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Add low-overhead InPlaceAppender (#8789)
- Internal for now. - Previously known as `FixedAppender` (during development). Co-authored-by: Elias Batek <0xEAB@users.noreply.github.com>
This commit is contained in:
John Colvin
GitHub
parent
1b242048c9
commit
bea3184479
1 changed files with 290 additions and 97 deletions
379
std/array.d
379
std/array.d
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@ -3571,18 +3571,11 @@ See_Also: $(LREF appender)
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struct Appender(A)
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if (isDynamicArray!A)
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{
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import core.memory : GC;
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import std.format.spec : FormatSpec;
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private alias T = ElementEncodingType!A;
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private struct Data
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{
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size_t capacity;
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Unqual!T[] arr;
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bool tryExtendBlock = false;
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}
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private Data* _data;
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InPlaceAppender!A* impl;
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/**
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* Constructs an `Appender` with a given array. Note that this does not copy the
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@ -3590,27 +3583,17 @@ if (isDynamicArray!A)
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* it will be used by the appender. After initializing an appender on an array,
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* appending to the original array will reallocate.
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*/
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this(A arr) @trusted
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this(A arr) @safe
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{
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// initialize to a given array.
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_data = new Data;
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_data.arr = cast(Unqual!T[]) arr; //trusted
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if (__ctfe)
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return;
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// We want to use up as much of the block the array is in as possible.
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// if we consume all the block that we can, then array appending is
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// safe WRT built-in append, and we can use the entire block.
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// We only do this for mutable types that can be extended.
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static if (isMutable!T && is(typeof(arr.length = size_t.max)))
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{
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immutable cap = arr.capacity; //trusted
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// Replace with "GC.setAttr( Not Appendable )" once pure (and fixed)
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if (cap > arr.length)
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arr.length = cap;
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impl = new InPlaceAppender!A(arr);
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}
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private void ensureInit() @safe
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{
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if (impl is null)
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{
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impl = new InPlaceAppender!A;
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}
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_data.capacity = arr.length;
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}
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/**
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@ -3623,14 +3606,10 @@ if (isDynamicArray!A)
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*/
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void reserve(size_t newCapacity)
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{
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if (_data)
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if (newCapacity != 0)
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{
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if (newCapacity > _data.capacity)
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ensureAddable(newCapacity - _data.arr.length);
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}
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else
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{
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ensureAddable(newCapacity);
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ensureInit();
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impl.reserve(newCapacity);
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}
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}
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@ -3641,11 +3620,11 @@ if (isDynamicArray!A)
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*/
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@property size_t capacity() const
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{
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return _data ? _data.capacity : 0;
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return impl ? impl.capacity : 0;
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}
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/// Returns: The number of elements appended.
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@property size_t length() const => _data ? _data.arr.length : 0;
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@property size_t length() const => (impl is null) ? 0 : impl.length;
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/**
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* Use opSlice() from now on.
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@ -3653,29 +3632,219 @@ if (isDynamicArray!A)
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*/
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@property inout(T)[] data() inout
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{
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return this[];
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return opSlice();
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}
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/**
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* Returns: The managed array.
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*/
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@property inout(T)[] opSlice() inout @trusted
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@property inout(T)[] opSlice() inout @safe
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{
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return impl ? impl.opSlice() : null;
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}
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/**
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* Appends `item` to the managed array. Performs encoding for
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* `char` types if `A` is a differently typed `char` array.
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*
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* Params:
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* item = the single item to append
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*/
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void put(U)(U item)
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if (InPlaceAppender!A.canPutItem!U)
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{
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ensureInit();
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impl.put(item);
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}
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// Const fixing hack.
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void put(Range)(Range items)
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if (InPlaceAppender!A.canPutConstRange!Range)
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{
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if (!items.empty)
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{
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ensureInit();
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impl.put(items);
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}
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}
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/**
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* Appends an entire range to the managed array. Performs encoding for
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* `char` elements if `A` is a differently typed `char` array.
