#include <db_cxx.h>
class DbMultipleDataBuilder
{
public:
DbMultipleDataBuilder(Dbt &dbt);
bool append(void *dbuf, size_t dlen);
bool reserve(void *&ddest, size_t dlen);
};
This class builds a bulk buffer for use when the DB_MULTIPLE flag is specified to either the Db::put() or Db::del() methods. The buffer in the Dbt passed to the constructor is filled by calls to DbMultipleDataBuilder.append() or DbMultipleDataBuilder.reserve().
The constructor takes a
The Dbt Handle
that must be configured to contain a buffer managed by the application,
with the ulen field set to the size of the buffer.
All instances of the bulk retrieval classes may be used only once, and to build the bulk buffer in the forward direction only.
Parameters are:
dbt
The dbt parameter is a
The Dbt Handle
that must already be configured to contain a buffer managed by the application, with the ulen field set to the size of the buffer, which must be a multiple of 4.
The DbMultipleDataBuilder.append() method
copies a data item to the end of the buffer.
The DbMultipleDataBuilder.append()
method returns false if the data does not fit
in the buffer and true otherwise.
Parameters are:
dbuf
A pointer to the data to be copied into the bulk buffer.
dlen
The number of bytes to be copied.
The DbMultipleDataBuilder.reserve()
method reserves space for the next data item in the bulk buffer.
Unlike the append(), no data is actually
copied into the bulk buffer by reserve():
copying the data is the responsibility of the application.
The DbMultipleDataBuilder.reserve()
method returns false if the data does
not fit in the buffer and true otherwise.
Parameters are:
ddest
Set to a pointer to the position in the bulk buffer reserved for the data item, if enough space is available.
dlen
The number of bytes to reserve.