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discard """
output: '''1
2
3
4
5
6
89
90
90
0 0 1
0 1 2
0 2 3
1 0 4
1 1 5
1 2 6
1 3 7
after 6 6'''
joinable: false
"""
import typetraits
type
myseq*[T] = object
len, cap: int
data: ptr UncheckedArray[T]
# XXX make code memory safe for overflows in '*'
var
allocCount, deallocCount: int
proc `=destroy`*[T](x: var myseq[T]) =
if x.data != nil:
when not supportsCopyMem(T):
for i in 0..<x.len: `=destroy`(x[i])
dealloc(x.data)
inc deallocCount
x.data = nil
x.len = 0
x.cap = 0
proc `=`*[T](a: var myseq[T]; b: myseq[T]) =
if a.data == b.data: return
if a.data != nil:
`=destroy`(a)
#dealloc(a.data)
#inc deallocCount
#a.data = nil
a.len = b.len
a.cap = b.cap
if b.data != nil:
a.data = cast[type(a.data)](alloc(a.cap * sizeof(T)))
inc allocCount
when supportsCopyMem(T):
copyMem(a.data, b.data, a.cap * sizeof(T))
else:
for i in 0..<a.len:
a.data[i] = b.data[i]
proc `=sink`*[T](a: var myseq[T]; b: myseq[T]) =
if a.data != nil and a.data != b.data:
dealloc(a.data)
inc deallocCount
a.len = b.len
a.cap = b.cap
a.data = b.data
proc resize[T](s: var myseq[T]) =
if s.cap == 0: s.cap = 8
else: s.cap = (s.cap * 3) shr 1
if s.data == nil: inc allocCount
s.data = cast[type(s.data)](realloc(s.data, s.cap * sizeof(T)))
proc reserveSlot[T](x: var myseq[T]): ptr T =
if x.len >= x.cap: resize(x)
result = addr(x.data[x.len])
inc x.len
template add*[T](x: var myseq[T]; y: T) =
reserveSlot(x)[] = y
proc shrink*[T](x: var myseq[T]; newLen: int) =
assert newLen <= x.len
assert newLen >= 0
when not supportsCopyMem(T):
for i in countdown(x.len - 1, newLen - 1):
`=destroy`(x.data[i])
x.len = newLen
proc grow*[T](x: var myseq[T]; newLen: int; value: T) =
if newLen <= x.len: return
assert newLen >= 0
if x.cap == 0: x.cap = newLen
else: x.cap = max(newLen, (x.cap * 3) shr 1)
if x.data == nil: inc allocCount
x.data = cast[type(x.data)](realloc(x.data, x.cap * sizeof(T)))
for i in x.len..<newLen:
x.data[i] = value
x.len = newLen
template default[T](t: typedesc[T]): T =
var v: T
v
proc setLen*[T](x: var myseq[T]; newLen: int) {.deprecated.} =
if newlen < x.len: shrink(x, newLen)
else: grow(x, newLen, default(T))
template `[]`*[T](x: myseq[T]; i: Natural): T =
assert i < x.len
x.data[i]
template `[]=`*[T](x: myseq[T]; i: Natural; y: T) =
assert i < x.len
x.data[i] = y
proc createSeq*[T](elems: varargs[T]): myseq[T] =
result.cap = elems.len
result.len = elems.len
result.data = cast[type(result.data)](alloc(result.cap * sizeof(T)))
inc allocCount
when supportsCopyMem(T):
copyMem(result.data, unsafeAddr(elems[0]), result.cap * sizeof(T))
else:
for i in 0..<result.len:
result.data[i] = elems[i]
proc len*[T](x: myseq[T]): int {.inline.} = x.len
proc main =
var s = createSeq(1, 2, 3, 4, 5, 6)
s.add 89
s.grow s.len + 2, 90
for i in 0 ..< s.len:
echo s[i]
var nested = createSeq(createSeq(1, 2, 3), createSeq(4, 5, 6, 7))
for i in 0 ..< nested.len:
for j in 0 ..< nested[i].len:
echo i, " ", j, " ", nested[i][j]
main()
echo "after ", allocCount, " ", deallocCount
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