memgraph/include/utils/iterator/map.hpp
Kruno Tomola Fabro 5a42e15c4a Alpha version of label indexes.
Squashed messages from 9 commits:

9.
Properties now uses PropertyFamily and contained classes.
Fetching,seting,clearing properties can be done with PropertyFamilyKey or PropertyTypeKey.
Hierarchy of newly added clases is:
Vertices -n-> PropertyFamily {name: String} <-1-n-> PropertyType {type: Property::Flags}
Edges -n-> PropertyFamily {name: String} <-1-n-> PropertyType {type: Property::Flags}

PropertyFamilyKey -> PropertyType
PropertyTypeKey -> PropertyType

PropertyType t0,t1;
let t0!=t1 be true
let t0.family==t1.family be true

then next is true
PropertyTypeKey{&t0}!=PropertyTypeKey{&t1}
PropertyFamilyKey{&t0}==PropertyFamilyKey{&t1}
PropertyFamilyKey{&t0}==PropertyTypeKey{&t1}
PropertyTypeKey{&t0}==PropertyFamilyKey{&t1}

8.
Intermedate commit.
Noticed that integration queries throw SEGFAULT.

7.
Defined interface for indexes.
Fixed three memory leaks.
Fixed integration_queries test which now passes.

6.
Commit which return Xorshift128plus to valid shape.

5.
Tmp commit.

4.
Label Index is compiling.

3.
tmp

2.
Vertex::Accessor now updates Label index.

1.
Applied changes for code review.
2016-08-18 15:34:36 +01:00

49 lines
1.2 KiB
C++

#pragma once
#include "utils/iterator/iterator_base.hpp"
#include "utils/option.hpp"
namespace iter
{
// Class which maps values returned by I iterator into value of type T with OP
// function.
// T - type of return value
// I - iterator type
// OP - type of mapper function
template <class T, class I, class OP>
class Map : public IteratorBase<T>
{
public:
Map() = delete;
// Map operation is designed to be used in chained calls which operate on a
// iterator. Map will in that usecase receive other iterator by value and
// std::move is a optimization for it.
Map(I &&iter, OP &&op) : iter(std::move(iter)), op(std::move(op)) {}
Option<T> next() final
{
auto item = iter.next();
if (item.is_present()) {
return Option<T>(op(item.take()));
} else {
return Option<T>();
}
}
private:
I iter;
OP op;
};
template <class I, class OP>
auto make_map(I &&iter, OP &&op)
{
// Compiler cant deduce type T. decltype is here to help with it.
return Map<decltype(op(iter.next().take())), I, OP>(std::move(iter),
std::move(op));
}
}