inet.af/netstack@v0.0.0-20220214151720-7585b01ddccf/tcpip/transport/tcp/segment_heap.go (about)

     1  // Copyright 2018 The gVisor Authors.
     2  //
     3  // Licensed under the Apache License, Version 2.0 (the "License");
     4  // you may not use this file except in compliance with the License.
     5  // You may obtain a copy of the License at
     6  //
     7  //     http://www.apache.org/licenses/LICENSE-2.0
     8  //
     9  // Unless required by applicable law or agreed to in writing, software
    10  // distributed under the License is distributed on an "AS IS" BASIS,
    11  // WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
    12  // See the License for the specific language governing permissions and
    13  // limitations under the License.
    14  
    15  package tcp
    16  
    17  import "container/heap"
    18  
    19  type segmentHeap []*segment
    20  
    21  var _ heap.Interface = (*segmentHeap)(nil)
    22  
    23  // Len returns the length of h.
    24  func (h *segmentHeap) Len() int {
    25  	return len(*h)
    26  }
    27  
    28  // Less determines whether the i-th element of h is less than the j-th element.
    29  func (h *segmentHeap) Less(i, j int) bool {
    30  	return (*h)[i].sequenceNumber.LessThan((*h)[j].sequenceNumber)
    31  }
    32  
    33  // Swap swaps the i-th and j-th elements of h.
    34  func (h *segmentHeap) Swap(i, j int) {
    35  	(*h)[i], (*h)[j] = (*h)[j], (*h)[i]
    36  }
    37  
    38  // Push adds x as the last element of h.
    39  func (h *segmentHeap) Push(x interface{}) {
    40  	*h = append(*h, x.(*segment))
    41  }
    42  
    43  // Pop removes the last element of h and returns it.
    44  func (h *segmentHeap) Pop() interface{} {
    45  	old := *h
    46  	n := len(old)
    47  	x := old[n-1]
    48  	old[n-1] = nil
    49  	*h = old[:n-1]
    50  	return x
    51  }