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WvBufCursorBase< T > Class Template Reference

#include <wvbufbase.h>

Inheritance diagram for WvBufCursorBase< T >:

Inheritance graph
[legend]
List of all members.

Detailed Description

template<class T>
class WvBufCursorBase< T >

A buffer that acts like a cursor over a portion of another buffer.

The underlying buffer's get() position is not affected by reading from this buffer.

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


Public Member Functions

 WvBufCursorBase (WvBufBase< T > &_buf, int _start, size_t _length)
 Creates a new buffer.
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 T * get (size_t count)
 Reads exactly the specified number of elements and returns a pointer to a storage location owned by the buffer.
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 T * peek (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.
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.
T * alloc (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.
T * mutablepeek (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< T > Buffer

Protected Attributes

WvBufCursorStore mystore
WvBufStorestore


Constructor & Destructor Documentation

template<class T>
WvBufCursorBase< T >::WvBufCursorBase WvBufBase< T > &  _buf,
int  _start,
size_t  _length
[inline]
 

Creates a new buffer.

Does not take ownership of the supplied buffer.

"_buf" is a pointer to the buffer to be wrapped "_start" is the buffer offset of the window start position "_length" is the length of the window


Member Function Documentation

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

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

Returns true if the buffer supports reading.

Returns: true if reading is supported

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().

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.

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

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

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

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

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

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

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

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.

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

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

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

Returns true if the buffer supports writing.

Returns: true if writing is supported

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

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

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

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

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

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

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

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

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

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

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

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


The documentation for this class was generated from the following file:
Generated on Sun Jul 10 15:30:33 2005 for WvStreams by  doxygen 1.4.0