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https://github.com/RPCSX/xed.git
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e7d734962c
Change-Id: I166833daaa56c33eca01bdf7b9aa6e74a490ba9a (cherry picked from commit 1212ba962dff6dfbfa0bd2469327ff447ce59058)
72 lines
2.2 KiB
Python
72 lines
2.2 KiB
Python
#!/usr/bin/env python
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# -*- python -*-
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#BEGIN_LEGAL
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#
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#Copyright (c) 2017 Intel Corporation
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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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#END_LEGAL
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import collections
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#The idea is to have different algorithms for finding hash
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#functions. So far we use only FKS and it seems to work well enough.
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class hash_fun_interface_t(object):
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def _raise_error(self):
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raise NotImplementedError("Hash function not implemented.")
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def apply(self, x):
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self._raise_error()
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def emit_cexpr(self, key_str):
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self.raise_error()
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def __str__(self):
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self._raise_error()
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def kind(self):
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self._raise_error()
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def is_perfect(keylist, hash_f):
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"Does each input map to a different bucket? If so, it is perfect."""
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bucket = set()
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for x in keylist:
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hash_val = hash_f.apply(x)
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if hash_val in bucket:
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# collision! ka-boom
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return None
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else:
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bucket.add(hash_val)
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return bucket
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def _measure_bucket_max(table, maxbin):
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"""check for buckets that are too large (_l1_bucket_max)"""
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okay = True
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max_bucket = 0
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bad_buckets = 0
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for k, vl in table.items():
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lvl = len(vl)
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if lvl >= maxbin:
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if lvl > max_bucket:
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max_bucket = lvl
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bad_buckets = bad_buckets + 1
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okay = False
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return okay
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def is_well_distributed(keylist, hash_f, maxbin):
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"""populate the buckets and see if any are too big"""
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table = collections.defaultdict(list)
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for t,x in keylist.items():
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hash_val = hash_f.apply(x)
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table[hash_val].append(t)
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okay = _measure_bucket_max(table, maxbin)
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return okay
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