80 lines
2.2 KiB
Go
80 lines
2.2 KiB
Go
// Copyright 2018 Google LLC
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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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// T is a required type parameter that must be an integral type.
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type T uint64
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// A Range represents a contiguous range of T.
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//
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// +stateify savable
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type Range struct {
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// Start is the inclusive start of the range.
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Start T
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// End is the exclusive end of the range.
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End T
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}
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// WellFormed returns true if r.Start <= r.End. All other methods on a Range
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// require that the Range is well-formed.
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func (r Range) WellFormed() bool {
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return r.Start <= r.End
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}
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// Length returns the length of the range.
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func (r Range) Length() T {
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return r.End - r.Start
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}
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// Contains returns true if r contains x.
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func (r Range) Contains(x T) bool {
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return r.Start <= x && x < r.End
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}
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// Overlaps returns true if r and r2 overlap.
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func (r Range) Overlaps(r2 Range) bool {
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return r.Start < r2.End && r2.Start < r.End
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}
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// IsSupersetOf returns true if r is a superset of r2; that is, the range r2 is
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// contained within r.
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func (r Range) IsSupersetOf(r2 Range) bool {
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return r.Start <= r2.Start && r.End >= r2.End
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}
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// Intersect returns a range consisting of the intersection between r and r2.
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// If r and r2 do not overlap, Intersect returns a range with unspecified
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// bounds, but for which Length() == 0.
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func (r Range) Intersect(r2 Range) Range {
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if r.Start < r2.Start {
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r.Start = r2.Start
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}
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if r.End > r2.End {
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r.End = r2.End
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}
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if r.End < r.Start {
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r.End = r.Start
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}
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return r
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}
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// CanSplitAt returns true if it is legal to split a segment spanning the range
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// r at x; that is, splitting at x would produce two ranges, both of which have
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// non-zero length.
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func (r Range) CanSplitAt(x T) bool {
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return r.Contains(x) && r.Start < x
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}
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