nim-stew/stew/ranges/memranges.nim

33 lines
955 B
Nim

import
ptr_arith
type
MemRange* = object
start: pointer
size: csize
template len*(mr: MemRange): int = mr.size
template `[]`*(mr: MemRange, idx: int): byte = (cast[ptr byte](shift(mr.start, idx)))[]
proc baseAddr*(mr: MemRange): pointer = mr.start
proc makeMemRange*(start: pointer, size: csize): MemRange =
result.start = start
result.size = size
proc toMemRange*(x: string): MemRange =
result.start = x.cstring.pointer
result.size = x.len
proc toMemRange*[T](x: openarray[T], fromIdx, toIdx: int): MemRange =
doAssert(fromIdx >= 0 and toIdx >= fromIdx and fromIdx < x.len and toIdx < x.len)
result.start = unsafeAddr x[fromIdx]
result.size = (toIdx - fromIdx + 1) * T.sizeof
proc toMemRange*[T](x: openarray[T], fromIdx: int): MemRange {.inline.} =
toMemRange(x, fromIdx, x.high)
proc toMemRange*[T](x: openarray[T]): MemRange {.inline.} =
toMemRange(x, 0, x.high)
template toMemRange*(mr: MemRange): MemRange = mr