AppSave Class Reference

This reference page is linked to from the following overview topics: Loading and Saving Plug-in Data.

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Detailed Description

See also:

Class AppLoad, Class AppDataChunk, Class CharacterStrings.

Description:

This class is available in release 2.0 and later only.

This class is a general chunk-ifying code useful for writing hierarchical data structures to a linear stream, such as an AppData block.

All methods of this class are implemented by the system.

AppSave will write hierarchical chunks into a private buffer, enlarging it as needed. When completed, use the methods BufferPtr() and NBytesWritten() to get at this buffer. (AppSave will delete the buffer in its DeleteThis() method , so you need to copy the buffer to save the data.)

The chunk hierarchy should always have a single highest level chunk. Chunks can be nested to any depth.

A Chunk can contain either sub-chunks, or data, but not both.

Sample Code:

AppSave *asave = NewAppSave(1000);
asave->BeginChunk(MAIN_CHUNK);
asave->BeginChunk(CHUNK1);
// .. write data
asave->EndChunk();
 
asave->BeginChunk(CHUNK2);
// .. write data
asave->EndChunk();
 
asave->BeginChunk(CHUNK3);
// .. write data
asave->EndChunk();
asave->EndChunk(); // end MAIN_CHUNK 

#include <appio.h>

Inheritance diagram for AppSave:

List of all members.

Public Member Functions
virtual void	DeleteThis ()=0
virtual BYTE *	BufferPtr ()=0
virtual int	NBytesWritten ()=0
virtual void	BeginChunk (USHORT id)=0
virtual void	EndChunk ()=0
virtual int	CurChunkDepth ()=0
virtual IOResult	Write (const void *buf, ULONG nbytes, ULONG *nwrit)=0
virtual IOResult	WriteWString (const char *str)=0
virtual IOResult	WriteWString (const mwchar_t *str)=0
virtual IOResult	WriteCString (const char *str)=0
virtual IOResult	WriteCString (const mwchar_t *str)=0
Protected Member Functions
virtual	~AppSave ()

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Constructor & Destructor Documentation

virtual ~AppSave

(

)

[inline, protected, virtual]

{}

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Member Function Documentation

virtual void DeleteThis

(

)

[pure virtual]

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Remarks:

This method deletes the AppSave instance.

virtual BYTE* BufferPtr

(

)

[pure virtual]

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Remarks:

This method is used after saving to get a pointer to the buffer created.

virtual int NBytesWritten

(

)

[pure virtual]

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Remarks:

This method returns the number of bytes that were written in the buffer.

virtual void BeginChunk

(

USHORT

id

)

[pure virtual]

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Remarks:

This method is used to begin a chunk. The ID passed need only be unique within the plug-ins data itself.

Parameters:

USHORT id

The id for the chunk.

virtual void EndChunk

(

)

[pure virtual]

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Remarks:

This method is used to end a chunk, and back-patch the length.

virtual int CurChunkDepth

(

)

[pure virtual]

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Remarks:

This method is used internally for checking balanced BeginChunk/EndChunk.

virtual IOResult Write	(	const void *	buf,
		ULONG	nbytes,
		ULONG *	nwrit
	)		[pure virtual]

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Remarks:

This method writes a block of bytes.

Parameters:

const void *buf

The buffer to write.

ULONG nbytes

The number of bytes to write.

ULONG *nwrit

The number of bytes actually written.

Returns:

IO_OK - The write was acceptable - no errors.

IO_ERROR - This is returned if an error occurred.

virtual IOResult WriteWString

(

const char *

str

)

[pure virtual]

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Remarks:

This method is used to write wide character strings.

Parameters:

const char *str

The string to write.

Returns:

IO_OK - The write was acceptable - no errors.

IO_ERROR - This is returned if an error occurred.

virtual IOResult WriteWString

(

const mwchar_t *

str

)

[pure virtual]

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Remarks:

This method is used to write wide character strings.

Parameters:

const wchar_t *str

The string to write.

Returns:

IO_OK - The write was acceptable - no errors.

IO_ERROR - This is returned if an error occurred.

virtual IOResult WriteCString

(

const char *

str

)

[pure virtual]

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Remarks:

This method is used to write single byte character strings.

Parameters:

const char *str

The string to write.

Returns:

IO_OK - The write was acceptable - no errors.

IO_ERROR - This is returned if an error occurred.

virtual IOResult WriteCString

(

const mwchar_t *

str

)

[pure virtual]

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Remarks:

This method is used to write single byte character strings.

Parameters:

const wchar_t *str

The string to write.

Returns:

IO_OK - The write was acceptable - no errors.

IO_ERROR - This is returned if an error occurred.