fixup

doc/api/stream.md

@@ -1084,7 +1084,7 @@ buffer will be returned.
 If the `size` argument is not specified, all of the data contained in the
 internal buffer will be returned.
 
-The `size` argument must be less than or equal to 2^31.
+The `size` argument must be less than or equal to 2^30.
 
 The `readable.read()` method should only be called on `Readable` streams
 operating in paused mode. In flowing mode, `readable.read()` is called

lib/_stream_readable.js

@@ -41,12 +41,9 @@ const {
   ERR_INVALID_ARG_TYPE,
   ERR_STREAM_PUSH_AFTER_EOF,
   ERR_METHOD_NOT_IMPLEMENTED,
-  ERR_STREAM_UNSHIFT_AFTER_END_EVENT,
-  ERR_VALUE_OUT_OF_RANGE
+  ERR_STREAM_UNSHIFT_AFTER_END_EVENT
 } = require('internal/errors').codes;
 
-const MAX_HWM = Math.pow(2, 31);
-
 // Lazy loaded to improve the startup performance.
 let StringDecoder;
 let createReadableStreamAsyncIterator;
@@ -377,6 +374,26 @@ Readable.prototype.setEncoding = function(enc) {
   return this;
 };
 
+// Don't raise the hwm > 1GB
+const MAX_HWM = Math.pow(2, 30);
+function computeNewHighWaterMark(n) {
+  if (n >= MAX_HWM) {
+    // TODO(ronag): Throw ERR_VALUE_OUT_OF_RANGE.
+    n = MAX_HWM;
+  } else {
+    // Get the next highest power of 2 to prevent increasing hwm excessively in
+    // tiny amounts
+    n--;
+    n |= n >>> 1;
+    n |= n >>> 2;
+    n |= n >>> 4;
+    n |= n >>> 8;
+    n |= n >>> 16;
+    n++;
+  }
+  return n;
+}
+
 // This function is designed to be inlinable, so please take care when making
 // changes to the function body.
 function howMuchToRead(n, state) {
@@ -409,18 +426,9 @@ Readable.prototype.read = function(n) {
   const state = this._readableState;
   const nOrig = n;
 
-  if (n > MAX_HWM) {
-    throw new ERR_VALUE_OUT_OF_RANGE('n');
-  }
-
-  // If we're asking for more than the current hwm, then raise the hwm to
-  // the next highest power of 2 to prevent increasing hwm excessively in
-  // tiny amounts.
+  // If we're asking for more than the current hwm, then raise the hwm.
   if (n > state.highWaterMark)
-    state.highWaterMark = Math.min(
-      MAX_HWM,
-      Math.pow(2, Math.ceil(Math.log(n) / Math.log(2)))
-    );
+    state.highWaterMark = computeNewHighWaterMark(n);
 
   if (n !== 0)
     state.emittedReadable = false;