LLBufferArray Class Reference

Class to represent scattered memory buffers and in-order segments of that buffered data. More...

#include <llbuffer.h>

Public Member Functions
	LLBufferArray ()


bool	append (S32 channel, const U8 *src, S32 len)
	Put data on a channel at the end of this buffer array.
S32	capacity () const
	Return the sum of all allocated bytes.
S32	count (S32 channel) const
	Count all bytes on channel.
S32	countAfter (S32 channel, U8 *start) const
	Count bytes in the buffer array on the specified channel.
bool	insertAfter (segment_iterator_t segment, S32 channel, const U8 *src, S32 len)
	Insert data into a buffer array after a particular segment.
bool	prepend (S32 channel, const U8 *src, S32 len)
	Put data on a channel at the front of this buffer array.
U8 *	readAfter (S32 channel, U8 start, U8 dest, S32 &len) const
	Read bytes in the buffer array on the specified channel.
U8 *	seek (S32 channel, U8 *start, S32 delta) const
	Find an address in a buffer array.


segment_iterator_t	beginSegment ()
	Get the first segment in the buffer array.
segment_iterator_t	constructSegmentAfter (U8 *address, LLSegment &segment)
	Get a segment iterator after address, and a constructed segment to represent the next linear block of memory.
segment_iterator_t	endSegment ()
	Get the one-past-the-end segment in the buffer array.
bool	eraseSegment (const segment_iterator_t &iter)
	Erase the segment if it is in the buffer array.
segment_iterator_t	getSegment (U8 *address)
	Get the segment which holds the given address.
const_segment_iterator_t	getSegment (U8 *address) const
	Get the segment which holds the given address.
segment_iterator_t	makeSegment (S32 channel, S32 length)
	Make a new segment at the end of buffer array.
segment_iterator_t	splitAfter (U8 *address)
	Split a segments so that address is the last address of one segment, and the rest of the original segment becomes another segment on the same channel.


bool	takeContents (LLBufferArray &source)
	Take the contents of another buffer array.
Protected Member Functions
bool	copyIntoBuffers (S32 channel, const U8 *src, S32 len, std::vector< LLSegment > &segments)
	Optimally put data in buffers, and reutrn segments.

LLChannelDescriptors	nextChannel ()
	Generate the next channel descriptor for this buffer array.
static LLChannelDescriptors	makeChannelConsumer (const LLChannelDescriptors &channels)
	Generate the a channel descriptor which consumes the output for the channel passed in.

Detailed Description

Class to represent scattered memory buffers and in-order segments of that buffered data.

*NOTE: This class needs to have an iovec interface

Constructor & Destructor Documentation

LLBufferArray::LLBufferArray ( )

LLBufferArray

Member Function Documentation

bool LLBufferArray::append	(	S32	channel,
		const U8 *	src,
		S32	len
	)

Put data on a channel at the end of this buffer array.

The data is copied from src into the buffer array. At least one new segment is created and put on the end of the array. This object will internally allocate new buffers if necessary.

Parameters:

	channel	The channel for this data
	src	The start of memory for the data to be copied
	len	The number of bytes of data to copy

Returns:: Returns true if the method worked.

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LLBufferArray::segment_iterator_t LLBufferArray::beginSegment ( )

Get the first segment in the buffer array.

Returns:: Returns the segment if there is one.

LLBufferArray::segment_iterator_t LLBufferArray::constructSegmentAfter	(	U8 *	address,
		LLSegment &	segment
	)

Get a segment iterator after address, and a constructed segment to represent the next linear block of memory.

This method is a helper by giving you the largest segment possible in the out-value param after the address provided. The iterator will be useful for iteration, while the segment can be used for direct access to memory after address if the return values isnot end. Passing in NULL will return beginSegment() which may be endSegment(). The segment returned will only be zero length if the return value equals end. This is really just a helper method, since all the information returned could be constructed through other methods.

Parameters:

	address	An address in the middle of the sought segment.
	segment[out]	segment to be used for reading or writing

Returns:: Returns an iterator which contains at least segment or endSegment() on failure.

bool LLBufferArray::copyIntoBuffers	(	S32	channel,
		const U8 *	src,
		S32	len,
		std::vector< LLSegment > &	segments
	)			`[protected]`

Optimally put data in buffers, and reutrn segments.

This is an internal function used to create buffers as necessary, and sequence the segments appropriately for the various ways to copy data from src into this. If this method fails, it may actually leak some space inside buffers, but I am not too worried about the slim possibility that we may have some 'dead' space which will be recovered when the buffer (which we will not lose) is deleted. Addressing this weakness will make the buffers almost as complex as a general memory management system.

Parameters:

	channel	The channel for this data
	src	The start of memory for the data to be copied
	len	The number of bytes of data to copy
	segments	Out-value for the segments created.

Returns:: Returns true if the method worked.

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S32 LLBufferArray::count ( S32 channel ) const [inline]

Count all bytes on channel.

Helper method which just calls countAfter().

Parameters:

channel

The channel to count.

Returns:: Returns the number of bytes in the channel.

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S32 LLBufferArray::countAfter	(	S32	channel,
		U8 *	start
	)			const

Count bytes in the buffer array on the specified channel.

Parameters:

	channel	The channel to count.
	start	The start address in the array for counting. You can specify NULL to start at the beginning.

