L_ReadFileCommentExt

#include "l_bitmap.h"

L_LTFIL_API L_INT L_ReadFileCommentExt (pszFile, uType, pComments, pBuffer, uLength, pLoadOptions)

L_TCHAR* pszFile;	/* file name */
L_UINT uType;	/* type of comment */
pFILECOMMENTS pComments;	/pointer to a structure containing information about the comments /
L_UCHAR* pBuffer;	/pointer to a buffer containing the comments /
L_UINT* uLength;	/pointer to the size of the comments./
pLOADFILEOPTION pLoadOptions;	/* pointer to optional extended load options */

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

Parameter	Description
pszFile	Character string containing the FlashPix file name.
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 that will hold all the comments
uLength	Pointer to the size of the buffer that will hold all the comments.
pLoadOptions	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 L_GetFileCommentSize
	Allocate a buffer of a corresponding size.
	Read the comments with L_ReadFileCommentExt
	Free the buffer

To write comments to a file, all the comments you wish to add to a new file must be set. L_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 L_SaveFile or L_SaveBitmap when creating a new file. If you wish to change a comment in an existing file, use L_WriteFileCommentExt.

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, Mobile.

See Also

Functions:	L_ReadFileComment, L_ReadFileComments
	L_SetComment,
	L_GetFileCommentSize
	L_WriteFileCommentExt
Topics:	Raster Image Functions: Maintaining File Comments,
	Loading and Saving Images

For a list of functions that utilize the LOADFILEOPTION or SAVEFILEOPTION structures, refer to Functions Utilizing the LOADFILEOPTION or SAVEFILEOPTION structures.

Example

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 ReadFileCommentExtExample(L_VOID)
{
   L_INT nRet;
   L_UINT32 uLength;
   L_TCHAR szMessage[80];
   HGLOBAL hTextToGet;
   L_UCHAR   *pTextToGet;
   L_FLOAT  *pFloat;
   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:
   /* Determine the size, in bytes, of the desired group of comments. */
   nRet = L_GetFileCommentSize(MAKE_IMAGE_PATH(TEXT("IMAGE1.FPX")), CMNT_FPXSUMMARYINFORMATION, &uLength, NULL);
   if(nRet != SUCCESS)
      return nRet;

   /* Allocate a buffer based on the size of the comments obtained by 
      nRet = L_GetFileCommentSize and stored in uLength. */
   hTextToGet = GlobalAlloc(GPTR, uLength);
   pTextToGet = (L_UCHAR *)GlobalLock(hTextToGet);

   /* Initialize the FileComments structure. */
   FileComments.count = CMNT_LAST + 1;
   FileComments.pointer = pPointer;
   FileComments.size = uSize;

   /* Read the group of comments into the buffer. */
   nRet = L_ReadFileCommentExt (MAKE_IMAGE_PATH(TEXT("IMAGE1.FPX")), CMNT_FPXSUMMARYINFORMATION,
                                    &FileComments, pTextToGet, &uLength, NULL);
    if(nRet != SUCCESS)
       return nRet;

   /* 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);
   }

   /* Free the buffer. */
   GlobalFree(hTextToGet);

   //Read groups of comments:
   nRet = L_GetFileCommentSize(MAKE_IMAGE_PATH(TEXT("IMAGE1.FPX")), CMNT_FPXSUMMARYINFORMATION | 
                        CMNT_FPXINTELLECTUALPROPERTYGROUP, &uLength, NULL);
   if(nRet != SUCCESS)
      return nRet;
   hTextToGet = GlobalAlloc(GPTR, uLength);
   pTextToGet = (L_UCHAR  *)GlobalLock(hTextToGet);
   FileComments.count = CMNT_LAST + 1;
   FileComments.pointer = pPointer;
   FileComments.size = uSize;
   nRet = L_ReadFileCommentExt (MAKE_IMAGE_PATH(TEXT("IMAGE1.FPX")), CMNT_FPXSUMMARYINFORMATION | 
   CMNT_FPXINTELLECTUALPROPERTYGROUP,
    &FileComments, pTextToGet, &uLength, NULL);
   if(nRet != SUCCESS)
      return nRet;
   pArray = (FPXCOMMENT_HEADER_ARRAY  *)pPointer[CMNT_FPXTITLE];
   pElement = (FPXCOMMENT_HEADER_ELEMENT *)   pPointer[CMNT_FPXEXPOSURETIME];
   if((pArray != NULL)&&(pElement != NULL))
   {
    pString = (L_CHAR  *)(pArray + 1);
    pFloat = (L_FLOAT  *)(pElement + 1);
    _stprintf_s(szMessage,80, TEXT("%hs-%f"), pString, *pFloat);
    MessageBox(NULL, szMessage, TEXT("Title & Exposure Time"), MB_OK);
   }
   GlobalFree(hTextToGet);

   //Read all comments:
   nRet = L_GetFileCommentSize(MAKE_IMAGE_PATH(TEXT("IMAGE1.FPX")), CMNT_ALL, &uLength, NULL);
   if(nRet != SUCCESS)
      return nRet;
   hTextToGet = GlobalAlloc(GPTR, uLength);
   pTextToGet = (L_UCHAR *)GlobalLock(hTextToGet);
   FileComments.count = CMNT_LAST + 1;
   FileComments.pointer = pPointer;
   FileComments.size = uSize;
   nRet = L_ReadFileCommentExt (MAKE_IMAGE_PATH(TEXT("IMAGE1.FPX")), CMNT_ALL, &FileComments, pTextToGet, &uLength, NULL);
   if(nRet != SUCCESS)
      return nRet;
   pArray = (FPXCOMMENT_HEADER_ARRAY *)pPointer[CMNT_FPXTITLE];
   pElement = (FPXCOMMENT_HEADER_ELEMENT *)   pPointer[CMNT_FPXEXPOSURETIME];
   if((pArray != NULL)&&(pElement != NULL))
   {
    pString = (L_CHAR *)(pArray + 1);
    pFloat =  (L_FLOAT *)(pElement + 1);
    _stprintf_s(szMessage,80, TEXT("%hs-%f"), pString, *pFloat);
    MessageBox(NULL, szMessage, TEXT("Title & Exposure Time"), MB_OK);
   }
   GlobalFree(hTextToGet);
   return SUCCESS;
}