ogrlayerarrow.h

/******************************************************************************
 *
 * Project:  OpenGIS Simple Features Reference Implementation
 * Purpose:  Parts of OGRLayer dealing with Arrow C interface
 * Author:   Even Rouault, <even dot rouault at spatialys.com>
 *
 ******************************************************************************
 * Copyright (c) 2023, Even Rouault <even dot rouault at spatialys.com>
 *
 * SPDX-License-Identifier: MIT
 ****************************************************************************/
 
#ifndef OGRLAYERARROW_H_DEFINED
#define OGRLAYERARROW_H_DEFINED
 
#include "cpl_port.h"
 
#include <map>
#include <string>
 
#include "ogr_recordbatch.h"
 
constexpr const char *ARROW_EXTENSION_NAME_KEY = "ARROW:extension:name";
constexpr const char *ARROW_EXTENSION_METADATA_KEY = "ARROW:extension:metadata";
constexpr const char *EXTENSION_NAME_OGC_WKB = "ogc.wkb";
constexpr const char *EXTENSION_NAME_GEOARROW_WKB = "geoarrow.wkb";
 
// Cf https://github.com/apache/arrow/blob/main/docs/source/format/CanonicalExtensions.rst#json
constexpr const char *EXTENSION_NAME_ARROW_JSON = "arrow.json";
 
// Cf https://github.com/apache/arrow/blob/main/docs/source/format/CanonicalExtensions.rst#timestamp-with-offset
constexpr const char *EXTENSION_NAME_ARROW_TIMESTAMP_WITH_OFFSET =
    "arrow.timestamp_with_offset";
// ATSWO = Arrow TimeStamp With Offset
constexpr const char *ATSWO_TIMESTAMP_FIELD_NAME = "timestamp";
constexpr const char *ATSWO_OFFSET_MINUTES_FIELD_NAME = "offset_minutes";
 
// GetArrowStream(GAS) options
constexpr const char *GAS_OPT_DATETIME_AS_STRING = "DATETIME_AS_STRING";
 
std::map<std::string, std::string>
    CPL_DLL OGRParseArrowMetadata(const char *pabyMetadata);
 
bool CPL_DLL OGRCloneArrowArray(const struct ArrowSchema *schema,
                                const struct ArrowArray *array,
                                struct ArrowArray *out_array);
 
bool CPL_DLL OGRCloneArrowSchema(const struct ArrowSchema *schema,
                                 struct ArrowSchema *out_schema);
 
class OGRArrowArrayStream
{
  public:
    inline OGRArrowArrayStream()
    {
        memset(&m_stream, 0, sizeof(m_stream));
    }
 
    inline ~OGRArrowArrayStream()
    {
        clear();
    }
 
    // cppcheck-suppress functionStatic
    inline void clear()
    {
        if (m_stream.release)
        {
            m_stream.release(&m_stream);
            m_stream.release = nullptr;
        }
    }
 
    inline ArrowArrayStream *get()
    {
        return &m_stream;
    }
 
    // cppcheck-suppress functionStatic
    inline int get_schema(struct ArrowSchema *schema)
    {
        return m_stream.get_schema(&m_stream, schema);
    }
 
    // cppcheck-suppress functionStatic
    inline int get_next(struct ArrowArray *array)
    {
        return m_stream.get_next(&m_stream, array);
    }
 
    inline OGRArrowArrayStream &operator=(OGRArrowArrayStream &&other)
    {
        if (this != &other)
        {
            clear();
            memcpy(&m_stream, &(other.m_stream), sizeof(m_stream));
            // Reset other content, in particular its "release" member
            // as per https://arrow.apache.org/docs/format/CDataInterface.html#moving-an-array
            memset(&(other.m_stream), 0, sizeof(m_stream));
        }
        return *this;
    }
 
  private:
    struct ArrowArrayStream m_stream{};
 
    OGRArrowArrayStream(const OGRArrowArrayStream &) = delete;
    OGRArrowArrayStream(OGRArrowArrayStream &&) = delete;
    OGRArrowArrayStream &operator=(const OGRArrowArrayStream &) = delete;
};
 
#endif  // OGRLAYERARROW_H_DEFINED