Returns:: Returns the number of bytes in the channel after start

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LLBufferArray::segment_iterator_t LLBufferArray::endSegment ( )

Get the one-past-the-end segment in the buffer array.

Returns:: Returns the iterator for an invalid segment location.

bool LLBufferArray::eraseSegment ( const segment_iterator_t & iter )

Erase the segment if it is in the buffer array.

Parameters:

iter

An iterator referring to the segment to erase.

Returns:: Returns true on success.

LLBufferArray::segment_iterator_t LLBufferArray::getSegment ( U8 * address )

Get the segment which holds the given address.

As opposed to some methods, passing a NULL will result in returning the end segment.

Parameters:

address

An address in the middle of the sought segment.

Returns:: Returns the iterator for the segment or endSegment() on failure.

LLBufferArray::const_segment_iterator_t LLBufferArray::getSegment ( U8 * address ) const

Get the segment which holds the given address.

As opposed to some methods, passing a NULL will result in returning the end segment.

Parameters:

address

An address in the middle of the sought segment.

Returns:: Returns the iterator for the segment or endSegment() on failure.

bool LLBufferArray::insertAfter	(	segment_iterator_t	segment,
		S32	channel,
		const U8 *	src,
		S32	len
	)

Insert data into a buffer array after a particular segment.

The data is copied from src into the buffer array. At least one new segment is created and put in the array. This object will internally allocate new buffers if necessary.

Parameters:

	segment	The segment in front of the new segments location
	channel	The channel for this data
	src	The start of memory for the data to be copied
	len	The number of bytes of data to copy

Returns:: Returns true if the method worked.

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LLBufferArray::segment_iterator_t LLBufferArray::makeSegment	(	S32	channel,
		S32	length
	)

Make a new segment at the end of buffer array.

This method will attempt to create a new and empty segment of the specified length. The segment created may be shorter than requested.

Parameters:

	channel[in]	The channel for the newly created segment.
	length[in]	The requested length of the segment.

Returns:: Returns an iterator which contains at least segment or endSegment() on failure.

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LLChannelDescriptors LLBufferArray::nextChannel ( )

Generate the next channel descriptor for this buffer array.

The channel descriptor interface is how the buffer array clients can know where to read and write data. Use this interface to get the 'next' channel set for usage. This is a bit of a simple hack until it's utility indicates it should be extended.

Returns:: Returns a valid channel descriptor set for input and output.

bool LLBufferArray::prepend	(	S32	channel,
		const U8 *	src,
		S32	len
	)

Put data on a channel at the front of this buffer array.

The data is copied from src into the buffer array. At least one new segment is created and put in the front of the array. This object will internally allocate new buffers if necessary.

Parameters:

	channel	The channel for this data
	src	The start of memory for the data to be copied
	len	The number of bytes of data to copy

Returns:: Returns true if the method worked.

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U8 * LLBufferArray::readAfter	(	S32	channel,
		U8 *	start,
		U8 *	dest,
		S32 &	len
	)			const

Read bytes in the buffer array on the specified channel.

You should prefer iterating over segments is possible since this method requires you to allocate large buffers - precisely what this class is trying to prevent. This method will skip any segments which are not on the given channel, so this method would usually be used to read a channel and copy that to a log or a socket buffer or something.

Parameters:

	channel	The channel to read.
	start	The start address in the array for reading. You can specify NULL to start at the beginning.
	dest	The destination of the data read. This must be at least len bytes long.
	len[in,out]	in How many bytes to read. out How many bytes were read.

Returns:: Returns the address of the last read byte.

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U8 * LLBufferArray::seek	(	S32	channel,
		U8 *	start,
		S32	delta
	)			const

Find an address in a buffer array.

Parameters:

	channel	The channel to seek in.
	start	The start address in the array for the seek operation. You can specify NULL to start the seek at the beginning, or pass in npos to start at the end.
	delta	How many bytes to seek through the array.

Returns:: Returns the address of the last read byte.

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LLBufferArray::segment_iterator_t LLBufferArray::splitAfter ( U8 * address )

Split a segments so that address is the last address of one segment, and the rest of the original segment becomes another segment on the same channel.

After this method call, getLastSegmentAddress(*getSegment(address)) == address should be true. This call will only create a new segment if the statement above is false before the call. Since you usually call splitAfter() to change a segment property, use getSegment() to perform those operations.

Parameters:

address

The address which will become the last address of the segment it is in.

Returns:: Returns an iterator to the segment which contains address which is endSegment() on failure.

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bool LLBufferArray::takeContents ( LLBufferArray & source )

Take the contents of another buffer array.

This method simply strips the contents out of the source buffery array - segments, buffers, etc, and appends them to this instance. After this operation, the source is empty and ready for reuse.

Parameters:

source

The source buffer

Returns:: Returns true if the operation succeeded.

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

/home/doug/src/oss/slitechat/trunk/LLChatLib/llmessage/llbuffer.h
/home/doug/src/oss/slitechat/trunk/LLChatLib/llmessage/llbuffer.cpp

LLChatLib: LLBufferArray Class Reference

LLBufferArray Class Reference

Public Member Functions

Protected Member Functions

Detailed Description

Constructor & Destructor Documentation

Member Function Documentation