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如何使用xmlite将XML存储在缓冲区中?

xmllite c++

1

Suri · 技术社区 · 15 年前

我试图在缓冲区上用xmllite编写XML数据,但没有任何API。写一个XML文件很好,但是在内存流上我无法计算我正在研究follwong链接API http://msdn.microsoft.com/en-us/library/ms752901(v=VS.85).aspx

1 回复 | 直到 14 年前

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2

Samuel Zhang 15 年前

你可以使用 SHCreateMemStream 或 CreateStreamOnHGlobal 创建内存流。以下是供您参考的示例代码:

CComPtr<IStream> spMemoryStream;
CComPtr<IXmlWriter> spWriter;
CComPtr<IXmlWriterOutput> pWriterOutput;

// Opens writeable output stream.
spMemoryStream.Attach(::SHCreateMemStream(NULL, 0));
if (spMemoryStream == NULL)
    return E_OUTOFMEMORY;

// Creates the xml writer and generates the content.
CHKHR(::CreateXmlWriter(__uuidof(IXmlWriter), (void**) &spWriter, NULL));
CHKHR(::CreateXmlWriterOutputWithEncodingName(spMemoryStream,
    NULL, L"utf-16", &pWriterOutput));
CHKHR(spWriter->SetOutput(pWriterOutput));
CHKHR(spWriter->SetProperty(XmlWriterProperty_Indent, TRUE));
CHKHR(spWriter->WriteStartDocument(XmlStandalone_Omit));
CHKHR(spWriter->WriteStartElement(NULL, L"root", NULL));
CHKHR(spWriter->WriteWhitespace(L"\n"));
CHKHR(spWriter->WriteCData(L"This is CDATA text."));
CHKHR(spWriter->WriteWhitespace(L"\n"));
CHKHR(spWriter->WriteEndDocument());
CHKHR(spWriter->Flush());

// Allocates enough memeory for the xml content.
STATSTG ssStreamData = {0};
CHKHR(spMemoryStream->Stat(&ssStreamData, STATFLAG_NONAME));
SIZE_T cbSize = ssStreamData.cbSize.LowPart;
LPWSTR pwszContent = (WCHAR*) new(std::nothrow) BYTE[cbSize + sizeof(WCHAR)];
if (pwszContent == NULL)
    return E_OUTOFMEMORY;

// Copies the content from the stream to the buffer.
LARGE_INTEGER position;
position.QuadPart = 0;
CHKHR(spMemoryStream->Seek(position, STREAM_SEEK_SET, NULL));
SIZE_T cbRead;
CHKHR(spMemoryStream->Read(pwszContent, cbSize, &cbRead));
pwszContent[cbSize / sizeof(WCHAR)] = L'\0';

wprintf(L"%s", pwszContent);

XMLLite的一个优点是它可以与IStream接口一起工作。它真的不在乎在场景后面的小溪究竟是什么样子。