73 lines
1.9 KiB
Go
73 lines
1.9 KiB
Go
/*
|
|
Copyright 2017 The Kubernetes Authors.
|
|
|
|
Licensed under the Apache License, Version 2.0 (the "License");
|
|
you may not use this file except in compliance with the License.
|
|
You may obtain a copy of the License at
|
|
|
|
http://www.apache.org/licenses/LICENSE-2.0
|
|
|
|
Unless required by applicable law or agreed to in writing, software
|
|
distributed under the License is distributed on an "AS IS" BASIS,
|
|
WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
|
|
See the License for the specific language governing permissions and
|
|
limitations under the License.
|
|
*/
|
|
|
|
package buffer
|
|
|
|
// RingGrowing is a growing ring buffer.
|
|
// Not thread safe.
|
|
type RingGrowing struct {
|
|
data []interface{}
|
|
n int // Size of Data
|
|
beg int // First available element
|
|
readable int // Number of data items available
|
|
}
|
|
|
|
// NewRingGrowing constructs a new RingGrowing instance with provided parameters.
|
|
func NewRingGrowing(initialSize int) *RingGrowing {
|
|
return &RingGrowing{
|
|
data: make([]interface{}, initialSize),
|
|
n: initialSize,
|
|
}
|
|
}
|
|
|
|
// ReadOne reads (consumes) first item from the buffer if it is available, otherwise returns false.
|
|
func (r *RingGrowing) ReadOne() (data interface{}, ok bool) {
|
|
if r.readable == 0 {
|
|
return nil, false
|
|
}
|
|
r.readable--
|
|
element := r.data[r.beg]
|
|
r.data[r.beg] = nil // Remove reference to the object to help GC
|
|
if r.beg == r.n-1 {
|
|
// Was the last element
|
|
r.beg = 0
|
|
} else {
|
|
r.beg++
|
|
}
|
|
return element, true
|
|
}
|
|
|
|
// WriteOne adds an item to the end of the buffer, growing it if it is full.
|
|
func (r *RingGrowing) WriteOne(data interface{}) {
|
|
if r.readable == r.n {
|
|
// Time to grow
|
|
newN := r.n * 2
|
|
newData := make([]interface{}, newN)
|
|
to := r.beg + r.readable
|
|
if to <= r.n {
|
|
copy(newData, r.data[r.beg:to])
|
|
} else {
|
|
copied := copy(newData, r.data[r.beg:])
|
|
copy(newData[copied:], r.data[:(to%r.n)])
|
|
}
|
|
r.beg = 0
|
|
r.data = newData
|
|
r.n = newN
|
|
}
|
|
r.data[(r.readable+r.beg)%r.n] = data
|
|
r.readable++
|
|
}
|