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/** |
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* Class: jaxon.utils.queue |
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* |
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* global: jaxon |
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*/ |
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(function(self) { |
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/** |
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* Construct and return a new queue object. |
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* |
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* @param {integer} size The number of entries the queue will be able to hold. |
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* |
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* @returns {object} |
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*/ |
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self.create = size => ({ |
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start: 0, |
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count: 0, |
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size: size, |
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end: 0, |
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elements: [], |
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paused: false, |
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}); |
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/** |
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* Check id a queue is empty. |
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* |
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* @param {object} oQueue The queue to check. |
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* |
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* @returns {boolean} |
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*/ |
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self.empty = oQueue => oQueue.count <= 0; |
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/** |
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* Check id a queue is empty. |
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* |
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* @param {object} oQueue The queue to check. |
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* |
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* @returns {boolean} |
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*/ |
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self.full = oQueue => oQueue.count >= oQueue.size; |
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/** |
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* Push a new object into the tail of the buffer maintained by the specified queue object. |
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* |
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* @param {object} oQueue The queue in which you would like the object stored. |
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* @param {object} obj The object you would like stored in the queue. |
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* |
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* @returns {integer} The number of entries in the queue. |
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*/ |
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self.push = (oQueue, obj) => { |
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// No push if the queue is full. |
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if(self.full(oQueue)) { |
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throw { code: 10003 }; |
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} |
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oQueue.elements[oQueue.end] = obj; |
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if(++oQueue.end >= oQueue.size) { |
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oQueue.end = 0; |
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} |
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return ++oQueue.count; |
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}; |
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/** |
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* Push a new object into the head of the buffer maintained by the specified queue object. |
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* |
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* This effectively pushes an object to the front of the queue... it will be processed first. |
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* |
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* @param {object} oQueue The queue in which you would like the object stored. |
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* @param {object} obj The object you would like stored in the queue. |
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* |
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* @returns {integer} The number of entries in the queue. |
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*/ |
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self.pushFront = (oQueue, obj) => { |
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// No push if the queue is full. |
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if(self.full(oQueue)) { |
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throw { code: 10003 }; |
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} |
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// Simply push if the queue is empty |
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if(self.empty(oQueue)) { |
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return self.push(oQueue, obj); |
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} |
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// Put the object one position back. |
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if(--oQueue.start < 0) { |
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oQueue.start = oQueue.size - 1; |
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} |
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oQueue.elements[oQueue.start] = obj; |
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return ++oQueue.count; |
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}; |
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/** |
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* Attempt to pop an object off the head of the queue. |
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* |
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* @param {object} oQueue The queue object you would like to modify. |
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* |
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* @returns {object|null} |
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*/ |
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self.pop = (oQueue) => { |
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if(self.empty(oQueue)) { |
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return null; |
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} |
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let obj = oQueue.elements[oQueue.start]; |
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delete oQueue.elements[oQueue.start]; |
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if(++oQueue.start >= oQueue.size) { |
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oQueue.start = 0; |
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} |
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oQueue.count--; |
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return obj; |
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}; |
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/** |
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* Attempt to pop an object off the head of the queue. |
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* |
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* @param {object} oQueue The queue object you would like to modify. |
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* |
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* @returns {object|null} |
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*/ |
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self.peek = (oQueue) => { |
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if(self.empty(oQueue)) { |
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return null; |
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} |
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return oQueue.elements[oQueue.start]; |
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}; |
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})(jaxon.utils.queue); |
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