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WvCircularBufBase< T > Class Template Reference

#include <wvbufbase.h>

Inherits WvBufBase< T >< T >.

Collaboration diagram for WvCircularBufBase< T >:

[legend]
List of all members.

Detailed Description

template<class T>
class WvCircularBufBase< T >

A buffer that wraps a pre-allocated array and provides read-write access to its elements using a circular buffering scheme rather than a purely linear one, as used by WvInPlaceBuf.

When there is insufficient contigous free/used space to satisfy a read or write request, the data is automatically reordered in-place to coalesce the free/used spaces into sufficiently large chunks. The process may also be manually triggered to explicitly renormalize the array and shift its contents to the front.

"T" is the type of object to store, must be a primitive or a struct without special initialization, copy, or assignment semantics

Definition at line 810 of file wvbufbase.h.

Public Member Functions

 WvCircularBufBase (T *_data, size_t _avail, size_t _size, bool _autofree=false)
 Creates a new circular buffer backed by the supplied array.

 WvCircularBufBase (size_t _size)
 Creates a new empty circular buffer backed by a new array.

 WvCircularBufBase ()
 Creates a new empty buffer with no backing array.

virtual ~WvCircularBufBase ()
 Destroys the buffer.

Tptr () const
 Returns the underlying array pointer.

size_t size () const
 Returns the total size of the buffer.

bool autofree () const
 Returns the autofree flag.

void setautofree (bool _autofree)
 Sets or clears the auto_free flag.

void reset (T *_data, size_t _avail, size_t _size, bool _autofree=false)
 Resets the underlying buffer pointer and properties.

void setavail (size_t _avail)
 Sets the amount of available data using the current buffer and resets the read index to the beginning of the buffer.

void normalize ()
 Normalizes the arrangement of the data such that the contents of the buffer are stored at the beginning of the array starting with the next element that would be returned by get(size_t).

WvBufStoregetstore ()
 Returns a pointer to the underlying storage class object.

bool isreadable () const
 Returns true if the buffer supports reading.

size_t used () const
 Returns the number of elements in the buffer currently available for reading.

const Tget (size_t count)
 Reads exactly the specified number of elements and returns a pointer to a storage location owned by the buffer.

T get ()
 Reads the next element from the buffer.

void skip (size_t count)
 Skips exactly the specified number of elements.

size_t optgettable () const
 Returns the optimal maximum number of elements in the buffer currently available for reading without incurring significant overhead.

void unget (size_t count)
 Ungets exactly the specified number of elements by returning them to the buffer for subsequent reads.

size_t ungettable () const
 Returns the maximum number of elements that may be ungotten at this time.

const Tpeek (int offset, size_t count)
 Returns a const pointer into the buffer at the specified offset to the specified number of elements without actually adjusting the current get() index.

T peek (int offset=0)
 Returns the element at the specified offset in the buffer.

size_t peekable (int offset)
size_t optpeekable (int offset)
void zap ()
 Clears the buffer.

void move (T *buf, size_t count)
 Efficiently copies the specified number of elements from the buffer to the specified UNINITIALIZED storage location and removes the elements from the buffer.

void copy (T *buf, int offset, size_t count)
 Efficiently copies the specified number of elements from the buffer to the specified UNINITIALIZED storage location but does not remove the elements from the buffer.

bool iswritable () const
 Returns true if the buffer supports writing.

size_t free () const
 Returns the number of elements that the buffer can currently accept for writing.

Talloc (size_t count)
 Allocates exactly the specified number of elements and returns a pointer to an UNINITIALIZED storage location owned by the buffer.

size_t optallocable () const
 Returns the optimal maximum number of elements that the buffer can currently accept for writing without incurring significant overhead.

void unalloc (size_t count)
 Unallocates exactly the specified number of elements by removing them from the buffer and releasing their storage.

size_t unallocable () const
 Returns the maximum number of elements that may be unallocated at this time.

