[node:buffer] Implement `isUtf8` and `isAscii` (#3498)

Co-authored-by: Jarred Sumner <709451+Jarred-Sumner@users.noreply.github.com>

3 files changed, 177 insertions, 1 deletions

diff --git a/packages/bun-types/buffer.d.ts b/packages/bun-types/buffer.d.ts
index eb7335871..fd7201677 100644
--- a/packages/bun-types/buffer.d.ts
+++ b/packages/bun-types/buffer.d.ts
@@ -2084,6 +2084,30 @@ declare module "buffer" {
       values(): IterableIterator<number>;
     }
     var Buffer: BufferConstructor;
+
+    /**
+     * This function returns `true` if `input` contains only valid UTF-8-encoded data,
+     * including the case in which `input` is empty.
+     *
+     * Throws if the `input` is a detached array buffer.
+     * @since Bun v0.6.13
+     * @param input The input to validate.
+     */
+    export function isUtf8(
+      input: TypedArray | ArrayBufferLike | DataView,
+    ): boolean;
+
+    /**
+     * This function returns `true` if `input` contains only valid ASCII-encoded data,
+     * including the case in which `input` is empty.
+     *
+     * Throws if the `input` is a detached array buffer.
+     * @since Bun v0.6.13
+     * @param input The input to validate.
+     */
+    export function isAscii(
+      input: TypedArray | ArrayBufferLike | DataView,
+    ): boolean;
   }
 }
 declare module "node:buffer" {
diff --git a/src/bun.js/modules/BufferModule.h b/src/bun.js/modules/BufferModule.h
index a96fb18c8..6e6e39e9c 100644
--- a/src/bun.js/modules/BufferModule.h
+++ b/src/bun.js/modules/BufferModule.h
@@ -2,11 +2,127 @@
 #include "../bindings/ZigGlobalObject.h"
 #include "JavaScriptCore/JSGlobalObject.h"
 #include "JavaScriptCore/ObjectConstructor.h"
+#include "simdutf.h"
 
 namespace Zig {
 using namespace WebCore;
 using namespace JSC;
 
+// TODO: Add DOMJIT fast path
+JSC_DEFINE_HOST_FUNCTION(jsBufferConstructorFunction_isUtf8,
+                         (JSC::JSGlobalObject * lexicalGlobalObject,
+                          JSC::CallFrame *callframe)) {
+  auto throwScope = DECLARE_THROW_SCOPE(lexicalGlobalObject->vm());
+
+  auto buffer = callframe->argument(0);
+  auto *bufferView = JSC::jsDynamicCast<JSC::JSArrayBufferView *>(buffer);
+  const char *ptr = nullptr;
+  size_t byteLength = 0;
+  if (bufferView) {
+    if (UNLIKELY(bufferView->isDetached())) {
+      throwTypeError(lexicalGlobalObject, throwScope,
+                     "ArrayBufferView is detached"_s);
+      return JSValue::encode({});
+    }
+
+    byteLength = bufferView->byteLength();
+
+    if (byteLength == 0) {
+      return JSValue::encode(jsBoolean(true));
+    }
+
+    ptr = reinterpret_cast<const char *>(bufferView->vector());
+  } else if (auto *arrayBuffer =
+                 JSC::jsDynamicCast<JSC::JSArrayBuffer *>(buffer)) {
+    auto *impl = arrayBuffer->impl();
+
+    if (!impl) {
+      return JSValue::encode(jsBoolean(true));
+    }
+
+    if (UNLIKELY(impl->isDetached())) {
+      throwTypeError(lexicalGlobalObject, throwScope,
+                     "ArrayBuffer is detached"_s);
+      return JSValue::encode({});
+    }
+
+    byteLength = impl->byteLength();
+
+    if (byteLength == 0) {
+      return JSValue::encode(jsBoolean(true));
+    }
+
+    ptr = reinterpret_cast<const char *>(impl->data());
+  } else {
+    throwVMError(
+        lexicalGlobalObject, throwScope,
+        createTypeError(lexicalGlobalObject,
+                        "First argument must be an ArrayBufferView"_s));
+    return JSValue::encode({});
+  }
+
+  RELEASE_AND_RETURN(throwScope, JSValue::encode(jsBoolean(
+                                     simdutf::validate_utf8(ptr, byteLength))));
+}
+
+// TODO: Add DOMJIT fast path
+JSC_DEFINE_HOST_FUNCTION(jsBufferConstructorFunction_isAscii,
+                         (JSC::JSGlobalObject * lexicalGlobalObject,
+                          JSC::CallFrame *callframe)) {
+  auto throwScope = DECLARE_THROW_SCOPE(lexicalGlobalObject->vm());
+
+  auto buffer = callframe->argument(0);
+  auto *bufferView = JSC::jsDynamicCast<JSC::JSArrayBufferView *>(buffer);
+  const char *ptr = nullptr;
+  size_t byteLength = 0;
+  if (bufferView) {
+
+    if (UNLIKELY(bufferView->isDetached())) {
+      throwTypeError(lexicalGlobalObject, throwScope,
+                     "ArrayBufferView is detached"_s);
+      return JSValue::encode({});
+    }
+
+    byteLength = bufferView->byteLength();
+
+    if (byteLength == 0) {
+      return JSValue::encode(jsBoolean(true));
+    }
+
+    ptr = reinterpret_cast<const char *>(bufferView->vector());
+  } else if (auto *arrayBuffer =
+                 JSC::jsDynamicCast<JSC::JSArrayBuffer *>(buffer)) {
+    auto *impl = arrayBuffer->impl();
+    if (UNLIKELY(impl->isDetached())) {
+      throwTypeError(lexicalGlobalObject, throwScope,
+                     "ArrayBuffer is detached"_s);
+      return JSValue::encode({});
+    }
+
+    if (!impl) {
+      return JSValue::encode(jsBoolean(true));
+    }
+
+    byteLength = impl->byteLength();
+
+    if (byteLength == 0) {
+      return JSValue::encode(jsBoolean(true));
+    }
+
+    ptr = reinterpret_cast<const char *>(impl->data());
+  } else {
+    throwVMError(
+        lexicalGlobalObject, throwScope,
+        createTypeError(lexicalGlobalObject,
+                        "First argument must be an ArrayBufferView"_s));
+    return JSValue::encode({});
+  }
+
+  RELEASE_AND_RETURN(
+      throwScope,
+      JSValue::encode(jsBoolean(simdutf::validate_ascii(ptr, byteLength))));
+}
+
 JSC_DEFINE_HOST_FUNCTION(jsFunctionNotImplemented,
                          (JSGlobalObject * globalObject,
                           CallFrame *callFrame)) {
@@ -106,6 +222,20 @@ inline void generateBufferSourceCode(JSC::JSGlobalObject *lexicalGlobalObject,
   exportProperty(JSC::Identifier::fromString(vm, "resolveObjectURL"_s),
                  resolveObjectURL);
 
