ContentCompareFiles

ContentCompareFiles is called in Synchronize dirs to compare two files by content, e.g. two text files with different line breaks, one Windows (CRLF) and one Unix (LF only).

Declaration

int __stdcall ContentCompareFiles(PROGRESSCALLBACKPROC progresscallback,int compareindex,TCHAR* filename1,TCHAR* filename2,FileDetailsStruct* filedetails);

Description of parameters

progresscallback	Callback function to inform the calling program about the compare progress. If progresscallback returned a value other than zero (0), the user pressed the Abort/Cancel button and the comparison MUST be aborted with return value -2. You should call this message only every 100-200 milliseconds or so, because callbacks are slow.
compareindex	The value returned by ContentGetSupportedField for this compare field (starting with 10000)
filename1	The first name to be compared
filename2	The second name to be compated
filedetails	A structure which informs the plugin about the size, timestamp and attributes of both files

Return value

1	The two files are equal, show equal sign in list
2	The two files are equal, show equal sign with 'TXT' below it in list
0	The two files are different
-1	Could not open at least one of the files
-2	Compare aborted
-3	The file cannot be compared with this function, please continue with the next plugin. Example: A plugin which compares two Word files by contents (even if the meta data is different) needs to return -3 if at least one of the two files isn't a Word file
100 or higher	The two files are equal. The plugin file contains a 16x16 icon resource with this numeric ID, to be loaded via LoadImage(DllHandle,MAKEINTRESOURCE(id),IMAGE_ICON,16,16,LR_SHARED); which will be shown between the two files. The icon must contain a 16 color image, and may also contain higher color images. Please test your icon at least with black on white and white on black window settings (Control panel - Display).There are two types of icons you can use: 1: If the value is <10000, the icon will be drawn in addition to the equal sign (which will be in black or white, depending on the color of the background). The upper 8 pixels (plus 1 pixel optional border) may be used for drawing the additional image or text. 2: If the value is >=10000, no equal sign will be drawn by TC, so the plugin can use the entire 16x16 space for drawing.

Remarks

• Do not return 0 (files different) if the two files are binary identical (containing exactly the same data) just because the plugin cannot compare them - this would break the normal compare function. Return -3 instead.
• It's recommended to make a binary comparison first if the plugin is for a broad range of files, so the user may use *.* as the file type. Example_ See our "filesys" sample content plugin (text comparison), which makes a binary comparison until it finds the first difference, and then continues with using its text comparison method.

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