Introduction -to dynamic buffers

diff -r ebc84c812384 -r 46218c8b8afa Symbian3/PDK/Source/GUID-6468F3CB-7828-5746-A868-AD525EB7D6BD.dita --- a/Symbian3/PDK/Source/GUID-6468F3CB-7828-5746-A868-AD525EB7D6BD.dita Thu Mar 11 15:24:26 2010 +0000 +++ b/Symbian3/PDK/Source/GUID-6468F3CB-7828-5746-A868-AD525EB7D6BD.dita Thu Mar 11 18:02:22 2010 +0000 @@ -1,42 +1,42 @@ - - - - - -Introduction -to dynamic buffersDescription of flat and segmented buffers in Symbian platform. -

A buffer is an area of memory which may contain data. Managing data in -buffers can be more or less complex, depending on the requirements:

if the data is of fixed -length, a fixed-length area of memory may be allocated, either on the stack -or the heap; a buffer descriptor (TBuf) may be used for this.
if the data is of varying -length, but the variation is relatively small, it may still be appropriate -to allocate the data within a non-extensible buffer such as TBuf: -programming is simple, and only a little memory is wasted
if the data is of significantly -varying length, the memory can be allocated on the heap, and the allocation -extended when necessary. The CBufFlat class is provided to -manage this
if the data’s length -varies so much that a single heap cell cannot reasonably be expected to hold -it all, then the data must be held in several heap cells, but these must appear -as one for convenience. The CBufSeg class is provided to -manage this

Symbian platform provides flat buffers, objects of type CBufFlat, -which are used to allocate and manage storage in a single allocated cell

Symbian platform provides segmented buffers, objects of type CBufSeg, -which are used to allocate and manage storage in several alloc cells.

Both types of buffer have a common base class, CBufBase. -This class specifies the main aspects of the programming interface. Having -a common base class allows the decision as to whether to use flat or segmented -buffers to be changed during program development, with minimal impact on code.

+ + + + + +Introduction +to dynamic buffersDescription of flat and segmented buffers in Symbian platform. +

A buffer is an area of memory which may contain data. Managing data in +buffers can be more or less complex, depending on the requirements:

if the data is of fixed +length, a fixed-length area of memory may be allocated, either on the stack +or the heap; a buffer descriptor (TBuf) may be used for this.
if the data is of varying +length, but the variation is relatively small, it may still be appropriate +to allocate the data within a non-extensible buffer such as TBuf: +programming is simple, and only a little memory is wasted
if the data is of significantly +varying length, the memory can be allocated on the heap, and the allocation +extended when necessary. The CBufFlat class is provided to +manage this
if the data’s length +varies so much that a single heap cell cannot reasonably be expected to hold +it all, then the data must be held in several heap cells, but these must appear +as one for convenience. The CBufSeg class is provided to +manage this

Symbian platform provides flat buffers, objects of type CBufFlat, +which are used to allocate and manage storage in a single allocated cell

Symbian platform provides segmented buffers, objects of type CBufSeg, +which are used to allocate and manage storage in several alloc cells.

Both types of buffer have a common base class, CBufBase. +This class specifies the main aspects of the programming interface. Having +a common base class allows the decision as to whether to use flat or segmented +buffers to be changed during program development, with minimal impact on code.

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