--- /dev/null
+<?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
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