From: Calvin Metcalf <calvin.metcalf@gmail.com>
Date: Tue, 6 Oct 2015 22:43:33 +0000 (-0400)
Subject: mask values to prevent them from overflowing
X-Git-Url: https://zoso.dev/?a=commitdiff_plain;h=4f1a7fc83a623a8d08b3c29066774a9973257f7a;p=buffer.git

mask values to prevent them from overflowing
---

diff --git a/index.js b/index.js
index bc1183f..8645ca4 100644
--- a/index.js
+++ b/index.js
@@ -1015,7 +1015,7 @@ Buffer.prototype.writeUInt8 = function writeUInt8 (value, offset, noAssert) {
   offset = offset | 0
   if (!noAssert) checkInt(this, value, offset, 1, 0xff, 0)
   if (!Buffer.TYPED_ARRAY_SUPPORT) value = Math.floor(value)
-  this[offset] = value
+  this[offset] = (value & 0xff)
   return offset + 1
 }
 
@@ -1032,7 +1032,7 @@ Buffer.prototype.writeUInt16LE = function writeUInt16LE (value, offset, noAssert
   offset = offset | 0
   if (!noAssert) checkInt(this, value, offset, 2, 0xffff, 0)
   if (Buffer.TYPED_ARRAY_SUPPORT) {
-    this[offset] = value
+    this[offset] = (value & 0xff)
     this[offset + 1] = (value >>> 8)
   } else {
     objectWriteUInt16(this, value, offset, true)
@@ -1046,7 +1046,7 @@ Buffer.prototype.writeUInt16BE = function writeUInt16BE (value, offset, noAssert
   if (!noAssert) checkInt(this, value, offset, 2, 0xffff, 0)
   if (Buffer.TYPED_ARRAY_SUPPORT) {
     this[offset] = (value >>> 8)
-    this[offset + 1] = value
+    this[offset + 1] = (value & 0xff)
   } else {
     objectWriteUInt16(this, value, offset, false)
   }
@@ -1068,7 +1068,7 @@ Buffer.prototype.writeUInt32LE = function writeUInt32LE (value, offset, noAssert
     this[offset + 3] = (value >>> 24)
     this[offset + 2] = (value >>> 16)
     this[offset + 1] = (value >>> 8)
-    this[offset] = value
+    this[offset] = (value & 0xff)
   } else {
     objectWriteUInt32(this, value, offset, true)
   }
@@ -1083,7 +1083,7 @@ Buffer.prototype.writeUInt32BE = function writeUInt32BE (value, offset, noAssert
     this[offset] = (value >>> 24)
     this[offset + 1] = (value >>> 16)
     this[offset + 2] = (value >>> 8)
-    this[offset + 3] = value
+    this[offset + 3] = (value & 0xff)
   } else {
     objectWriteUInt32(this, value, offset, false)
   }
@@ -1136,7 +1136,7 @@ Buffer.prototype.writeInt8 = function writeInt8 (value, offset, noAssert) {
   if (!noAssert) checkInt(this, value, offset, 1, 0x7f, -0x80)
   if (!Buffer.TYPED_ARRAY_SUPPORT) value = Math.floor(value)
   if (value < 0) value = 0xff + value + 1
-  this[offset] = value
+  this[offset] = (value & 0xff)
   return offset + 1
 }
 
@@ -1145,7 +1145,7 @@ Buffer.prototype.writeInt16LE = function writeInt16LE (value, offset, noAssert)
   offset = offset | 0
   if (!noAssert) checkInt(this, value, offset, 2, 0x7fff, -0x8000)
   if (Buffer.TYPED_ARRAY_SUPPORT) {
-    this[offset] = value
+    this[offset] = (value & 0xff)
     this[offset + 1] = (value >>> 8)
   } else {
     objectWriteUInt16(this, value, offset, true)
@@ -1159,7 +1159,7 @@ Buffer.prototype.writeInt16BE = function writeInt16BE (value, offset, noAssert)
   if (!noAssert) checkInt(this, value, offset, 2, 0x7fff, -0x8000)
   if (Buffer.TYPED_ARRAY_SUPPORT) {
     this[offset] = (value >>> 8)
-    this[offset + 1] = value
+    this[offset + 1] = (value & 0xff)
   } else {
     objectWriteUInt16(this, value, offset, false)
   }
@@ -1171,7 +1171,7 @@ Buffer.prototype.writeInt32LE = function writeInt32LE (value, offset, noAssert)
   offset = offset | 0
   if (!noAssert) checkInt(this, value, offset, 4, 0x7fffffff, -0x80000000)
   if (Buffer.TYPED_ARRAY_SUPPORT) {
-    this[offset] = value
+    this[offset] = (value & 0xff)
     this[offset + 1] = (value >>> 8)
     this[offset + 2] = (value >>> 16)
     this[offset + 3] = (value >>> 24)
@@ -1190,7 +1190,7 @@ Buffer.prototype.writeInt32BE = function writeInt32BE (value, offset, noAssert)
     this[offset] = (value >>> 24)
     this[offset + 1] = (value >>> 16)
     this[offset + 2] = (value >>> 8)
-    this[offset + 3] = value
+    this[offset + 3] = (value & 0xff)
   } else {
     objectWriteUInt32(this, value, offset, false)
   }
diff --git a/test/write.js b/test/write.js
index 1163e50..4039d19 100644
--- a/test/write.js
+++ b/test/write.js
@@ -114,9 +114,9 @@ test('hex of write{Uint,Int}{8,16,32}{LE,BE} with overflow', function (t) {
   }
   t.end()
 })
-test('android issue', function (t) {
+test('large values do not imporoperly roll over (ref #80)', function (t) {
   var nums = [-25589992, -633756690, -898146932]
-  var out = new Buffer(12)
+  var out = new B(12)
   out.fill(0)
   out.writeInt32BE(nums[0], 0)
   var newNum = out.readInt32BE(0)