Poco::MemoryPool
// Library: Foundation
// Package: Core
// Module: MemoryPool
功能：提供一个内存池，以减少new和delete的调用，提高效率，这往往是为服务端提供的。
public方法void* get();void release(void* ptr);int allocated() const;int available() const;get 方法返回内存池中的一个内存块的地址，以对其进行操作。release则将内存块还给内存池，但并不delete。allocated()返回已经分配的内存块数，avaliable指示内存池还有多少内存块可以使用。
get可能会抛出内存池内存耗尽异常。
void MemoryPoolTest::testMemoryPool(){MemoryPool pool1(100, 0, 10);assert (pool1.blockSize() == 100);assert (pool1.allocated() == 0);assert (pool1.available() == 0);std::vector<void*> ptrs;for (int i = 0; i < 10; ++i){ptrs.push_back(pool1.get());assert (pool1.allocated() == i + 1);assert (pool1.available() == 0);}try{pool1.get();fail("pool exhausted - must throw exception");}catch (Poco::OutOfMemoryException&){}int av = 0;for (std::vector<void*>::iterator it = ptrs.begin(); it != ptrs.end(); ++it){pool1.release(*it);++av;assert (pool1.available() == av);}MemoryPool pool2(32, 5, 10);assert (pool2.available() == 5);assert (pool2.blockSize() == 32);assert (pool2.allocated() == 5);}