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*
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* Params:
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* items = the range of items to append
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*/
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void put(Range)(Range items)
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if (InPlaceAppender!A.canPutRange!Range)
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{
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if (!items.empty)
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{
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ensureInit();
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impl.put(items);
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}
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}
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/**
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* Appends to the managed array.
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*
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* See_Also: $(LREF Appender.put)
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*/
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alias opOpAssign(string op : "~") = put;
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// only allow overwriting data on non-immutable and non-const data
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static if (isMutable!T)
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{
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/**
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* Clears the managed array. This allows the elements of the array to be reused
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* for appending.
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*
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* Note: clear is disabled for immutable or const element types, due to the
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* possibility that `Appender` might overwrite immutable data.
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*/
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void clear() @safe pure nothrow
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{
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if (impl)
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{
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impl.clear();
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}
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}
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/**
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* Shrinks the managed array to the given length.
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*
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* Throws: `Exception` if newlength is greater than the current array length.
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* Note: shrinkTo is disabled for immutable or const element types.
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*/
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void shrinkTo(size_t newlength) @safe pure
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{
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import std.exception : enforce;
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if (impl)
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{
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impl.shrinkTo(newlength);
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}
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else
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{
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enforce(newlength == 0, "Attempting to shrink empty Appender with non-zero newlength");
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}
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}
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}
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/**
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* Gives a string in the form of `Appender!(A)(data)`.
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*
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* Params:
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* w = A `char` accepting
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* $(REF_ALTTEXT output range, isOutputRange, std, range, primitives).
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* fmt = A $(REF FormatSpec, std, format) which controls how the array
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* is formatted.
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* Returns:
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* A `string` if `writer` is not set; `void` otherwise.
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*/
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string toString()() const
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{
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return InPlaceAppender!A.toStringImpl(Unqual!(typeof(this)).stringof, impl ? impl.data : null);
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}
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/// ditto
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template toString(Writer)
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if (isOutputRange!(Writer, char))
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{
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void toString(scope ref Writer w, scope const ref FormatSpec!char fmt) const
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{
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InPlaceAppender!A.toStringImpl(Unqual!(typeof(this)).stringof, impl ? impl.data : null, w, fmt);
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}
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}
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}
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///
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@safe pure nothrow unittest
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{
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auto app = appender!string();
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string b = "abcdefg";
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foreach (char c; b)
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app.put(c);
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assert(app[] == "abcdefg");
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int[] a = [ 1, 2 ];
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auto app2 = appender(a);
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app2.put(3);
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app2.put([ 4, 5, 6 ]);
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assert(app2[] == [ 1, 2, 3, 4, 5, 6 ]);
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}
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package(std) struct InPlaceAppender(A)
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if (isDynamicArray!A)
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{
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import core.memory : GC;
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import std.format.spec : FormatSpec;
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private alias T = ElementEncodingType!A;
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private
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{
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size_t _capacity;
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Unqual!T[] arr;
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bool tryExtendBlock = false;
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}
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@disable this(ref InPlaceAppender);
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this(A arrIn) @trusted
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{
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arr = cast(Unqual!T[]) arrIn; //trusted
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if (__ctfe)
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return;
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// We want to use up as much of the block the array is in as possible.
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// if we consume all the block that we can, then array appending is
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// safe WRT built-in append, and we can use the entire block.
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// We only do this for mutable types that can be extended.