Tmutablepeek (int offset, size_t count)
 Returns a non-const pointer info the buffer at the specified offset to the specified number of elements without actually adjusting the current get() index.

void put (const T *data, size_t count)
 Writes the specified number of elements from the specified storage location into the buffer at its tail.

void put (T &value)
 Writes the element into the buffer at its tail.

void poke (const T *data, int offset, size_t count)
 Efficiently copies the specified number of elements from the specified storage location into the buffer at a particular offset.

void poke (T &value, int offset)
 Writes the element into the buffer at the specified offset.

void merge (Buffer &inbuf, size_t count)
 Efficiently moves count bytes from the specified buffer into this one.

void merge (Buffer &inbuf)
 Efficiently merges the entire contents of a buffer into this one.


Protected Types

typedef T Elem
typedef WvBufBase< TBuffer

Protected Attributes

WvCircularBufStore mystore
WvBufStorestore


Member Typedef Documentation

template<class T>
typedef WvBufBase<T> WvBufBaseCommonImpl< T >::Buffer [protected, inherited]
 

Definition at line 40 of file wvbufbase.h.

template<class T>
typedef T WvCircularBufBase< T >::Elem [protected]
 

Reimplemented from WvBufBaseCommonImpl< T >.

Definition at line 813 of file wvbufbase.h.


Constructor & Destructor Documentation

template<class T>
WvCircularBufBase< T >::WvCircularBufBase T _data,
size_t  _avail,
size_t  _size,
bool  _autofree = false
[inline]
 

Creates a new circular buffer backed by the supplied array.

"_data" is the array of data to wrap "_avail" is the amount of data available for reading at the beginning of the buffer "_size" is the size of the array "_autofree" is if true, the array will be freed when discarded

Definition at line 827 of file wvbufbase.h.

template<class T>
WvCircularBufBase< T >::WvCircularBufBase size_t  _size  )  [inline, explicit]
 

Creates a new empty circular buffer backed by a new array.

"_size" is the size of the array

Definition at line 838 of file wvbufbase.h.

template<class T>
WvCircularBufBase< T >::WvCircularBufBase  )  [inline]
 

Creates a new empty buffer with no backing array.

Definition at line 843 of file wvbufbase.h.

template<class T>
virtual WvCircularBufBase< T >::~WvCircularBufBase  )  [inline, virtual]
 

Destroys the buffer.

Frees the underlying array if autofree().

Definition at line 853 of file wvbufbase.h.


Member Function Documentation

template<class T>
T* WvBufBaseCommonImpl< T >::alloc size_t  count  )  [inline, inherited]
 

Allocates exactly the specified number of elements and returns a pointer to an UNINITIALIZED storage location owned by the buffer.

The pointer is only valid until the next non-const buffer member is called. eg. alloc(size_t)

If count == 0, a NULL pointer may be returned.

It is an error for count to be greater than free().

For best results, call this function multiple times with count no greater than optallocable() each time.

After this operation, at least count elements may be unallocated.

"count" is the number of elements Returns: the element storage pointer

Definition at line 376 of file wvbufbase.h.

Referenced by WvFunctorEncoder< signed short int, float, WvPCMSigned16ToUnnormFloatFunctor >::_typedencode(), file_hack_end(), WvStream::getline(), main(), WvStream::read(), and WvDsp::uread().

template<class T>
bool WvCircularBufBase< T >::autofree  )  const [inline]
 

Returns the autofree flag.

Returns: the autofree flag

Definition at line 880 of file wvbufbase.h.

template<class T>
void WvBufBaseCommonImpl< T >::copy T buf,
int  offset,
size_t  count
[inline, inherited]
 

Efficiently copies the specified number of elements from the buffer to the specified UNINITIALIZED storage location but does not remove the elements from the buffer.

It is an error for count to be greater than peekable(offset).

For maximum efficiency, choose as large a count as possible.

The pointer buf may be NULL only if count == 0.

"buf" is the buffer that will receive the elements "offset" is the buffer offset "count" is the number of elements

Definition at line 327 of file wvbufbase.h.

template<class T>
size_t WvBufBaseCommonImpl< T >::free  )  const [inline, inherited]
 

Returns the number of elements that the buffer can currently accept for writing.

