wp/wp-includes/Requests/IDNAEncoder.php
changeset 7 cf61fcea0001
child 18 be944660c56a
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/wp/wp-includes/Requests/IDNAEncoder.php	Mon Oct 14 17:39:30 2019 +0200
@@ -0,0 +1,388 @@
+<?php
+
+/**
+ * IDNA URL encoder
+ *
+ * Note: Not fully compliant, as nameprep does nothing yet.
+ *
+ * @package Requests
+ * @subpackage Utilities
+ * @see https://tools.ietf.org/html/rfc3490 IDNA specification
+ * @see https://tools.ietf.org/html/rfc3492 Punycode/Bootstrap specification
+ */
+class Requests_IDNAEncoder {
+	/**
+	 * ACE prefix used for IDNA
+	 *
+	 * @see https://tools.ietf.org/html/rfc3490#section-5
+	 * @var string
+	 */
+	const ACE_PREFIX = 'xn--';
+
+	/**#@+
+	 * Bootstrap constant for Punycode
+	 *
+	 * @see https://tools.ietf.org/html/rfc3492#section-5
+	 * @var int
+	 */
+	const BOOTSTRAP_BASE         = 36;
+	const BOOTSTRAP_TMIN         = 1;
+	const BOOTSTRAP_TMAX         = 26;
+	const BOOTSTRAP_SKEW         = 38;
+	const BOOTSTRAP_DAMP         = 700;
+	const BOOTSTRAP_INITIAL_BIAS = 72;
+	const BOOTSTRAP_INITIAL_N    = 128;
+	/**#@-*/
+
+	/**
+	 * Encode a hostname using Punycode
+	 *
+	 * @param string $string Hostname
+	 * @return string Punycode-encoded hostname
+	 */
+	public static function encode($string) {
+		$parts = explode('.', $string);
+		foreach ($parts as &$part) {
+			$part = self::to_ascii($part);
+		}
+		return implode('.', $parts);
+	}
+
+	/**
+	 * Convert a UTF-8 string to an ASCII string using Punycode
+	 *
+	 * @throws Requests_Exception Provided string longer than 64 ASCII characters (`idna.provided_too_long`)
+	 * @throws Requests_Exception Prepared string longer than 64 ASCII characters (`idna.prepared_too_long`)
+	 * @throws Requests_Exception Provided string already begins with xn-- (`idna.provided_is_prefixed`)
+	 * @throws Requests_Exception Encoded string longer than 64 ASCII characters (`idna.encoded_too_long`)
+	 *
+	 * @param string $string ASCII or UTF-8 string (max length 64 characters)
+	 * @return string ASCII string
+	 */
+	public static function to_ascii($string) {
+		// Step 1: Check if the string is already ASCII
+		if (self::is_ascii($string)) {
+			// Skip to step 7
+			if (strlen($string) < 64) {
+				return $string;
+			}
+
+			throw new Requests_Exception('Provided string is too long', 'idna.provided_too_long', $string);
+		}
+
+		// Step 2: nameprep
+		$string = self::nameprep($string);
+
+		// Step 3: UseSTD3ASCIIRules is false, continue
+		// Step 4: Check if it's ASCII now
+		if (self::is_ascii($string)) {
+			// Skip to step 7
+			if (strlen($string) < 64) {
+				return $string;
+			}
+
+			throw new Requests_Exception('Prepared string is too long', 'idna.prepared_too_long', $string);
+		}
+
+		// Step 5: Check ACE prefix
+		if (strpos($string, self::ACE_PREFIX) === 0) {
+			throw new Requests_Exception('Provided string begins with ACE prefix', 'idna.provided_is_prefixed', $string);
+		}
+
+		// Step 6: Encode with Punycode
+		$string = self::punycode_encode($string);
+
+		// Step 7: Prepend ACE prefix
+		$string = self::ACE_PREFIX . $string;
+
+		// Step 8: Check size
+		if (strlen($string) < 64) {
+			return $string;
+		}
+
+		throw new Requests_Exception('Encoded string is too long', 'idna.encoded_too_long', $string);
+	}
+
+	/**
+	 * Check whether a given string contains only ASCII characters
+	 *
+	 * @internal (Testing found regex was the fastest implementation)
+	 *
+	 * @param string $string
+	 * @return bool Is the string ASCII-only?
