I want to find a chunk of data that's delimited on each size by a specific 4-byte sequence. This can be embedded anywhere in an arbitrary binary file.

My first idea is to set the $/ to this 4-byte sequence and then read using the normal <FILEHANDLE> syntax, examining each "record" until I see the one that looks like the one I want.

However, the random breaks in the file other than the two I want could be any length. I can imagine Perl getting bogged down reading gigaabyte strings into contiguous memory while scanning for the RecordSeperator, only to have me throw the data away as uninteresting!

If I could set a maximum length and a Seperator, or have a way to skip records without reading them, it would be great. But I don't see those abilities in the built-in Perl stream support.

Any suggestions on a portable, interesting, instructive, and efficient way to accomplish this?

—John

In reply to How do I search this binary file? by John M. Dlugosz

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