Please specify whether your issue is about:

• a possible bug
• a question about package functionality
• a suggested code or documentation change, improvement to the code, or feature request

I often am given MS Office files that have missing extensions or incorrect ones (e.g. a novice user tried to 'convert' them to csv by renaming them). Not only are these zip files, they can have the same file signature as LibreOffice files and who knows what else.

This is a function that scans for files that are specific to MS Office and LibreOffice/OpenOffice.

As with #236, my question is: would this function be useful to contribute to rio, for example to augment the current extension-only dispatch of readxl and readODS methods.

Put your code here:

isfilezipdoc <- function(filename, 
                                     docpaths=c(MSO='[Content_Types].xml',
                                                         OO='META-INF/manifest.xml'), tf=TRUE){
    matchedpaths <- docpaths %in% unzip(filename,list=TRUE)[,1] 
    if(tf) return(any(matchedpaths))
    return(names(docpaths[matchedpaths])) 
}