58 lines
1.4 KiB
Python
58 lines
1.4 KiB
Python
#
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# micro_blob.py
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#
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# This source file is part of the FoundationDB open source project
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#
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# Copyright 2013-2018 Apple Inc. and the FoundationDB project authors
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#
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# Licensed under the Apache License, Version 2.0 (the "License");
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# you may not use this file except in compliance with the License.
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# You may obtain a copy of the License at
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#
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# http://www.apache.org/licenses/LICENSE-2.0
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#
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# Unless required by applicable law or agreed to in writing, software
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# distributed under the License is distributed on an "AS IS" BASIS,
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# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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# See the License for the specific language governing permissions and
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# limitations under the License.
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#
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import fdb
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fdb.api_version(300)
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db = fdb.open()
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@fdb.transactional
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def clear_subspace(tr, subspace):
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tr.clear_range_startswith(subspace.key())
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CHUNK_LARGE = 5
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blob = fdb.Subspace(('B',))
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@fdb.transactional
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def write_blob(tr, data):
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if not len(data):
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return
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num_chunks = (len(data) + CHUNK_LARGE - 1) / CHUNK_LARGE
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chunk_size = (len(data) + num_chunks) / num_chunks
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chunks = [(n, n + chunk_size) for n in range(0, len(data), chunk_size)]
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for start, end in chunks:
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tr[blob[start]] = data[start:end]
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@fdb.transactional
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def read_blob(tr):
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value = ''
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for k, v in tr[blob.range()]:
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value += v
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return value
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clear_subspace(db, blob)
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write_blob(db, 'ABCDEFGHIJKLMNOPQRSTUVWXYZ')
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print read_blob(db)
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