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static if (isMutable!T && is(typeof(arrIn.length = size_t.max)))
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{
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immutable cap = arrIn.capacity; //trusted
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// Replace with "GC.setAttr( Not Appendable )" once pure (and fixed)
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if (cap > arrIn.length)
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arrIn.length = cap;
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}
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_capacity = arrIn.length;
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}
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void reserve(size_t newCapacity)
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{
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if (newCapacity > _capacity)
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ensureAddable(newCapacity - arr.length);
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}
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@property size_t capacity() const
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{
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return _capacity;
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}
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@property size_t length() const => arr.length;
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@property inout(T)[] data() inout
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{
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return this[];
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}
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inout(T)[] opSlice() inout @trusted
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{
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/* @trusted operation:
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* casting Unqual!T[] to inout(T)[]
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*/
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return cast(typeof(return))(_data ? _data.arr : null);
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return cast(typeof(return)) arr;
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}
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// ensure we can add nelems elements, resizing as necessary
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private void ensureAddable(size_t nelems)
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{
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if (!_data)
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_data = new Data;
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immutable len = _data.arr.length;
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immutable len = arr.length;
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immutable reqlen = len + nelems;
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if (_data.capacity >= reqlen)
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if (_capacity >= reqlen)
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return;
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// need to increase capacity
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@ -3683,17 +3852,17 @@ if (isDynamicArray!A)
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{
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static if (__traits(compiles, new Unqual!T[1]))
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{
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_data.arr.length = reqlen;
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arr.length = reqlen;
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}
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else
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{
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// avoid restriction of @disable this()
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_data.arr = _data.arr[0 .. _data.capacity];
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foreach (i; _data.capacity .. reqlen)
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_data.arr ~= Unqual!T.init;
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arr = arr[0 .. _capacity];
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foreach (i; _capacity .. reqlen)
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arr ~= Unqual!T.init;
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}
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_data.arr = _data.arr[0 .. len];
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_data.capacity = reqlen;
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arr = arr[0 .. len];
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_capacity = reqlen;
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}
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else
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{
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@ -3701,11 +3870,11 @@ if (isDynamicArray!A)
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// Time to reallocate.
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// We need to almost duplicate what's in druntime, except we
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// have better access to the capacity field.
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auto newlen = appenderNewCapacity!(T.sizeof)(_data.capacity, reqlen);
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auto newlen = appenderNewCapacity!(T.sizeof)(_capacity, reqlen);
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// first, try extending the current block
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if (_data.tryExtendBlock)
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if (tryExtendBlock)
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{
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immutable u = (() @trusted => GC.extend(_data.arr.ptr, nelems * T.sizeof, (newlen - len) * T.sizeof))();
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immutable u = (() @trusted => GC.extend(arr.ptr, nelems * T.sizeof, (newlen - len) * T.sizeof))();
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if (u)
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{
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// extend worked, update the capacity
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@ -3714,11 +3883,10 @@ if (isDynamicArray!A)
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// at large unused blocks.
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static if (hasIndirections!T)
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{
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immutable addedSize = u - (_data.capacity * T.sizeof);
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() @trusted { memset(_data.arr.ptr + _data.capacity, 0, addedSize); }();
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immutable addedSize = u - (_capacity * T.sizeof);
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() @trusted { memset(arr.ptr + _capacity, 0, addedSize); }();
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}
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_data.capacity = u / T.sizeof;
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_capacity = u / T.sizeof;
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return;
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}
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}
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@ -3732,11 +3900,11 @@ if (isDynamicArray!A)
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~ "available pointer range");
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auto bi = (() @trusted => GC.qalloc(nbytes, blockAttribute!T))();
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_data.capacity = bi.size / T.sizeof;
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_capacity = bi.size / T.sizeof;
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import core.stdc.string : memcpy;
