Since seek after the end is not considered an error, I doubt that "while (gzseek ($fh, $eof) == 0) $eof += $d;" will get into infinite loop.
(PHP 4, PHP 5)
gzseek — Seek on a gz-file pointer
$whence= SEEK_SET ] )
Sets the file position indicator for the given file pointer to the given offset byte into the file stream. Equivalent to calling (in C) gzseek(zp, offset, SEEK_SET).
If the file is opened for reading, this function is emulated but can be extremely slow. If the file is opened for writing, only forward seeks are supported; gzseek() then compresses a sequence of zeroes up to the new starting position.
The gz-file pointer. It must be valid, and must point to a file successfully opened by gzopen().
The seeked offset.
SEEK_SET- Set position equal to
SEEK_CUR- Set position to current location plus
whenceis not specified, it is assumed to be
Upon success, returns 0; otherwise, returns -1. Note that seeking past EOF is not considered an error.
Example #1 gzseek() example
$gz = gzopen('somefile.gz', 'r');
contrary to the notes, gzseek() returns -1 if I try to seek past the end of the file. here is a function that will return the last seekable position, and put the file pointer there.
/** sets the file pointer at the end of the file
* and returns the number of bytes in the file.
$d = 1<<14;
$eof = $d;
while ( gzseek($fh, $eof) == 0 ) $eof += $d;
while ( $d > 1 )
$d >>= 1;
$eof += $d * (gzseek($fh, $eof)? -1 : 1);