+	 */
+	protected static function is_ascii($string) {
+		return (preg_match('/(?:[^\x00-\x7F])/', $string) !== 1);
+	}
+
+	/**
+	 * Prepare a string for use as an IDNA name
+	 *
+	 * @todo Implement this based on RFC 3491 and the newer 5891
+	 * @param string $string
+	 * @return string Prepared string
+	 */
+	protected static function nameprep($string) {
+		return $string;
+	}
+
+	/**
+	 * Convert a UTF-8 string to a UCS-4 codepoint array
+	 *
+	 * Based on Requests_IRI::replace_invalid_with_pct_encoding()
+	 *
+	 * @throws Requests_Exception Invalid UTF-8 codepoint (`idna.invalidcodepoint`)
+	 * @param string $input
+	 * @return array Unicode code points
+	 */
+	protected static function utf8_to_codepoints($input) {
+		$codepoints = array();
+
+		// Get number of bytes
+		$strlen = strlen($input);
+
+		for ($position = 0; $position < $strlen; $position++) {
+			$value = ord($input[$position]);
+
+			// One byte sequence:
+			if ((~$value & 0x80) === 0x80) {
+				$character = $value;
+				$length = 1;
+				$remaining = 0;
+			}
+			// Two byte sequence:
+			elseif (($value & 0xE0) === 0xC0) {
+				$character = ($value & 0x1F) << 6;
+				$length = 2;
+				$remaining = 1;
+			}
+			// Three byte sequence:
+			elseif (($value & 0xF0) === 0xE0) {
+				$character = ($value & 0x0F) << 12;
+				$length = 3;
+				$remaining = 2;
+			}
+			// Four byte sequence:
+			elseif (($value & 0xF8) === 0xF0) {
+				$character = ($value & 0x07) << 18;
+				$length = 4;
+				$remaining = 3;
+			}
+			// Invalid byte:
+			else {
+				throw new Requests_Exception('Invalid Unicode codepoint', 'idna.invalidcodepoint', $value);
+			}
+
+			if ($remaining > 0) {
+				if ($position + $length > $strlen) {
+					throw new Requests_Exception('Invalid Unicode codepoint', 'idna.invalidcodepoint', $character);
+				}
+				for ($position++; $remaining > 0; $position++) {
+					$value = ord($input[$position]);
+
+					// If it is invalid, count the sequence as invalid and reprocess the current byte:
+					if (($value & 0xC0) !== 0x80) {
+						throw new Requests_Exception('Invalid Unicode codepoint', 'idna.invalidcodepoint', $character);
+					}
+
+					$character |= ($value & 0x3F) << (--$remaining * 6);
+				}
+				$position--;
+			}
+
+			if (
+				// Non-shortest form sequences are invalid
+				   $length > 1 && $character <= 0x7F
+				|| $length > 2 && $character <= 0x7FF
+				|| $length > 3 && $character <= 0xFFFF
+				// Outside of range of ucschar codepoints
+				// Noncharacters
+				|| ($character & 0xFFFE) === 0xFFFE
+				|| $character >= 0xFDD0 && $character <= 0xFDEF
+				|| (
+					// Everything else not in ucschar
+					   $character > 0xD7FF && $character < 0xF900
+					|| $character < 0x20
+					|| $character > 0x7E && $character < 0xA0
+					|| $character > 0xEFFFD
+				)
+			) {
+				throw new Requests_Exception('Invalid Unicode codepoint', 'idna.invalidcodepoint', $character);
+			}
+
+			$codepoints[] = $character;
+		}
+
+		return $codepoints;
+	}
+
+	/**
+	 * RFC3492-compliant encoder
+	 *
+	 * @internal Pseudo-code from Section 6.3 is commented with "#" next to relevant code
+	 * @throws Requests_Exception On character outside of the domain (never happens with Punycode) (`idna.character_outside_domain`)
+	 *
+	 * @param string $input UTF-8 encoded string to encode
+	 * @return string Punycode-encoded string
+	 */
+	public static function punycode_encode($input) {
+		$output = '';
+#		let n = initial_n
+		$n = self::BOOTSTRAP_INITIAL_N;
+#		let delta = 0
+		$delta = 0;
+#		let bias = initial_bias
+		$bias = self::BOOTSTRAP_INITIAL_BIAS;
+#		let h = b = the number of basic code points in the input
+		$h = $b = 0; // see loop
+#		copy them to the output in order
+		$codepoints = self::utf8_to_codepoints($input);
+		$extended = array();
+
+		foreach ($codepoints as $char) {
+			if ($char < 128) {
+				// Character is valid ASCII
+				// TODO: this should also check if it's valid for a URL
+				$output .= chr($char);
+				$h++;
+			}
+			// Check if the character is non-ASCII, but below initial n
+			// This never occurs for Punycode, so ignore in coverage
+			// @codeCoverageIgnoreStart
+			elseif ($char < $n) {
+				throw new Requests_Exception('Invalid character', 'idna.character_outside_domain', $char);
