Simplify fast buffer constructor

lib/buffer.js

@@ -114,7 +114,7 @@ function Buffer (subject, encoding, offset) {
 
     if (this.length > Buffer.poolSize) {
       // Big buffer, just alloc one.
-      this.parent = new SlowBuffer(subject, encoding);
+      this.parent = new SlowBuffer(this.length);
       this.offset = 0;
 
     } else {
@@ -123,19 +123,16 @@ function Buffer (subject, encoding, offset) {
       this.parent = pool;
       this.offset = pool.used;
       pool.used += this.length;
+    }
 
-      // Do we need to write stuff?
-      if (type !== 'number') {
-        // Assume object is an array
-        if (type === 'object') {
-          for (var i = 0; i < this.length; i++) {
-            this.parent[i + this.offset] = subject[i];
-          }
-        } else {
-          // We are a string
-          this.write(subject, 0, encoding);
-        }
+    // Assume object is an array
+    if (Array.isArray(subject)) {
+      for (var i = 0; i < this.length; i++) {
+        this.parent[i + this.offset] = subject[i];
       }
+    } else if (type == 'string') {
+      // We are a string
+      this.write(subject, 0, encoding);
     }
   }