RangeQuerySelectUpdating_Overwrite.h

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/*
 * SWC-DB© Copyright since 2019 Alex Kashirin <kashirin.alex@gmail.com>
 * License details at <https://github.com/kashirin-alex/swc-db/#license>
 */
 
#ifndef swcdb_ranger_callbacks_RangeQuerySelectUpdating_Overwrite_h
#define swcdb_ranger_callbacks_RangeQuerySelectUpdating_Overwrite_h
 
 
#include "swcdb/ranger/callbacks/RangeQuerySelectUpdating.h"
 
 
namespace SWC { namespace Ranger { namespace Callback {
 
 
class RangeQuerySelectUpdating_Overwrite final
    : public RangeQuerySelectUpdating {
  public:
 
  typedef std::shared_ptr<RangeQuerySelectUpdating_Overwrite> Ptr;
 
  SWC_CAN_INLINE
  RangeQuerySelectUpdating_Overwrite(const Comm::ConnHandlerPtr& conn,
                                     const Comm::Event::Ptr& ev,
                                     DB::Specs::Interval&& req_spec,
                                     const RangePtr& a_range)
                                    : RangeQuerySelectUpdating(
                                        conn,
                                        ev,
                                        std::move(req_spec),
                                        a_range
                                      ) {
    only_keys = false;
  }
 
  virtual ~RangeQuerySelectUpdating_Overwrite() noexcept { }
 
  void update_cell_value(DB::Cells::Cell& cell) override {
    StaticBuffer v;
    DB::Types::Encoder encoder = cell.get_value(v, false);
    uint32_t sz;
 
    uint32_t pos = spec.updating->operation.get_pos();
    if(pos >= v.size) {
      pos = v.size;
      sz = v.size + spec.updating->vlen;
    } else {
      sz = spec.updating->vlen < v.size - pos
        ? v.size
        : spec.updating->vlen + pos;
    }
    uint8_t* ptr = static_cast<uint8_t*>(
      memcpy(
        new uint8_t[sz],
        v.base,
        pos
      )
    );
    memcpy(
      ptr + pos,
      spec.updating->value,
      spec.updating->vlen
    );
    uint32_t at = pos + spec.updating->vlen;
    if(at < v.size) {
      memcpy(
        ptr + at,
        v.base + at,
        v.size - at
      );
    }
 
    if(spec.updating->encoder != DB::Types::Encoder::DEFAULT)
      encoder = spec.updating->encoder;
    if(encoder == DB::Types::Encoder::DEFAULT) {
      cell.own = true;
      cell.value = ptr;
      cell.vlen = sz;
    } else {
      cell.set_value(encoder, ptr, sz);
      delete [] ptr;
    }
 
  }
 
};
 
 
}}}
#endif // swcdb_ranger_callbacks_RangeQuerySelectUpdating_Overwrite_h