In general, your approach is fine. Perl function "read" uses streams which in turn use data caching. So, it is fast to read even by 2 bytes. If your files are only few megabytes large, then you may read them completely into string but I don't think it will improve speed, because in my tests, stream was still obtaining data in the same chunks size, so number of system calls didn't change.
One comment on your use of "pack/unpack". Somehow you overuse it. For example, when searching for eye catcher just do "next unless $buffer eq '==';". When converting binary length just do "my $length = unpack('s', $buffer);".
One more thing. You don't check the return value of "read". Especially when you read "$length - 4" bytes. The file might be corrupted and you'll never get desired number of bytes. Plus, you say, your records may contain incorrect length, then what would be you strategy for recovery in this situation? Potentially the length may point to the middle of the next record.
-
Are you posting in the right place? Check out Where do I post X? to know for sure.
-
Posts may use any of the Perl Monks Approved HTML tags. Currently these include the following:
<code> <a> <b> <big>
<blockquote> <br /> <dd>
<dl> <dt> <em> <font>
<h1> <h2> <h3> <h4>
<h5> <h6> <hr /> <i>
<li> <nbsp> <ol> <p>
<small> <strike> <strong>
<sub> <sup> <table>
<td> <th> <tr> <tt>
<u> <ul>
-
Snippets of code should be wrapped in
<code> tags not
<pre> tags. In fact, <pre>
tags should generally be avoided. If they must
be used, extreme care should be
taken to ensure that their contents do not
have long lines (<70 chars), in order to prevent
horizontal scrolling (and possible janitor
intervention).
-
Want more info? How to link
or How to display code and escape characters
are good places to start.
|