diff options
Diffstat (limited to 'lib/system/strs_v2.nim')
| -rw-r--r-- | lib/system/strs_v2.nim | 141 |
1 files changed, 112 insertions, 29 deletions
diff --git a/lib/system/strs_v2.nim b/lib/system/strs_v2.nim index aa644522f..404b4f78d 100644 --- a/lib/system/strs_v2.nim +++ b/lib/system/strs_v2.nim @@ -29,44 +29,77 @@ template contentSize(cap): int = cap + 1 + sizeof(NimStrPayloadBase) template frees(s) = if not isLiteral(s): - deallocShared(s.p) + when compileOption("threads"): + deallocShared(s.p) + else: + dealloc(s.p) + +template allocPayload(newLen: int): ptr NimStrPayload = + when compileOption("threads"): + cast[ptr NimStrPayload](allocShared(contentSize(newLen))) + else: + cast[ptr NimStrPayload](alloc(contentSize(newLen))) + +template allocPayload0(newLen: int): ptr NimStrPayload = + when compileOption("threads"): + cast[ptr NimStrPayload](allocShared0(contentSize(newLen))) + else: + cast[ptr NimStrPayload](alloc0(contentSize(newLen))) + +template reallocPayload(p: pointer, newLen: int): ptr NimStrPayload = + when compileOption("threads"): + cast[ptr NimStrPayload](reallocShared(p, contentSize(newLen))) + else: + cast[ptr NimStrPayload](realloc(p, contentSize(newLen))) + +template reallocPayload0(p: pointer; oldLen, newLen: int): ptr NimStrPayload = + when compileOption("threads"): + cast[ptr NimStrPayload](reallocShared0(p, contentSize(oldLen), contentSize(newLen))) + else: + cast[ptr NimStrPayload](realloc0(p, contentSize(oldLen), contentSize(newLen))) proc resize(old: int): int {.inline.} = if old <= 0: result = 4 - elif old < 65536: result = old * 2 + elif old <= high(int16): result = old * 2 else: result = old * 3 div 2 # for large arrays * 3/2 is better -proc prepareAdd(s: var NimStringV2; addlen: int) {.compilerRtl.} = +proc prepareAdd(s: var NimStringV2; addLen: int) {.compilerRtl.} = + let newLen = s.len + addLen if isLiteral(s): let oldP = s.p # can't mutate a literal, so we need a fresh copy here: - s.p = cast[ptr NimStrPayload](allocShared0(contentSize(s.len + addlen))) - s.p.cap = s.len + addlen + s.p = allocPayload(newLen) + s.p.cap = newLen if s.len > 0: # we are about to append, so there is no need to copy the \0 terminator: - copyMem(unsafeAddr s.p.data[0], unsafeAddr oldP.data[0], s.len) + copyMem(unsafeAddr s.p.data[0], unsafeAddr oldP.data[0], min(s.len, newLen)) + elif oldP == nil: + # In the case of `newString(0) & ""`, since `src.len == 0`, `appendString` + # will not set the `\0` terminator, so we set it here. + s.p.data[0] = '\0' else: let oldCap = s.p.cap and not strlitFlag - if s.len + addlen > oldCap: - let newCap = max(s.len + addlen, resize(oldCap)) - s.p = cast[ptr NimStrPayload](reallocShared0(s.p, contentSize(oldCap), contentSize(newCap))) + if newLen > oldCap: + let newCap = max(newLen, resize(oldCap)) + s.p = reallocPayload(s.p, newCap) s.p.cap = newCap + if newLen < newCap: + zeroMem(cast[pointer](addr s.p.data[newLen+1]), newCap - newLen) -proc nimAddCharV1(s: var NimStringV2; c: char) {.compilerRtl.} = +proc nimAddCharV1(s: var NimStringV2; c: char) {.compilerRtl, inl.} = + #if (s.p == nil) or (s.len+1 > s.p.cap and not strlitFlag): prepareAdd(s, 1) s.p.data[s.len] = c - s.p.data[s.len+1] = '\0' inc s.len + s.p.data[s.len] = '\0' proc toNimStr(str: cstring, len: int): NimStringV2 {.compilerproc.} = if len <= 0: result = NimStringV2(len: 0, p: nil) else: - var p = cast[ptr NimStrPayload](allocShared0(contentSize(len))) + var p = allocPayload(len) p.cap = len - if len > 0: - # we are about to append, so there is no need to copy the \0 terminator: - copyMem(unsafeAddr p.data[0], str, len) + copyMem(unsafeAddr p.data[0], str, len+1) result = NimStringV2(len: len, p: p) proc cstrToNimstr(str: cstring): NimStringV2 {.compilerRtl.} = @@ -75,7 +108,7 @@ proc cstrToNimstr(str: cstring): NimStringV2 {.compilerRtl.} = proc nimToCStringConv(s: NimStringV2): cstring {.compilerproc, nonReloadable, inline.} = if s.len == 0: result = cstring"" - else: result = cstring(unsafeAddr s.p.data) + else: result = cast[cstring](unsafeAddr s.p.data) proc appendString(dest: var NimStringV2; src: NimStringV2) {.compilerproc, inline.