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if (len)
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() @trusted { memcpy(bi.base, _data.arr.ptr, len * T.sizeof); }();
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_data.arr = (() @trusted => (cast(Unqual!T*) bi.base)[0 .. len])();
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() @trusted { memcpy(bi.base, arr.ptr, len * T.sizeof); }();
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arr = (() @trusted => (cast(Unqual!T*) bi.base)[0 .. len])();
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// we requested new bytes that are not in the existing
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// data. If T has pointers, then this new data could point at stale
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@ -3747,7 +3915,7 @@ if (isDynamicArray!A)
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memset(bi.base + (len * T.sizeof), 0, (newlen - len) * T.sizeof);
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}();
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_data.tryExtendBlock = true;
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tryExtendBlock = true;
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// leave the old data, for safety reasons
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}
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}
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@ -3763,13 +3931,13 @@ if (isDynamicArray!A)
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enum bool canPutConstRange =
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isInputRange!(Unqual!Range) &&
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!isInputRange!Range &&
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is(typeof(Appender.init.put(Range.init.front)));
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is(typeof(InPlaceAppender.init.put(Range.init.front)));
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}
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private template canPutRange(Range)
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{
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enum bool canPutRange =
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isInputRange!Range &&
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is(typeof(Appender.init.put(Range.init.front)));
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is(typeof(InPlaceAppender.init.put(Range.init.front)));
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}
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/**
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@ -3798,13 +3966,13 @@ if (isDynamicArray!A)
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import core.lifetime : emplace;
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ensureAddable(1);
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immutable len = _data.arr.length;
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immutable len = arr.length;
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auto bigData = (() @trusted => _data.arr.ptr[0 .. len + 1])();
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auto bigData = (() @trusted => arr.ptr[0 .. len + 1])();
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auto itemUnqual = (() @trusted => & cast() item)();
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emplace(&bigData[len], *itemUnqual);
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//We do this at the end, in case of exceptions
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_data.arr = bigData;
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arr = bigData;
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}
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}
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@ -3848,16 +4016,16 @@ if (isDynamicArray!A)
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auto bigDataFun(size_t extra)
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{
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ensureAddable(extra);
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return (() @trusted => _data.arr.ptr[0 .. _data.arr.length + extra])();
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return (() @trusted => arr.ptr[0 .. arr.length + extra])();
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}
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auto bigData = bigDataFun(items.length);
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immutable len = _data.arr.length;
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immutable len = arr.length;
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immutable newlen = bigData.length;
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alias UT = Unqual!T;
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static if (is(typeof(_data.arr[] = items[])) &&
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static if (is(typeof(arr[] = items[])) &&
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!hasElaborateAssign!UT && isAssignable!(UT, ElementEncodingType!Range))
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{
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bigData[len .. newlen] = items[];
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@ -3873,7 +4041,7 @@ if (isDynamicArray!A)
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}
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//We do this at the end, in case of exceptions
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_data.arr = bigData;
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arr = bigData;
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}
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else static if (isSomeChar!T && isSomeChar!(ElementType!Range) &&
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!is(immutable T == immutable ElementType!Range))
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@ -3916,10 +4084,7 @@ if (isDynamicArray!A)
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*/
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void clear() @trusted pure nothrow
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{
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if (_data)
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{
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_data.arr = _data.arr.ptr[0 .. 0];
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}
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arr = arr.ptr[0 .. 0];
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}
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/**
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@ -3931,13 +4096,8 @@ if (isDynamicArray!A)
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void shrinkTo(size_t newlength) @trusted pure
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{
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import std.exception : enforce;
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if (_data)
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{
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enforce(newlength <= _data.arr.length, "Attempting to shrink Appender with newlength > length");
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_data.arr = _data.arr.ptr[0 .. newlength];
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}
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else
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enforce(newlength == 0, "Attempting to shrink empty Appender with non-zero newlength");
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enforce(newlength <= arr.length, "Attempting to shrink Appender with newlength > length");
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arr = arr.ptr[0 .. newlength];
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}
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}
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@ -3952,13 +4112,18 @@ if (isDynamicArray!A)
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* Returns:
|
||||
* A `string` if `writer` is not set; `void` otherwise.
