Validate name-start code points for identifier <#2>, minus tests

Author: westonruter

src/Parsing/ParserState.php

@@ -113,9 +113,31 @@ public function getSettings()
      *
      * @throws UnexpectedTokenException
      */
-    public function parseIdentifier($bIgnoreCase = true)
+    public function parseIdentifier($bIgnoreCase = true, $bNameStartCodePoint = true)
     {
-        $sResult = $this->parseCharacter(true);
+        $sResult = null;
+        $bCanParseCharacter = true;
+
+        if ($bNameStartCodePoint) {
+            // Check if 3 code points would start an identifier.
+            // See <https://drafts.csswg.org/css-syntax-3/#would-start-an-identifier>.
+            $sNameStartCodePoint = '[a-zA-Z_]|[\x80-\xFF]';
+            $sEscapeCode = '\\[^\r\n\f]';
+
+            if (
+                ! (
+                    preg_match("/^-([-${sNameStartCodePoint}]|${sEscapeCode})/isSu", $this->peek(3)) ||
+                    preg_match("/^${sNameStartCodePoint}/isSu", $this->peek()) ||
+                    preg_match("/^${sEscapeCode}/isS", $this->peek(2))
+                )
+            ) {
+                $bCanParseCharacter = false;
+            }
+        }
+
+        if ($bCanParseCharacter) {
+            $sResult = $this->parseCharacter(true);
+        }
         if ($sResult === null) {
             throw new UnexpectedTokenException($sResult, $this->peek(5), 'identifier', $this->iLineNo);
         }
@@ -179,14 +201,15 @@ public function parseCharacter($bIsForIdentifier)
         }
         if ($bIsForIdentifier) {
             $peek = ord($this->peek());
-            // Ranges: a-z A-Z 0-9 - _
+            $peek = ord($this->peek());
+            // Matches a name code point. See <https://drafts.csswg.org/css-syntax-3/#name-code-point>.
             if (
-                ($peek >= 97 && $peek <= 122)
-                || ($peek >= 65 && $peek <= 90)
-                || ($peek >= 48 && $peek <= 57)
-                || ($peek === 45)
-                || ($peek === 95)
-                || ($peek > 0xa1)
+                ($peek >= 97 && $peek <= 122) ||
+                ($peek >= 65 && $peek <= 90) ||
+                ($peek >= 48 && $peek <= 57) ||
+                ($peek === 45) ||
+                ($peek === 95) ||
+                ($peek > 0x81)
             ) {
                 return $this->consume(1);
             }

src/Value/Color.php

@@ -29,7 +29,7 @@ public static function parse(ParserState $oParserState)
         $aColor = [];
         if ($oParserState->comes('#')) {
             $oParserState->consume('#');
-            $sValue = $oParserState->parseIdentifier(false);
+            $sValue = $oParserState->parseIdentifier(false, false);
             if ($oParserState->strlen($sValue) === 3) {
                 $sValue = $sValue[0] . $sValue[0] . $sValue[1] . $sValue[1] . $sValue[2] . $sValue[2];
             } elseif ($oParserState->strlen($sValue) === 4) {