Move script data length checks to top of loop

Author: sirreal

src/wp-includes/html-api/class-wp-html-tag-processor.php

@@ -1495,14 +1495,22 @@ private function skip_script_data(): bool {
 
 		while ( false !== $at && $at < $doc_length ) {
 			$at += strcspn( $html, '-<', $at );
+			/*
+			 * Ultimately a SCRIPT closer (`</script>`) must be found or this function will
+			 * return false.
+			 * `</script` is the longest sequence that can be matched, so subsequent length checks
+			 * are redundant.
+			 */
+			if ( $at + 8 >= $doc_length ) {
+				return false;
+			}
 
 			/*
 			 * For all script states a "-->"  transitions
 			 * back into the normal unescaped script mode,
 			 * even if that's the current state.
 			 */
 			if (
-				$at + 2 < $doc_length &&
 				'-' === $html[ $at ] &&
 				'-' === $html[ $at + 1 ] &&
 				'>' === $html[ $at + 2 ]
@@ -1512,10 +1520,6 @@ private function skip_script_data(): bool {
 				continue;
 			}
 
-			if ( $at + 1 >= $doc_length ) {
-				return false;
-			}
-
 			/*
 			 * Everything of interest past here starts with "<".
 			 * Check this character and advance position regardless.
@@ -1537,7 +1541,6 @@ private function skip_script_data(): bool {
 			 * parsing after updating the state.
 			 */
 			if (
-				$at + 2 < $doc_length &&
 				'!' === $html[ $at ] &&
 				'-' === $html[ $at + 1 ] &&
 				'-' === $html[ $at + 2 ]
@@ -1561,7 +1564,6 @@ private function skip_script_data(): bool {
 			 * proceed scanning to the next potential token in the text.
 			 */
 			if ( ! (
-				$at + 6 < $doc_length &&
 				( 's' === $html[ $at ] || 'S' === $html[ $at ] ) &&
 				( 'c' === $html[ $at + 1 ] || 'C' === $html[ $at + 1 ] ) &&
 				( 'r' === $html[ $at + 2 ] || 'R' === $html[ $at + 2 ] ) &&