Merge pull request #80 from uber/fix-i64

Fix i64 coercion from large numbers
thriftrw · Oct 22, 2015 · 0601fdf · 0601fdf
2 parents e917b4f + bb3f1c5
commit 0601fdf
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Showing 2 changed files with 11 additions and 2 deletions.
diff --git a/i64.js b/i64.js
@@ -45,7 +45,7 @@ I64RW.prototype.writeInto = function writeInto(value, buffer, offset) {
         value.copy(buffer, offset, 0, 8);
         return new bufrw.WriteResult(null, offset + 8);
     } else if (typeof value === 'number') {
-        buffer.writeInt32BE(value / Math.pow(32), offset, true);
+        buffer.writeInt32BE(value / Math.pow(2, 32), offset, true);
         buffer.writeInt32BE(value, offset + 4, true);
         return new bufrw.WriteResult(null, offset + 8);
     } else if (Array.isArray(value)) {

diff --git a/test/i64.js b/test/i64.js
@@ -137,7 +137,7 @@ test('fail to coerce object bad lo value', function t(assert) {
     assert.end();
 });
 
-test('coerce number', function t(assert) {
+test('coerce small number', function t(assert) {
     var buffer = new Buffer(8);
     var res = bufferRW.writeInto(10, buffer, 0);
     assert.ifError(res.err, 'write into buffer');
@@ -146,6 +146,15 @@ test('coerce number', function t(assert) {
     assert.end();
 });
 
+test('coerce large number', function t(assert) {
+    var buffer = new Buffer(8);
+    var res = bufferRW.writeInto(Math.pow(2, 50), buffer, 0);
+    assert.ifError(res.err, 'write into buffer');
+    assert.equals(res.offset, 8, 'offset after write');
+    assert.deepEquals(buffer, new Buffer('0004000000000000', 'hex'), 'written value');
+    assert.end();
+});
+
 test('coerce array of bytes', function t(assert) {
     var buffer = new Buffer(8);
     var res = bufferRW.writeInto([1, 2, 3, 4, 5, 6, 7, 8], buffer, 0);