Returns: the number of elements

Definition at line 350 of file wvbufbase.h.

template<class T>
T WvBufBaseCommonImpl< T >::get  )  [inline, inherited]
 

Reads the next element from the buffer.

It is an error to invoke this method if used() == 0.

After this operation, at least 1 element may be ungotten.

Returns: the element

Definition at line 269 of file wvbufbase.h.

Referenced by WvBufBaseCommonImpl< unsigned >::get(), and WvBufBase< unsigned char >::getch().

template<class T>
const T* WvBufBaseCommonImpl< T >::get size_t  count  )  [inline, inherited]
 

Reads exactly the specified number of elements and returns a pointer to a storage location owned by the buffer.

The pointer is only valid until the next non-const buffer member is called. eg. alloc(size_t)

If count == 0, a NULL pointer may be returned.

It is an error for count to be greater than used().

For maximum efficiency, call this function multiple times with count no greater than optgettable() each time.

After this operation, at least count elements may be ungotten.

Definition at line 113 of file wvbufbase.h.

Referenced by WvSyslog::_end_line(), WvLogBuffer::_end_line(), WvFunctorEncoder< signed short int, float, WvPCMSigned16ToUnnormFloatFunctor >::_typedencode(), WvStream::flush_outbuf(), WvStream::getline(), WvProtoStream::next_token(), WvStream::read(), WvProtoStream::token_remaining(), and WvDsp::uwrite().

template<class T>
WvBufStore* WvBufBaseCommonImpl< T >::getstore  )  [inline, inherited]
 

Returns a pointer to the underlying storage class object.

Returns: the low-level storage class object pointer, non-null

Definition at line 69 of file wvbufbase.h.

template<class T>
bool WvBufBaseCommonImpl< T >::isreadable  )  const [inline, inherited]
 

Returns true if the buffer supports reading.

Returns: true if reading is supported

Definition at line 81 of file wvbufbase.h.

template<class T>
bool WvBufBaseCommonImpl< T >::iswritable  )  const [inline, inherited]
 

Returns true if the buffer supports writing.

Returns: true if writing is supported

Definition at line 339 of file wvbufbase.h.

template<class T>
void WvBufBaseCommonImpl< T >::merge Buffer inbuf  )  [inline, inherited]
 

Efficiently merges the entire contents of a buffer into this one.

"inbuf" is the buffer from which to read

Definition at line 565 of file wvbufbase.h.

template<class T>
void WvBufBaseCommonImpl< T >::merge Buffer inbuf,
size_t  count
[inline, inherited]
 

Efficiently moves count bytes from the specified buffer into this one.

In some cases, this may be a zero-copy operation.

It is an error for count to be greater than inbuf.used().

For maximum efficiency, choose as large a count as possible.

After this operation, an indeterminate number of elements may be ungotten from inbuf.

"inbuf" is the buffer from which to read "count" is the number of elements

Definition at line 555 of file wvbufbase.h.

Referenced by WvEncoderStream::finish_read(), WvEncoderStream::flush_read(), WvBufBaseCommonImpl< unsigned >::merge(), WvStream::unread(), and WvDsp::uread().

template<class T>
void WvBufBaseCommonImpl< T >::move T buf,
size_t  count
[inline, inherited]
 

Efficiently copies the specified number of elements from the buffer to the specified UNINITIALIZED storage location and removes the elements from the buffer.

It is an error for count to be greater than used().

For maximum efficiency, choose as large a count as possible.

The pointer buf may be NULL only if count == 0.

After this operation, an indeterminate number of elements may be ungotten.

"buf" is the buffer that will receive the elements "count" is the number of elements

Definition at line 306 of file wvbufbase.h.

Referenced by WvBufBase< unsigned char >::getstr(), WvBufBase< unsigned char >::move(), WvEncoderStream::uread(), and WvDsp::uread().

template<class T>
T* WvBufBaseCommonImpl< T >::mutablepeek int  offset,
size_t  count
[inline, inherited]
 

Returns a non-const pointer info the buffer at the specified offset to the specified number of elements without actually adjusting the current get() index.

