L_ReadFileTags

//Example 1: This example will read all the tags, comments and geo keys stored in a disk file. 
L_INT ReadFileTagsExample1(L_VOID) 
{ 
   FILEINFO fi; 
   L_INT nRet; 
   L_UINT i, uTagCount=0, uCommentCount=0, uGeoKeyCount=0; 
   pLEADFILETAG pTags = NULL, pCurrentTag, pGeoKeys = NULL, pCurrentGeoKey; 
   L_SIZE_T uTagDataSize = 0, uCommentDataSize = 0, uGeoKeyDataSize = 0; 
   L_UCHAR *pTagData = NULL, *pCommentData = NULL, *pGeoKeyData = NULL; 
   L_CHAR *pszAscii = NULL; 
   pLEADFILECOMMENT pComments = NULL, pCurrentComment; 
   L_TCHAR szImageFileName[L_MAXPATH] ; 
   lstrcpy(szImageFileName,MAKE_IMAGE_PATH(TEXT("ImageProcessingDemo\\image1.jpg"))); 
 
 
   // Get the format of the file 
   ZeroMemory(&fi, sizeof(FILEINFO)); 
   fi.uStructSize = sizeof(FILEINFO); 
   nRet = L_FileInfo(szImageFileName, &fi, sizeof(FILEINFO), 0, NULL); 
   if(nRet != SUCCESS) 
      return nRet; 
 
   // Read all the tags in the file 
   if(nRet == SUCCESS && L_TagsSupported(fi.Format)) 
   { 
      // Yes, read all the tags from the file 
      nRet = L_ReadFileTags( 
         szImageFileName, 
         0, 
         &uTagCount, 
         &pTags, 
         &uTagDataSize, 
         &pTagData, 
         NULL); 
   } 
 
   // Read all the comments in the file 
   if(nRet == SUCCESS && L_CommentsSupported(fi.Format)) 
   { 
      // Yes, read all the comments from the file 
      nRet = L_ReadFileComments( 
         szImageFileName, 
         0, 
         &uCommentCount, 
         &pComments, 
         &uCommentDataSize, 
         &pCommentData, 
         NULL); 
   } 
 
   // Read all the geo keys in the file 
   if(nRet == SUCCESS && L_GeoKeysSupported(fi.Format)) 
   { 
      // Yes, read all the geo keys from the file 
      nRet = L_ReadFileGeoKeys( 
         szImageFileName, 
         0, 
         &uGeoKeyCount, 
         &pGeoKeys, 
         &uGeoKeyDataSize, 
         &pGeoKeyData, 
         NULL); 
   } 
 
   if(nRet == SUCCESS) 
   { 
      if(uTagCount > 0) 
      { 
         // Show the tags 
         wprintf(L"Tags\n"); 
         for(i = 0; i < uTagCount; i++) 
         { 
            pCurrentTag = &pTags[i]; 
 
            // If this tag is of type ASCII, get its data 
            if(pCurrentTag->uType == TAG_ASCII) 
            { 
               pszAscii = (L_CHAR*)malloc(pCurrentTag->uDataSize + 1); 
               ZeroMemory(pszAscii, pCurrentTag->uDataSize + 1); 
               CopyMemory(pszAscii, pTagData + pCurrentTag->uDataOffset, pCurrentTag->uDataSize); 
            } 
            else 
            { 
               pszAscii = NULL; 
            } 
 
            printf("Id: 0x%X, data length: %u, data: %s\n", pCurrentTag->uTag, pCurrentTag->uDataSize, pszAscii != NULL ? pszAscii : "Binary data"); 
         } 
 
         L_FreeFileTags(uTagCount, pTags, uTagDataSize, pTagData); 
      } 
 
      if(uCommentCount > 0) 
      { 
         // Show the Comments 
         wprintf(L"Comments\n"); 
         for(i = 0; i < uCommentCount; i++) 
         { 
            pCurrentComment = &pComments[i]; 
 
            // If this comment is of type ASCII, get its data 
            printf("Id: 0x%X, data length: %u\n", pCurrentComment->uType, pCurrentComment->uDataSize); 
         } 
 
