ŸŒcsv中的字符不会显示php

I am new to encoding so please be patient. I am working on a system where a user upload a csv, what i need to do is to display the content and then save it in the database. (utf-8 encoding)

I have been asked to fix a issue with some french alphabet characters that weren't displayed correctly. I have almost solved the problem, I am displaying characters such as

ÀàÂâÆÄäÇçÉéÈèÊêËëÎîÏïÔôœÖöÙùÛûÜüÿ

However the two mentioned in the title Ÿ Œ are not displayed correctly yet on the webpage.

Here is my php code so far:

// say in the csv we have "ÖüÜßŸÀàÂ"
$content = file_get_contents(addslashes($file_name));
var_dump($content) // output: string(54) "���ߟ��� "
if(!mb_detect_encoding($content, 'UTF-8, ISO-8859-1', true)){
     $data = iconv('macintosh', 'UTF-8', $content);
} 
// deal with known encoding types
else if(mb_detect_encoding($content, 'UTF-8, ISO-8859-1', true) == 'ISO-8859-1'){
    //$data  = mb_convert_encoding($content, 'UTF-8', mb_detect_encoding($content, 'UTF-8, ISO-8859-1', true)); // does not work
    $data = iconv('ISO-8859-1', 'UTF-8', $content); //does not work

}else if(mb_detect_encoding($content, 'UTF-8, ISO-8859-1', true) == 'UTF-8'){
    $data = $content
}
//if i print $data "Ÿ Œ " are not printed out... they got lost somewhere

       //do more stuff here

the file I am dealing with has an encoding type of ISO-8859-1(when i print out mb_detect_encoding($content, 'UTF-8, ISO-8859-1', true) it displays ISO-8859-1).

Is there anyone that have an idea on how to deal with this special cases?

The characters Ÿ and Œ are not representable in ISO-8859-1. It seems that the incoming data is actually windows-1252 (Windows Latin 1) encoded, since windows-1252 has graphic characters, including Ÿ and Œ, in some code positions that are reserved for control characters in ISO-8859-1.

So you should probably add windows-1252 to the list of recognized encodings and treat recognized ISO-8859-1 as windows-1252, i.e use iconv('windows-1252', 'UTF-8', $content) even when ISO-8859-1 has bee recognized. Windows-1252 data mislabeled as ISO-8859-1 is very common.