diff options
Diffstat (limited to 'lib/system/seqs_v2.nim')
| -rw-r--r-- | lib/system/seqs_v2.nim | 96 |
1 files changed, 79 insertions, 17 deletions
diff --git a/lib/system/seqs_v2.nim b/lib/system/seqs_v2.nim index b71b81762..572e77408 100644 --- a/lib/system/seqs_v2.nim +++ b/lib/system/seqs_v2.nim @@ -8,7 +8,7 @@ # -# import typetraits +# import std/typetraits # strs already imported allocateds for us. @@ -16,8 +16,6 @@ {.push warning[StrictNotNil]: off.} # See https://github.com/nim-lang/Nim/issues/21401 -proc supportsCopyMem(t: typedesc): bool {.magic: "TypeTrait".} - ## Default seq implementation used by Nim's core. type NimSeqPayloadBase = object @@ -50,6 +48,15 @@ proc newSeqPayload(cap, elemSize, elemAlign: int): pointer {.compilerRtl, raises else: result = nil +proc newSeqPayloadUninit(cap, elemSize, elemAlign: int): pointer {.compilerRtl, raises: [].} = + # Used in `newSeqOfCap()`. + if cap > 0: + var p = cast[ptr NimSeqPayloadBase](alignedAlloc(align(sizeof(NimSeqPayloadBase), elemAlign) + cap * elemSize, elemAlign)) + p.cap = cap + result = p + else: + result = nil + template `+!`(p: pointer, s: int): pointer = cast[pointer](cast[int](p) +% s) @@ -70,15 +77,48 @@ proc prepareSeqAdd(len: int; p: pointer; addlen, elemSize, elemAlign: int): poin var p = cast[ptr NimSeqPayloadBase](p) let oldCap = p.cap and not strlitFlag let newCap = max(resize(oldCap), len+addlen) + var q: ptr NimSeqPayloadBase if (p.cap and strlitFlag) == strlitFlag: - var q = cast[ptr NimSeqPayloadBase](alignedAlloc0(headerSize + elemSize * newCap, elemAlign)) + q = cast[ptr NimSeqPayloadBase](alignedAlloc(headerSize + elemSize * newCap, elemAlign)) + copyMem(q +! headerSize, p +! headerSize, len * elemSize) + else: + let oldSize = headerSize + elemSize * oldCap + let newSize = headerSize + elemSize * newCap + q = cast[ptr NimSeqPayloadBase](alignedRealloc(p, oldSize, newSize, elemAlign)) + + zeroMem(q +! headerSize +! len * elemSize, addlen * elemSize) + q.cap = newCap + result = q + +proc zeroNewElements(len: int; q: pointer; addlen, elemSize, elemAlign: int) {. + noSideEffect, tags: [], raises: [], compilerRtl.} = + {.noSideEffect.}: + let headerSize = align(sizeof(NimSeqPayloadBase), elemAlign) + zeroMem(q +! headerSize +! len * elemSize, addlen * elemSize) + +proc prepareSeqAddUninit(len: int; p: pointer; addlen, elemSize, elemAlign: int): pointer {. + noSideEffect, tags: [], raises: [], compilerRtl.} = + {.noSideEffect.}: + let headerSize = align(sizeof(NimSeqPayloadBase), elemAlign) + if addlen <= 0: + result = p + elif p == nil: + result = newSeqPayloadUninit(len+addlen, elemSize, elemAlign) + else: + # Note: this means we cannot support things that have internal pointers as + # they get reallocated here. This needs to be documented clearly. + var p = cast[ptr NimSeqPayloadBase](p) + let oldCap = p.cap and not strlitFlag + let newCap = max(resize(oldCap), len+addlen) + if (p.cap and strlitFlag) == strlitFlag: + var q = cast[ptr NimSeqPayloadBase](alignedAlloc(headerSize + elemSize * newCap, elemAlign)) copyMem(q +! headerSize, p +! headerSize, len * elemSize) q.cap = newCap result = q else: let oldSize = headerSize + elemSize * oldCap let newSize = headerSize + elemSize * newCap - var q = cast[ptr NimSeqPayloadBase](alignedRealloc0(p, oldSize, newSize, elemAlign)) + var q = cast[ptr NimSeqPayloadBase](alignedRealloc(p, oldSize, newSize, elemAlign)) q.cap = newCap result = q @@ -95,16 +135,17 @@ proc shrink*[T](x: var seq[T]; newLen: Natural) {.tags: [], raises: [].} = {.noSideEffect.}: cast[ptr NimSeqV2[T]](addr x).len = newLen -proc grow*[T](x: var seq[T]; newLen: Natural; value: T) = +proc grow*[T](x: var seq[T]; newLen: Natural; value: T) {.nodestroy.