lmdb::stream Namespace Reference

Functions
mdb_size_t	count (MDB_cursor *cur)
std::pair< epee::span< const std::uint8_t >, epee::span< const std::uint8_t > >	get (MDB_cursor &cur, MDB_cursor_op op, std::size_t key, std::size_t value)

Function Documentation

count()

mdb_size_t lmdb::stream::count

(

MDB_cursor *

cur

)

Definition at line 39 of file value_stream.cpp.

        {
            mdb_size_t out = 0;
            if (cur)
            {
                const int rc = mdb_cursor_count(cur, &out);
                if (rc)
                    ELECTRONEUM_THROW(lmdb::error(rc), "mdb_cursor_count");
            }
            return out;
        }

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get()

std::pair< epee::span< const std::uint8_t >, epee::span< const std::uint8_t > > lmdb::stream::get	(	MDB_cursor &	cur,
		MDB_cursor_op	op,
		std::size_t	key,
		std::size_t	value )

Calls mdb_cursor_get and does some error checking.

Parameters

cur	is given to mdb_cursor_get without modification.
op	is passed to mdb_cursor_get without modification.
key	expected key size or 0 to skip key size check.
value	expected value size or 0 to skip value size check.

Exceptions

std::system_error	if key != 0 and key_.mv_size != key.
std::system_error	if value != 0 and value_.mv_size != value.
std::system_error	if mdb_cursor_get returns any error other than MDB_NOTFOUND.

Returns

{key bytes, value bytes} or two empty spans if MDB_NOTFOUND.

Definition at line 52 of file value_stream.cpp.

        {
            MDB_val key_bytes{};
            MDB_val value_bytes{};
            const int rc = mdb_cursor_get(&cur, &key_bytes, &value_bytes, op);
            if (rc)
            {
                if (rc == MDB_NOTFOUND)
                    return {};
                ELECTRONEUM_THROW(lmdb::error(rc), "mdb_cursor_get");
            }
 
            if (key && key != key_bytes.mv_size)
                ELECTRONEUM_THROW(lmdb::error(MDB_BAD_VALSIZE), "mdb_cursor_get key");
 
            if (value && (value_bytes.mv_size % value != 0 || value_bytes.mv_size == 0))
                ELECTRONEUM_THROW(lmdb::error(MDB_BAD_VALSIZE), "mdb_cursor_get value");
 
            return {lmdb::to_byte_span(key_bytes), lmdb::to_byte_span(value_bytes)};
        }

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