pysequence.h

Go to the documentation of this file.

/** @file
 *  @author Bram de Greve (bram@cocamware.com)
 *  @author Tom De Muer (tom@cocamware.com)
 *
 *  *** BEGIN LICENSE INFORMATION ***
 *  
 *  The contents of this file are subject to the Common Public Attribution License 
 *  Version 1.0 (the "License"); you may not use this file except in compliance with 
 *  the License. You may obtain a copy of the License at 
 *  http://lass.sourceforge.net/cpal-license. The License is based on the 
 *  Mozilla Public License Version 1.1 but Sections 14 and 15 have been added to cover 
 *  use of software over a computer network and provide for limited attribution for 
 *  the Original Developer. In addition, Exhibit A has been modified to be consistent 
 *  with Exhibit B.
 *  
 *  Software distributed under the License is distributed on an "AS IS" basis, WITHOUT 
 *  WARRANTY OF ANY KIND, either express or implied. See the License for the specific 
 *  language governing rights and limitations under the License.
 *  
 *  The Original Code is LASS - Library of Assembled Shared Sources.
 *  
 *  The Initial Developer of the Original Code is Bram de Greve and Tom De Muer.
 *  The Original Developer is the Initial Developer.
 *  
 *  All portions of the code written by the Initial Developer are:
 *  Copyright (C) 2004-2025 the Initial Developer.
 *  All Rights Reserved.
 *  
 *  Contributor(s):
 *
 *  Alternatively, the contents of this file may be used under the terms of the 
 *  GNU General Public License Version 2 or later (the GPL), in which case the 
 *  provisions of GPL are applicable instead of those above.  If you wish to allow use
 *  of your version of this file only under the terms of the GPL and not to allow 
 *  others to use your version of this file under the CPAL, indicate your decision by 
 *  deleting the provisions above and replace them with the notice and other 
 *  provisions required by the GPL License. If you do not delete the provisions above,
 *  a recipient may use your version of this file under either the CPAL or the GPL.
 *  
 *  *** END LICENSE INFORMATION ***
 */
 
#ifndef LASS_GUARDIAN_OF_INCLUSION_UTIL_PYSEQUENCE_H
#define LASS_GUARDIAN_OF_INCLUSION_UTIL_PYSEQUENCE_H
 
#include "python_common.h"
#include "pyshadow_object.h"
#include "shadowee_traits.h"
#include "exception.h"
#include "container.h"
#include "argument_traits.h"
#include "../util/string_cast.h"
#include "../stde/extended_algorithm.h"
 
#include <vector>
#include <list>
#include <deque>
 
namespace lass
{
namespace python
{
namespace impl
{
    class LASS_PYTHON_DLL PySequenceImplBase: public ContainerImplBase
    {
    public:
        typedef std::unique_ptr<PySequenceImplBase> TPimpl; 
        virtual TPimpl copy() const = 0;
        virtual bool reserve(Py_ssize_t n) = 0;
        virtual bool append(const TPyObjPtr& i) = 0;
        virtual bool pop(Py_ssize_t i) = 0;
        virtual PyObject* item(Py_ssize_t i) const = 0;
        virtual PyObject* slice(Py_ssize_t low, Py_ssize_t high, Py_ssize_t step) const = 0;
        virtual int assItem(Py_ssize_t i, PyObject* obj) = 0;
        virtual int assSlice(Py_ssize_t low, Py_ssize_t high, Py_ssize_t step, PyObject* obj) = 0;
        virtual int contains(PyObject* obj) const = 0;
        virtual bool inplaceConcat(PyObject* obj) = 0;
        virtual bool inplaceRepeat(Py_ssize_t n) = 0;
    };
 
    template<typename Container> 
    class PySequenceContainer: public ContainerImpl<Container, PySequenceImplBase>
    {
    public:
        typedef ContainerImpl<Container, PySequenceImplBase> TBase;
        typedef typename TBase::TContainerPtr TContainerPtr;
        typedef typename TBase::TConstContainerPtr TConstContainerPtr;
        typedef typename TBase::TContainerTraits TContainerTraits;
        typedef typename TContainerTraits::iterator TIterator;
        typedef typename TContainerTraits::const_iterator TConstIterator;
        typedef ArgumentTraits<typename TContainerTraits::value_type> TArgTraits;
        typedef PySequenceImplBase::TPimpl TPimpl;
 
