HashStream Class

HashStream Class

A wrapper stream that calculates a hash of the base stream as it is being read. The calculated hash is only available after the stream is closed or CalculateHash is called. After calling CalculateHash, any further reads on the streams will not change the CalculatedHash. If an ExpectedHash is specified and is not equal to the calculated hash, Close or CalculateHash methods will throw an ClientException. If CalculatedHash is calculated for only the portion of the stream that is read.

Inheritance Hierarchy

SystemObject
  SystemMarshalByRefObject
    System.IOStream
      Aliyun.OSS.Common.InternalWrapperStream
        Aliyun.OSS.Common.InternalHashStream
          Aliyun.OSS.Common.InternalHashStreamT

Namespace: Aliyun.OSS.Common.Internal
Assembly: Aliyun.OSS (in Aliyun.OSS.dll) Version: 2.5.1.0 (2.5.1)

Syntax

C++

Copy

public abstract class HashStream : WrapperStream

Public MustInherit Class HashStream
	Inherits WrapperStream

public ref class HashStream abstract : public WrapperStream

[<AbstractClassAttribute>]
type HashStream =  
    class
        inherit WrapperStream
    end

The HashStream type exposes the following members.

Constructors

	Name	Description
	HashStream(Stream, Int64)	Initializes an HashStream with a hash algorithm and a base stream.
	HashStream(Stream, Byte, Int64)	Initializes an HashStream with a hash algorithm and a base stream.

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Methods

	Name	Description
	BeginRead	Begins an asynchronous read operation. (Inherited from Stream.)
	BeginWrite	Begins an asynchronous write operation. (Inherited from Stream.)
	CalculateHash	Calculates the hash for the stream so far and disables any further hashing.
	Close	Closes the underlying stream and finishes calculating the hash. If an ExpectedHash is specified and is not equal to the calculated hash, this method will throw an ClientException. (Overrides WrapperStreamClose.)
	CompareHashes	Compares two hashes (arrays of bytes).
	CreateObjRef	Creates an object that contains all the relevant information required to generate a proxy used to communicate with a remote object. (Inherited from MarshalByRefObject.)
	CreateWaitHandle	Obsolete. Allocates a WaitHandle object. (Inherited from Stream.)
	Dispose	Releases all resources used by the Stream. (Inherited from Stream.)
	Dispose(Boolean)	Releases the unmanaged resources used by the HashStream and optionally releases the managed resources (Overrides StreamDispose(Boolean).)
	EndRead	Waits for the pending asynchronous read to complete. (Inherited from Stream.)
	EndWrite	Ends an asynchronous write operation. (Inherited from Stream.)
	Equals	Determines whether the specified Object is equal to the current Object. (Inherited from Object.)
	Finalize	Allows an Object to attempt to free resources and perform other cleanup operations before the Object is reclaimed by garbage collection. (Inherited from Object.)
	Flush	Clears all buffers for this stream and causes any buffered data to be written to the underlying device. (Inherited from WrapperStream.)
	GetHashCode	Serves as a hash function for a particular type. (Inherited from Object.)
	GetLifetimeService	Retrieves the current lifetime service object that controls the lifetime policy for this instance. (Inherited from MarshalByRefObject.)
	GetNonWrapperBaseStream	Returns the first base non-WrapperStream. (Inherited from WrapperStream.)
	GetSeekableBaseStream	Returns the first base non-WrapperStream. (Inherited from WrapperStream.)
	GetType	Gets the Type of the current instance. (Inherited from Object.)
	InitializeLifetimeService	Obtains a lifetime service object to control the lifetime policy for this instance. (Inherited from MarshalByRefObject.)
	MemberwiseClone	Creates a shallow copy of the current Object. (Inherited from Object.)
	MemberwiseClone(Boolean)	Creates a shallow copy of the current MarshalByRefObject object. (Inherited from MarshalByRefObject.)
	Read	Reads a sequence of bytes from the current stream and advances the position within the stream by the number of bytes read. (Overrides WrapperStreamRead(Byte, Int32, Int32).)
	ReadByte	Reads a byte from the stream and advances the position within the stream by one byte, or returns -1 if at the end of the stream. (Inherited from Stream.)
	Reset	Resets the hash stream to starting state. Use this if the underlying stream has been modified and needs to be rehashed without reconstructing the hierarchy.
	SearchWrappedStream(OssFuncStream, Boolean)	(Inherited from WrapperStream.)
	Seek	Sets the position within the current stream. HashStream does not support seeking, attempting to call Seek will throw NotSupportedException. (Overrides WrapperStreamSeek(Int64, SeekOrigin).)
	SetLength	Sets the length of the current stream. (Inherited from WrapperStream.)
	ToString	Returns a String that represents the current Object. (Inherited from Object.)
	Write	Writes a sequence of bytes to the current stream and advances the current position within this stream by the number of bytes written. (Inherited from WrapperStream.)
	WriteByte	Writes a byte to the current position in the stream and advances the position within the stream by one byte. (Inherited from Stream.)

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Properties

	Name	Description
	Algorithm	Algorithm to use to calculate hash.
	BaseStream	Base stream. (Inherited from WrapperStream.)
	CalculatedHash	Calculated hash for the stream. This value is set only after the stream is closed.
	CanRead	Gets a value indicating whether the current stream supports reading. True if the stream supports reading; otherwise, false. (Inherited from WrapperStream.)
	CanSeek	Gets a value indicating whether the current stream supports seeking. HashStream does not support seeking, this will always be false. (Overrides WrapperStreamCanSeek.)
	CanTimeout	Gets a value that determines whether the current stream can time out. (Inherited from Stream.)
	CanWrite	Gets a value indicating whether the current stream supports writing. True if the stream supports writing; otherwise, false. (Inherited from WrapperStream.)
	CurrentPosition	Current position in the stream.
	ExpectedHash	Expected hash value. Compared against CalculatedHash upon Close(). If the hashes are different, an ClientException is thrown.
	ExpectedLength	Expected length of stream.
	FinishedHashing	True if hashing is finished and no more hashing should be done; otherwise false.
	Length	Gets the overridden length used to construct the HashStream (Overrides WrapperStreamLength.)
	Position	Gets or sets the position within the current stream. HashStream does not support seeking, attempting to set Position will throw NotSupportedException. (Overrides WrapperStreamPosition.)
	ReadTimeout	Gets or sets a value, in miliseconds, that determines how long the stream will attempt to read before timing out. (Inherited from WrapperStream.)
	WriteTimeout	Gets or sets a value, in miliseconds, that determines how long the stream will attempt to write before timing out. (Inherited from WrapperStream.)

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Exceptions

Exception	Condition
ClientException	Exception thrown during Close() or CalculateHash(), if ExpectedHash is set and is different from CalculateHash that the stream calculates, provided that CalculatedHash is not a zero-length byte array.

Reference

Aliyun.OSS.Common.Internal Namespace