LJp2FileFormat::ReadBoxMemory

#include "ltwrappr.h"

L_INT LJp2FileFormat::ReadBoxMemory(pBuffer, uBufferSize, eBoxType, plBox, uBoxIndex)

L_UINT8 * pBuffer;	/* pointer to a JPEG 2000 file in memory */
L_SIZE_T uBufferSize;	/* size of JPEG 2000 file in bytes */
eJP2BOXTYPE eBoxType;	/* box type */
L_VOID ** plBox;	/* pointer to a pointer */
L_UINT32 uBoxIndex;	/* box index */

Reads a box of type eBoxType at uBoxIndex from a JPEG 2000 file in memory.

Parameter	Description
pBuffer	Pointer to a JPEG 2000 file in memory.
uBufferSize	Size of JPEG 2000 file in bytes.
eBoxType	Box type. It specifies the type of the box to be read from the file.
plBox	Pointer to a pointer to be updated with the box data structure.
uBoxIndex	Zero based box index. It specifies the box the user wants to read.

Returns

SUCCESS	The function was successful.
< 1	An error occurred. Refer to Return Codes.

Comments

LJp2FileFormat::ReadBoxMemory reads a box of type eBoxType at uBoxIndex from a JPEG 2000 file in memory.

If the uBoxIndex is greater than the number of boxes the function returns: ERROR_INV_PARAMETER.

L_JP2B_RESOLUTION and L_JPXB_RESOLUTION boxes cant be read using this function. All of the engines boxes will be reset and updated with the new loaded boxes only.

Required DLLs and Libraries

LTJP2
LFJ2K
LTIMGEFX

For a listing of the exact DLLs and Libraries needed, based on the toolkit version, refer to Files To Be Included With Your Application.

See Also

Functions:	LJp2FileFormat::FreeBoxes, LJp2FileFormat::ReadBox, LJp2FileFormat::AppendBoxes, LJp2FileFormat::AppendBoxesMemory
Topics:	Implementing JPEG 2000 Plug in Features
	Raster Image Functions: Working with JPEG 2000

Example

This example reads an MPEG7 box stored in a JPEG 2000 file.

L_LTJP2SAM_CLIB L_INT LJp2FileFormat__ReadBoxMemoryExample(L_UINT8* pFileBuffer, L_SIZE_T uFileSize, L_UINT8 ** pMPEG7Data, L_SIZE_T* puSize)
{
   LJp2FileFormat Engine;
   L_INT  nRet;
   pL_JP2_MPEG7_BOX pMPEG7Box;
   L_JP2_FILEINFO Jp2FileInfo;
   
   Jp2FileInfo.uStructSize = sizeof(L_JP2_FILEINFO);
   Engine.GetFileInfoMemory( pFileBuffer, uFileSize,&Jp2FileInfo);
   if(Jp2FileInfo.MPEG7.uNumOfBoxes == 0)
      return 0;
   nRet = Engine.ReadBoxMemory(pFileBuffer, uFileSize,L_JPXB_MPEG7, (L_VOID**)&pMPEG7Box,0);
   if(nRet != SUCCESS)
      return nRet;
   
   *pMPEG7Data = (L_UINT8*)malloc(pMPEG7Box->uDataSize);
   memcpy(*pMPEG7Data, pMPEG7Box->pData,pMPEG7Box->uDataSize);
   *puSize = pMPEG7Box->uDataSize;
   
   /*Free the read box*/
   Engine.FreeBoxes( L_JPXB_MPEG7, pMPEG7Box, 1);
   /*Free File Info structure*/
   Engine.FreeFileInfo( &Jp2FileInfo);
   
   return SUCCESS;
}