Deflate.h File Reference

#include "utils/Buffer.h"

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Functions
bool	IsDeflated (const Buffer &data)
	Checks whether given data is deflated. More...
bool	DeflateData (Buffer &data)
	Deflates given data. More...
bool	DeflateData (const Buffer &input, Buffer &output)
	Deflates given data. More...
bool	InflateData (Buffer &data)
	Inflates given data. More...
bool	InflateData (const Buffer &input, Buffer &output)
	Inflates given data. More...

Variables
const uint8	DeflateHeaderByte

Function Documentation

bool DeflateData

(

Buffer &

data

)

Deflates given data.

Parameters

[in,out]

data

Data to be deflated, overwritten by result.

Return values

true	Deflation ran successfully.
false	Error occurred during deflation.

Definition at line 37 of file Deflate.cpp.

References DeflateData().

Referenced by DeflateData(), MarshalDeflate(), and MailDB::SendMail().

{
    Buffer dataDeflated;
    if( !DeflateData( data, dataDeflated ) )
        return false;

    data = dataDeflated;
    return true;
}

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bool DeflateData	(	const Buffer &	input,
		Buffer &	output
	)

Deflates given data.

Parameters

[in]	input	Data to be deflated.
[out]	output	Destination of deflated data.

Return values

true	Deflation ran successfully.
false	Error occurred during deflation.

Definition at line 47 of file Deflate.cpp.

References Buffer::end(), Buffer::ResizeAt(), and Buffer::size().

{
    const Buffer::iterator<uint8> out = output.end<uint8>();

    size_t outputSize = compressBound( input.size() );
    output.ResizeAt( out, outputSize );

    int res = compress( &*out, (uLongf*)&outputSize, &input[0], input.size() );

    if( Z_OK == res )
    {
        output.ResizeAt( out, outputSize );
        return true;
    }
    else
    {
        output.ResizeAt( out, 0 );
        return false;
    }
}

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bool InflateData

(

Buffer &

data

)

Inflates given data.

Parameters

[in,out]

data

Data to be inflated, overwritten by result.

Return values

true	Inflation ran successfully.
false	Failed to inflate data.

Definition at line 68 of file Deflate.cpp.

References InflateData().

Referenced by InflateData(), and InflateUnmarshal().

{
    Buffer dataInflated;
    if( !InflateData( data, dataInflated ) )
        return false;

    data = dataInflated;
    return true;
}

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bool InflateData	(	const Buffer &	input,
		Buffer &	output
	)

Inflates given data.

One of the key things of the ZLIB stuff is that we 'sometimes' don't know the size of the uncompressed data. My idea is to fix this regarding the first phase of the parsing of the data (the parser) is to go trough a couple of output buffer size.

The first buffer size would be 2x the initial buffer size, implying that the compression ratio is about 50%. The second buffer size would be 4x the initial buffer size, implying that the compression ratio is about 75%. The third buffer size would be 8x the initial buffer size implying that the compression ratio is about 87.5%.

We would go on in this progress until we find buffer size big enough to hold uncompressed data.

This theory is really stupid because there is no way to actually know.

Parameters

[in]	input	Data to be inflated.
[out]	output	Destination for inflated data.

Return values

true	Inflation ran successfully.
false	Failed to inflate data.

Definition at line 78 of file Deflate.cpp.

References Buffer::end(), Buffer::ResizeAt(), and Buffer::size().

{
    const Buffer::iterator<uint8> out = output.end<uint8>();

    size_t outputSize = 0;
    size_t sizeMultiplier = 0;

    int res = 0;
    do
    {
        outputSize = ( input.size() << ++sizeMultiplier );
        output.ResizeAt( out, outputSize );

        res = uncompress( &*out, (uLongf*)&outputSize, &input[0], input.size() );
    } while( Z_BUF_ERROR == res );

    if( Z_OK == res )
    {
        output.ResizeAt( out, outputSize );
        return true;
    }
    else
    {
        output.ResizeAt( out, 0 );
        return false;
    }
}

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bool IsDeflated

(

const Buffer &

data

)

Checks whether given data is deflated.

Parameters

[in]

data

Data to be checked.

Return values

true	Data is deflated.
false	Data is not deflated.

Definition at line 32 of file Deflate.cpp.

References DeflateHeaderByte.

Referenced by InflateUnmarshal().

{
    return ( DeflateHeaderByte == data[0] );
}

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Variable Documentation

const uint8 DeflateHeaderByte

Definition at line 30 of file Deflate.cpp.

Referenced by IsDeflated().