Merge pull request #36 from benaadams/patch-1

jkotas · jkotas · commit cbf5cbf6c257 · 2015-02-04T13:18:29.000-08:00
Avoid unnecessary work for identical locations in Buffer.BlockCopy
diff --git a/src/vm/comutilnative.cpp b/src/vm/comutilnative.cpp
@@ -1443,9 +1443,12 @@ FCIMPL5(VOID, Buffer::BlockCopy, ArrayBase *src, int srcOffset, ArrayBase *dst,
     if (srcLen < (SIZE_T)srcOffset + (SIZE_T)count || dstLen < (SIZE_T)dstOffset + (SIZE_T)count) {
         FCThrowArgumentVoid(NULL, W("Argument_InvalidOffLen"));
     }
+    
+    PTR_BYTE srcPtr = src->GetDataPtr() + srcOffset;
+    PTR_BYTE dstPtr = dst->GetDataPtr() + dstOffset;
 
-    if (count > 0) {
-        memmove(dst->GetDataPtr() + dstOffset, src->GetDataPtr() + srcOffset, count);
+    if ((srcPtr != dstPtr) && (count > 0)) {
+        memmove(dstPtr, srcPtr, count);
     }
 
     FC_GC_POLL();

Original file line number	Diff line number	Diff line change
`@@ -1443,9 +1443,12 @@ FCIMPL5(VOID, Buffer::BlockCopy, ArrayBase src, int srcOffset, ArrayBase dst,`
`1443`	`1443`	`if (srcLen < (SIZE_T)srcOffset + (SIZE_T)count \|\| dstLen < (SIZE_T)dstOffset + (SIZE_T)count) {`
`1444`	`1444`	`FCThrowArgumentVoid(NULL, W("Argument_InvalidOffLen"));`
`1445`	`1445`	`}`
	`1446`	`+`
	`1447`	`+ PTR_BYTE srcPtr = src->GetDataPtr() + srcOffset;`
	`1448`	`+ PTR_BYTE dstPtr = dst->GetDataPtr() + dstOffset;`
`1446`	`1449`
`1447`		`- if (count > 0) {`
`1448`		`- memmove(dst->GetDataPtr() + dstOffset, src->GetDataPtr() + srcOffset, count);`
	`1450`	`+ if ((srcPtr != dstPtr) && (count > 0)) {`
	`1451`	`+ memmove(dstPtr, srcPtr, count);`
`1449`	`1452`	`}`
`1450`	`1453`
`1451`	`1454`	`FC_GC_POLL();`