perf: replace base64.h with simdutf SIMD-accelerated codec

android/CMakeLists.txt

@@ -16,7 +16,7 @@ include_directories(
 add_library(
   ${PACKAGE_NAME}
   SHARED
-  ../cpp/base64.h
+  ../cpp/simdutf.cpp
   ../cpp/react-native-quick-base64.cpp
   ../cpp/react-native-quick-base64.h
   cpp-adapter.cpp

cpp/react-native-quick-base64.cpp

@@ -1,11 +1,35 @@
 #include "react-native-quick-base64.h"
-#include "base64.h"
+#include "simdutf.h"
 
+#include <algorithm>
 #include <iostream>
-#include <sstream>
 
 using namespace facebook;
 
+static simdutf::base64_options b64opts(bool url) noexcept {
+  return url ? simdutf::base64_url : simdutf::base64_default;
+}
+
+// Mirrors v8base64::decode (V8 builtins-typed-array.cc lines 513–516).
+// loose lastChunkHandling: accepts inputs without '=' padding.
+// decode_up_to_bad_char: mirrors V8's ArrayBufferFromBase64 (line 516).
+// base64_default_or_url: accepts both standard (+/) and URL-safe (-_) alphabets.
+static std::string decode(const std::string& input) {
+  size_t max_len = simdutf::maximal_binary_length_from_base64(input.data(), input.size());
+  std::string result(max_len, '\0');
+  size_t out_len = max_len;
+  auto r = simdutf::base64_to_binary_safe(
+      input.data(), input.size(), result.data(), out_len,
+      simdutf::base64_default_or_url,
+      simdutf::last_chunk_handling_options::loose,
+      /*decode_up_to_bad_char*/ true);
+  if (r.error != simdutf::error_code::SUCCESS) {
+    throw std::runtime_error("Input is not valid base64-encoded data");
+  }
+  result.resize(out_len);
+  return result;
+}
+
 // Returns false if the passed value is not a string or an ArrayBuffer.
 bool valueToString(jsi::Runtime& runtime, const jsi::Value& value, std::string* str) {
   if (value.isString()) {
@@ -43,7 +67,10 @@ void installBase64(jsi::Runtime& jsiRuntime) {
           url = arguments[1].asBool();
         }
         try {
-          std::string strBase64 = base64_encode(str, url);
+          auto opts = b64opts(url);
+          std::string strBase64(simdutf::base64_length_from_binary(str.size(), opts), '\0');
+          auto outlen = simdutf::binary_to_base64(str.data(), str.size(), strBase64.data(), opts);
+          strBase64.resize(outlen);
           return jsi::Value(jsi::String::createFromUtf8(runtime, strBase64));
         } catch (const std::runtime_error& error) {
           throw jsi::JSError(runtime, error.what());
@@ -69,7 +96,12 @@ void installBase64(jsi::Runtime& jsiRuntime) {
           removeLinebreaks = arguments[1].asBool();
         }
         try {
-          std::string str = base64_decode(strBase64, removeLinebreaks);
+          if (removeLinebreaks) {
+            strBase64.erase(std::remove(strBase64.begin(), strBase64.end(), '\n'), strBase64.end());
+          } else if (strBase64.find('\n') != std::string::npos) {
+            throw std::runtime_error("Input is not valid base64-encoded data");
+          }
+          std::string str = decode(strBase64);
           jsi::Function arrayBufferCtor = runtime.global().getPropertyAsFunction(runtime, "ArrayBuffer");
           jsi::Object o = arrayBufferCtor.callAsConstructor(runtime, (int)str.length()).getObject(runtime);
           jsi::ArrayBuffer buf = o.getArrayBuffer(runtime);