Protected Members

The KcsChunkSet class has the following protected members.

Table 3-1 KcsChunkSet

Protected Member	Description
virtual KcsStatus readChunkBuffer(const KcsChunkId aChunkId, void *aChunk,unsigned long *aSizeRead, unsigned long aSizeWanted = 0);	Reads a chunk of bytes indicated by a chunk Id. KCS_CHUNK_ID_ERR is returned if no chunk Ids match in the profile. Assumes the aChunk buffer is allocated. Get the buffer size with getChunkSize() which is defined in Table 3-2.
virtual KcsStatus writeChunkBuffer(const KcsChunkId aChunkId, void *aChunk, const unsigned long aSize, KcsCompressBoolean aCompress = KcsCompress, KcsLocationEnum aLocationEnum = KcsLocationUnspecified, long aOffset = KcsNoOffsetSpecified);	Writes a chunk of bytes to a new chunk in the profile, given a void *. Returns a new chunk Id. If a particular location or offset is specified, other chunks are moved to write this chunk at the specified location.

Public Members

The KcsChunkSet class has the following public members.

Table 3-2 KcsChunkSet

Public Member	Description
virtual KcsStatus createChunkId(KcsChunkId *aNewChunkId, unsigned long aChunkSize = 0, KcsLocationEnum aLocationEnum = aKcsLocationUnspecified, long aChunkOffset = KcsNoOffsetSpecified, KcsRegisterBoolean aRegister = KcsIgnoreIdSpecified);	Allocates aNewChunkId for a chunk introduced to the data type. Puts a new entry into the chunk map. The size of the chunk can be specified, or by default equals 0. The chunk location can be specified in aLocationEnum and aChunkOffset or defaults can be used. Creates specific chunk ids with aRegister.
virtual KcsStatus deleteChunk(const long aChunkId);	Deletes the chunk (and its chunk map entry) identified by a chunkId. You are required to check whether any other objects are using this chunk.
virtual unsigned long getChunkSetLength(KcsStatus *aStatus);	Returns the length of the domain of the chunk set.

Table 3-2 KcsChunkSet(Continued)

Public Member	Description
virtual long getChunkSetOffset(KcsStatus *aStatus);	Returns the offset of the beginning of the domain of the chunk set.
virtual unsigned long getChunkSize(KcsStatus *aStatus, KcsChunkId aChunkId);	Returns the chunk size identified by aChunkId. If the chunk is compressed, returns the uncompressed chunk size.
virtual KcsIO * getIO();	Returns the chunk set's I/O object.
virtual KcsChunkId getTopChunkId(KcsStatus *aStatus, unsigned long aSize = 0, long aOffset = KcsNoOffsetSpecified);	Returns the chunk Id of the top chunk which stores information about other chunks. Read this chunk first because it tells what is contained in the other chunks. Or you can specify the size of the chunk and the chunk's offset; by default, aSize = 0 and aOffset = KcsNoOffsetSpecified. If no top chunk exists , call createChunkId().
virtual Boolean isEqual(KcsChunkSet * aNotherCS);	Checks if this chunk set is the same as another chunk set.
KcsChunkSet(KcsStatus *aStatus);	Constructor without an I/O object.
KcsChunkSet(KcsStatus *aStatus, KcsIO *aIoObj, unsigned long aChunkSetLength = KcsUseEOF, KcsSaveBoolean aSaveMapping = KcsSaveChunkSet);	Constructor of a chunk set instance based on an I/O object. aChunkSetLength can be set to the length of the static store managed by the chunk set if not equal to the length managed by the I/O object. Otherwise, by default, aChunkSetLength is set to the end of the static store managed by the I/O object. When a particular file format does not allow writing out the chunk map, aSaveMapping is False; otherwise, aSaveMapping is, by default, True indicating that the chunk containing the chunk map should be saved.
~KcsChunkSet();	Destructor.
KcsStatus readChunk(const KcsChunkId aChunkId, void *aChunk, unsigned long *aSizeRead, unsigned long aSizeWanted = 0);	Reads a chunk set.
virtual KcsStatus setChunkSetOffset(long aOffset);	Sets aOffset to the beginning of the domain of the chunk set.

Table 3-2 KcsChunkSet(Continued)

Public Member	Description
virtual KcsStatus setChunkSetPrivateOffset(const long aOffset)	Sets the chunk set's private offset.
virtual KcsStatus setIO(KcsIO *aIoObj);	Sets the chunk set's I/O object.
virtual unsigned long updateChunkUseCount(KcsStatus *aStatus, KcsChunkId aChunkId, long aDelta, unsigned long aComparisonCount);	Calls the ChunkMap object to change the use count of a particular chunk. Compares the use count with an expected value, aComparisonCount.
KcsStatus writeChunk(KcsChunkId aChunkId, void* aChunk, const unsigned long aSize, KcsCompressBoolean aCompress = KcsCompress, KcsLocationEnum aLocationEnum = KcsLocationUnspecified, long aOffset = KcsNoOffsetSpecified);	Writes a chunk set.

Example

The following code shows you some examples of how to use these KcsChunkSet class member functions: getChunkSet(), getChunkSize(), readChunk() and writeChunk().

Code Example 3-1 Getting, Reading and Writing a Chunk

KcsChunkId myChunkId; KcsStatus aStat; KcsChunkSet* chunkSet; char* mftData; u_long mftSize; u_long mftWanted; // Get the chunk data chunkSet = getChunkSet(); if (chunkSet == NULL) return (KCS_INTERNAL_CLASS_CORRUPTED); //Get the size mftSize = chunkSet->getChunkSize(&aStat, myChunkId); if (aStat != KCS_SUCCESS)

Code Example 3-1 Getting, Reading and Writing a Chunk (Continued)

return(aStat); //Make space for the data mftData = NULL; if ((mftData = malloc((u_int)mftSize)) == NULL) { return (KCS_MEM_ALLOC_ERR); } //Read it aStat = chunkSet->readChunk(myChunkId, mftData, &mftWanted, mftSize); if (aStat != KCS_SUCCESS) return (aStat); //Zero it out and write it back memset(mftData, 0, mftSize); aStat = chunkSet->writeChunk(myChunkId, mftData, mftSize); if (aStat != KCS_SUCCESS) return (aStat);