get sodium working on 32 bit systems (should help with #7)

packages/sodium/lib/src/ffi/api/pwhash_ffi.dart

@@ -21,7 +21,8 @@ class PwhashFFI with PwHashValidations implements Pwhash {
   @override
   int get bytesMin => sodium.crypto_pwhash_bytes_min();
   @override
-  int get bytesMax => sodium.crypto_pwhash_bytes_max();
+  int get bytesMax =>
+      sodium.crypto_pwhash_bytes_max().toUnsigned(sizeOf<IntPtr>() * 8);
 
   @override
   int get memLimitMin => sodium.crypto_pwhash_memlimit_min();
@@ -32,7 +33,8 @@ class PwhashFFI with PwHashValidations implements Pwhash {
   @override
   int get memLimitSensitive => sodium.crypto_pwhash_memlimit_sensitive();
   @override
-  int get memLimitMax => sodium.crypto_pwhash_memlimit_max();
+  int get memLimitMax =>
+      sodium.crypto_pwhash_memlimit_max().toUnsigned(sizeOf<IntPtr>() * 8);
 
   @override
   int get opsLimitMin => sodium.crypto_pwhash_opslimit_min();
@@ -43,12 +45,14 @@ class PwhashFFI with PwHashValidations implements Pwhash {
   @override
   int get opsLimitSensitive => sodium.crypto_pwhash_opslimit_sensitive();
   @override
-  int get opsLimitMax => sodium.crypto_pwhash_opslimit_max();
+  int get opsLimitMax =>
+      sodium.crypto_pwhash_opslimit_max().toUnsigned(sizeOf<IntPtr>() * 8);
 
   @override
   int get passwdMin => sodium.crypto_pwhash_passwd_min();
   @override
-  int get passwdMax => sodium.crypto_pwhash_passwd_max();
+  int get passwdMax =>
+      sodium.crypto_pwhash_passwd_max().toUnsigned(sizeOf<IntPtr>() * 8);
 
   @override
   int get saltBytes => sodium.crypto_pwhash_saltbytes();

packages/sodium/lib/src/ffi/api/sodium_ffi.dart

@@ -34,7 +34,7 @@ class SodiumFFI implements Sodium {
   Uint8List pad(Uint8List buf, int blocksize) {
     final maxLen = buf.length + blocksize;
     SodiumPointer<Uint8>? extendedBuffer;
-    SodiumPointer<Uint64>? paddedLength;
+    SodiumPointer<size_t>? paddedLength;
     try {
       extendedBuffer = SodiumPointer.alloc(sodium, count: maxLen)..fill(buf);
       paddedLength = SodiumPointer.alloc(sodium, zeroMemory: true);
@@ -56,7 +56,7 @@ class SodiumFFI implements Sodium {
   @override
   Uint8List unpad(Uint8List buf, int blocksize) {
     SodiumPointer<Uint8>? extendedBuffer;
-    SodiumPointer<Uint64>? unpaddedLength;
+    SodiumPointer<size_t>? unpaddedLength;
     try {
       extendedBuffer = buf.toSodiumPointer(
         sodium,

packages/sodium/lib/src/ffi/bindings/libsodium.ffi.dart

@@ -10599,7 +10599,7 @@ class __fsid_t extends ffi.Struct {
   external ffi.Array<ffi.Int32> __val;
 }
 
-typedef size_t = ffi.Uint64;
+typedef size_t = ffi.IntPtr;
 
 class crypto_aead_aes256gcm_state_ extends ffi.Struct {
   @ffi.Array.multi([512])

packages/sodium/lib/src/ffi/bindings/sodium_pointer.dart

@@ -835,6 +835,8 @@ abstract class _StaticallyTypedSizeOf {
         return sizeOf<Float>();
       case Double:
         return sizeOf<Double>();
+      case IntPtr:
+        return sizeOf<IntPtr>();
       default:
         throw UnsupportedError(
           'Cannot create a SodiumPointer for $T. T must be a primitive type',

packages/sodium/test/integration/cases/pwhash_test_case.dart

@@ -7,7 +7,9 @@ import '../test_case.dart';
 import '../test_runner.dart';
 
 class PwhashTestCase extends TestCase {
-  PwhashTestCase(TestRunner runner) : super(runner);
+  final bool is32Bit;
+
+  PwhashTestCase(TestRunner runner, {this.is32Bit = false}) : super(runner);
 
   @override
   String get name => 'pwhash';
@@ -24,7 +26,11 @@ class PwhashTestCase extends TestCase {
       expect(sut.memLimitInteractive, 67108864, reason: 'memLimitInteractive');
       expect(sut.memLimitModerate, 268435456, reason: 'memLimitModerate');
       expect(sut.memLimitSensitive, 1073741824, reason: 'memLimitSensitive');
-      expect(sut.memLimitMax, 4398046510080, reason: 'memLimitMax');
+      expect(
+        sut.memLimitMax,
+        is32Bit ? 2147483648 : 4398046510080,
+        reason: 'memLimitMax',
+      );
 
       expect(sut.opsLimitMin, 1, reason: 'opsLimitMin');
       expect(sut.opsLimitInteractive, 2, reason: 'opsLimitInteractive');

packages/sodium/test/integration/test_runner.dart

@@ -34,6 +34,8 @@ abstract class TestRunner {
 
   final bool isSumoTest;
 
+  bool get is32Bit => false;
+
   TestRunner({
     required this.isSumoTest,
   });
@@ -50,7 +52,7 @@ abstract class TestRunner {
         SignTestCase(this),
         GenericHashTestCase(this),
         ShortHashTestCase(this),
-        PwhashTestCase(this),
+        PwhashTestCase(this, is32Bit: is32Bit),
         KdfTestCase(this),
         KxTestCase(this),
       ];
@@ -89,7 +91,8 @@ abstract class TestRunner {
 
       // ignore: avoid_print
       print(
-        'Running integration tests with libsodium version: ${_sodium.version}',
+        'Running integration tests with libsodium version: ${_sodium.version} '
+        '(${is32Bit ? '32 bit' : '64 bit'})',
       );
     });
 

packages/sodium/test/integration/vm_test.dart

@@ -11,6 +11,9 @@ import 'test_runner.dart';
 class VmTestRunner extends TestRunner {
   VmTestRunner() : super(isSumoTest: true);
 
+  @override
+  bool get is32Bit => sizeOf<IntPtr>() == 4;
+
   @override
   Future<Sodium> loadSodium() async {
     String libSodiumPath;

packages/sodium_libs/example/integration_test/app_test.dart

@@ -9,9 +9,15 @@ import 'package:sodium_libs_example/main.dart' show MyApp;
 
 import '../../../sodium/test/integration/test_runner.dart';
 
+import 'arch_detection_fallback.dart'
+    if (dart.library.ffi) 'arch_detection_ffi.dart' as arch;
+
 class FlutterTestRunner extends TestRunner {
   FlutterTestRunner() : super(isSumoTest: true);
 
+  @override
+  bool get is32Bit => arch.is32Bit;
+
   @override
   Future<Sodium> loadSodium() => SodiumInit.init();
 

packages/sodium_libs/example/integration_test/arch_detection_fallback.dart

@@ -0,0 +1 @@
+const is32Bit = false;

packages/sodium_libs/example/integration_test/arch_detection_ffi.dart

@@ -0,0 +1,3 @@
+import 'dart:ffi';
+
+final is32Bit = sizeOf<IntPtr>() == 4;