GMemoryStream和std::iostream转换

说明：

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typedef QBuffer GBuffer; class GMemoryStream : public GBuffer {     ... }; class std::stringstream : public std::iostream{...};

1.GMemoryStream转换为std::iostream

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// 1.定义 QBuffer QBuffer buff; buff.open(QBuffer::ReadWrite); buff.write("liujm", 5); // 2.定义 stringstream std::stringstream strBuff; // 3.将 QBuffer 写入 stringstream strBuff.write(buff.buffer().data(), buff.size());   // 测试 char* arr = new char[buff.size() + 1]; strBuff >> arr; cout << arr << endl;     // liujm delete arr;

For example

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void loadFromStream(std::iostream &io) {     io.seekg(0, ios::end);  // the ending of a stream     int nCount = io.tellg();     io.seekg(0, ios::beg);  // the beginning of a stream       char* arr = new char[nCount + 1];     io.read(arr, nCount);     *(arr + nCount) = '\0';     cout << arr << endl;       delete arr; }   void bufferToIostream() {        QBuffer buff;     buff.open(QBuffer::ReadWrite);     buff.write("liujm", 5);     std::stringstream strBuff;     strBuff.write(buff.buffer().data(), buff.size());     loadFromStream(strBuff); }

2.std::iostream转换为GMemoryStream

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// 1.定义 stringstream std::stringstream strBuff; strBuff.write("liujm", 5); strBuff << '\0'; strBuff.write("liujm", 5); // 2.定义 QBuffer QBuffer buff; buff.open(QIODevice::ReadWrite); // 3.将 stringstream 中的流写入 QBuffer buff.write(strBuff.str().c_str(), strBuff.str().size());   // 测试 char* arr = new char[1 + strBuff.str().size()]; buff.seek(0); buff.read(arr, strBuff.str().size()); *(arr + strBuff.str().size()) = 0; cout << arr << endl;    // 注意：此处打印出的结果只有liujm，而不是liujm\0liujm，因为对于c风格的字符串\0就是结尾。QBuffer 流中的数据是 liujm\0liujm delete arr;

For example

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void saveToStream(std::iostream &io) {     // ...     io.write("liujm", 5); }   void iostreamToBuffer() {     std::stringstream strBuff;     saveToStream(strBuff);     QBuffer buff;     buff.open(QIODevice::ReadWrite);     buff.write(strBuff.str().c_str(), strBuff.str().size()); }