[Code] uses regular, from the specified starting position, in the source string to intercept the fixed length string (including Chinese) [fourth edition]
[Code] uses regular, starting from the specified starting position, in the source string to intercept a certain length of string [fourth edition]
[code] uses regular expressions, starting at the specified starting position, to intercept a certain length of string in the source string [fourth correction]
[code] uses regular expressions, starting at the head of a string, to intercept a string of bytes of length in the source string
[code] uses regular expressions, starting at the specified starting position, to intercept a certain length of string in the source string
(BTW: The Chinese code is very complex also some unreasonable place high is 0xa1-0xfe (does not contain 0xff because 0xFF namely 255 in the Telnet protocol has the important function), the low 0x40-0xfe, but GBK in order to and the Unicode mapping to extend the high position to the 0X81 -0xfe
Description of whether the last byte intercepts errors in Chinese:
The last byte, if it intercepts half of the Chinese, then it should be a high-bit byte, whose ASCII code is greater than 0X81.
Because the high byte of Chinese is greater than 0x81, and the low byte is not limited.
A complete kanji: [0x81-0xfe][0x40-0xfe]
Therefore, the use of regular expressions, and then take out Chinese and non-Chinese characters, Chinese characters first.
The last byte, if it intercepts half of the Chinese, then she will be a non-Chinese character, and it is the high byte of the Chinese character
To determine if the byte is in [0x81-0xfe], you can know whether to intercept the error.
// ---------------------------------------------------------------
File name:preg_substr.php
Description: Use regular expressions to intercept a certain amount of string from the source string, starting at the specified starting position
// -----------------------------------------------------------
Function description
Function Name: PREG_SUBSTR
Function Version: Fourth revision
function function: Use regular expressions to intercept a certain amount of string from the source string, starting at the specified starting position
Function parameters:
$strSource: Source string
$intStart: Starting position, default = 0 means starting from scratch
$intLen: Intercept length, default is 32
function Preg_substr ($strSource, $intStart =0, $intLen =32)
{
Is_int ($intLen)? 0:die ("Len isn ' t a integer");
Is_int ($intStart)? 0:die ("Start isn t a integer");
if ($intStart >=0 && $intLen >0 && @preg_match ('/^ (. {'). $intStart. '}) (. {0, '. $intLen. '}) /si ', $strSource)) {
@preg_match ('/^ (. {'). $intStart. '}) (. {0, '. $intLen. '}) /si ', $strSource, $regs);
@preg_match_all ('/([x81-xfe].|.) /sim ', $regs [1], $regs 1, Preg_pattern_order);
@preg_match ('/^[x81-xfe]$/', $regs 1[1][count ($regs 1[1])-1])? $intStart--:0;
@preg_match ('/^ (. {'). $intStart. '}) (. {0, '. $intLen. '}) /si ', $strSource, $regs);
@preg_match_all ('/([x81-xfe].|.) /sim ', $regs [2], $regs 1, Preg_pattern_order);
@preg_match ('/^[x81-xfe]$/', $regs 1[1][count ($regs 1[1])-1])? $intLen--:0;
@preg_match ('/^ (. {'). $intStart. '}) (. {0, '. $intLen. '}) /si ', $strSource, $regs);
$strResult = $regs [2];
}else{
$strResult = "";
}
return $strResult;
}
function Preg_substr2 ($strSource, $intStart =0, $intLen =32)
{
Is_int ($intLen)? 0:die ("Len isn ' t a integer");
Is_int ($intStart)? 0:die ("Start isn t a integer");
if ($intStart >=0 && $intLen >=0)
{
$strResult = substr ($strSource, 0, $intStart);
@preg_match_all ('/([x81-xfe].|.) /sim ', $strResult, $regs, Preg_pattern_order);
if (@preg_match ('/^[x81-xfe]$/', $regs [1][count ($regs [1])-1], $regs)) {
$intStart--;
}
$strResult = substr ($strSource, $intStart, $intLen);
@preg_match_all ('/([x81-xfe].|.) /sim ', $strResult, $regs, Preg_pattern_order);
if (@preg_match ('/^[x81-xfe]$/', $regs [1][count ($regs [1])-1], $regs)) {
$strResult = substr ($strSource, $intStart,--$intLen);
}
}
return $strResult;
}
$strHTML = << <>
Ab
http://www.bkjia.com/PHPjc/631416.html www.bkjia.com true http://www.bkjia.com/PHPjc/631416.html techarticle [code] uses regular, from the specified starting position, in the source string to intercept the fixed length string (including Chinese) [fourth] [code] with the regular, starting from the specified starting position, intercepted in the source string ...
