CodecReader Class Reference

A helper class for implementing CodecReaders. More...

#include "client/data/codec.h"

Inheritance diagram for CodecReader:

List of all members.

Public Member Functions
	CodecReader (DataReader *source, Closure *deleter, int64 chunk_size, int64 buffer_size, bool encoding)
	Standard constructor.
virtual	~CodecReader ()
	Standard destructor.
virtual util::Status	Init ()
	Called when resetting readers (seeking to start)
Protected Member Functions
bool	encoding () const
	Returns whether the reader was constructed for encoding or decoding.
virtual int64	DoReadToBuffer (int64 max_bytes, char *storage)
	Reads from internal transformed buffer, replentishing it as necessary.
virtual int64	DoSetOffset (int64 to_offset)
	Implements seeking through the transformed stream.
virtual util::Status	EncodeChunk (const StringPiece &from, bool final, char *to, int64 *to_len)=0
	Hook for codecs to encode a chunk.
virtual util::Status	DecodeChunk (const StringPiece &from, bool final, char *to, int64 *to_len)=0
	Hook for codecs to decode a chunk.

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Detailed Description

A helper class for implementing CodecReaders.

This class assumes bounded transformation sizes for a given input size.

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Constructor & Destructor Documentation

CodecReader	(	DataReader *	source,
		Closure *	deleter,
		int64	chunk_size,
		int64	buffer_size,
		bool	encoding
	)

Standard constructor.

Parameters:

[in]	source	The untarnsformed stream the codec is processing.
[in]	deleter	The deleter if this is to be a managed stream.
[in]	chunk_size	The size of source data to accumulate for each transform (until the very last one)
[in]	buffer_size	The size to allocate for transformed data.
[in]	encoding	Whether this reader is encoding or decoding determines whether we'll EncodeChunk or DecodeChunk.

virtual ~CodecReader

(

)

[virtual]

Standard destructor.

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Member Function Documentation

virtual util::Status DecodeChunk	(	const StringPiece &	from,
		bool	final,
		char *	to,
		int64 *	to_len
	)		[protected, pure virtual]

Hook for codecs to decode a chunk.

Parameters:

[in]	from	The raw chunk from the source stream.
[in]	final	True if this is the final chunk.
[in]	to	The target buffer must be allocated big enough.
[in,out]	to_len	The size of the 'to' buffer on input. The amount of data written into 'to' on output.

virtual int64 DoReadToBuffer	(	int64	max_bytes,
		char *	storage
	)		[protected, virtual]

Reads from internal transformed buffer, replentishing it as necessary.

This method is compliant with the base DataReader::DoReadToBuffer semantics. In particular, results are never non-negative and 0 does not have any special meaning with regard to errors or being done.

Parameters:

[in]	max_bytes	Max bytes to copy from buffer.
[in]	storage	The storage to read into.

Returns:

Number of bytes read will never be more than the constructed buffer_size, at least for the base class.

Implements DataReader.

virtual int64 DoSetOffset

(

int64

to_offset

)

[protected, virtual]

Implements seeking through the transformed stream.

This method is compliant with the base DataReader::DoSetOffset semantics.

Reimplemented from DataReader.

virtual util::Status EncodeChunk	(	const StringPiece &	from,
		bool	final,
		char *	to,
		int64 *	to_len
	)		[protected, pure virtual]

Hook for codecs to encode a chunk.

Parameters:

[in]	from	The raw chunk from the source stream.
[in]	final	True if this is the final chunk.
[in]	to	The target buffer must be allocated big enough.
[in,out]	to_len	The size of the 'to' buffer on input. The amount of data written into 'to' on output.

bool encoding

(

)

const [inline, protected]

Returns whether the reader was constructed for encoding or decoding.

virtual util::Status Init

(

)

[virtual]

Called when resetting readers (seeking to start)

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The documentation for this class was generated from the following file:

• googleapis/client/data/codec.h