MPxCacheFormat Class Reference

#include <MPxCacheFormat.h>

Class Description

CacheFormat definition.

The MPxCacheFormat class can be used to implement support for new cache file formats in Maya.

Examples:

Public Types
enum	FileAccessMode { kRead, kWrite, kReadWrite }
	Cache file access modes. More...

Public Member Functions
	MPxCacheFormat ()
	The default class constructor. More...
virtual	~MPxCacheFormat ()
	Class destructor. More...
virtual MStatus	open (const MString &fileName, FileAccessMode mode)
	Attempt to open the specified cache format. More...
virtual void	close ()
	Close the current current cache file.
virtual MStatus	isValid ()
	Confirm whether the current cache file is valid. More...
virtual MStatus	rewind ()
	Rewind the current cache pointer to the start of the cache. More...
virtual MString	extension ()
	Returns the extension used by this format. More...
virtual MStatus	readHeader ()
	Read the header from the current cache file, and store any data that may be required. More...
virtual MStatus	writeHeader (const MString &version, MTime &startTime, MTime &endTime)
	Write the header for the current cache. More...
virtual void	beginWriteChunk ()
	Perform any actions required prior to writing a chunk's information. More...
virtual void	endWriteChunk ()
	Perform any actions required after writing a chunk's information.
virtual MStatus	beginReadChunk ()
	Start the read process for this chunk. More...
virtual void	endReadChunk ()
	End the read process for this chunk. More...
virtual MStatus	writeTime (MTime &time)
	Write the current time to the cache. More...
virtual MStatus	readTime (MTime &time)
	Read the current time from the cache. More...
virtual MStatus	findTime (MTime &time, MTime &foundTime)
	Find a specific time in the cache. More...
virtual MStatus	readNextTime (MTime &foundTime)
	Read the next time from the cache. More...
virtual unsigned	readArraySize ()
	Read the size of an array in the cache. More...
virtual MStatus	writeDoubleArray (const MDoubleArray &)
	Write an array of doubles to the cache. More...
virtual MStatus	writeFloatArray (const MFloatArray &)
	Write a array of floats to the cache. More...
virtual MStatus	writeIntArray (const MIntArray &)
	Write a array of int to the cache. More...
virtual MStatus	writeDoubleVectorArray (const MVectorArray &array)
	Write an array of double-precision vectors to the cache. More...
virtual MStatus	writeFloatVectorArray (const MFloatVectorArray &array)
	Write an array of single-precision vectors to the cache. More...
virtual MStatus	writeInt32 (int)
	Write an integer to the cache. More...
virtual MStatus	readDoubleArray (MDoubleArray &, unsigned size)
	Read an array of doubles from the cache. More...
virtual MStatus	readFloatArray (MFloatArray &, unsigned size)
	Read an array of floats from the cache. More...
virtual MStatus	readIntArray (MIntArray &, unsigned size)
	Read an array of ints from the cache. More...
virtual MStatus	readDoubleVectorArray (MVectorArray &, unsigned arraySize)
	Read an array of double-precision vectors from the cache. More...
virtual MStatus	readFloatVectorArray (MFloatVectorArray &array, unsigned arraySize)
	Read an array of single-precision vectors from the cache. More...
virtual int	readInt32 ()
	Read an integer from the cache. More...
virtual MStatus	writeChannelName (const MString &name)
	Write a channel to the cache. More...
virtual MStatus	findChannelName (const MString &name)
	Seek to a specific channel in the cache. More...
virtual MStatus	readChannelName (MString &name)
	Find the next channel name. More...
virtual bool	handlesDescription ()
	Report whether this format handles the format description itself (usually provided by the default xml description file). More...
virtual MStatus	readDescription (MCacheFormatDescription &description, const MString &descriptionFileLocation, const MString &baseFileName)
	Obtain the format description information. More...
virtual MStatus	writeDescription (const MCacheFormatDescription &description, const MString &descriptionFileLocation, const MString &baseFileName)
	Store the format description information. More...

Static Public Member Functions
static const char *	className ()
	Returns the name of this class. More...

Member Enumeration Documentation

enum FileAccessMode

Cache file access modes.

Enumerator
kRead	read only
kWrite	write only
kReadWrite	read and write (e.g. append, edit, etc.)

Constructor & Destructor Documentation

OPENMAYA_MAJOR_NAMESPACE_OPEN MPxCacheFormat

(

)

The default class constructor.

Initialize the format.

~MPxCacheFormat ( )

virtual

Class destructor.

Automatically releases the associated format.

Member Function Documentation

MStatus open ( const MString &  fileName, FileAccessMode  mode  )

virtual

Attempt to open the specified cache format.

