gzseek Seek on a gz-file pointer php函数


gzseek

(PHP 4, PHP 5)

gzseekSeek on a gz-file pointer

说明

int gzseek ( resource $zp , int $offset [, int $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.

参数

zp

The gz-file pointer. It must be valid, and must point to a file successfully opened by gzopen().

offset

The seeked offset.

whence

whence values are:

  • SEEK_SET - Set position equal to offset bytes.
  • SEEK_CUR - Set position to current location plus offset.

If whence is not specified, it is assumed to be SEEK_SET.

返回值

Upon success, returns 0; otherwise, returns -1. Note that seeking past EOF is not considered an error.

范例

Example #1 gzseek() example

<?php
$gz 
gzopen('somefile.gz''r');
gzseek($gz,2);
echo 
gzgetc($gz);
gzclose($gz);
?>

参见

  • gztell() - Tell gz-file pointer read/write position
  • gzrewind() - Rewind the position of a gz-file pointer



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hash_init Initialize an incremental hashing context
hash_update Pump data into an active hashing context
hash_update_file Pump data into an active hashing context from a file
hash_update_stream Pump data into an active hashing context from an open stream
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