Determining UCS-2 Code Points for UTF-8 Characters in PHP

The task at hand is to extract the UCS-2 code points for characters within a given UTF-8 string. To accomplish this, a custom PHP function can be defined.

Firstly, it's important to understand the UTF-8 encoding scheme. Each character is represented by a sequence of 1 to 4 bytes, depending on its Unicode code point. The ranges for each byte size are as follows:

• 0xxxxxxx: 1 byte
• 110xxxxx 10xxxxxx: 2 bytes
• 1110xxxx 10xxxxxx 10xxxxxx: 3 bytes
• 11110xxx 10xxxxxx 10xxxxxx 10xxxxxx: 4 bytes

To determine the number of bytes per character, examine the first byte:

• 0: 1 byte character
• 110: 2 byte character
• 1110: 3 byte character
• 11110: 4 byte character
• 10: Continuation byte
• 11111: Invalid character

Once the number of bytes is determined, bit manipulation can be used to extract the code point.

Custom PHP Function:

Based on the above analysis, here's a custom PHP function that takes a single UTF-8 character as input and returns its UCS-2 code point:

function get_ucs2_codepoint($char)
{
    // Initialize the code point
    $codePoint = 0;

    // Get the first byte
    $firstByte = ord($char);

    // Determine the number of bytes
    if ($firstByte 
Example Usage:
To use the function, simply provide a UTF-8 character as input:
$char = "ñ";
$codePoint = get_ucs2_codepoint($char);
echo "UCS-2 code point: $codePoint\n";
Output:
UCS-2 code point: 241