Other than the fact that the returned storage is mutable, operates identically to peek(int, size_t).

"offset" is the buffer offset "count" is the number of elements Returns: the element storage pointer

Definition at line 458 of file wvbufbase.h.

Referenced by WvStream::getline().

template<class T>
void WvCircularBufBase< T >::normalize  )  [inline]
 

Normalizes the arrangement of the data such that the contents of the buffer are stored at the beginning of the array starting with the next element that would be returned by get(size_t).

After invocation, ungettable() may equal 0.

Definition at line 935 of file wvbufbase.h.

template<class T>
size_t WvBufBaseCommonImpl< T >::optallocable  )  const [inline, inherited]
 

Returns the optimal maximum number of elements that the buffer can currently accept for writing without incurring significant overhead.

Invariants:

Returns: the number of elements

Definition at line 394 of file wvbufbase.h.

Referenced by WvFunctorEncoder< signed short int, float, WvPCMSigned16ToUnnormFloatFunctor >::_typedencode().

template<class T>
size_t WvBufBaseCommonImpl< T >::optgettable  )  const [inline, inherited]
 

Returns the optimal maximum number of elements in the buffer currently available for reading without incurring significant overhead.

Invariants:

Returns: the number of elements

Definition at line 151 of file wvbufbase.h.

Referenced by WvFunctorEncoder< signed short int, float, WvPCMSigned16ToUnnormFloatFunctor >::_typedencode().

template<class T>
size_t WvBufBaseCommonImpl< T >::optpeekable int  offset  )  [inline, inherited]
 

Definition at line 233 of file wvbufbase.h.

Referenced by WvBufBase< unsigned char >::strchr().

template<class T>
T WvBufBaseCommonImpl< T >::peek int  offset = 0  )  [inline, inherited]
 

Returns the element at the specified offset in the buffer.

It is an error to invoke this method if used() == 0.

"offset" is the offset, default 0 Returns: the element

Definition at line 283 of file wvbufbase.h.

template<class T>
const T* WvBufBaseCommonImpl< T >::peek int  offset,
size_t  count
[inline, inherited]
 

Returns a const pointer into the buffer at the specified offset to the specified number of elements without actually adjusting the current get() index.

The pointer is only valid until the next non-const buffer member is called. eg. alloc(size_t)

If count == 0, a NULL pointer may be returned.

If offset is greater than zero, then elements will be returned beginning with the with the offset'th element that would be returned by get(size_t).

If offset equals zero, then elements will be returned beginning with the next one available for get(size_t).

If offset is less than zero, then elements will be returned beginning with the first one that would be returned on a get(size_t) following an unget(-offset).

It is an error for count to be greater than peekable(offset).

For maximum efficiency, call this function multiple times with count no greater than that returned by optpeekable(size_t) at incremental offsets.

"offset" is the buffer offset "count" is the number of elements Returns: the element storage pointer

Definition at line 222 of file wvbufbase.h.

Referenced by WvGdbmHash< K, D >::datumize< T >::datumize(), WvOakleyAuth::get_other_public_key(), WvBufBaseCommonImpl< unsigned >::peek(), WvBufBase< unsigned char >::peekch(), UniIniGen::refresh(), and WvBufBase< unsigned char >::strchr().

template<class T>
size_t WvBufBaseCommonImpl< T >::peekable int  offset  )  [inline, inherited]
 

Definition at line 228 of file wvbufbase.h.

template<class T>
void WvBufBaseCommonImpl< T >::poke T value,
int  offset
[inline, inherited]
 

Writes the element into the buffer at the specified offset.

It is an error to invoke this method if free() == 0.

After this operation, at least 1 element may be unallocated.

"value" is the element "offset" is the buffer offset

Definition at line 532 of file wvbufbase.h.

template<class T>
void WvBufBaseCommonImpl< T >::poke const T data,
int  offset,
size_t  count
[inline, inherited]
 

Efficiently copies the specified number of elements from the specified storage location into the buffer at a particular offset.