        PySequenceContainer(const TContainerPtr& container, bool readOnly = false): 
            TBase(container, readOnly)
        {
        }
        ~PySequenceContainer() 
        {
        }
        const TPyObjPtr asNative() const override
        {
            return pyBuildList(this->begin(), this->next(this->begin(), this->length()));
        }
        TPimpl copy() const override
        {
            TContainerPtr copy = TContainerTraits::copy(this->container());
            return TPimpl(new PySequenceContainer(copy));
        }
        bool reserve(Py_ssize_t n) override
        {
            if (!this->checkWritable())
            {
                return false;
            }
            TContainerTraits::reserve(this->container(), n);
            return true;
        }
        bool append(const TPyObjPtr& obj) override
        {
            if (!this->checkWritable())
            {
                return false;
            }
            typename TArgTraits::TStorage value;
            if (pyGetSimpleObject(obj.get(), value) != 0)
            {
                return false;
            }
            TIterator end = this->next(this->begin(), this->length());
            TContainerTraits::insert(this->container(), end, TArgTraits::arg(value));
            return true;
        }
        bool pop(Py_ssize_t i) override
        {
            if (!this->checkWritable())
            {
                return false;
            }
            if (!this->checkIndex(i))
            {
                return false;
            }
            TContainerTraits::erase(this->container(), this->next(this->begin(), i), this->next(this->begin(), i + 1));
            return true;
        }
        PyObject* item(Py_ssize_t i) const override
        {
            if (!this->checkIndex(i))
            {
                return 0;
            }
            return pyBuildSimpleObject(*this->next(this->begin(), i));
        }
        PyObject* slice(Py_ssize_t low, Py_ssize_t high, Py_ssize_t step) const override
        {
            const Py_ssize_t size = this->length();
            low = num::clamp(low, Py_ssize_t(0), size);
            high = num::clamp(high, low, size);
            step = std::max(step, Py_ssize_t(1));
            const Py_ssize_t n = (high - low + step - 1) / step;
            TPyObjPtr s(PyList_New(n));
            TConstIterator first = this->next(this->begin(), low);
            for (Py_ssize_t i = 0; i < n; ++i)
            {
                if (i > 0)
                {
                    // this odd place of advancing is to avoid stepping beyond end
                    std::advance(first, step);
                }
                PyList_SET_ITEM(s.get(), i, pyBuildSimpleObject(*first));
            }
            return fromSharedPtrToNakedCast(s);
        }
        int assItem(Py_ssize_t i, PyObject* obj) override
        {
            if (!this->checkWritable() || !this->checkIndex(i))
            {
                return -1;
            }
            if (obj == 0)
            {
                return assSlice(i, i + 1, 1, 0);
            }
            if (pyGetSimpleObject(obj, *this->next(this->begin(), i)) != 0)
            {
                return -1;
            }
            return 0;
        }
        int assSlice(Py_ssize_t low, Py_ssize_t high, Py_ssize_t step, PyObject* other) override
        {
            if (!this->checkWritable())
            {
                return -1;
            }
            const Py_ssize_t size = this->length();
            low = num::clamp(low, Py_ssize_t(0), size);
            high = num::clamp(high, low, size);
            step = std::max(step, Py_ssize_t(1));
            TConstContainerPtr b;
            if (other)
            {
                if (pyGetSimpleObject(other, b) != 0)
                {
                    return -1;
                }
                if (&this->container() == b.get())
                {
                    b = TContainerTraits::copy(*b);
                }
            }
            if (step == 1)
            {
                const TIterator first = this->next(this->begin(), low);
                const TIterator last = this->next(first, high - low);
                TContainerTraits::erase(this->container(), first, last);
                if (b)
                {
                    const TConstIterator bFirst = TContainerTraits::begin(*b);
                    const TConstIterator bLast = this->next(bFirst, TContainerTraits::size(*b));
                    TContainerTraits::insert(this->container(), this->next(this->begin(), low), bFirst, bLast);
                }
            }
            else
            {
                if (b)
                {
                    const Py_ssize_t sliceLength = (high - low + step - 1) / step;
                    const Py_ssize_t bLength = TContainerTraits::size(*b);
                    if (sliceLength != bLength)
                    {
                        std::ostringstream buffer;
                        buffer << "cannot assign sequence of length " << bLength << " to an extended slice of length " << sliceLength;
                        PyErr_SetString(PyExc_ValueError, buffer.str().c_str());
                        return -1;
                    }
                    TIterator left = this->next(this->begin(), low);
                    TConstIterator right = TContainerTraits::begin(*b);
                    while (low < high)
                    {
                        *left = *right++;
                        low += step;
                        if (low < high) // make sure you don't step beyond end
                        {
                            left = this->next(left, step);
                        }
                    }
                }
                else
                {
                    while (low < high)
                    {
                        TContainerTraits::erase(this->container(), this->next(this->begin(), low));
                        low += step - 1;
                        --high;
                    }
                }
            }
            return 0;
        }
        int contains(PyObject* obj) const override
        {
            typename TArgTraits::TStorage value;
            if (pyGetSimpleObject(obj, value) != 0)
            {
                if (PyErr_ExceptionMatches(PyExc_TypeError))
                {
                    // type is not convertible and hence is not found
                    // this corresponds to the Python behavior
                    PyErr_Clear();
                    return 0;
                }
                return -1;
            }
            TConstIterator end = this->next(this->begin(), this->length());
            if (std::find(this->begin(), end, TArgTraits::arg(value)) != end)
            {
                return 1;
            }
            return 0;
        }
        bool inplaceConcat(PyObject* other) override
        {
            if (!this->checkWritable())
            {
                return false;
            }
            TConstContainerPtr b;
            if (pyGetSimpleObject(other, b) != 0)
            {
                return false;
            }
            if (&this->container() == b.get())
            {
                b = TContainerTraits::copy(*b);
            }
            const TIterator end = this->next(this->begin(), this->length());
            const TConstIterator first = TContainerTraits::begin(*b);
            const TConstIterator last = this->next(first, TContainerTraits::size(*b));
            TContainerTraits::insert(this->container(), end, first, last);
            return true;
        }
        bool inplaceRepeat(Py_ssize_t n) override
        {
            if (!this->checkWritable())
            {
                return false;
            }
            TContainerTraits::inplace_repeat(this->container(),n);
            return true;
        }
    private:
        bool checkIndex(Py_ssize_t& i) const
        {
            const Py_ssize_t size = this->length();
            if (i < 0 || i >= size) 
            {
                PyErr_SetString(PyExc_IndexError,"list assignment index out of range");
                return false;
            }
            return true;
        }
    };
 
