Merge pull request #990 from micro/buffer
Add debug/buffer package as a simple ring buffer
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commit
04ee4b04ad
58
debug/buffer/buffer.go
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58
debug/buffer/buffer.go
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@ -0,0 +1,58 @@
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// Package buffer provides a simple ring buffer for storing local data
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package buffer
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import (
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"sync"
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)
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type Buffer struct {
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size int
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sync.RWMutex
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vals []interface{}
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}
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func (b *Buffer) Put(v interface{}) {
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b.Lock()
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defer b.Unlock()
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// append to values
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b.vals = append(b.vals, v)
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// trim if bigger than size required
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if len(b.vals) > b.size {
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b.vals = b.vals[1:]
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}
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}
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// Get returns the last n entries
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func (b *Buffer) Get(n int) []interface{} {
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// reset any invalid values
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if n > b.size || n < 0 {
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n = b.size
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}
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b.RLock()
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defer b.RUnlock()
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// create a delta
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delta := b.size - n
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// if all the values are less than delta
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if len(b.vals) < delta {
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return b.vals
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}
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// return the delta set
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return b.vals[delta:]
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}
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func (b *Buffer) Size() int {
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return b.size
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}
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// New returns a new buffer of the given size
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func New(i int) *Buffer {
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return &Buffer{
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size: i,
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}
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}
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52
debug/buffer/buffer_test.go
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52
debug/buffer/buffer_test.go
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@ -0,0 +1,52 @@
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package buffer
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import (
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"testing"
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)
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func TestBuffer(t *testing.T) {
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b := New(10)
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// test one value
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b.Put("foo")
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v := b.Get(1)
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if val := v[0].(string); val != "foo" {
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t.Fatalf("expected foo got %v", val)
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}
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b = New(10)
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// test 10 values
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for i := 0; i < 10; i++ {
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b.Put(i)
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}
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v = b.Get(10)
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for i := 0; i < 10; i++ {
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val := v[i].(int)
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if val != i {
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t.Fatalf("expected %d got %d", i, val)
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}
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}
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// test more values
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for i := 0; i < 10; i++ {
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v := i * 2
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b.Put(v)
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}
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v = b.Get(10)
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for i := 0; i < 10; i++ {
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val := v[i].(int)
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expect := i * 2
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if val != expect {
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t.Fatalf("expected %d got %d", expect, val)
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}
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}
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}
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