From aa21f463fecd100247a58eb2612f572c49a30b17 Mon Sep 17 00:00:00 2001
From: Daniel Huigens <d.huigens@protonmail.com>
Date: Fri, 29 Jun 2018 15:22:18 +0200
Subject: [PATCH] Heap & asm pooling

---
 src/aes/aes.js | 40 +++++++++++++++++++++++++++++++++++-----
 1 file changed, 35 insertions(+), 5 deletions(-)

diff --git a/src/aes/aes.js b/src/aes/aes.js
index a52d90a..71474ba 100644
--- a/src/aes/aes.js
+++ b/src/aes/aes.js
@@ -2,18 +2,40 @@ import { AES_asm } from './aes.asm';
 import { _heap_init, _heap_write, is_bytes, is_number } from '../utils';
 import { IllegalArgumentError, SecurityError } from '../errors';
 
+const heap_pool = [];
+const asm_pool = [];
+
 export class AES {
   constructor(key, iv, padding, heap, asm) {
     this.nonce = null;
     this.counter = 0;
     this.counterSize = 0;
 
-    this.heap = _heap_init(Uint8Array, heap).subarray(AES_asm.HEAP_DATA);
-    this.asm = asm || AES_asm(null, this.heap.buffer);
     this.mode = null;
-    this.key = null;
 
-    this.AES_reset(key, iv, padding);
+    this.key = key;
+    this.iv = iv;
+    this.padding = padding;
+
+    this.acquireResources(heap, asm);
+  }
+
+  acquireResources(heap, asm) {
+    if (!this.heap && !this.asm) {
+      console.log(heap, heap_pool.slice(-1));
+      this.heap = _heap_init(Uint8Array, heap || heap_pool.pop()).subarray(AES_asm.HEAP_DATA);
+      this.asm = asm || asm_pool.pop() || AES_asm(null, this.heap.buffer);
+      this.AES_reset(this.key, this.iv, this.padding);
+    }
+  }
+
+  releaseResources() {
+    if (this.heap.buffer.byteLength !== 0x100000) { // shared asm.js heap
+      heap_pool.push(new Uint8Array(this.heap.buffer));
+      asm_pool.push(this.asm);
+      this.heap = undefined;
+      this.asm = undefined;
+    }
   }
 
   /**
@@ -114,7 +136,7 @@ export class AES {
       this.iv = iv;
       this.asm.set_iv(ivview.getUint32(0), ivview.getUint32(4), ivview.getUint32(8), ivview.getUint32(12));
     } else {
-      this.iv = null;
+      this.iv = undefined;
       this.asm.set_iv(0, 0, 0, 0);
     }
   }
@@ -198,6 +220,8 @@ export class AES {
    * @param {Uint8Array} data
    */
   AES_Encrypt_finish(data) {
+    this.acquireResources();
+
     var presult = null,
       prlen = 0;
 
@@ -239,6 +263,8 @@ export class AES {
     this.pos = 0;
     this.len = 0;
 
+    this.releaseResources();
+
     return this;
   }
 
@@ -299,6 +325,8 @@ export class AES {
    * @param {Uint8Array} data
    */
   AES_Decrypt_finish(data) {
+    this.acquireResources();
+
     var presult = null,
       prlen = 0;
 
@@ -352,6 +380,8 @@ export class AES {
     this.pos = 0;
     this.len = 0;
 
+    this.releaseResources();
+
     return this;
   }
 }