diff --git a/python/mozbuild/mozbuild/chunkify.py b/python/mozbuild/mozbuild/chunkify.py new file mode 100644 index 000000000000..da4b0791dae5 --- /dev/null +++ b/python/mozbuild/mozbuild/chunkify.py @@ -0,0 +1,57 @@ +# This Source Code Form is subject to the terms of the Mozilla Public +# License, v. 2.0. If a copy of the MPL was not distributed with this file, +# You can obtain one at http://mozilla.org/MPL/2.0/. + +# This file is a direct clone of +# https://github.com/bhearsum/chunkify/blob/master/chunkify/__init__.py +# of version 1.2. Its license (MPL2) is contained in repo root LICENSE file. +# Please make modifications there where possible. + +from itertools import islice + + +class ChunkingError(Exception): + pass + + +def split_evenly(n, chunks): + """Split an integer into evenly distributed list + + >>> split_evenly(7, 3) + [3, 2, 2] + + >>> split_evenly(12, 3) + [4, 4, 4] + + >>> split_evenly(35, 10) + [4, 4, 4, 4, 4, 3, 3, 3, 3, 3] + + >>> split_evenly(1, 2) + Traceback (most recent call last): + ... + ChunkingError: Number of chunks is greater than number + + """ + if n < chunks: + raise ChunkingError("Number of chunks is greater than number") + if n % chunks == 0: + # Either we can evenly split or only 1 chunk left + return [n / chunks] * chunks + # otherwise the current chunk should be a bit larger + max_size = n / chunks + 1 + return [max_size] + split_evenly(n - max_size, chunks - 1) + + +def chunkify(things, this_chunk, chunks): + if this_chunk > chunks: + raise ChunkingError("this_chunk is greater than total chunks") + + dist = split_evenly(len(things), chunks) + start = sum(dist[:this_chunk-1]) + end = start + dist[this_chunk-1] + + try: + return things[start:end] + except TypeError: + return islice(things, start, end) +