+  exportProperty(JSC::Identifier::fromString(vm, "isAscii"_s),
+                 JSC::JSFunction::create(vm, globalObject, 1, "isAscii"_s,
+                                         jsBufferConstructorFunction_isAscii,
+                                         ImplementationVisibility::Public,
+                                         NoIntrinsic,
+                                         jsBufferConstructorFunction_isUtf8));
+
+  exportProperty(JSC::Identifier::fromString(vm, "isUtf8"_s),
+                 JSC::JSFunction::create(vm, globalObject, 1, "isUtf8"_s,
+                                         jsBufferConstructorFunction_isUtf8,
+                                         ImplementationVisibility::Public,
+                                         NoIntrinsic,
+                                         jsBufferConstructorFunction_isUtf8));
+
   exportNames.append(vm.propertyNames->defaultKeyword);
   exportValues.append(defaultObject);
 }
diff --git a/test/js/node/buffer.test.js b/test/js/node/buffer.test.js
index e0d8f5486..99562fedd 100644
--- a/test/js/node/buffer.test.js
+++ b/test/js/node/buffer.test.js
@@ -1,4 +1,4 @@
-import { Buffer, SlowBuffer } from "buffer";
+import { Buffer, SlowBuffer, isAscii, isUtf8 } from "buffer";
 import { describe, it, expect, beforeEach, afterEach } from "bun:test";
 import { gc } from "harness";
 
@@ -7,6 +7,28 @@ const BufferModule = await import("buffer");
 beforeEach(() => gc());
 afterEach(() => gc());
 
+it("isAscii", () => {
+  expect(isAscii(new Buffer("abc"))).toBeTrue();
+  expect(isAscii(new Buffer(""))).toBeTrue();
+  expect(isAscii(new Buffer([32, 32, 128]))).toBeFalse();
+  expect(isAscii(new Buffer("What did the 🦊 say?"))).toBeFalse();
+
+  expect(isAscii(new Buffer("").buffer)).toBeTrue();
+  expect(isAscii(new Buffer([32, 32, 128]).buffer)).toBeFalse();
+});
+
+it("isUtf8", () => {
+  expect(isUtf8(new Buffer("abc"))).toBeTrue();
+  expect(isAscii(new Buffer(""))).toBeTrue();
+  expect(isUtf8(new Buffer("What did the 🦊 say?"))).toBeTrue();
+  expect(isUtf8(new Buffer([129, 129, 129]))).toBeFalse();
+
+  expect(isUtf8(new Buffer("abc").buffer)).toBeTrue();
+  expect(isAscii(new Buffer("").buffer)).toBeTrue();
+  expect(isUtf8(new Buffer("What did the 🦊 say?").buffer)).toBeTrue();
+  expect(isUtf8(new Buffer([129, 129, 129]).buffer)).toBeFalse();
+});
+
 // https://github.com/oven-sh/bun/issues/2052
 it("Buffer global is settable", () => {
   var prevBuffer = globalThis.Buffer;