = { workspace = true }
 itertools = { workspace = true }
+libc = { workspace = true }
 num-complex = { workspace = true }
 rustpython-vm = { workspace = true, features = ["threading", "compiler", "importlib", "host_env"] }
 rustpython-stdlib = {workspace = true, features = ["threading"] }
diff --git a/crates/capi/src/lib.rs b/crates/capi/src/lib.rs
index fb3bc687f4d..638a78d6327 100644
--- a/crates/capi/src/lib.rs
+++ b/crates/capi/src/lib.rs
@@ -26,6 +26,7 @@ pub mod object;
 pub mod pycapsule;
 pub mod pyerrors;
 pub mod pylifecycle;
+pub mod pymem;
 pub mod pystate;
 pub mod refcount;
 pub mod setobject;
diff --git a/crates/capi/src/pymem.rs b/crates/capi/src/pymem.rs
new file mode 100644
index 00000000000..6c8b66f5d3e
--- /dev/null
+++ b/crates/capi/src/pymem.rs
@@ -0,0 +1,46 @@
+use core::ffi::c_void;
+
+#[unsafe(no_mangle)]
+pub unsafe extern "C" fn PyMem_Malloc(n: usize) -> *mut c_void {
+    unsafe { libc::malloc(if n == 0 { 1 } else { n }) }
+}
+
+#[unsafe(no_mangle)]
+pub unsafe extern "C" fn PyMem_Calloc(nelem: usize, elsize: usize) -> *mut c_void {
+    unsafe {
+        libc::calloc(
+            if nelem == 0 || elsize == 0 { 1 } else { nelem },
+            if nelem == 0 || elsize == 0 { 1 } else { elsize },
+        )
+    }
+}
+
+#[unsafe(no_mangle)]
+pub unsafe extern "C" fn PyMem_Realloc(ptr: *mut c_void, new_size: usize) -> *mut c_void {
+    unsafe { libc::realloc(ptr, if new_size == 0 { 1 } else { new_size }) }
+}
+
+#[unsafe(no_mangle)]
+pub unsafe extern "C" fn PyMem_Free(ptr: *mut c_void) {
+    unsafe { libc::free(ptr) }
+}
+
+#[unsafe(no_mangle)]
+pub unsafe extern "C" fn PyMem_RawMalloc(n: usize) -> *mut c_void {
+    unsafe { libc::malloc(n) }
+}
+
+#[unsafe(no_mangle)]
+pub unsafe extern "C" fn PyMem_RawCalloc(nelem: usize, elsize: usize) -> *mut c_void {
+    unsafe { libc::calloc(nelem, elsize) }
+}
+
+#[unsafe(no_mangle)]
+pub unsafe extern "C" fn PyMem_RawRealloc(ptr: *mut c_void, new_size: usize) -> *mut c_void {
+    unsafe { libc::realloc(ptr, new_size) }
+}
+
+#[unsafe(no_mangle)]
+pub unsafe extern "C" fn PyMem_RawFree(ptr: *mut c_void) {
+    unsafe { libc::free(ptr) }
+}