It is important that this function only return success if the cache file is definitely supported by this implementation.

Parameters

[in]	fileName	Name of the cache file to open
[in]	mode	Access mode for the cache file

Returns

• MS::kSuccess if the cache is supported by this implementation
• MS::kFailure otherwise

MStatus isValid ( )

virtual

Confirm whether the current cache file is valid.

Returns

• MS::kSuccess if the current cache file is valid
• MS::kFailure otherwise

MStatus rewind ( )

virtual

Rewind the current cache pointer to the start of the cache.

Returns

• MS::kSuccess if the pointer is rewound
• MS::kFailure otherwise

MString extension ( )

virtual

Returns the extension used by this format.

This is not the same as the format's key, which is used by the plugin to identify itself.

Returns

The extension used by this format, with no leading period, e.g. "xcf" not ".xcf"

MStatus readHeader ( )

virtual

Read the header from the current cache file, and store any data that may be required.

Returns

• MS::kSuccess current header is valid and has been read
• MS::kFailure otherwise

MStatus writeHeader ( const MString &  version, MTime &  startTime, MTime &  endTime  )

virtual

Write the header for the current cache.

Parameters

[in]	version	Maya supplied cache version
[in]	startTime	startTime for this cache, in ticks. There are 6000 ticks per second
[in]	endTime	endTime for this cache, in ticks. There are 6000 ticks per second

Returns

• MS::kSuccess if the cache's header has been written successfully
• MS::kFailure otherwise

void beginWriteChunk ( )

virtual

Perform any actions required prior to writing a chunk's information.

A chunk contains the cache information for a specific time, and may contain multiple channels.

MStatus beginReadChunk ( )

virtual

Start the read process for this chunk.

Anything written by beginWriteChunk() should be read and validated by this method.

A chunk contains the cache information for a specific time, and may contain multiple channels.

Returns

• MS::kSuccess if the cache's chunk information has been written successfully
• MS::kFailure otherwise

void endReadChunk ( )

virtual

End the read process for this chunk.

Anything written by the endWriteChunk should be read and validated by this method.

Returns

• MS::kSuccess if the cache's chunk information has been read successfully
• MS::kFailure otherwise

MStatus writeTime ( MTime &  time )

virtual

Write the current time to the cache.

Parameters

[in]

time

Time to write.

Returns

• MS::kSuccess if the time is successfully written to the cache
• MS::kFailure otherwise

MStatus readTime ( MTime &  time )

virtual

Read the current time from the cache.

Parameters

[out]

time

Current time from the cache.

Returns

• MS::kSuccess if the time is successfully read from the cache
• MS::kFailure otherwise

MStatus findTime ( MTime &  time, MTime &  foundTime  )

virtual

Find a specific time in the cache.

Parameters

[in]	time	Time to look for.
[out]	foundTime	Nearest time found.

Returns

• MS::kSuccess if the time is successfully read from the cache
• MS::kFailure otherwise

MStatus readNextTime ( MTime &  foundTime )

virtual

Read the next time from the cache.

Parameters

[out]

foundTime

the time found

Returns

• MS::kSuccess if the time is successfully read from the cache
• MS::kFailure otherwise

unsigned readArraySize ( )

virtual

Read the size of an array in the cache.

Returns

• MS::kSuccess if the size is successfully read from the cache
• MS::kFailure otherwise

MStatus writeDoubleArray ( const MDoubleArray &  array )

virtual

Write an array of doubles to the cache.

Parameters

[in]

array

Array of values to be written.

Returns

• MS::kSuccess if the array is successfully written to the cache
• MS::kFailure otherwise

MStatus writeFloatArray ( const MFloatArray &  array )

virtual

Write a array of floats to the cache.

Parameters

[in]

array

Array of values to be written.

Returns

• MS::kSuccess if the array is successfully written to the cache
• MS::kFailure otherwise

MStatus writeIntArray ( const MIntArray &  array )

virtual

Write a array of int to the cache.

Parameters

[in]

array

Array of values to be written.

Returns

• MS::kSuccess if the array is successfully written to the cache
• MS::kFailure otherwise

MStatus writeDoubleVectorArray ( const MVectorArray &  array )

virtual

Write an array of double-precision vectors to the cache.

Parameters

[in]

array

Array of values to be written.

Returns

• MS::kSuccess if the array is successfully written to the cache
• MS::kFailure otherwise

MStatus writeFloatVectorArray ( const MFloatVectorArray &  array )

virtual

Write an array of single-precision vectors to the cache.

Parameters

[in]

array

Array of values to be written.

Returns

• MS::kSuccess if the array is successfully written to the cache
• MS::kFailure otherwise

MStatus writeInt32 ( int  value )

virtual

Write an integer to the cache.

