ref(wasm): use brotli-11 + z85 wasm encoding

Author: natemoo-re

tasks/bundle-wasm.ts

@@ -1,13 +1,59 @@
-import { encodeBase64 } from "@std/encoding/base64";
+import { brotliCompressSync, constants } from "node:zlib";
+
+const Z85 =
+  "0123456789abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ.-:+=^!/*?&<>()[]{}@%$#";
+
+function encodeZ85(data: Uint8Array): string {
+  let padLen = (4 - (data.length % 4)) % 4;
+  let src = data;
+  if (padLen > 0) {
+    src = new Uint8Array(data.length + padLen);
+    src.set(data);
+  }
+  let out: string[] = [];
+  for (let i = 0; i < src.length; i += 4) {
+    let v =
+      src[i] * 16777216 +
+      src[i + 1] * 65536 +
+      src[i + 2] * 256 +
+      src[i + 3];
+    out.push(
+      Z85[Math.floor(v / 52200625)],
+      Z85[Math.floor(v / 614125) % 85],
+      Z85[Math.floor(v / 7225) % 85],
+      Z85[Math.floor(v / 85) % 85],
+      Z85[v % 85],
+    );
+  }
+  return out.join("");
+}
 
 const wasm = await Deno.readFile("clayterm.wasm");
-const base64 = encodeBase64(wasm);
 
-const source = `const bin = atob("${base64}");
-const bytes = new Uint8Array(bin.length);
-for (let i = 0; i < bin.length; i++) bytes[i] = bin.charCodeAt(i);
-export const compiled = await WebAssembly.compile(bytes);
+const compressed = new Uint8Array(
+  brotliCompressSync(wasm, {
+    params: {
+      [constants.BROTLI_PARAM_QUALITY]: 11,
+      [constants.BROTLI_PARAM_SIZE_HINT]: wasm.length,
+      [constants.BROTLI_PARAM_LGWIN]: 24,
+    },
+  }),
+);
+
+const z85 = encodeZ85(compressed);
+
+// Decoder uses division instead of >>> to avoid 32-bit truncation on values near 0xFFFFFFFF.
+const source = `import{brotliDecompressSync}from"node:zlib";
+const Z="0123456789abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ.-:+=^!/*?&<>()[]{}@%$#";
+const T=new Uint8Array(128);for(let i=0;i<85;i++)T[Z.charCodeAt(i)]=i;
+function d(s:string,n:number){const b=new Uint8Array(n);let o=0;for(let i=0;i<s.length&&o<n;i+=5){const v=T[s.charCodeAt(i)]*52200625+T[s.charCodeAt(i+1)]*614125+T[s.charCodeAt(i+2)]*7225+T[s.charCodeAt(i+3)]*85+T[s.charCodeAt(i+4)];if(o<n)b[o++]=Math.floor(v/16777216);if(o<n)b[o++]=Math.floor(v/65536)%256;if(o<n)b[o++]=Math.floor(v/256)%256;if(o<n)b[o++]=v%256;}return b;}
+const compressed=d(${JSON.stringify(z85)},${compressed.byteLength});
+export const compiled=await WebAssembly.compile(new Uint8Array(brotliDecompressSync(compressed)));
 `;
 
 await Deno.writeTextFile("wasm.ts", source);
-console.log(`wrote wasm.ts (${wasm.length} bytes encoded)`);
+console.log(
+  `wrote wasm.ts (${wasm.length} → ${compressed.byteLength} bytes compressed, ${z85.length} bytes z85, ${
+    Math.round(z85.length / wasm.length * 100)
+  }%)`,
+);