From d78316247cb202d817b4cd9b2bd022c80925acd8 Mon Sep 17 00:00:00 2001
From: kcbanner <kcbanner@gmail.com>
Date: Tue, 5 Nov 2024 00:56:59 -0500
Subject: [PATCH 1/2] Use the new @extern field, .is_dll_import, to link the
 memory allocation functions from a shared library with the -msvc ABI

---
 src/memory.zig | 34 ++++++++++++++++++++++------------
 1 file changed, 22 insertions(+), 12 deletions(-)

diff --git a/src/memory.zig b/src/memory.zig
index 132631f..5ed96e9 100644
--- a/src/memory.zig
+++ b/src/memory.zig
@@ -1,4 +1,5 @@
 const std = @import("std");
+const options = @import("zmesh_options");
 
 pub fn init(alloc: std.mem.Allocator) void {
     std.debug.assert(mem_allocator == null and mem_allocations == null);
@@ -7,10 +8,27 @@ pub fn init(alloc: std.mem.Allocator) void {
     mem_allocations = std.AutoHashMap(usize, usize).init(alloc);
     mem_allocations.?.ensureTotalCapacity(32) catch unreachable;
 
-    zmeshMallocPtr = zmeshMalloc;
-    zmeshCallocPtr = zmeshCalloc;
-    zmeshReallocPtr = zmeshRealloc;
-    zmeshFreePtr = zmeshFree;
+    const zmeshMallocPtr = @extern(*?*const fn (size: usize) callconv(.C) ?*anyopaque, .{
+        .name = "zmeshMallocPtr",
+        .is_dll_import = options.shared,
+    });
+    const zmeshCallocPtr = @extern(*?*const fn (num: usize, size: usize) callconv(.C) ?*anyopaque, .{
+        .name = "zmeshCallocPtr",
+        .is_dll_import = options.shared,
+    });
+    const zmeshReallocPtr = @extern(*?*const fn (ptr: ?*anyopaque, size: usize) callconv(.C) ?*anyopaque, .{
+        .name = "zmeshReallocPtr",
+        .is_dll_import = options.shared,
+    });
+    const zmeshFreePtr = @extern(*?*const fn (maybe_ptr: ?*anyopaque) callconv(.C) void, .{
+        .name = "zmeshFreePtr",
+        .is_dll_import = options.shared,
+    });
+
+    zmeshMallocPtr.* = zmeshMalloc;
+    zmeshCallocPtr.* = zmeshCalloc;
+    zmeshReallocPtr.* = zmeshRealloc;
+    zmeshFreePtr.* = zmeshFree;
     meshopt_setAllocator(zmeshMalloc, zmeshFree);
 }
 
@@ -33,8 +51,6 @@ var mem_allocations: ?std.AutoHashMap(usize, usize) = null;
 var mem_mutex: std.Thread.Mutex = .{};
 const mem_alignment = 16;
 
-extern var zmeshMallocPtr: ?*const fn (size: usize) callconv(.C) ?*anyopaque;
-
 pub fn zmeshMalloc(size: usize) callconv(.C) ?*anyopaque {
     mem_mutex.lock();
     defer mem_mutex.unlock();
@@ -50,8 +66,6 @@ pub fn zmeshMalloc(size: usize) callconv(.C) ?*anyopaque {
     return mem.ptr;
 }
 
-extern var zmeshCallocPtr: ?*const fn (num: usize, size: usize) callconv(.C) ?*anyopaque;
-
 fn zmeshCalloc(num: usize, size: usize) callconv(.C) ?*anyopaque {
     const ptr = zmeshMalloc(num * size);
     if (ptr != null) {
@@ -66,8 +80,6 @@ pub fn zmeshAllocUser(user: ?*anyopaque, size: usize) callconv(.C) ?*anyopaque {
     return zmeshMalloc(size);
 }
 
-extern var zmeshReallocPtr: ?*const fn (ptr: ?*anyopaque, size: usize) callconv(.C) ?*anyopaque;
-
 fn zmeshRealloc(ptr: ?*anyopaque, size: usize) callconv(.C) ?*anyopaque {
     mem_mutex.lock();
     defer mem_mutex.unlock();
@@ -91,8 +103,6 @@ fn zmeshRealloc(ptr: ?*anyopaque, size: usize) callconv(.C) ?*anyopaque {
     return mem.ptr;
 }
 
-extern var zmeshFreePtr: ?*const fn (maybe_ptr: ?*anyopaque) callconv(.C) void;
-
 fn zmeshFree(maybe_ptr: ?*anyopaque) callconv(.C) void {
     if (maybe_ptr) |ptr| {
         mem_mutex.lock();

From 447a933ea187e7e3f8fb03be32196dbb8a3cbf83 Mon Sep 17 00:00:00 2001
From: kcbanner <kcbanner@gmail.com>
Date: Sat, 28 Jun 2025 13:41:50 -0400
Subject: [PATCH 2/2] - Alignment fixup

---
 src/memory.zig | 8 ++++----
 1 file changed, 4 insertions(+), 4 deletions(-)

diff --git a/src/memory.zig b/src/memory.zig
index 5ed96e9..2c6da37 100644
--- a/src/memory.zig
+++ b/src/memory.zig
@@ -49,7 +49,7 @@ extern fn meshopt_setAllocator(
 var mem_allocator: ?std.mem.Allocator = null;
 var mem_allocations: ?std.AutoHashMap(usize, usize) = null;
 var mem_mutex: std.Thread.Mutex = .{};
-const mem_alignment = 16;
+const mem_alignment: std.mem.Alignment = .@"16";
 
 pub fn zmeshMalloc(size: usize) callconv(.C) ?*anyopaque {
     mem_mutex.lock();
@@ -87,9 +87,9 @@ fn zmeshRealloc(ptr: ?*anyopaque, size: usize) callconv(.C) ?*anyopaque {
     const old_size = if (ptr != null) mem_allocations.?.get(@intFromPtr(ptr.?)).? else 0;
 
     const old_mem = if (old_size > 0)
-        @as([*]align(mem_alignment) u8, @ptrCast(@alignCast(ptr)))[0..old_size]
+        @as([*]align(mem_alignment.toByteUnits()) u8, @ptrCast(@alignCast(ptr)))[0..old_size]
     else
-        @as([*]align(mem_alignment) u8, undefined)[0..0];
+        @as([*]align(mem_alignment.toByteUnits()) u8, undefined)[0..0];
 
     const mem = mem_allocator.?.realloc(old_mem, size) catch @panic("zmesh: out of memory");
 
@@ -109,7 +109,7 @@ fn zmeshFree(maybe_ptr: ?*anyopaque) callconv(.C) void {
         defer mem_mutex.unlock();
 
         const size = mem_allocations.?.fetchRemove(@intFromPtr(ptr)).?.value;
-        const mem = @as([*]align(mem_alignment) u8, @ptrCast(@alignCast(ptr)))[0..size];
+        const mem = @as([*]align(mem_alignment.toByteUnits()) u8, @ptrCast(@alignCast(ptr)))[0..size];
         mem_allocator.?.free(mem);
     }
 }