62 lines
1.1 KiB
Go
62 lines
1.1 KiB
Go
/*
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* Copyright (c) 2013 IBM Corp.
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*
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* All rights reserved. This program and the accompanying materials
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* are made available under the terms of the Eclipse Public License v1.0
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* which accompanies this distribution, and is available at
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* http://www.eclipse.org/legal/epl-v10.html
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*
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* Contributors:
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* Seth Hoenig
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* Allan Stockdill-Mander
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* Mike Robertson
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*/
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package mqtt
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import (
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"sync"
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)
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// MId is 16 bit message id as specified by the MQTT spec.
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// In general, these values should not be depended upon by
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// the client application.
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type MId uint16
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type messageIds struct {
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sync.RWMutex
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index map[uint16]Token
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}
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const (
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midMin uint16 = 1
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midMax uint16 = 65535
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)
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func (mids *messageIds) freeID(id uint16) {
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mids.Lock()
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defer mids.Unlock()
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delete(mids.index, id)
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}
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func (mids *messageIds) getID(t Token) uint16 {
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mids.Lock()
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defer mids.Unlock()
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for i := midMin; i < midMax; i++ {
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if _, ok := mids.index[i]; !ok {
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mids.index[i] = t
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return i
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}
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}
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return 0
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}
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func (mids *messageIds) getToken(id uint16) Token {
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mids.RLock()
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defer mids.RUnlock()
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if token, ok := mids.index[id]; ok {
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return token
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}
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return nil
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}
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