LFile::ReadCommentExt

#include "ltwrappr.h"

virtual L_INT LFile::ReadCommentExt(uType, pComments, pBuffer, puLength, pLoadFileOption=NULL)

L_UINT uType;	/* type of comment*/
pFILECOMMENTS pComments;	/* pointer to a structure */
L_UCHAR * pBuffer;	/* pointer to a buffer */
L_UINT * puLength;	/* pointer to a variable to be updated */
pLOADFILEOPTION pLoadFileOption;	/* pointer to optional extended load options */

Gets a single comment, a group of comments or several groups of comments from a file.

Parameter	Description
uType	The type of comment. Refer to Types of File Comments. A group of comments may be obtained such as CMNT_FPXSUMMARYINFORMATION, or more than one group of comments may be retrieved by using OR as in CMNT_FPXSUMMARYINFORMATION \| CMNT_FPXFILESOURCEGROUP, or all comments may be obtained by using CMNT_ALL. See Example listed below. For more information concerning FlashPix file comments, see FlashPix File Comments.
pComments	Pointer to a structure which contains a data value indicating the number of comments stored, a pointer to an array of pointers which in turn point to the individual Comments, and a pointer to an array of integers which indicate the size of each Comment stored.
pBuffer	Pointer to the buffer object that will hold all the comments.
puLength	Pointer to a variable to be updated with the size of the buffer that will hold all the comments.
pLoadFileOption	Pointer to optional extended load options. Pass NULL to use the default load options.

Returns

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

Comments

Presently this function only works with FlashPix format files.

The basic order of function calls to retrieve comments is as follows:

Get the size of the comments with LFile::GetCommentSize
Allocate a buffer of a corresponding size.
Read the comments with LFile::ReadComment
Free the buffer

To write comments to a file, all the comments you wish to add to a new file must be set. LFileSettings::SetComment sets each comment individually, but it does not save the comments to the file, it prepares the values for the next save.. Once all comments are set, the comments are saved using any function which saves files, such as LFile::SaveFile or LFile::Save when creating a new file. If you wish to change a comment in an existing file, use LFile::WriteComment.

Required DLLs and Libraries

LTFIL
File format DLLs

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

Platforms

Win32, x64.

See Also

Functions:	Class Members
Topics:	Raster Image Functions: Maintaining File Comments
	Loading and Saving Images

Example

#define MAKE_IMAGE_PATH(pFileName) TEXT("C:\\Users\\Public\\Documents\\LEADTOOLS Images\\")pFileName
typedef struct _FPXCOMMENT_HEADER_ELEMENT
{
   L_UINT32 size; 
   L_UINT32 type; 
} FPXCOMMENT_HEADER_ELEMENT;
typedef struct _FPXCOMMENT_HEADER_ARRAY
{
   L_UINT32 size; 
   L_UINT32 type; 
   L_UINT32 elements; 
}FPXCOMMENT_HEADER_ARRAY;
L_INT LFile_ReadCommnetExtExample()
{
   L_INT nRet = SUCCESS;
   L_UINT uLength;
   L_TCHAR szMessage[80];
   L_CHAR  *pTextToGet;
   L_UINT32  *pLong;
   L_CHAR  *pString;
   FPXCOMMENT_HEADER_ARRAY  *pArray;
   FPXCOMMENT_HEADER_ELEMENT  *pElement;
   FILECOMMENTS FileComments;
   L_UCHAR  *pPointer [CMNT_LAST + 1];
   L_UINT uSize[CMNT_LAST + 1];
   /*Read one group of comments:*/
   L_INT nStatus;
   LFile file;
   LBuffer Buff;
   /* Determine the size, in bytes, of the desired group of comments. */
   file.SetFileName(MAKE_IMAGE_PATH(TEXT("image1.FPX")));
   nStatus = file.GetCommentSize(CMNT_FPXSUMMARYINFORMATION, &uLength);
   /* Allocate a buffer based on the size of the comments obtained by LFile::GetCommentSize and stored in uLength. */
   nRet = Buff.Reallocate(uLength);
   if(nRet != SUCCESS)
      return nRet;
   pTextToGet = (L_CHAR  *)Buff.Lock();
   /* Initialize the FileComments structure. */
   FileComments.count = CMNT_LAST + 1;
   FileComments.pointer = pPointer;
   FileComments.size = uSize;
   /* Read the group of comments into the buffer. */
   nStatus = file.ReadCommentExt(CMNT_FPXSUMMARYINFORMATION,&FileComments,(L_UCHAR *) pTextToGet, &uLength);
   /* Extract the desired individual comments from within the group */
   pArray = (FPXCOMMENT_HEADER_ARRAY  *)pPointer [CMNT_FPXTITLE];
   pElement = (FPXCOMMENT_HEADER_ELEMENT  *)   pPointer [CMNT_FPXSECURITY];
   /* Test to be sure the comments exist. If they exist, print them.*/
   if((pArray != NULL)&&(pElement != NULL))
   {
      pString = (L_CHAR*)(pArray + 1);
      pLong = (L_UINT32  *)(pElement + 1);
      wsprintf(szMessage, TEXT("%hs-%ul"), pString, *pLong);
      MessageBox(NULL, szMessage, TEXT("Title & Security"), MB_OK);
   }
   return SUCCESS;
}