Removes the inner loop in the endtable check written tables (#5803)

google · Mar 12, 2020 · 0dba639 · 0dba639
1 parent 0e3fdd0
commit 0dba639
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Showing 2 changed files with 11 additions and 13 deletions.
diff --git a/swift/Sources/FlatBuffers/ByteBuffer.swift b/swift/Sources/FlatBuffers/ByteBuffer.swift
@@ -118,7 +118,7 @@ public final class ByteBuffer {
     ///   - size: Size of Value being written to the buffer
     func push(struct value: UnsafeMutableRawPointer, size: Int) {
         ensureSpace(size: UInt32(size))
-        _memory.advanced(by: writerIndex - size).copyMemory(from: value, byteCount: size)
+        memcpy(_memory.advanced(by: writerIndex - size), value, size)
         defer { value.deallocate() }
         _writerSize += size
     }

diff --git a/swift/Sources/FlatBuffers/FlatBufferBuilder.swift b/swift/Sources/FlatBuffers/FlatBufferBuilder.swift
@@ -174,19 +174,17 @@ public final class FlatBufferBuilder {
 
         var isAlreadyAdded: Int?
 
-        mainLoop: for table in _vtables {
-            let vt1 = _bb.capacity - Int(table)
-            let vt2 = _bb.writerIndex
-            let len = _bb.read(def: Int16.self, position: vt1)
-            guard len == _bb.read(def: Int16.self, position: vt2) else { break }
-            for i in stride(from: sizeofVoffset, to: Int(len), by: sizeofVoffset) {
-                let vt1ReadValue = _bb.read(def: Int16.self, position: vt1 + i)
-                let vt2ReadValue = _bb.read(def: Int16.self, position: vt2 + i)
-                if vt1ReadValue != vt2ReadValue {
-                    break mainLoop
-                }
-            }
+        let vt2 = _bb.memory.advanced(by: _bb.writerIndex)
+        let len2 = vt2.load(fromByteOffset: 0, as: Int16.self)
+
+        for table in _vtables {
+            let position = _bb.capacity - Int(table)
+            let vt1 = _bb.memory.advanced(by: position)
+            let len1 = _bb.read(def: Int16.self, position: position)
+            if (len2 != len1 || 0 != memcmp(vt1, vt2, Int(len2))) { continue }
+
             isAlreadyAdded = Int(table)
+            break
         }
 
         if let offset = isAlreadyAdded {