If offset <= used() and offset + count > used(), the remaining data is simply tacked onto the end of the buffer with put().

It is an error for count to be greater than free() - offset.

"data" is the buffer that contains the elements "count" is the number of elements "offset" is the buffer offset, default 0

Definition at line 501 of file wvbufbase.h.

Referenced by WvBufBaseCommonImpl< unsigned >::poke(), and WvBufBase< unsigned char >::poke().

template<class T>
T* WvCircularBufBase< T >::ptr  )  const [inline]
 

Returns the underlying array pointer.

Returns: the element pointer

Definition at line 860 of file wvbufbase.h.

template<class T>
void WvBufBaseCommonImpl< T >::put T value  )  [inline, inherited]
 

Writes the element into the buffer at its tail.

It is an error to invoke this method if free() == 0.

After this operation, at least 1 element may be unallocated.

"valid" is the element

Definition at line 516 of file wvbufbase.h.

template<class T>
void WvBufBaseCommonImpl< T >::put const T data,
size_t  count
[inline, inherited]
 

Writes the specified number of elements from the specified storage location into the buffer at its tail.

It is an error for count to be greater than free().

For maximum efficiency, choose as large a count as possible.

The pointer buf may be NULL only if count == 0.

After this operation, at least count elements may be unallocated.

"data" is the buffer that contains the elements "count" is the number of elements

Definition at line 480 of file wvbufbase.h.

Referenced by WvSyslog::_begin_line(), WvSyslog::_end_line(), WvLogBuffer::_end_line(), WvSyslog::_mid_line(), WvLogBuffer::_mid_line(), WvOakleyAuth::create_secret(), fixnl(), WvStream::getline(), WvBufBase< unsigned char >::put(), WvBufBase< unsigned char >::putch(), WvBufBase< unsigned char >::putstr(), UniIniGen::refresh(), strreplace(), WvProtoStream::token_remaining(), WvProtoStream::tokline(), url_encode(), WvSSLStream::uwrite(), WvEncoderStream::uwrite(), WvDsp::uwrite(), WvBufStream::uwrite(), WvStream::write(), and wvtcl_encode().

template<class T>
void WvCircularBufBase< T >::reset T _data,
size_t  _avail,
size_t  _size,
bool  _autofree = false
[inline]
 

Resets the underlying buffer pointer and properties.

If the old and new buffer pointers differ and the old buffer was specified as auto_free, the old buffer is destroyed.

"_data" is the array of data to wrap "_avail" is the amount of data available for reading at the beginning of the buffer "_size" is the size of the array "_autofree" is if true, the array will be freed when discarded

Definition at line 907 of file wvbufbase.h.

Referenced by WvCircularBuf::reset().

template<class T>
void WvCircularBufBase< T >::setautofree bool  _autofree  )  [inline]
 

Sets or clears the auto_free flag.

"_autofree" is if true, the array will be freed when discarded

Definition at line 890 of file wvbufbase.h.

template<class T>
void WvCircularBufBase< T >::setavail size_t  _avail  )  [inline]
 

Sets the amount of available data using the current buffer and resets the read index to the beginning of the buffer.

"_avail" is the amount of data available for reading at the beginning of the buffer

Definition at line 921 of file wvbufbase.h.

template<class T>
size_t WvCircularBufBase< T >::size  )  const [inline]
 

Returns the total size of the buffer.

Returns: the number of elements

Definition at line 870 of file wvbufbase.h.

template<class T>
void WvBufBaseCommonImpl< T >::skip size_t  count  )  [inline, inherited]
 

Skips exactly the specified number of elements.

This is equivalent to invoking get(size_t) with the count and discarding the result, but may be faster for certain types of buffers. As with get(size_t), the call may be followed up by an unget(size_t).

"count" is the number of elements

Definition at line 133 of file wvbufbase.h.

template<class T>
void WvBufBaseCommonImpl< T >::unalloc size_t  count  )  [inline, inherited]
 

Unallocates exactly the specified number of elements by removing them from the buffer and releasing their storage.

