buffer: reapply 07c0667

indutny · rvagg · commit 1cd794f1296e · 2015-08-22T20:11:25.000+10:00
Original commit message: buffer: align chunks on 8-byte boundary When slicing global pool - ensure that the underlying buffer's data ptr is 8-byte alignment to do not ruin expectations of 3rd party C++ addons. NOTE: 0.10 node.js always returned aligned pointers and io.js should do this too for compatibility. PR-URL: #2487 Reviewed-By: Trevor Norris <trev.norris@gmail.com>
diff --git a/lib/buffer.js b/lib/buffer.js
@@ -21,6 +21,15 @@ function createPool() {
 }
 
 
+function alignPool() {
+ // Ensure aligned slices
+ if (poolOffset & 0x7) {
+ poolOffset |= 0x7;
+ poolOffset++;
+ }
+}
+
+
 function Buffer(arg) {
 // Common case.
 if (typeof arg === 'number') {
@@ -66,6 +75,7 @@ function allocate(size) {
 createPool();
 var b = binding.slice(allocPool, poolOffset, poolOffset + size);
 poolOffset += size;
+ alignPool();
 return b;
 } else {
 return binding.create(size);
@@ -86,6 +96,7 @@ function fromString(string, encoding) {
 var actual = allocPool.write(string, poolOffset, encoding);
 var b = binding.slice(allocPool, poolOffset, poolOffset + actual);
 poolOffset += actual;
+ alignPool();
 return b;
 }
 

-Original file line number
+Diff line change
+}
 +functionalignPool(){
 +// Ensure aligned slices
 +if(poolOffset&0x7){
 +poolOffset|=0x7;
 +poolOffset++;
 +}
 +}
++
++
 functionBuffer(arg){
 // Common case.
 if(typeofarg==='number'){
 createPool();
 varb=binding.slice(allocPool,poolOffset,poolOffset+size);
 poolOffset+=size;
 +alignPool();
 returnb;
 }else{
 returnbinding.create(size);
 varactual=allocPool.write(string,poolOffset,encoding);
 varb=binding.slice(allocPool,poolOffset,poolOffset+actual);
 poolOffset+=actual;
 +alignPool();
 returnb;
+}