misc.py 文件源码

def load_lmdb(lmdb_file, n_records=None):
    import lmdb
    import numpy as np
    lmdb_file = expand_user(lmdb_file)
    if os.path.exists(lmdb_file):
        data = []
        env = lmdb.open(lmdb_file, readonly=True, max_readers=512)
        with env.begin() as txn:
            cursor = txn.cursor()
            begin_st = time.time()
            print("Loading lmdb file {} into memory".format(lmdb_file))
            for key, value in cursor:
                _, target, _ = key.decode('ascii').split(':')
                target = int(target)
                img = cv2.imdecode(np.fromstring(value, np.uint8), cv2.IMREAD_COLOR)
                data.append((img, target))
                if n_records is not None and len(data) >= n_records:
                    break
        env.close()
        print("=> Done ({:.4f} s)".format(time.time() - begin_st))
        return data
    else:
        print("Not found lmdb file".format(lmdb_file))