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Optimized swapping of ref array elements.

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This commit is contained in:
Yuriy Glukhov 2016-08-08 14:08:10 +03:00
commit 8d86c6ed84
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lib/system.nim
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@ -1744,6 +1744,13 @@ proc swap*[T](a, b: var T) {.magic: "Swap", noSideEffect.}
## swaps the values `a` and `b`. This is often more efficient than ## swaps the values `a` and `b`. This is often more efficient than
## ``tmp = a; a = b; b = tmp``. Particularly useful for sorting algorithms. ## ``tmp = a; a = b; b = tmp``. Particularly useful for sorting algorithms.
when not defined(js) and not defined(booting):
template swapRefsInArray*{swap(arr[a], arr[b])}(arr: openarray[ref], a, b: int) =
# Optimize swapping of array elements if they are refs. Default swap
# implementation will cause unsureAsgnRef to be emitted which causes
# unnecessary slow down in this case.
swap(cast[ptr pointer](addr arr[a])[], cast[ptr pointer](addr arr[b])[])
template `>=%` *(x, y: untyped): untyped = y <=% x template `>=%` *(x, y: untyped): untyped = y <=% x
## treats `x` and `y` as unsigned and compares them. ## treats `x` and `y` as unsigned and compares them.
## Returns true iff ``unsigned(x) >= unsigned(y)``. ## Returns true iff ``unsigned(x) >= unsigned(y)``.