    class Sequence;
    typedef PyObjectPtr<Sequence>::Type TSequencePtr;
 
    /** Object for interfacing sequence-like objects with Python 
    */
    class LASS_PYTHON_DLL Sequence : public PyObjectPlus, util::NonCopyable
    {
        PY_HEADER(PyObjectPlus)
 
    public:
        template<typename Container> Sequence( const util::SharedPtr<Container>& container )
        {
            TPimpl pimpl(new PySequenceContainer<Container>(
                LASS_ENFORCE_POINTER(container)));
            init(std::move(pimpl));
        }
        template<typename Container> Sequence( const util::SharedPtr<const Container>& container ) 
        {
            TPimpl pimpl(new PySequenceContainer<Container>(
                LASS_ENFORCE_POINTER(container).template constCast<Container>(), true));
            init(std::move(pimpl));
        }
        template<typename Container> Sequence( const Container& container )
        {
            util::SharedPtr<Container> p(ContainerTraits<Container>::copy(container));
            TPimpl pimpl(new PySequenceContainer<Container>(p, true));
            init(std::move(pimpl));
        }
 
        const TSequencePtr copy() const;
        void clear();
        void reserve(Py_ssize_t n);
        void append(const TPyObjPtr& obj);
        const TPyObjPtr pop(Py_ssize_t i);
        const TPyObjPtr pop_back();
        const TPyObjPtr asList() const;
        const TPyObjPtr iter() const;
        std::string repr() const;
 
