Functions used to handle strings in mixed typesetting in PHP

/*
When we are dealing with Chinese data, we often have to deal with some situations, the following is
These situations, I do some of the functions that have been used in practice
If you have any questions, please contact me.
oicq:86804
*/
# to determine whether a location is the left or right part of a Chinese character, or not
# return value-1 left 0 not Chinese character 1 right
# usage
/*
$a = ' This is Chinese ';
Print Is_chinese ($a, 1); 0
Print Is_chinese ($a, 8); -1
Print Is_chinese ($a, 9); 1
*/
Function Is_chinese (& $str, $location) {
$ch = true;
$i = $location;
while (Ord ($str [$i]) >0xa0 && $i >= 0) {
$ch =! $ch;
$i--;
}
if ($i!= $location) {
$f _str = $ch? 1:-1;
}
else {
$f _str = false;
}
return $f _str;
}
# Chinese string inversion function
# If a string with a Chinese character is strrev upside down, it will produce garbled
/*
Print Cstrrev (' is Chinese '); The SI siht in the paper
*/
Function Cstrrev (& $str) {
$long = strlen ($STR);
for ($f _str= ', $chinese =false, $i = $long-1; $i >=0; $i-) {
if (Ord ($str [$i]) > 0xa0) {
$chinese =! $chinese;
if ($chinese = = False) {
$f _str. = $str [$i]. $str [$i +1];
}
}
else {
$f _str. = $str [$i];
}
}
return $f _str;
}
/* Chinese string intercept function
Some Chinese string intercept functions often have some problems, such as in some automatic line-wrapping programs
$a = "1 of 2";
After the interception of two times,
Csubstr ($STR, $a, 0,2);
Csubstr ($STR, $a, 2,2)
This may be the result because the loading position points to the right byte in "medium"
1, 2
Using this function will produce the correct result
1, 2
*/
# start position, starting from 0
# long = 0 is taken from start to end of string
# Ltor = True when characters are left to right, false to right to left
# $cn _len characters in bytes or words, if the number of words, then a Chinese when a byte calculation
Function Csubstr (& $str, $start =0, $long =0, $ltor =true, $cn _len=2) {
if ($long = = 0) $long = strlen ($STR);
if ($ltor = = false) $str = Cstrrev ($STR);