commit 328b4f4e34ba915481707a7eb24eba860925712e
author Nam T. Nguyen <namnguyen@google.com> Fri Jan 12 12:55:19 2018 -0800
committer Nam T. Nguyen <namnguyen@google.com> Fri Jan 12 12:55:19 2018 -0800
tree 4b60ac916962104c30d58cf2e0dc31099be7b6c2
parent 645147dd50597e17708474afa9df864ceb6ea9c8

Fix #31: Make shifts work at width boundaries.

lib/src/int32.dart

diff --git a/lib/src/int32.dart b/lib/src/int32.dart
index 562ff0c..db8ecd0 100644
--- a/lib/src/int32.dart
+++ b/lib/src/int32.dart
@@ -239,7 +239,9 @@
     if (n < 0) {
       throw new ArgumentError(n);
     }
-    n &= 31;
+    if (n >= 32) {
+      return ZERO;
+    }
     return new Int32(_i << n);
   }
 
@@ -247,7 +249,9 @@
     if (n < 0) {
       throw new ArgumentError(n);
     }
-    n &= 31;
+    if (n >= 32) {
+      return isNegative ? const Int32._internal(-1) : ZERO;
+    }
     int value;
     if (_i >= 0) {
       value = _i >> n;
@@ -261,7 +265,9 @@
     if (n < 0) {
       throw new ArgumentError(n);
     }
-    n &= 31;
+    if (n >= 32) {
+      return ZERO;
+    }
     int value;
     if (_i >= 0) {
       value = _i >> n;

lib/src/int64.dart

diff --git a/lib/src/int64.dart b/lib/src/int64.dart
index c25b8fa..a84cbd9 100644
--- a/lib/src/int64.dart
+++ b/lib/src/int64.dart
@@ -343,7 +343,9 @@
     if (n < 0) {
       throw new ArgumentError.value(n);
     }
-    n &= 63;
+    if (n >= 64) {
+      return ZERO;
+    }
 
     int res0, res1, res2;
     if (n < _BITS) {
@@ -367,7 +369,9 @@
     if (n < 0) {
       throw new ArgumentError.value(n);
     }
-    n &= 63;
+    if (n >= 64) {
+      return isNegative ? const Int64._bits(_MASK, _MASK, _MASK2) : ZERO;
+    }
 
     int res0, res1, res2;
 
@@ -410,7 +414,9 @@
     if (n < 0) {
       throw new ArgumentError.value(n);
     }
-    n &= 63;
+    if (n >= 64) {
+      return ZERO;
+    }
 
     int res0, res1, res2;
     int a2 = _MASK2 & _h; // Ensure a2 is positive.

test/int32_test.dart

diff --git a/test/int32_test.dart b/test/int32_test.dart
index 63149cf..afa7eeb 100644
--- a/test/int32_test.dart
+++ b/test/int32_test.dart
@@ -294,12 +294,18 @@
   group("bitshift operators", () {
     test("<<", () {
       expect(new Int32(0x12345678) << 7, new Int32(0x12345678 << 7));
+      expect(new Int32(0x12345678) << 32, Int32.ZERO);
+      expect(new Int32(0x12345678) << 33, Int32.ZERO);
       expect(() => new Int32(17) << -1, throwsArgumentError);
       expect(() => new Int32(17) << null, throwsNoSuchMethodError);
     });
 
     test(">>", () {
       expect(new Int32(0x12345678) >> 7, new Int32(0x12345678 >> 7));
+      expect(new Int32(0x12345678) >> 32, Int32.ZERO);
+      expect(new Int32(0x12345678) >> 33, Int32.ZERO);
+      expect(new Int32(-42) >> 32, new Int32(-1));
+      expect(new Int32(-42) >> 33, new Int32(-1));
       expect(() => new Int32(17) >> -1, throwsArgumentError);
       expect(() => new Int32(17) >> null, throwsNoSuchMethodError);
     });
@@ -307,6 +313,10 @@
     test("shiftRightUnsigned", () {
       expect(new Int32(0x12345678).shiftRightUnsigned(7),
           new Int32(0x12345678 >> 7));
+      expect(new Int32(0x12345678).shiftRightUnsigned(32), Int32.ZERO);
+      expect(new Int32(0x12345678).shiftRightUnsigned(33), Int32.ZERO);
+      expect(new Int32(-42).shiftRightUnsigned(32), Int32.ZERO);
+      expect(new Int32(-42).shiftRightUnsigned(33), Int32.ZERO);
       expect(() => (new Int32(17).shiftRightUnsigned(-1)), throwsArgumentError);
       expect(() => (new Int32(17).shiftRightUnsigned(null)),
           throwsNoSuchMethodError);

test/int64_test.dart

diff --git a/test/int64_test.dart b/test/int64_test.dart
index fbd008d..8106c2e 100644
--- a/test/int64_test.dart
+++ b/test/int64_test.dart
@@ -494,6 +494,8 @@
           new Int64.fromInts(0xd048d115, 0x9d159c00));
       expect(new Int64(-1) << 5, new Int64(-32));
       expect(new Int64(-1) << 0, new Int64(-1));
+      expect(new Int64(42) << 64, Int64.ZERO);
+      expect(new Int64(42) << 65, Int64.ZERO);
       expect(() => new Int64(17) << -1, throwsArgumentError);
       expect(() => new Int64(17) << null, throwsNoSuchMethodError);
     });
@@ -506,6 +508,8 @@
           new Int64.fromInts(0xffe48d04, 0x8d1159d1));
       expect(
           new Int64.fromInts(0xFFFFFFF, 0xFFFFFFFF) >> 34, new Int64(67108863));
+      expect(new Int64(42) >> 64, Int64.ZERO);
+      expect(new Int64(42) >> 65, Int64.ZERO);
       for (int n = 0; n <= 66; n++) {
         expect(new Int64(-1) >> n, new Int64(-1));
       }
@@ -590,6 +594,8 @@
           new Int64.fromInts(0x00000000, 0x00092345));
       expect(new Int64.fromInts(0x00000000, 0x00009234),
           new Int64.fromInts(0x92345678, 0x9abcdef0).shiftRightUnsigned(48));
+      expect(new Int64(-1).shiftRightUnsigned(64), Int64.ZERO);
+      expect(new Int64(1).shiftRightUnsigned(64), Int64.ZERO);
       expect(() => new Int64(17).shiftRightUnsigned(-1), throwsArgumentError);
       expect(() => new Int64(17).shiftRightUnsigned(null),
           throwsNoSuchMethodError);