Merge pull request #88 from kkebo/memmove

Author: kkebo

Sources/Support/memmove.swift

@@ -0,0 +1,21 @@
+@_silgen_name("memmove")
+func memmove(
+    _ dst: UnsafeMutableRawPointer,
+    _ src: UnsafeRawPointer,
+    _ n: Int,
+) -> UnsafeMutableRawPointer {
+    let dst = unsafe dst.bindMemory(to: UInt8.self, capacity: n)
+    var dstSpan = unsafe MutableSpan(_unsafeStart: dst, count: n)
+    let src = unsafe src.bindMemory(to: UInt8.self, capacity: n)
+    let srcSpan = unsafe Span(_unsafeStart: src, count: n)
+    if unsafe dst < src {
+        for i in dstSpan.indices {
+            dstSpan[i] = srcSpan[i]
+        }
+    } else {
+        for i in dstSpan.indices.reversed() {
+            dstSpan[i] = srcSpan[i]
+        }
+    }
+    return .init(dst)
+}