Matlab LMDB wrapper for UNIX environment.
- See LMDB website.
- The implementation is based on mexplus.
See also matlab-leveldb.
The package does not contain any data serialization. Use char for storing keys and values. Those using Caffe might want to use a Datum converter in the caffe-extension branch also.
Specify the MATLABDIR path.
make MATLABDIR=/usr/local/MATLAB/R2015a
make test
Edit Makefile to customize the build process.
In the caffe-extension branch, also specify the path to caffe.
make MATLABDIR=/usr/local/MATLAB/R2015a CAFFEDIR=../caffe
% Open and close.
database = lmdb.DB('./db', 'MAPSIZE', 1024^3);
clear database;
readonly_database = lmdb.DB('./db', 'RDONLY', true, 'NOLOCK', true);
clear readonly_database;
% Read and write.
database.put('key1', 'value1');
database.put('key2', 'value2');
value1 = database.get('key1');
database.remove('key1');
% Iterator.
database.each(@(key, value) disp([key, ': ', value]));
count = database.reduce(@(key, value, count) count + 1, 0);
% Cursor.
cursor = database.cursor('RDONLY', true);
while cursor.next()
key = cursor.key;
value = cursor.value;
end
clear cursor;
% Transaction.
transaction = database.begin();
try
transaction.put('key1', 'value1');
transaction.put('key2', 'value2');
transaction.commit();
catch exception
transaction.abort();
end
clear transaction;
% Dump.
keys = database.keys();
values = database.values();
See help documentation of each function, or visit LMDB documentation to understand the flags.
The caffe-extension branch includes utilities to convert Datum protocol buffer.
% Make plain datum.
image = imread('peppers.png');
label = 1;
datum = caffe_pb.toDatum(image, label);
% Make encoded datum.
fid = fopen('peppers.png', 'r');
png_image = fread(fid, inf, 'uint8=>uint8');
fclose(fid);
label = 1;
datum = caffe_pb.toEncodedDatum(png_image, label);
% Read datum.
[png_image, label] = caffe_pb.fromDatum(datum);
- Finer transaction API.