/*
* 用于实现 IRandomAccessStream, IBuffer, Stream, byte[] 之间相互转换的帮助类
*/
using System;
using System.IO;
using System.Runtime.InteropServices.WindowsRuntime;
using System.Threading.Tasks;
using Windows.Storage.Streams;
namespace XamlDemo.FileSystem
{
/// <summary>
/// 转来转去的帮助类
/// </summary>
public class ConverterHelper
{
public async static Task<IRandomAccessStream> Buffer2RandomAccessStream(IBuffer buffer)
{
IRandomAccessStream randomStream = new InMemoryRandomAccessStream();
DataWriter dataWriter = new DataWriter(randomStream);
dataWriter.WriteBuffer(buffer, 0, buffer.Length);
await dataWriter.StoreAsync();
return randomStream;
}
public static IBuffer RandomAccessStream2Buffer(IRandomAccessStream randomStream)
{
Stream stream = WindowsRuntimeStreamExtensions.AsStreamForRead(randomStream.GetInputStreamAt(0));
MemoryStream memoryStream = new MemoryStream();
if (stream != null)
{
byte[] bytes = Stream2Bytes(stream);
if (bytes != null)
{
var binaryWriter = new BinaryWriter(memoryStream);
binaryWriter.Write(bytes);
}
}
IBuffer buffer = WindowsRuntimeBufferExtensions.GetWindowsRuntimeBuffer(memoryStream, 0, (int)memoryStream.Length);
return buffer;
}
public async static Task<IRandomAccessStream> Stream2RandomAccessStream(Stream stream)
{
byte[] bytes = Stream2Bytes(stream);
IRandomAccessStream randomStream = new InMemoryRandomAccessStream();
DataWriter dataWriter = new DataWriter(randomStream.GetOutputStreamAt(0));
dataWriter.WriteBytes(bytes);
await dataWriter.StoreAsync();
return randomStream;
}
public static Stream RandomAccessStream2Stream(IRandomAccessStream randomStream)
{
Stream stream = WindowsRuntimeStreamExtensions.AsStreamForRead(randomStream.GetInputStreamAt(0));
return stream;
}
public static Stream Buffer2Stream(IBuffer buffer)
{
Stream stream = WindowsRuntimeBufferExtensions.AsStream(buffer);
return stream;
}
public static IBuffer Stream2Buffer(Stream stream)
{
MemoryStream memoryStream = new MemoryStream();
if (stream != null)
{
byte[] bytes = Stream2Bytes(stream);
if (bytes != null)
{
var binaryWriter = new BinaryWriter(memoryStream);
binaryWriter.Write(bytes);
}
}
IBuffer buffer = WindowsRuntimeBufferExtensions.GetWindowsRuntimeBuffer(memoryStream, 0, (int)memoryStream.Length);
return buffer;
}
public static FileInputStream RandomAccessStream2FileInputStream(IRandomAccessStream randomStream)
{
FileInputStream inputStream = randomStream.GetInputStreamAt(0) as FileInputStream;
return inputStream;
}
public static FileOutputStream RandomAccessStream2FileOutputStream(IRandomAccessStream randomStream)
{
FileOutputStream outputStream = randomStream.GetOutputStreamAt(0) as FileOutputStream;
return outputStream;
}
public static IBuffer String2Buffer(string str)
{
using (InMemoryRandomAccessStream memoryStream = new InMemoryRandomAccessStream())
{
using (DataWriter dataWriter = new DataWriter(memoryStream))
{
dataWriter.WriteString(str);
return dataWriter.DetachBuffer();
}
}
}
public static string Buffer2String(IBuffer buffer)
{
using (DataReader dataReader = DataReader.FromBuffer(buffer))
{
string fileContent = dataReader.ReadString(buffer.Length);
return fileContent;
}
}
public static IBuffer Bytes2Buffer(byte[] bytes)
{
using (var dataWriter = new DataWriter())
{
dataWriter.WriteBytes(bytes);
return dataWriter.DetachBuffer();
}
}
public static byte[] Buffer2Bytes(IBuffer buffer)
{
using (var dataReader = DataReader.FromBuffer(buffer))
{
var bytes = new byte[buffer.Length];
dataReader.ReadBytes(bytes);
return bytes;
}
}
public static byte[] Stream2Bytes(Stream stream)
{
if (stream.CanSeek) // stream.Length 已确定
{
byte[] bytes = new byte[stream.Length];
stream.Read(bytes, 0, bytes.Length);
stream.Seek(0, SeekOrigin.Begin);
return bytes;
}
else // stream.Length 不确定
{
int initialLength = 32768; // 32k
byte[] buffer = new byte[initialLength];
int read = 0;
int chunk;
while ((chunk = stream.Read(buffer, read, buffer.Length – read)) > 0)
{
read += chunk;
if (read == buffer.Length)
{
int nextByte = stream.ReadByte();
if (nextByte == -1)
{
return buffer;
}
byte[] newBuffer = new byte[buffer.Length * 2];
Array.Copy(buffer, newBuffer, buffer.Length);
newBuffer[read] = (byte)nextByte;
buffer = newBuffer;
read++;
}
}
byte[] ret = new byte[read];
Array.Copy(buffer, ret, read);
return ret;
}
}
public static Stream Bytes2Stream(byte[] bytes)
{
Stream stream = new MemoryStream(bytes);
return stream;
}
}
}
