Set of some common functions in php

/* Obtain the Client IP Address */
Function getIP (){
If (getenv ("HTTP_CLIENT_IP") & strcasecmp (getenv ("HTTP_CLIENT_IP"), "unknown ")){
$ Ip = getenv ("HTTP_CLIENT_IP ");
}
Else if (getenv ("HTTP_X_FORWARDED_FOR") & strcasecmp (getenv ("HTTP_X_FORWARDED_FOR"), "unknown ")){
$ Ip = getenv ("HTTP_X_FORWARDED_FOR ");
}
Else if (getenv ("REMOTE_ADDR") & strcasecmp (getenv ("REMOTE_ADDR"), "unknown ")){
$ Ip = getenv ("REMOTE_ADDR ");
}
Else if (isset ($ _ SERVER ['remote _ ADDR ']) & $ _ SERVER ['remote _ ADDR '] & strcasecmp ($ _ SERVER ['remote _ ADDR'], "unknown ")){
$ Ip = $ _ SERVER ['remote _ ADDR '];
}
Else {
$ Ip = "unknown ";
}

Return ($ ip );
}

/* IP address verification function */
Function checkIP ($ ip ){
Return preg_match (2 [0-4] \ d | 25 [0-5] | [01]? \ D ?) \.) {3} (2 [0-4] \ d | 25 [0-5] | [01]? \ D ?);
}

/* User input content filtering function */
Function getStr ($ str ){
$ Tmpstr = trim ($ str );
$ Tmpstr = strip_tags ($ tmpstr );
$ Tmpstr = htmlspecialchars ($ tmpstr );

/* Add character Escaping */
$ Tmpstr = addslashes ($ tmpstr );

Return $ tmpstr;
}

/* Capacity and size calculation function */
Function sizecount ($ filesize ){
If ($ filesize> = 1073741824 ){
$ Filesize = round ($ filesize/1073741824*100)/100. 'G ';
} Elseif ($ filesize >=1048576 ){
$ Filesize = round ($ filesize/1048576*100)/100. 'M ';
} Elseif ($ filesize >=1024 ){
$ Filesize = round ($ filesize/1024*100)/100. 'K ';
} Else {
$ Filesize = $ filesize. 'bytes ';
}
Return $ filesize;
}

/* Simple anti-SQL Injection function */
Function getSQL ($ feild ){
$ Tmpfeild = mysql_escape_string ($ feild );

Return $ tmpfeild;
}
/* $ Num must be an English character or number 0-9 */
Function getNums ($ num ){
Return (ctype_alnum ($ num ));
}

/* $ Char must be an English character */
Function getChar ($ char ){
Return (ctype_alpha ($ char ));
}
/* Match qq (5-12) digits */
Function getQQ ($ qq ){
Return preg_match ("/^ \ B [0-9] {5, 12} \ B/", $ qq );
}
/* Match the email address */
Function getEmail ($ email ){
Return strlen ($ email)> 6 & preg_match ("/^ \ w + @ (\ w + \.) + [com] | [cn] $/", $ email );
// Preg_match ("/^ [\ w \-\.] + @ [\ w \-\.] + (\. \ w +) + $/", $ email );
}

/* Generate an email connection */
Function emailconv ($ email, $ tolink = 1 ){
$ Email = str_replace (array ('@', '.'), array ('@', '.'), $ email );
Return $ tolink? '<A href = "mailto:'. $ email. '">'. $ email. '</a>': $ email;
}

/* Check whether the ip address is accessible */
Function ipaccess ($ ip, $ accesslist ){
Return preg_match ("/^ (". str_replace (array ("\ r \ n", ''), array ('|',''), preg_quote ($ accesslist ,'/')). ")/", $ ip );
}

/* If the title is too long, this function can display the first few characters. The remaining characters are replaced */
Function cutstr ($ string, $ length ){
If (strlen ($ string)> $ length ){
For ($ I = 0; $ I <$ length-3; $ I ++ ){
/* Returns the ordinal value of the character */
$ Strcut. = ord ($ string [$ I]) & gt; 127? $ String [$ I]. $ string [++ $ I]: $ string [$ I];
}
Return $ strcut .'...';
} Else {
Return $ string;
}
}