You can not select more than 25 topics
Topics must start with a letter or number, can include dashes ('-') and can be up to 35 characters long.
99 lines
2.9 KiB
99 lines
2.9 KiB
<?php
|
|
/** @license MIT
|
|
* Copyright 2018 J. King et al.
|
|
* See LICENSE and AUTHORS files for details */
|
|
|
|
declare(strict_types=1);
|
|
namespace MensBeam\Intl\Encoding;
|
|
|
|
class XUserDefined implements Encoding {
|
|
use GenericEncoding;
|
|
|
|
const NAME = "x-user-defined";
|
|
const LABELS = ["x-user-defined"];
|
|
|
|
/** Retrieve the next character in the string, in UTF-8 encoding
|
|
*
|
|
* The returned character may be a replacement character, or the empty string if the end of the string has been reached
|
|
*/
|
|
public function nextChar(): string {
|
|
// get the byte at the current position
|
|
$b = @$this->string[$this->posChar];
|
|
if ($b === "") {
|
|
return "";
|
|
}
|
|
$this->posChar++;
|
|
$p = ord($b);
|
|
if ($p < 0x80) {
|
|
// if the byte is an ASCII character or end of input, simply return it
|
|
return $b;
|
|
} else {
|
|
return UTF8::encode(0xF700 + $p);
|
|
}
|
|
}
|
|
|
|
/** Decodes the next character from the string and returns its code point number
|
|
*
|
|
* If the end of the string has been reached, false is returned
|
|
*
|
|
* @return int|bool
|
|
*/
|
|
public function nextCode() {
|
|
// get the byte at the current position
|
|
$b = @$this->string[$this->posChar];
|
|
if ($b === "") {
|
|
return false;
|
|
}
|
|
$this->posChar++;
|
|
$p = ord($b);
|
|
if ($p < 0x80) {
|
|
// if the byte is an ASCII character or end of input, simply return it
|
|
return $p;
|
|
} else {
|
|
return 0xF700 + $p;
|
|
}
|
|
}
|
|
|
|
/** Advance $distance characters through the string
|
|
*
|
|
* If $distance is negative, the operation will be performed in reverse
|
|
*
|
|
* If the end (or beginning) of the string was reached before the end of the operation, the remaining number of requested characters is returned
|
|
*/
|
|
public function seek(int $distance): int {
|
|
if ($distance > 0) {
|
|
while ($this->posChar < $this->lenByte && $distance > 0) {
|
|
$this->nextCode();
|
|
$distance--;
|
|
}
|
|
return $distance;
|
|
} elseif ($distance < 0) {
|
|
$distance = abs($distance);
|
|
while ($this->posChar > 0 && $distance > 0) {
|
|
$this->posChar--;
|
|
$distance--;
|
|
}
|
|
return $distance;
|
|
} else {
|
|
return 0;
|
|
}
|
|
}
|
|
|
|
/** Returns the current byte position of the decoder */
|
|
public function posByte(): int {
|
|
return $this->posChar;
|
|
}
|
|
|
|
/** Calculates the length of the string in code points
|
|
*
|
|
* Note that this may involve processing to the end of the string
|
|
*/
|
|
public function lenChar(): int {
|
|
return $this->lenByte;
|
|
}
|
|
|
|
/** Returns whether the character pointer is at the end of the string */
|
|
public function eof(): bool {
|
|
return $this->posChar >= $this->lenByte;
|
|
}
|
|
}
|
|
|