COPYPP

support field copy in different c++ data type.

• COPYPP
  • Required
  • Usage
    • struct/class
    • json string
    • array copy
    • stl support
  • Integration
    • copy the single header file
    • cmake
    • vcpkg
    • conan
  • License

Required

c++20

Usage

• COPYPP_FIELDS_NON_INTRUSIVE(destination, source, field1, field2, ...) is to be defined inside the namespace of the class/struct to create code for.
• COPYPP_FIELDS_INTRUSIVE(field1, field2, field3, ...) is to be defined outside the namespace of class/struct to create code for. This macro can also access private members.
• copy between json string and struct
• support array copy

include the header file

#include <icurve/copypp.hh>

struct/class

COPYPP_FIELDS_NON_INTRUSIVE defination the need to copy class

class A {
public:
    int id;
    std::string name;
    bool sex;

public:
    A() = default;
    A(int id, std::string name, bool sex) : id(id), name(name), sex(sex) {}
};

class B {
public:
    int id;
    std::string name;
    bool sex;

public:
    B() = default;
    B(int id, std::string name, bool sex) : id(id), name(name), sex(sex) {}
};

add the fields

// need to copy fields from A to B
COPYPP_FIELDS_NON_INTRUSIVE(B, A, id, name, sex)

// declare variables
A a(1, "curve", true);
B b;
// copy a.{fields} the b
icurve::copy(b, a);

COPYPP_FIELDS_INTRUSIVE:

defination the class

class AA {
private:
    int id;
    std::string name;
    bool sex;

public:
    AA() = default;
    AA(int id, std::string name, bool sex) : id(id), name(name), sex(sex) {}
public:
    COPYPP_FIELDS_INTRUSIVE(AA, id, name, sex)
};
class BB {
private:
    int id;
    std::string name;
    bool sex;

public:
    BB() = default;
    BB(int id, std::string name, bool sex) : id(id), name(name), sex(sex) {}
public:
    COPYPP_FIELDS_INTRUSIVE(BB, id, name, sex)
};

AA a(10, "curve", true);
BB b;
icurve::copy(b, a);

json string

copypp support copy between json's string and struct, this copy depency nlohmann-json library, so you need

1. install the nlohmann-json lib
2. add #include <nlohmann-json> before the copypp header #include <icurve/copypp.hh> file
3. use COPYPP_FIELDS_INTRUSIVE defination method

#include <nlohmann/json.hpp>
#include "copypp_only.h"

void func() {
    BB b;
    std::string s = R"({"id":5,"name":"i-curve", "age": 25})";
    icurve::copy(b, s); // copy from string to struct
    icurve::copy(s, b); // copy from struct to string
}

array copy

c style array, you need to delivery the array message

AA a[3];
BB b[2] = {BB(1, "first", true), BB(2, "second", false)};
icurve::copy<AA, 3, BB, 2>(a, b);

c++ style array

std::array<AA,3> a;
std::array<BB, 2> b = {BB(1, "first", true), BB(2, "second", false)};
icurve::copy(a, b);

stl support

copypp support stl copy, condition:

1. the source has forward end iterator(begin, end)
2. the destiontion has forward iterator(begin, and)
3. if the destination has back_insert_iterator, copypp will copy the all source item. Otherwise, it only copy the minimum length between source and destination

copypp can copy it, even in a different stl type.

AA a[3];
BB b[2] = {BB(1, "first", true), BB(2, "second", false)};
std::span<AA> aa(a);
std::span<BB> bb(b);
icurve::copy(aa, bb);

If it's vector, you can directly use it.

vector<AA> a;
vector<BB> b = {BB(1, "first", true), BB(2, "second", false)};
icurve::copy(a, b);

different stl type

if the destionation can append item, it will clear destionation and append new item.

std::vector<AA> a = {AA(1, "first", true), AA(2, "second", false)};
std::list<BB> b; // copy all items
icurve::copy(b, a);

std::vector<AA> a = {AA(1, "first", true), AA(2, "second", false)};
std::array<BB, 1> b;
std::array<BB, 3> c;
icurve::copy(b, a); // will copy 1 item(min(a.size(), b.size())
icurve::copy(c, a); // will copy 2 items(min(a.size(), c.size()))

Integration

---

copy the single header file

copypp_only.hh is the single required file in include/icurve or released here. You need to copy to your include directories. then use it by

#include <copypp_only.hh>

using copy = icurve::copy;

cmake

clone the project and build.

git clone https://github.com/i-curve/copypp.git
cd copypp && mkdir build && cd build
# build and shut the test.if you open the test, you must install the fmt package.
cmake -DCOPYPP_TEST=OFF .
make

install

make install

vcpkg

if you use the vcpkg, you can install it by

vcpkg install copypp

conan

conanfile.txt

[requires]
copypp/[version]

License

---

{copypp} is distributed under the MIT License.