add 32 bit architecture support (#24)

CHANGELOG.md

@@ -1,3 +1,7 @@
+## 0.0.4+4
+
+* Added support for 32 bit architecture.
+
 ## 0.0.4+3
 
 * Fixed type casting issue between `Uint8List` and `Uint64List` while passing callback arguments from C side to Dart side.

README.md

@@ -6,7 +6,7 @@ This is a [GSoC 2021 project](https://summerofcode.withgoogle.com/projects/#4757
 
 ## Supported Platforms
 
-Currently, 64 bit Android and Desktop Platforms (Linux, Windows and MacOS) are supported.
+Currently, Android and Desktop Platforms (Linux, Windows and MacOS) are supported.
 
 ## Requirements
 

pubspec.yaml

@@ -3,7 +3,7 @@
 # BSD-style license that can be found in the LICENSE file.
 
 name: cronet
-version: 0.0.4+3
+version: 0.0.4+4
 homepage: https://github.com/google/cronet.dart
 description: Experimental Cronet dart bindings.
 

src/wrapper.cc

@@ -9,6 +9,7 @@
 #include "../third_party/dart-sdk/dart_tools_api.h"
 #include <iostream>
 #include <stdarg.h>
+#include <stdlib.h>
 #include <string.h>
 #include <unordered_map>
 
@@ -127,8 +128,12 @@ Dart_CObject CallbackArgBuilder(int num, ...) {
   void *request_buffer = malloc(sizeof(uint64_t) * num);
   uint64_t *buf = reinterpret_cast<uint64_t *>(request_buffer);
 
+  // uintptr_r will get implicitly casted to uint64_t. So, when the code is
+  // executed in 32 bit mode, the upper 32 bit of buf[i] will be 0 extended
+  // automatically. This is required because, on the Dart side these addresses
+  // are viewed as 64 bit integers.
   for (int i = 0; i < num; i++) {
-    buf[i] = va_arg(valist, uint64_t);
+    buf[i] = va_arg(valist, uintptr_t);
   }
 
   c_request_data.type = Dart_CObject_kExternalTypedData;