} = if src.len > 0: @@ -85,23 +118,24 @@ proc appendString(dest: var NimStringV2; src: NimStringV2) {.compilerproc, inlin proc appendChar(dest: var NimStringV2; c: char) {.compilerproc, inline.} = dest.p.data[dest.len] = c - dest.p.data[dest.len+1] = '\0' inc dest.len + dest.p.data[dest.len] = '\0' proc rawNewString(space: int): NimStringV2 {.compilerproc.} = # this is also 'system.newStringOfCap'. if space <= 0: result = NimStringV2(len: 0, p: nil) else: - var p = cast[ptr NimStrPayload](allocShared0(contentSize(space))) + var p = allocPayload(space) p.cap = space + p.data[0] = '\0' result = NimStringV2(len: 0, p: p) proc mnewString(len: int): NimStringV2 {.compilerproc.} = if len <= 0: result = NimStringV2(len: 0, p: nil) else: - var p = cast[ptr NimStrPayload](allocShared0(contentSize(len))) + var p = allocPayload0(len) p.cap = len result = NimStringV2(len: len, p: p) @@ -109,13 +143,30 @@ proc setLengthStrV2(s: var NimStringV2, newLen: int) {.compilerRtl.} = if newLen == 0: discard "do not free the buffer here, pattern 's.setLen 0' is common for avoiding allocations" else: - if newLen > s.len or isLiteral(s): - prepareAdd(s, newLen - s.len) + if isLiteral(s): + let oldP = s.p + s.p = allocPayload(newLen) + s.p.cap = newLen + if s.len > 0: + copyMem(unsafeAddr s.p.data[0], unsafeAddr oldP.data[0], min(s.len, newLen)) + if newLen > s.len: + zeroMem(cast[pointer](addr s.p.data[s.len]), newLen - s.len + 1) + else: + s.p.data[newLen] = '\0' + else: + zeroMem(cast[pointer](addr s.p.data[0]), newLen + 1) + elif newLen > s.len: + let oldCap = s.p.cap and not strlitFlag + if newLen > oldCap: + let newCap = max(newLen, resize(oldCap)) + s.p = reallocPayload0(s.p, oldCap, newCap) + s.p.cap = newCap + s.p.data[newLen] = '\0' s.len = newLen proc nimAsgnStrV2(a: var NimStringV2, b: NimStringV2) {.compilerRtl.} = - if a.p == b.p: return + if a.p == b.p and a.len == b.len: return if isLiteral(b): # we can shallow copy literals: frees(a) @@ -127,15 +178,47 @@ proc nimAsgnStrV2(a: var NimStringV2, b: NimStringV2) {.compilerRtl.} = # 'let y = newStringOfCap(); var x = y' # on the other hand... These get turned into moves now. frees(a) - a.p = cast[ptr NimStrPayload](allocShared0(contentSize(b.len))) + a.p = allocPayload(b.len) a.p.cap = b.len a.len = b.len copyMem(unsafeAddr a.p.data[0], unsafeAddr b.p.data[0], b.len+1) -proc nimPrepareStrMutationV2(s: var NimStringV2) {.compilerRtl.} = +proc nimPrepareStrMutationImpl(s: var NimStringV2) = + let oldP = s.p + # can't mutate a literal, so we need a fresh copy here: + s.p = allocPayload(s.len) + s.p.cap = s.len + copyMem(unsafeAddr s.p.data[0], unsafeAddr oldP.data[0], s.len+1) + +proc nimPrepareStrMutationV2(s: var NimStringV2) {.compilerRtl, inl.} = if s.p != nil and (s.p.cap and strlitFlag) == strlitFlag: - let oldP = s.p - # can't mutate a literal, so we need a fresh copy here: - s.p = cast[ptr NimStrPayload](allocShared0(contentSize(s.len))) - s.p.cap = s.len - copyMem(unsafeAddr s.p.data[0], unsafeAddr oldP.data[0], s.len+1) + nimPrepareStrMutationImpl(s) + +proc prepareMutation*(s: var string) {.inline.} = + # string literals are "copy on write", so you need to call + # `prepareMutation` before modifying the strings via `addr`. + {.cast(noSideEffect).}: + let s = unsafeAddr s + nimPrepareStrMutationV2(cast[ptr NimStringV2](s)[]) + +proc nimAddStrV1(s: var NimStringV2; src: NimStringV2) {.compilerRtl, inl.} = + #if (s.p == nil) or (s.len+1 > s.p.cap and not strlitFlag): + prepareAdd(s, src.len) + appendString s, src + +proc nimDestroyStrV1(s: NimStringV2) {.compilerRtl, inl.} = + frees(s) + +proc nimStrAtLe(s: string; idx: int; ch: char): bool {.compilerRtl, inl.} = + result = idx < s.len and s[idx] <= ch + +func capacity*(self: string): int {.inline.} = + ## Returns the current capacity of the string. + # See https://github.com/nim-lang/RFCs/issues/460 + runnableExamples: + var str = newStringOfCap(cap = 42) + str.add "Nim" + assert str.capacity == 42 + + let str = cast[ptr NimStringV2](unsafeAddr self) + result = if str.p != nil: str.p.cap and not strlitFlag else: 0 |