private unsafe string MarshalAndFreeRocksDbString(IntPtr resultPtr, long resultLength, Encoding encoding)
{
var result = CurrentFramework.CreateString((sbyte *)resultPtr.ToPointer(), 0, (int)resultLength, encoding);
rocksdb_free(resultPtr);
return(result);
}
/// <summary>
/// Executes a multi_get with automatic marshalling
/// </summary>
/// <param name="db"></param>
/// <param name="read_options"></param>
/// <param name="keys"></param>
/// <param name="numKeys">when non-zero, specifies the number of keys in the array to fetch</param>
/// <param name="keyLengths">when non-null specifies the lengths of each key to fetch</param>
/// <param name="errptrs">when non-null, must be an array that will be populated with error codes</param>
/// <param name="values">when non-null is a pre-allocated array to put the resulting values in</param>
/// <param name="cf"></param>
/// <returns></returns>
public unsafe KeyValuePair <string, string>[] rocksdb_multi_get(
IntPtr db,
IntPtr read_options,
string[] keys,
IntPtr[] errptrs,
ulong numKeys = 0,
KeyValuePair <string, string>[] values = null,
ColumnFamilyHandle[] cf = null,
Encoding encoding = null)
{
if (encoding == null)
{
encoding = Encoding.UTF8;
}
int count = numKeys == 0 ? keys.Length : (int)numKeys;
IntPtr[] keyPtrs = new IntPtr[count];
var keyLengths = new ulong[count];
IntPtr[] valuePtrs = new IntPtr[count];
ulong[] valueLengths = new ulong[count];
if (values == null)
{
values = new KeyValuePair <string, string> [count];
}
if (errptrs == null)
{
errptrs = new IntPtr[count];
}
// first we have to encode each key
for (int i = 0; i < count; i++)
{
var key = keys[i];
fixed(char *k = key)
{
var klength = key.Length;
int bklength = encoding.GetByteCount(k, klength);
var bk = Marshal.AllocHGlobal(bklength);
encoding.GetBytes(k, klength, (byte *)bk.ToPointer(), bklength);
keyPtrs[i] = bk;
keyLengths[i] = (ulong)bklength;
}
}
if (cf == null)
{
rocksdb_multi_get(db, read_options, (ulong)count, keyPtrs, keyLengths, valuePtrs, valueLengths, errptrs);
}
else
{
IntPtr[] cfhs = new IntPtr[cf.Length];
for (int i = 0; i < count; i++)
{
cfhs[i] = cf[i].Handle;
}
rocksdb_multi_get_cf(db, read_options, cfhs, (ulong)count, keyPtrs, keyLengths, valuePtrs, valueLengths, errptrs);
}
// free the buffers allocated for each encoded key
foreach (var keyPtr in keyPtrs)
{
Marshal.FreeHGlobal(keyPtr);
}
// now marshal all of the values
for (int i = 0; i < count; i++)
{
var resultPtr = valuePtrs[i];
if (resultPtr != IntPtr.Zero)
{
var bv = (sbyte *)resultPtr.ToPointer();
var bvLength = valueLengths[i];
values[i] = new KeyValuePair <string, string>(keys[i], CurrentFramework.CreateString(bv, 0, (int)bvLength, encoding));
rocksdb_free(resultPtr);
}
else
{
values[i] = new KeyValuePair <string, string>(keys[i], null);
}
}
return(values);
}
private unsafe string MarshalString(IntPtr resultPtr, long resultLength, Encoding encoding)
{
return(CurrentFramework.CreateString((sbyte *)resultPtr.ToPointer(), 0, (int)resultLength, encoding));
}