This operation may always be safely performed with count less than or equal to that specified in the last alloc(size_t) or put(const T*, size_t) if no non-const buffer members have been called since then.

If count == 0, nothing happens.

It is an error for count to be greater than unallocable().

"count" is the number of elements

Definition at line 418 of file wvbufbase.h.

Referenced by file_hack_end(), WvStream::getline(), main(), WvStream::read(), UniIniGen::refresh(), and WvDsp::uread().

template<class T>
size_t WvBufBaseCommonImpl< T >::unallocable  )  const [inline, inherited]
 

Returns the maximum number of elements that may be unallocated at this time.

For all practical purposes, this number will always be at least as large as the amount currently in use. It is provided primarily for symmetry, but also to handle cases where buffer reading (hence used()) is not supported by the implementation.

Invariants:

Returns: the number of elements

Definition at line 440 of file wvbufbase.h.

template<class T>
void WvBufBaseCommonImpl< T >::unget size_t  count  )  [inline, inherited]
 

Ungets exactly the specified number of elements by returning them to the buffer for subsequent reads.

This operation may always be safely performed with count less than or equal to that specified in the last get(size_t) if no non-const buffer members have been called since then.

If count == 0, nothing happens.

It is an error for count to be greater than ungettable().

"count" is the number of elements

Definition at line 174 of file wvbufbase.h.

Referenced by WvStream::flush_outbuf().

template<class T>
size_t WvBufBaseCommonImpl< T >::ungettable  )  const [inline, inherited]
 

Returns the maximum number of elements that may be ungotten at this time.

Returns: the number of elements

Definition at line 185 of file wvbufbase.h.

Referenced by WvStream::flush_outbuf().

template<class T>
size_t WvBufBaseCommonImpl< T >::used  )  const [inline, inherited]
 

Returns the number of elements in the buffer currently available for reading.

This function could also be called gettable().

Definition at line 92 of file wvbufbase.h.

Referenced by WvSyslog::_end_line(), WvLogBuffer::_end_line(), WvGdbmHash< K, D >::datumize< T >::datumize(), WvEncoderStream::flush_internal(), WvStream::flush_outbuf(), WvStream::flush_then_close(), WvBufBaseCommonImpl< unsigned >::get(), WvStream::getline(), WvBufBase< unsigned char >::getstr(), UniClientConn::isok(), WvFDStream::nowrite(), WvStreamClone::post_select(), WvFDStream::post_select(), WvStreamClone::pre_select(), WvStream::pre_select(), WvFDStream::pre_select(), WvEncoderStream::pre_select(), UniClientConn::pre_select(), WvStream::read(), UniIniGen::refresh(), WvBufBase< unsigned char >::strchr(), WvProtoStream::token_remaining(), WvEncoderStream::uread(), WvDsp::uread(), WvFDStream::uwrite(), WvDsp::uwrite(), WvStream::write(), and wvtcl_encode().

template<class T>
void WvBufBaseCommonImpl< T >::zap  )  [inline, inherited]
 

Clears the buffer.

For many types of buffers, calling zap() will increased the amount of free space available for writing (see below) by an amount greater than used(). Hence it is wise to zap() a buffer just before writing to it to maximize free space.

After this operation, used() == 0, and often ungettable() == 0.

Definition at line 254 of file wvbufbase.h.

Referenced by WvSyslog::_end_line(), WvLogBuffer::_end_line(), WvStream::flush_outbuf(), WvProtoStream::tokline(), and WvStream::unread().


Member Data Documentation

template<class T>
WvCircularBufStore WvCircularBufBase< T >::mystore [protected]
 

Definition at line 815 of file wvbufbase.h.

template<class T>
WvBufStore* WvBufBaseCommonImpl< T >::store [protected, inherited]
 

Definition at line 42 of file wvbufbase.h.


The documentation for this class was generated from the following file:
Generated on Sat Feb 21 21:06:05 2004 for WvStreams by doxygen 1.3.5