From febec0cf105023a8a90a9b8ffefe0e8010a999fa Mon Sep 17 00:00:00 2001
From: Kelvin Ly <kelvin.ly1618@gmail.com>
Date: Fri, 12 May 2023 04:35:10 -0400
Subject: [PATCH] Shrink the webassembly binary down to a reasonable size; TODO
 actually test it out

---
 wordle_opt/Cargo.toml |  2 +-
 wordle_opt/src/lib.rs | 51 ++++++++++++++++++++++++++++++++++++-------
 2 files changed, 44 insertions(+), 9 deletions(-)

diff --git a/wordle_opt/Cargo.toml b/wordle_opt/Cargo.toml
index b287053..0fcfdb6 100644
--- a/wordle_opt/Cargo.toml
+++ b/wordle_opt/Cargo.toml
@@ -8,8 +8,8 @@ crate-type = ["cdylib"]
 bench = false
 
 [profile.release]
-debug = true
 lto = true
+opt-level = 's'
 
 # See more keys and their definitions at https://doc.rust-lang.org/cargo/reference/manifest.html
 
diff --git a/wordle_opt/src/lib.rs b/wordle_opt/src/lib.rs
index 907913d..e333eb4 100644
--- a/wordle_opt/src/lib.rs
+++ b/wordle_opt/src/lib.rs
@@ -1,22 +1,52 @@
+use std::alloc::{alloc, dealloc, Layout};
+
 extern crate wee_alloc;
 
 #[global_allocator]
 static ALLOC: wee_alloc::WeeAlloc = wee_alloc::WeeAlloc::INIT;
 
-
 // webassembly version of all the wordle logic
 // because the javascript version is slow as hell on firefox
 use std::os::raw::c_char;
 
-static mut LOOKUP: Option<Vec<u8>> = None;
-static mut STRINGS: Option<Vec<u8>> = None;
-static mut STR_IDXS: Option<Vec<*const c_char>> = None;
+static mut LOOKUP: Option<&'static mut [u8]> = None;
+static mut STRINGS: Option<&'static mut [u8]> = None;
+static mut STR_IDXS: Option<&'static mut [*const c_char]> = None;
+
+fn unwrap_or_abort<T>(v: Option<T>) -> T {
+    match v {
+        Some(v) => v,
+        None => std::process::abort(),
+    }
+}
+
+unsafe fn alloc_ary<T>(sz: usize) -> &'static mut [T] {
+    let layout = unwrap_or_abort(Layout::from_size_align(
+            sz*std::mem::size_of::<T>(),
+            std::mem::align_of::<T>()
+        ).ok());
+    let ptr = alloc(layout) as *mut T;
+    std::slice::from_raw_parts_mut(ptr, sz)
+}
+
+unsafe fn dealloc_ary<T>(v: &'static mut [T]) {
+    let layout = unwrap_or_abort(Layout::from_size_align(
+            v.len()*std::mem::size_of::<T>(),
+            std::mem::align_of::<T>()
+        ).ok());
+    dealloc(v.as_ptr() as *mut u8, layout);
+}
+
 
 #[no_mangle]
 pub extern fn init_strings(sz: usize) -> *mut c_char {
     unsafe {
-        STRINGS = Some(vec![0u8; sz]);
-        STRINGS.as_deref_mut().map(|v| v.as_mut_ptr() as *mut c_char).unwrap()
+        if let Some(v) = &mut STRINGS {
+            dealloc_ary(v);
+            STRINGS = None;
+        }
+        STRINGS = Some(alloc_ary(sz));
+        unwrap_or_abort(STRINGS.as_deref_mut().map(|v| v.as_mut_ptr() as *mut c_char))
     }
 }
 
@@ -30,9 +60,14 @@ pub extern fn init_idx() -> usize {
 pub extern fn init_lookup() -> *mut c_char {
     unsafe {
         let num_strings = STR_IDXS.as_ref().map(|idxs| idxs.len()).unwrap_or(0);
+        if let Some(v) = &mut LOOKUP {
+            dealloc_ary(v);
+            STRINGS = None;
+        }
 
-        LOOKUP = Some(vec![0u8; num_strings*num_strings]);
-        LOOKUP.as_deref_mut().map(|v| v.as_mut_ptr() as *mut c_char).unwrap()
+        LOOKUP = Some(alloc_ary(num_strings*num_strings));
+        unwrap_or_abort(
+            LOOKUP.as_deref_mut().map(|v| v.as_mut_ptr() as *mut c_char))
     }
 }