        const std::type_info& type() const;
        void* raw(bool writable) const;
 
        static Py_ssize_t length(PyObject* self);
        static PyObject* concat(PyObject* self, PyObject* other);
        static PyObject* repeat(PyObject* self, Py_ssize_t n);
        static PyObject* item(PyObject* self, Py_ssize_t i);
        static int assItem(PyObject* self, Py_ssize_t i, PyObject* obj);
        static int contains(PyObject* a, PyObject* obj);
        static PyObject* inplaceConcat(PyObject* self, PyObject* other);
        static PyObject* inplaceRepeat(PyObject* self, Py_ssize_t n);
        static PyObject* subscript(PyObject* self, PyObject* key);
        static int assSubscript(PyObject* self, PyObject* key, PyObject* value);
 
    private:
        typedef PySequenceImplBase::TPimpl TPimpl;
 
        Sequence(TPimpl&& pimpl);
        void init(TPimpl&& pimpl);
 
        TPimpl pimpl_;
    };
 
    template <>
    struct ShadowTraits<Sequence>: public ShadowTraitsContainer< Sequence, ShadowTraits<Sequence> >
    {
        template <typename Container> static int getObjectImpl(PyObject* obj, util::SharedPtr<Container>& value, bool writable)
        {
            if (!PySequence_Check(obj))
            {
                PyErr_SetString(PyExc_TypeError, "not a sequence");
                return 1;
            }
 
            // check if we have our own Sequence object, then take a shortcut
            if (obj->ob_type == Sequence::_lassPyClassDef.type())
            {
                const Sequence* const sequence = static_cast<Sequence*>(obj);
                void* const raw = sequence->raw(writable);
                if (raw && typeid(value) == sequence->type())
                {
                    value = *static_cast< util::SharedPtr<Container>* >(raw);
                    return 0;
                }
            }
 
            const util::SharedPtr<Container> result(new Container);
            const Py_ssize_t size = PySequence_Length(obj);
            ContainerTraits<Container>::reserve(*result, size);
            typedef ArgumentTraits<typename Container::value_type> TArgTraits;
            for (Py_ssize_t i = 0; i < size; ++i)
            {
                typename TArgTraits::TStorage temp;
                TPyObjPtr item( PySequence_ITEM(obj, i) );
                if (pyGetSimpleObject( item.get() , temp ) != 0)
                {
                    std::ostringstream buffer;
                    buffer << "sequence element " << i;
                    impl::addMessageHeader(buffer.str().c_str());
                    return 1;
                }
                result->emplace_back(TArgTraits::arg(temp));
            }
            value = std::move(result);
            return 0;
        }
    };
}
 
template <typename ContainerType>
struct ShadoweeTraitsSequence: meta::True
{
    typedef impl::Sequence TShadow;
    typedef impl::ShadowTraits<impl::Sequence> TShadowTraits;
    typedef SharedPointerTraits<ContainerType> TPointerTraits;
};
 
/** @ingroup Python
 *  @internal
 */
template< typename C, typename A>
struct ShadoweeTraits< std::vector< C, A > >:
    public ShadoweeTraitsSequence< std::vector< C, A > >
{
};
 
/** @ingroup Python
 *  @internal
 */
template< typename C, typename A>
struct ShadoweeTraits< std::list< C, A > >:
    public ShadoweeTraitsSequence< std::list< C, A > >
{
};
 
/** @ingroup Python
 *  @internal
 */
template< typename C, typename A>
struct ShadoweeTraits< std::deque< C, A > >:
    public ShadoweeTraitsSequence< std::deque< C, A > >
{
};
 
}
}
 
#endif
 
#ifdef LASS_GUARDIAN_OF_INCLUSION_STDE_STATIC_VECTOR_H
 
namespace lass
{
namespace python
{
/** @ingroup Python
 *  @internal
 */
template< typename C, size_t maxsize>
struct ShadoweeTraits< stde::static_vector< C, maxsize > >:
    public ShadoweeTraitsSequence< stde::static_vector< C, maxsize > >
{
};
}
}
 
#endif
 
// EOF