} = let oldLen = x.len #sysAssert newLen >= x.len, "invalid newLen parameter for 'grow'" if newLen <= oldLen: return var xu = cast[ptr NimSeqV2[T]](addr x) if xu.p == nil or (xu.p.cap and not strlitFlag) < newLen: - xu.p = cast[typeof(xu.p)](prepareSeqAdd(oldLen, xu.p, newLen - oldLen, sizeof(T), alignof(T))) + xu.p = cast[typeof(xu.p)](prepareSeqAddUninit(oldLen, xu.p, newLen - oldLen, sizeof(T), alignof(T))) xu.len = newLen for i in oldLen .. newLen-1: - xu.p.data[i] = value + wasMoved(xu.p.data[i]) + `=copy`(xu.p.data[i], value) proc add*[T](x: var seq[T]; y: sink T) {.magic: "AppendSeqElem", noSideEffect, nodestroy.} = ## Generic proc for adding a data item `y` to a container `x`. @@ -117,7 +158,7 @@ proc add*[T](x: var seq[T]; y: sink T) {.magic: "AppendSeqElem", noSideEffect, n let oldLen = x.len var xu = cast[ptr NimSeqV2[T]](addr x) if xu.p == nil or (xu.p.cap and not strlitFlag) < oldLen+1: - xu.p = cast[typeof(xu.p)](prepareSeqAdd(oldLen, xu.p, 1, sizeof(T), alignof(T))) + xu.p = cast[typeof(xu.p)](prepareSeqAddUninit(oldLen, xu.p, 1, sizeof(T), alignof(T))) xu.len = oldLen+1 # .nodestroy means `xu.p.data[oldLen] = value` is compiled into a # copyMem(). This is fine as know by construction that @@ -125,7 +166,7 @@ proc add*[T](x: var seq[T]; y: sink T) {.magic: "AppendSeqElem", noSideEffect, n # We also save the `wasMoved + destroy` pair for the sink parameter. xu.p.data[oldLen] = y -proc setLen[T](s: var seq[T], newlen: Natural) = +proc setLen[T](s: var seq[T], newlen: Natural) {.nodestroy.} = {.noSideEffect.}: if newlen < s.len: shrink(s, newlen) @@ -134,7 +175,7 @@ proc setLen[T](s: var seq[T], newlen: Natural) = if newlen <= oldLen: return var xu = cast[ptr NimSeqV2[T]](addr s) if xu.p == nil or (xu.p.cap and not strlitFlag) < newlen: - xu.p = cast[typeof(xu.p)](prepareSeqAdd(oldLen, xu.p, newlen - oldLen, sizeof(T), alignof(T))) + xu.p = cast[typeof(xu.p)](prepareSeqAddUninit(oldLen, xu.p, newlen - oldLen, sizeof(T), alignof(T))) xu.len = newlen for i in oldLen..<newlen: xu.p.data[i] = default(T) @@ -143,11 +184,9 @@ proc newSeq[T](s: var seq[T], len: Natural) = shrink(s, 0) setLen(s, len) -proc sameSeqPayload(x: pointer, y: pointer): bool {.compilerproc, inline.} = +proc sameSeqPayload(x: pointer, y: pointer): bool {.compilerRtl, inl.} = result = cast[ptr NimRawSeq](x)[].p == cast[ptr NimRawSeq](y)[].p -template capacityImpl(sek: NimSeqV2): int = - if sek.p != nil: (sek.p.cap and not strlitFlag) else: 0 func capacity*[T](self: seq[T]): int {.inline.} = ## Returns the current capacity of the seq. @@ -157,9 +196,32 @@ func capacity*[T](self: seq[T]): int {.inline.} = lst.add "Nim" assert lst.capacity == 42 - {.cast(noSideEffect).}: - let sek = unsafeAddr self - result = capacityImpl(cast[ptr NimSeqV2[T]](sek)[]) + let sek = cast[ptr NimSeqV2[T]](unsafeAddr self) + result = if sek.p != nil: sek.p.cap and not strlitFlag else: 0 +func setLenUninit*[T](s: var seq[T], newlen: Natural) {.nodestroy.} = + ## Sets the length of seq `s` to `newlen`. `T` may be any sequence type. + ## New slots will not be initialized. + ## + ## If the current length is greater than the new length, + ## `s` will be truncated. + ## ```nim + ## var x = @[10, 20] + ## x.setLenUninit(5) + ## x[4] = 50 + ## assert x[4] == 50 + ## x.setLenUninit(1) + ## assert x == @[10] + ## ``` + {.noSideEffect.}: + if newlen < s.len: + shrink(s, newlen) + else: + let oldLen = s.len + if newlen <= oldLen: return + var xu = cast[ptr NimSeqV2[T]](addr s) + if xu.p == nil or (xu.p.cap and not strlitFlag) < newlen: + xu.p = cast[typeof(xu.p)](prepareSeqAddUninit(oldLen, xu.p, newlen - oldLen, sizeof(T), alignof(T))) + xu.len = newlen {.pop.} # See https://github.com/nim-lang/Nim/issues/21401 |