help with filename format checking

[greedyisg00d]

the filename format must be in company name + date uploaded(mm/dd/yyyy) + size in bytes(12 digits) for example:

companyxyz03012010000000001432.zip

how can I check if the user followed this exact format? Therefore an error message will show when invalid filename format is uploaded.

thanks

[bradgrafelman]

What kind of constraints do you have on 'company name' ? Is this value available to the script at the time the file is uploaded so you could do a simple string comparison?

Also, why make the uploader figure out those last two conditions? If the answer is 'yes' to my question above, why not just rename the file after it's uploaded? Seems like that would be a lot easier rather than a) forcing the user to name it exactly so, and b) verifying that they have done this.

[johanafm]

If you use some kind of authentication, you should allready know what company a user belongs to, so you have the first part of the file name. If you don't, any user can upload a file seemingly coming from any other company.
Adding the date and filesize is easily done in php, but this information is also allready available from the file system (file creation time and file size).

But all you need to do is concatenate these parts together to get your filename.