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Reapor-Yurnero
059879e143
This change was derived from a change by: Reapor-Yurnero <reapor.yurnero@gmail.com> And has been modified by: Adin Scannell <ascannell@google.com> (The original change author is preserved for the commit.) This change implements gap tracking in the segment set by adding additional information in each node, and using that information to speed up gap finding from a linear scan to a O(log(n)) walk of the tree. This gap tracking is optional, and will default to off except for segment instances that set gapTracking equal to 1 in their const lists. PiperOrigin-RevId: 312621607
55 lines
1.5 KiB
Go
55 lines
1.5 KiB
Go
// Copyright 2018 The gVisor 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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package segment
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type setFunctions struct{}
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// MinKey returns the minimum key for the set.
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func (s setFunctions) MinKey() int {
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return -s.MaxKey() - 1
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}
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// MaxKey returns the maximum key for the set.
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func (setFunctions) MaxKey() int {
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return int(^uint(0) >> 1)
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}
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func (setFunctions) ClearValue(*int) {}
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func (setFunctions) Merge(_ Range, val1 int, _ Range, _ int) (int, bool) {
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return val1, true
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}
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func (setFunctions) Split(_ Range, val int, _ int) (int, int) {
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return val, val
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}
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type gapSetFunctions struct {
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setFunctions
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}
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// MinKey is adjusted to make sure no add overflow would happen in test cases.
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// e.g. A gap with range {MinInt32, 2} would cause overflow in Range().Length().
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//
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// Normally Keys should be unsigned to avoid these issues.
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func (s gapSetFunctions) MinKey() int {
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return s.setFunctions.MinKey() / 2
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}
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// MaxKey returns the maximum key for the set.
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func (s gapSetFunctions) MaxKey() int {
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return s.setFunctions.MaxKey() / 2
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}
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