The PHP implementation intercepts the N-character method that starts at a location in the GBK document

This article mainly introduces the implementation of PHP to intercept GBK document at the beginning of a certain location of the N-character method, interested in a friend's reference, I hope to be helpful to everyone.

cut.php:

#!/usr/bin/php<?phpdefine (' input_file ', ' t.txt ');d efine (' output_file ', ' a.txt '); $pos = max (Intval ($argv [1]), 0); $len = Max (Intval ($argv [2]), 0); $file _size = filesize (input_file), if ($pos >= $file _size) exit; $fp = fopen (input_file, ' RB '); $point = 0; Current byte position$string = '; while (Ftell ($FP) < $file _size) {  if ($point >= $pos + $len) break; $byte = Fread ($fp, 1);   PHP version >= 5.4  $char = unpack (' C ', $byte) [1];  if ($char <= 0x7f) {    //single byte    if ($point >= $pos) $string. = $byte;    $point + = 1;    Continue;  } else {    //double bytes    if ($point >= $pos) {      $string. = $byte. Fread ($fp, 1);     } else {      fseek ($fp , 1, seek_cur);    }    $point + = 1;    Continue;  }  } Fclose ($FP); File_put_contents (Output_file, $string);? >

Source File T.txt content:

Dkei20 Wang Nnso

Test command:

./cut.php 6 1

View results:

Hexdump-c t.txt && hexdump-c a.txt

The above is the whole content of this article, I hope that everyone's study has helped.