Add a more efficient implementation for String(::ReinterpretArray)

Author: lntricate1

base/strings/string.jl

@@ -77,6 +77,20 @@ function String(v::Vector{UInt8})
     setfield!(v, :ref, memoryref(Memory{UInt8}()))
     return str
 end
+function String(v::ReinterpretArray{UInt8, 1, S, Vector{S}, IsReshaped}) where {S, IsReshaped}
+    len = length(v)
+    len == 0 && return ""
+    ref = v.parent.ref
+    if ref.ptr_or_offset == ref.mem.ptr
+        str = ccall(:jl_genericmemory_to_string, Ref{String}, (Any, Int), ref.mem, len)
+    else
+        str = ccall(:jl_pchar_to_string, Ref{String}, (Ptr{S}, Int), ref, len)
+    end
+    # optimized empty!(v.parent); sizehint!(v.parent, 0) calls
+    setfield!(v.parent, :size, (0,))
+    setfield!(v.parent, :ref, memoryref(Memory{S}()))
+    return str
+end
 
 "Create a string re-using the memory, if possible.
 Mutating or reading the memory after calling this function is undefined behaviour."