|
||||
*/
|
||||
string toString()() const
|
||||
auto toString() const
|
||||
{
|
||||
return toStringImpl(Unqual!(typeof(this)).stringof, data);
|
||||
}
|
||||
|
||||
static auto toStringImpl(string typeName, const T[] arr)
|
||||
{
|
||||
import std.format.spec : singleSpec;
|
||||
|
||||
auto app = appender!string();
|
||||
InPlaceAppender!string app;
|
||||
auto spec = singleSpec("%s");
|
||||
immutable len = _data ? _data.arr.length : 0;
|
||||
immutable len = arr.length;
|
||||
// different reserve lengths because each element in a
|
||||
// non-string-like array uses two extra characters for `, `.
|
||||
static if (isSomeString!A)
|
||||
|
|
@ -3971,26 +4136,26 @@ if (isDynamicArray!A)
|
|||
// length, as it assumes each element is only one char
|
||||
app.reserve((len * 3) + 25);
|
||||
}
|
||||
toString(app, spec);
|
||||
toStringImpl(typeName, arr, app, spec);
|
||||
return app.data;
|
||||
}
|
||||
|
||||
import std.format.spec : FormatSpec;
|
||||
|
||||
/// ditto
|
||||
template toString(Writer)
|
||||
void toString(Writer)(scope ref Writer w, scope const ref FormatSpec!char fmt) const
|
||||
if (isOutputRange!(Writer, char))
|
||||
{
|
||||
void toString(ref Writer w, scope const ref FormatSpec!char fmt) const
|
||||
toStringImpl(Unqual!(typeof(this)).stringof, data, w, fmt);
|
||||
}
|
||||
|
||||
static void toStringImpl(Writer)(string typeName, const T[] data, scope ref Writer w,
|
||||
scope const ref FormatSpec!char fmt)
|
||||
{
|
||||
import std.format.write : formatValue;
|
||||
import std.range.primitives : put;
|
||||
put(w, Unqual!(typeof(this)).stringof);
|
||||
put(w, typeName);
|
||||
put(w, '(');
|
||||
formatValue(w, data, fmt);
|
||||
put(w, ')');
|
||||
}
|
||||
}
|
||||
}
|
||||
|
||||
///
|
||||
|
|
@ -4032,6 +4197,16 @@ if (isDynamicArray!A)
|
|||
assert(app3[] == "Appender!(int[])(0001, 0002, 0003)");
|
||||
}
|
||||
|
||||
@safe pure unittest
|
||||
{
|
||||
auto app = appender!(char[])();
|
||||
app ~= "hello";
|
||||
app.clear;
|
||||
// not a promise, just nothing else exercises capacity
|
||||
// and this is the expected sort of behaviour
|
||||
assert(app.capacity >= 5);
|
||||
}
|
||||
|
||||
// https://issues.dlang.org/show_bug.cgi?id=17251
|
||||
@safe pure nothrow unittest
|
||||
{
|
||||
|
|
@ -4294,6 +4469,24 @@ unittest
|
|||
assert(app2.capacity >= 5);
|
||||
}
|
||||
|
||||
/++
|
||||
Convenience function that returns a $(LREF InPlaceAppender) instance,
|
||||
optionally initialized with `array`.
|
||||
+/
|
||||
package(std) InPlaceAppender!A inPlaceAppender(A)()
|
||||
if (isDynamicArray!A)
|
||||
{
|
||||
return InPlaceAppender!A(null);
|
||||
}
|
||||
/// ditto
|
||||
package(std) InPlaceAppender!(E[]) inPlaceAppender(A : E[], E)(auto ref A array)
|
||||
{
|
||||
static assert(!isStaticArray!A || __traits(isRef, array),
|
||||
"Cannot create InPlaceAppender from an rvalue static array");
|
||||
|
||||
return InPlaceAppender!(E[])(array);
|
||||
}
|
||||
|
||||
/++
|
||||
Convenience function that returns an $(LREF Appender) instance,
|
||||
optionally initialized with `array`.
|
||||
|
|
|
|||
Loading…
Add table
Add a link
Reference in a new issue