         L_FreeFileComments(uCommentCount, pComments, uCommentDataSize, pCommentData); 
      } 
 
      if(uGeoKeyCount > 0) 
      { 
         // Show the geo keys 
         wprintf(L"GeoKeys\n"); 
         for(i = 0; i < uGeoKeyCount; i++) 
         { 
            pCurrentGeoKey = &pGeoKeys[i]; 
 
            // If this geo key is of type ASCII, get its data 
            if(pCurrentGeoKey->uType == TAG_ASCII) 
            { 
               pszAscii = (L_CHAR*)malloc(pCurrentGeoKey->uDataSize + 1); 
               ZeroMemory(pszAscii, pCurrentGeoKey->uDataSize + 1); 
               CopyMemory(pszAscii, pGeoKeyData + pCurrentGeoKey->uDataOffset, pCurrentGeoKey->uDataSize); 
            } 
            else 
            { 
               pszAscii = NULL; 
            } 
 
            printf("Id: 0x%X, data length: %u, data: %s\n", pCurrentGeoKey->uTag, pCurrentGeoKey->uDataSize, pszAscii != NULL ? pszAscii : "Binary data"); 
         } 
 
         L_FreeFileTags(uGeoKeyCount, pGeoKeys, uGeoKeyDataSize, pGeoKeyData); 
      } 
   } 
   return SUCCESS; 
} 
 
//Example 2: This example will read a custom tag contained inside a Canon MakerNote tag. The Canon MakerNote tag contains an offset into a SubIFD containing Canon-specific tags. You can do a web search for "canon makernote specification" to get the details on the Canon Makernote tag. 
L_INT ReadCanonSerialNumber2(HWND hWnd, TCHAR *pszFile) 
{ 
   // read the MakerNote tag 
   // Step1: Find the ExifIFD tag offset 
   L_UINT16 uType = TAG_LONG; 
   L_UINT   uCount = 1; 
   L_INT    nExifIFDOffset; 
   L_INT    nTagSize = L_ReadFileTag(pszFile, 0x8769, &uType, &uCount, &nExifIFDOffset, NULL); 
 
   if(nTagSize != 4) 
      return -5000; // custom error: this file is not an Exif file 
 
   // set up the LOADFILEOPTION structure to read tags from the Exif IFD 
   LOADFILEOPTION LoadFileOption; 
   L_GetDefaultLoadFileOption(&LoadFileOption, sizeof(LoadFileOption)); 
   LoadFileOption.IFD = nExifIFDOffset; 
   LoadFileOption.Flags = ELO_USEIFD; 
 
   // step2: Find the offset of the MakerNote tag. Use L_EnumFileTags instead of L_ReadFileTag 
   //        because it is the only way to get the offset value for a tag with more than 4 bytes 
   L_UINT uTags; 
   LEADFILETAG *pTags; 
   L_INT nRet = L_ReadFileTags(pszFile, READFILEMETADATA_NOMEMORY, &uTags, &pTags, NULL, NULL, &LoadFileOption); 
   if(nRet != SUCCESS) 
      return nRet; 
 
   for(UINT u = 0; u < uTags; u++) 
   { 
      if(pTags[u].uTag == 0x927C) // makernote tag 
      { 
         // read the makernote tags 
         LoadFileOption.IFD = pTags[u].uDataOffset; 
 
         // The Canon Makernote tags lists the Camera Serial number  
         // 12    Camera Serial Number    Special - To display serial number as on camera use: printf( "%04X%05d", highword, lowword ) 
         nTagSize = L_ReadFileTag(pszFile, 12, &uType, &uCount, NULL, &LoadFileOption); 
 
         if(nTagSize == 4) 
         { 
            L_UINT uSerialNumber; 
            nTagSize = L_ReadFileTag(pszFile, 12, &uType, &uCount, &uSerialNumber, &LoadFileOption); 
            if(nTagSize == 4) 
            { 
               TCHAR s[50]; 
               _stprintf_s(s, _countof(s), TEXT("%04X%05d"), HIWORD(uSerialNumber), LOWORD(uSerialNumber)); 
               MessageBox(hWnd, s, TEXT("Serial Number"), MB_OK); 
            } 
         } 
         L_FreeFileTags(uTags, pTags, 0, NULL); 
 
         return SUCCESS; 
      } 
   } 
 
   L_FreeFileTags(uTags, pTags, 0, NULL); 
 
   return -5001; // custom error: did not find the tag 
}