187 lines
3.2 KiB
C++
187 lines
3.2 KiB
C++
#include "Queue.h"
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Queue::Queue(uint len)
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{
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_Buffer = NULL;
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SetCapacity(len);
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}
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// 使用缓冲区初始化缓冲区。注意，此时指针位于0，而内容长度为缓冲区长度
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Queue::Queue(ByteArray& bs)
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{
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_Buffer = bs.GetBuffer();
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_Capacity = bs.Length();
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_size = 0;
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_head = 0;
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_tail = 0;
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//Safe = false;
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}
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// 销毁缓冲区
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Queue::~Queue()
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{
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assert_ptr(this);
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if(_needFree)
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{
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if(_Buffer != _Arr) delete[] _Buffer;
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_Buffer = NULL;
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}
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}
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void Queue::SetCapacity(uint len)
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{
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if(len <= ArrayLength(_Arr))
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{
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// 释放旧的
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if(_needFree && _Buffer && _Buffer != _Arr) delete[] _Buffer;
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len = ArrayLength(_Arr);
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_Buffer = _Arr;
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_needFree = false;
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}
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else
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{
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_Buffer = new byte[len];
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_needFree = true;
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}
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_Capacity = len;
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_size = 0;
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_head = 0;
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_tail = 0;
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}
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void Queue::SetLength(uint len)
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{
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_size = len;
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}
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void Queue::Clear()
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{
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_size = 0;
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_head = 0;
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_tail = 0;
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}
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void Queue::Push(byte dat)
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{
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_Buffer[_head++] = dat;
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_head %= _Capacity;
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_size++;
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}
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byte Queue::Pop()
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{
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if(_size == 0) return 0;
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_size--;
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/*
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昨晚发现串口频繁收发一段数据后出现丢数据现象，也即是size为0，然后tail比head小，刚开始小一个字节，然后会逐步拉大。
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经过分析得知，ARM指令没有递加递减指令，更没有原子操作。
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size拿出来减一，然后再保存回去，但是保存回去之前，串口接收中断写入，拿到了旧的size，导致最后的size比原计划要小1。
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该问题只能通过关闭中断来解决。为了减少关中断时间以提升性能，增加了专门的Read方法。
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*/
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byte dat = _Buffer[_tail++];
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_tail %= _Capacity;
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return dat;
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}
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byte Queue::Peek() const
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{
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return _Buffer[_tail];
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}
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uint Queue::Write(const ByteArray& bs, bool safe)
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{
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byte* buf = bs.GetBuffer();
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uint len = bs.Length();
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uint rs = 0;
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while(true)
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{
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// 计算这一个循环剩下的位置
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uint count = _Capacity - _head;
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// 如果要写入的数据足够存放
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if(len <= count)
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{
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memcpy(_Buffer + _head, buf, len);
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rs += len;
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_head += len;
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_head %= _Capacity;
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break;
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}
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// 否则先写一段，指针回到开头
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memcpy(_Buffer + _head, buf, count);
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buf += count;
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rs += count;
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len -= count;
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_head = 0;
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}
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if(safe)
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{
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SmartIRQ irq;
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_size += rs;
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}
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else
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{
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_size += rs;
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}
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return rs;
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}
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uint Queue::Read(ByteArray& bs, bool safe)
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{
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if(_size == 0) return 0;
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byte* buf = bs.GetBuffer();
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uint len = bs.Length();
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if(len > _size) len = _size;
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uint rs = 0;
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while(true)
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{
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// 计算这一个循环剩下的位置
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uint count = _Capacity - _tail;
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// 如果要写入的数据足够存放
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if(len <= count)
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{
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memcpy(buf, _Buffer + _tail, len);
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rs += len;
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_tail += len;
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_tail %= _Capacity;
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break;
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}
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// 否则先写一段，指针回到开头
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memcpy(buf + _tail, _Buffer, count);
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buf += count;
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rs += count;
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len -= count;
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_tail = 0;
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}
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if(safe)
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{
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SmartIRQ irq;
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_size -= rs;
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if(_size == 0) _tail = _head;
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}
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else
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{
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_size -= rs;
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if(_size == 0) _tail = _head;
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}
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bs.SetLength(rs, true);
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return rs;
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}
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