Merge pull request #990 from micro/buffer

Add debug/buffer package as a simple ring buffer
This commit is contained in:
Asim Aslam 2019-11-26 14:27:39 +00:00 committed by GitHub
commit 04ee4b04ad
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2 changed files with 110 additions and 0 deletions

58
debug/buffer/buffer.go Normal file
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// Package buffer provides a simple ring buffer for storing local data
package buffer
import (
"sync"
)
type Buffer struct {
size int
sync.RWMutex
vals []interface{}
}
func (b *Buffer) Put(v interface{}) {
b.Lock()
defer b.Unlock()
// append to values
b.vals = append(b.vals, v)
// trim if bigger than size required
if len(b.vals) > b.size {
b.vals = b.vals[1:]
}
}
// Get returns the last n entries
func (b *Buffer) Get(n int) []interface{} {
// reset any invalid values
if n > b.size || n < 0 {
n = b.size
}
b.RLock()
defer b.RUnlock()
// create a delta
delta := b.size - n
// if all the values are less than delta
if len(b.vals) < delta {
return b.vals
}
// return the delta set
return b.vals[delta:]
}
func (b *Buffer) Size() int {
return b.size
}
// New returns a new buffer of the given size
func New(i int) *Buffer {
return &Buffer{
size: i,
}
}

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package buffer
import (
"testing"
)
func TestBuffer(t *testing.T) {
b := New(10)
// test one value
b.Put("foo")
v := b.Get(1)
if val := v[0].(string); val != "foo" {
t.Fatalf("expected foo got %v", val)
}
b = New(10)
// test 10 values
for i := 0; i < 10; i++ {
b.Put(i)
}
v = b.Get(10)
for i := 0; i < 10; i++ {
val := v[i].(int)
if val != i {
t.Fatalf("expected %d got %d", i, val)
}
}
// test more values
for i := 0; i < 10; i++ {
v := i * 2
b.Put(v)
}
v = b.Get(10)
for i := 0; i < 10; i++ {
val := v[i].(int)
expect := i * 2
if val != expect {
t.Fatalf("expected %d got %d", expect, val)
}
}
}