Parameters

[in]

value

the value to be written

Returns

• MS::kSuccess if the value is successfully written to the cache
• MS::kFailure otherwise

MStatus readDoubleArray ( MDoubleArray &  array, unsigned  size  )

virtual

Read an array of doubles from the cache.

Parameters

[out]	array	Array of values read.
[in]	size	Number of elements expected.

Returns

• MS::kSuccess if the array is successfully read from the cache
• MS::kFailure otherwise

MStatus readFloatArray ( MFloatArray &  array, unsigned  size  )

virtual

Read an array of floats from the cache.

Parameters

[out]	array	Array of values read.
[in]	size	Number of elements expected.

Returns

• MS::kSuccess if the array is successfully read from the cache
• MS::kFailure otherwise

MStatus readIntArray ( MIntArray &  array, unsigned  size  )

virtual

Read an array of ints from the cache.

Parameters

[out]	array	Array of values read.
[in]	size	Number of elements expected.

Returns

• MS::kSuccess if the array is successfully read from the cache
• MS::kFailure otherwise

MStatus readDoubleVectorArray ( MVectorArray &  array, unsigned  arraySize  )

virtual

Read an array of double-precision vectors from the cache.

Parameters

[out]	array	Array of values read.
[in]	arraySize	Number of elements expected.

Returns

• MS::kSuccess if the array is successfully read from the cache
• MS::kFailure otherwise

MStatus readFloatVectorArray ( MFloatVectorArray &  array, unsigned  size  )

virtual

Read an array of single-precision vectors from the cache.

Parameters

[out]	array	Array of values read.
[in]	size	Number of elements expected.

Returns

• MS::kSuccess if the array is successfully read from the cache
• MS::kFailure otherwise

int readInt32 ( )

virtual

Read an integer from the cache.

Returns

The value read from the cache

MStatus writeChannelName ( const MString &  name )

virtual

Write a channel to the cache.

Parameters

[in]

name

the channel to be written

Returns

• MS::kSuccess if the channel is successfully written to the cache
• MS::kFailure otherwise

MStatus findChannelName ( const MString &  name )

virtual

Seek to a specific channel in the cache.

Parameters

[in]

name

the channel to seek

Returns

• MS::kSuccess if the channel is found
• MS::kFailure otherwise

MStatus readChannelName ( MString &  name )

virtual

Find the next channel name.

Parameters

[in]

name

the name that is found

Returns

• MS::kSuccess if there is a channel
• MS::kFailure otherwise

bool handlesDescription ( )

virtual

Report whether this format handles the format description itself (usually provided by the default xml description file).

If the format handles the description itself, it must provide implementations of readDescription() and writeDescription().

Returns

True if this format handles the description, else false.

MStatus readDescription ( MCacheFormatDescription &  description, const MString &  descriptionFileLocation, const MString &  baseFileName  )

virtual

Obtain the format description information.

If the format returns true for handlesDescription(), then it must implement this method. The implementation should in turn call MCacheFormatDescription::setDistribution(), setTimePerFrame(), addDescriptionInfo() and addChannel() as appropriate using the supplied description object.

In the default implementation, the xml description file is stored at descriptionFileLocation + baseFileName + ".xml"

Parameters

[out]	description	the description object to be set up
[in]	descriptionFileLocation	the default location of the description file
[in]	baseFileName	the default file name (without extension) of the description file

Returns

• MS::kSuccess if the description was successfully read
• MS::kFailure otherwise

MStatus writeDescription ( const MCacheFormatDescription &  description, const MString &  descriptionFileLocation, const MString &  baseFileName  )

virtual

Store the format description information.

If the format returns true for handlesDescription(), then it must implement this method. The implementation should in turn call MCacheFormatDescription::getDistribution(), getTimePerFrame(), getStartAndEndTimes(), getDescriptionInfo(), getNumChannels() and the various getChannelXXX() methods using the supplied description object as appropriate and store this information in such a way that it can be retrieved by readDescription().

In the default implementation, the xml description file is stored at descriptionFileLocation + baseFileName + ".xml"

Note that the plug-in is not required to store the description in a file using descriptionFileLocation and baseFileName. However, it must be able to retrieve the same description using just these strings to identify the source of the data.

Parameters

[in]	description	the description object that describes the format
[in]	descriptionFileLocation	the default location of the description file
[in]	baseFileName	the default file name (without extension) of the description file

Returns

• MS::kSuccess if the description was successfully read
• MS::kFailure otherwise

const char * className ( )

static

Returns the name of this class.

Returns

The name of this class.

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

• MPxCacheFormat.h
• MPxCacheFormat.cpp