From 7fd3166f9bcf20fcbfcd6c4052c5a8b5a043933f Mon Sep 17 00:00:00 2001
From: Alexey Andreev <konsoletyper@gmail.com>
Date: Wed, 27 Sep 2023 14:30:20 +0200
Subject: [PATCH] wasm: support Date.toString

---
 .../org/teavm/classlib/java/util/TDate.java   | 12 ++++---
 .../org/teavm/backend/wasm/wasm-runtime.js    | 31 ++++++++++++++-----
 2 files changed, 31 insertions(+), 12 deletions(-)

diff --git a/classlib/src/main/java/org/teavm/classlib/java/util/TDate.java b/classlib/src/main/java/org/teavm/classlib/java/util/TDate.java
index 4f6273494..f2f3dd39a 100644
--- a/classlib/src/main/java/org/teavm/classlib/java/util/TDate.java
+++ b/classlib/src/main/java/org/teavm/classlib/java/util/TDate.java
@@ -370,8 +370,10 @@ public class TDate implements TComparable<TDate> {
 
     @Override
     public String toString() {
-        if (PlatformDetector.isLowLevel()) {
-            return toStringLowLevel(value);
+        if (PlatformDetector.isC()) {
+            return toStringC(value);
+        } else if (PlatformDetector.isWebAssembly()) {
+            return toStringWebAssembly(value);
         } else {
             return JSDate.create(value).stringValue();
         }
@@ -380,8 +382,10 @@ public class TDate implements TComparable<TDate> {
     @Import(name = "teavm_date_format")
     @NoSideEffects
     @RuntimeInclude("date.h")
-    @UnsupportedOn(Platforms.WEBASSEMBLY)
-    private static native String toStringLowLevel(long date);
+    private static native String toStringC(long date);
+
+    @Import(module = "teavm", name = "dateToString")
+    private static native String toStringWebAssembly(double date);
 
     @Deprecated
     public String toLocaleString() {
diff --git a/core/src/main/resources/org/teavm/backend/wasm/wasm-runtime.js b/core/src/main/resources/org/teavm/backend/wasm/wasm-runtime.js
index b9d8a7f17..dac22a5f6 100644
--- a/core/src/main/resources/org/teavm/backend/wasm/wasm-runtime.js
+++ b/core/src/main/resources/org/teavm/backend/wasm/wasm-runtime.js
@@ -50,11 +50,25 @@ TeaVM.wasm = function() {
         let memory = instance.exports.memory.buffer;
         let arrayPtr = instance.exports.teavm_stringData(string);
         let length = instance.exports.teavm_arrayLength(arrayPtr);
-        let arrayData = new DataView(memory, instance.exports.teavm_charArrayData(arrayPtr), length * 2);
+        let arrayData = new Uint16Array(memory, instance.exports.teavm_charArrayData(arrayPtr), length * 2);
         for (let i = 0; i < length; ++i) {
-            putwchar(arrayData.getUint16(i * 2, true));
+            putwchar(arrayData[i]);
         }
     }
+    function dateToString(timestamp, controller) {
+        const s = new Date(timestamp).toString();
+        let instance = controller.instance;
+        let result = instance.allocateString(s.length);
+        if (result === 0) {
+            return 0;
+        }
+        let resultAddress = instance.objectArrayData(instance.stringData(result));
+        let resultView = new Uint16Array(instance.exports.memory.buffer, resultAddress, s.length);
+        for (let i = 0; i < s.length; ++i) {
+            resultView[i] = s.charCodeAt(i);
+        }
+        return result;
+    }
     function logInt(i) {
         lineBuffer += i.toString();
     }
@@ -87,14 +101,15 @@ TeaVM.wasm = function() {
         controller.complete = false;
         obj.teavm = {
             currentTimeMillis: currentTimeMillis,
-            nanoTime: function() { return performance.now(); },
+            nanoTime: () => performance.now(),
             putwcharsOut: (chars, count) => putwchars(controller, chars, count),
             putwcharsErr: (chars, count) => putwchars(controller, chars, count),
             getNativeOffset: getNativeOffset,
             logString: string => logString(string, controller),
             logInt: logInt,
             logOutOfMemory: () => console.log("Out of memory"),
-            teavm_interrupt: () => interrupt(controller)
+            teavm_interrupt: () => interrupt(controller),
+            dateToString: (timestamp) => dateToString(timestamp, controller)
         };
 
         obj.teavmMath = Math;
@@ -184,16 +199,16 @@ TeaVM.wasm = function() {
             }
             return new Promise((resolve, reject) => {
                 let javaArgs = teavm.allocateStringArray(args.length);
-                let javaArgsData = new DataView(teavm.memory.buffer, teavm.objectArrayData(javaArgs), args.length * 4);
+                let javaArgsData = new Int32Array(teavm.memory.buffer, teavm.objectArrayData(javaArgs), args.length);
                 for (let i = 0; i < args.length; ++i) {
                     let arg = args[i];
                     let javaArg = teavm.allocateString(arg.length);
                     let javaArgAddress = teavm.objectArrayData(teavm.stringData(javaArg));
-                    let javaArgData = new DataView(teavm.memory.buffer, javaArgAddress, arg.length * 2);
+                    let javaArgData = new Uint16Array(teavm.memory.buffer, javaArgAddress, arg.length);
                     for (let j = 0; j < arg.length; ++j) {
-                        javaArgData.setUint16(j * 2, arg.charCodeAt(j), true);
+                        javaArgData[j] = arg.charCodeAt(j);
                     }
-                    javaArgsData.setInt32(i * 4, javaArg, true);
+                    javaArgsData[i] = javaArg;
                 }
 
                 controller.resolve = resolve;