+			}
+			// @codeCoverageIgnoreEnd
+			else {
+				$extended[$char] = true;
+			}
+		}
+		$extended = array_keys($extended);
+		sort($extended);
+		$b = $h;
+#		[copy them] followed by a delimiter if b > 0
+		if (strlen($output) > 0) {
+			$output .= '-';
+		}
+#		{if the input contains a non-basic code point < n then fail}
+#		while h < length(input) do begin
+		while ($h < count($codepoints)) {
+#			let m = the minimum code point >= n in the input
+			$m = array_shift($extended);
+			//printf('next code point to insert is %s' . PHP_EOL, dechex($m));
+#			let delta = delta + (m - n) * (h + 1), fail on overflow
+			$delta += ($m - $n) * ($h + 1);
+#			let n = m
+			$n = $m;
+#			for each code point c in the input (in order) do begin
+			for ($num = 0; $num < count($codepoints); $num++) {
+				$c = $codepoints[$num];
+#				if c < n then increment delta, fail on overflow
+				if ($c < $n) {
+					$delta++;
+				}
+#				if c == n then begin
+				elseif ($c === $n) {
+#					let q = delta
+					$q = $delta;
+#					for k = base to infinity in steps of base do begin
+					for ($k = self::BOOTSTRAP_BASE; ; $k += self::BOOTSTRAP_BASE) {
+#						let t = tmin if k <= bias {+ tmin}, or
+#								tmax if k >= bias + tmax, or k - bias otherwise
+						if ($k <= ($bias + self::BOOTSTRAP_TMIN)) {
+							$t = self::BOOTSTRAP_TMIN;
+						}
+						elseif ($k >= ($bias + self::BOOTSTRAP_TMAX)) {
+							$t = self::BOOTSTRAP_TMAX;
+						}
+						else {
+							$t = $k - $bias;
+						}
+#						if q < t then break
+						if ($q < $t) {
+							break;
+						}
+#						output the code point for digit t + ((q - t) mod (base - t))
+						$digit = $t + (($q - $t) % (self::BOOTSTRAP_BASE - $t));
+						$output .= self::digit_to_char($digit);
+#						let q = (q - t) div (base - t)
+						$q = floor(($q - $t) / (self::BOOTSTRAP_BASE - $t));
+#					end
+					}
+#					output the code point for digit q
+					$output .= self::digit_to_char($q);
+#					let bias = adapt(delta, h + 1, test h equals b?)
+					$bias = self::adapt($delta, $h + 1, $h === $b);
+#					let delta = 0
+					$delta = 0;
+#					increment h
+					$h++;
+#				end
+				}
+#			end
+			}
+#			increment delta and n
+			$delta++;
+			$n++;
+#		end
+		}
+
+		return $output;
+	}
+
+	/**
+	 * Convert a digit to its respective character
+	 *
+	 * @see https://tools.ietf.org/html/rfc3492#section-5
+	 * @throws Requests_Exception On invalid digit (`idna.invalid_digit`)
+	 *
+	 * @param int $digit Digit in the range 0-35
+	 * @return string Single character corresponding to digit
+	 */
+	protected static function digit_to_char($digit) {
+		// @codeCoverageIgnoreStart
+		// As far as I know, this never happens, but still good to be sure.
+		if ($digit < 0 || $digit > 35) {
+			throw new Requests_Exception(sprintf('Invalid digit %d', $digit), 'idna.invalid_digit', $digit);
+		}
+		// @codeCoverageIgnoreEnd
+		$digits = 'abcdefghijklmnopqrstuvwxyz0123456789';
+		return substr($digits, $digit, 1);
+	}
+
+	/**
+	 * Adapt the bias
+	 *
+	 * @see https://tools.ietf.org/html/rfc3492#section-6.1
+	 * @param int $delta
+	 * @param int $numpoints
+	 * @param bool $firsttime
+	 * @return int New bias
+	 */
+	protected static function adapt($delta, $numpoints, $firsttime) {
+#	function adapt(delta,numpoints,firsttime):
+#		if firsttime then let delta = delta div damp
+		if ($firsttime) {
+			$delta = floor($delta / self::BOOTSTRAP_DAMP);
+		}
+#		else let delta = delta div 2
+		else {
+			$delta = floor($delta / 2);
+		}
+#		let delta = delta + (delta div numpoints)
+		$delta += floor($delta / $numpoints);
+#		let k = 0
+		$k = 0;
+#		while delta > ((base - tmin) * tmax) div 2 do begin
+		$max = floor(((self::BOOTSTRAP_BASE - self::BOOTSTRAP_TMIN) * self::BOOTSTRAP_TMAX) / 2);
+		while ($delta > $max) {
+#			let delta = delta div (base - tmin)
+			$delta = floor($delta / (self::BOOTSTRAP_BASE - self::BOOTSTRAP_TMIN));
+#			let k = k + base
+			$k += self::BOOTSTRAP_BASE;
+#		end
+		}
+#		return k + (((base - tmin + 1) * delta) div (delta + skew))
+		return $k + floor(((self::BOOTSTRAP_BASE - self::BOOTSTRAP_TMIN + 1) * $delta) / ($delta + self::BOOTSTRAP_SKEW));
+	}
+}
\ No newline at end of file