Write a simple benchmark

src/import.h

 #pragma once
 
+int now(void);
 void print(int);
+
+void start_warm(void);
+void start_bench(void);

src/zlib-exports.c

@@ -6,7 +6,7 @@
 
 #include "import.h"
 
-#define RAW_DATA_SIZE ((uInt)2 * 1024 * 1024)
+#define RAW_DATA_SIZE ((uInt)20 * 1024 * 1024)
 
 static unsigned char *make_random_bytes(uInt size) {
     unsigned char *buffer = malloc(size);
@@ -18,6 +18,42 @@ static unsigned char *make_random_bytes(uInt size) {
     return buffer;
 }
 
+export void run_benchmark(void) {
+    // Make a random byte sequence
+    srand(0);
+    unsigned char *raw_bytes = make_random_bytes(RAW_DATA_SIZE);
+
+    int level = 9;
+    int n = 10;
+
+    uLongf deflated_size = compressBound(RAW_DATA_SIZE);
+    unsigned char *deflated_bytes = malloc(deflated_size);
+
+    // Warming up
+    start_warm();
+
+    for (int i = 0; i < 5; i++) {
+        int start_time = now();
+        compress2(deflated_bytes, &deflated_size, raw_bytes, RAW_DATA_SIZE, level);
+        int end_time = now();
+        int duration = end_time - start_time;
+
+        print(duration);
+    }
+
+    // Benchmark
+    start_bench();
+
+    for (int i = 0; i < n; i++) {
+        int start_time = now();
+        compress2(deflated_bytes, &deflated_size, raw_bytes, RAW_DATA_SIZE, level);
+        int end_time = now();
+        int duration = end_time - start_time;
+
+        print(duration);
+    }
+}
+
 export int run_test(void) {
     // Make a random byte sequence
     srand(0);

test.js

@@ -4,9 +4,15 @@ const wasm = require('webassembly');
 (async () => {
   const zlib = await wasm.load(`${__dirname}/build/zlib.wasm`, {
     imports: {
+      now: Date.now,
       print: console.log,
+
+      start_warm() { console.log('warming up'); },
+      start_bench() { console.log('benchmark'); },
     },
   });
 
   assert.strictEqual(zlib.exports.run_test(), 0);
+
+  zlib.exports.run_benchmark();
 })();