Prototype strspn equivalent

lib/Encoding/AbstractEncoding.php

@@ -11,6 +11,8 @@ abstract class AbstractEncoding  implements Decoder {
     protected const MODE_REPLACE = 1;
     protected const MODE_FATAL = 2;
 
+    protected const HIGH_BYTES = "\x80\x81\x82\x83\x84\x85\x86\x87\x88\x89\x8A\x8B\x8C\x8D\x8E\x8F\x90\x91\x92\x93\x94\x95\x96\x97\x98\x99\x9A\x9B\x9C\x9D\x9E\x9F\xA0\xA1\xA2\xA3\xA4\xA5\xA6\xA7\xA8\xA9\xAA\xAB\xAC\xAD\xAE\xAF\xB0\xB1\xB2\xB3\xB4\xB5\xB6\xB7\xB8\xB9\xBA\xBB\xBC\xBD\xBE\xBF\xC0\xC1\xC2\xC3\xC4\xC5\xC6\xC7\xC8\xC9\xCA\xCB\xCC\xCD\xCE\xCF\xD0\xD1\xD2\xD3\xD4\xD5\xD6\xD7\xD8\xD9\xDA\xDB\xDC\xDD\xDE\xDF\xE0\xE1\xE2\xE3\xE4\xE5\xE6\xE7\xE8\xE9\xEA\xEB\xEC\xED\xEE\xEF\xF0\xF1\xF2\xF3\xF4\xF5\xF6\xF7\xF8\xF9\xFA\xFB\xFC\xFD\xFE\xFF";
+
     /** @var string $string The string being decoded */
     protected $string;
     /** @var int $posByte The current byte position in the string */
@@ -162,6 +164,24 @@ abstract class AbstractEncoding  implements Decoder {
         }
     }
 
+    public function asciiSpan(string $mask, int $length = null): string {
+        $mask = preg_replace('/[\x80-\xFF]/gs', "", $mask);
+        $len = strspn($this->string, $mask, $this->posByte, $length);
+        $out = substr($this->string, $this->posByte, $len);
+        $this->posByte += $len;
+        $this->posChar += $len;
+        return $out;
+    }
+
+    public function asciiSpanNot(string $mask, int $length = null): string {
+        $mask .= self::HIGH_BYTES;
+        $len = strcspn($this->string, $mask, $this->posByte, $length);
+        $out = substr($this->string, $this->posByte, $len);
+        $this->posByte += $len;
+        $this->posChar += $len;
+        return $out;
+    }
+
     /** Returns a copy of the decoder's state to keep in memory */
     protected function stateSave(): array {
         $out = ['errCount' => sizeof($this->errStack)];

lib/Encoding/Decoder.php

@@ -80,4 +80,26 @@ interface Decoder {
 
     /** Generates an iterator which steps through each code point in the string  */
     public function codes(): \Generator;
+
+    /** Fast-forwards through a span of ASCII characters matching the supplied mask, returning any consumed characters
+     * 
+     * The mask must consist only of ASCII characters. 
+     * 
+     * Note that if the empty string is returned, this does not necessarily signal the end of the string
+     * 
+     * @param string $mask The set of ASCII characters to match
+     * @param int $length The maximum number oof characters to advance by
+     */
+    public function asciiSpan(string $mask, int $length = null): string;
+
+    /** Fast-forwards through a span of ASCII characters not matching the supplied mask, returning any consumed characters
+     * 
+     * The mask must consist only of ASCII characters. 
+     * 
+     * Note that if the empty string is returned, this does not necessarily signal the end of the string
+     * 
+     * @param string $mask The set of ASCII characters to not match
+     * @param int $length The maximum number oof characters to advance by
+     */
+    public function asciiSpanNot(string $mask, int $length = null): string;
 }

lib/Encoding/ISO2022JP.php

@@ -184,6 +184,40 @@ class ISO2022JP extends AbstractEncoding implements ModalCoder, Decoder {
         return $distance;
     }
 
+    public function asciiSpan(string $mask, int $length = null): string {
+        if ($this->mode === self::ASCII_STATE) {
+            $exc = '/[\x0E\x0F\x1B\x80-\xFF]/gs';
+        } elseif ($this->mode === self::ROMAN_STATE) {
+            $exc = '/[\x0E\x0F\x1B\x5C\x7E\x80-\xFF]/gs';
+        } else {
+            // in other modes ASCII characters are never returned
+            return "";
+        }
+        $mask = preg_replace($exc, "", $mask);
+        $len = strspn($this->string, $mask, $this->posByte, $length);
+        $out = substr($this->string, $this->posByte, $len);
+        $this->posByte += $len;
+        $this->posChar += $len;
+        return $out;
+    }
+
+    public function asciiSpanNot(string $mask, int $length = null): string {
+        if ($this->mode === self::ASCII_STATE) {
+            $mask .= "\x0E\x0F\x1B";
+        } elseif ($this->mode === self::ROMAN_STATE) {
+            $mask .= "\x0E\x0F\x1B\x5C\x7E";
+        } else {
+            // in other modes ASCII characters are never returned
+            return "";
+        }
+        $mask .= self::HIGH_BYTES;
+        $len = strcspn($this->string, $mask, $this->posByte, $length);
+        $out = substr($this->string, $this->posByte, $len);
+        $this->posByte += $len;
+        $this->posChar += $len;
+        return $out;
+    }
+
     protected function stateSave(): array {
         $out = parent::stateSave();
         $out['modeCount'] = sizeof($this->modeStack);

lib/Encoding/Replacement.php

@@ -122,4 +122,12 @@ class Replacement implements Decoder {
             yield 0 => $this->nextCode();
         }
     }
+
+    public function asciiSpan(string $mask, int $length = null): string {
+        return "";
+    }
+
+    public function asciiSpanNot(string $mask, int $length = null): string {
+        return "";
+    }
 }

lib/Encoding/UTF16.php

@@ -84,6 +84,54 @@ abstract class UTF16 extends AbstractEncoding {
         }
     }
 
+    public function asciiSpan(string $mask, int $length = null): string {
+        // UTF-16 has no ASCII characters, so we must do things the hard way
+        $out = "";
+        while (true) {
+            $c1 = @$this->string[$this->posByte];
+            $c2 = @$this->string[$this->posByte + 1];
+            $b = ord(self::BE ? $c1 : $c2);
+            if (!$b) {
+                $c = self::BE ? $c2 : $c1;
+                $b = ord($c);
+                if ($b < 0x80 && strpos($mask, $c) !== false && $c1 !== "" && $c2 !== "") {
+                    $out .= $c;
+                    $this->posByte += 2;
+                    $this->posChar++;
+                } else {
+                    break;
+                }
+            } else {
+                break;
+            }
+        }
+        return $out;
+    }
+
+    public function asciiSpanNot(string $mask, int $length = null): string {
+        // this is a copy of asciiSpan above with only the strpos check reversed
+        $out = "";
+        while (true) {
+            $c1 = @$this->string[$this->posByte];
+            $c2 = @$this->string[$this->posByte + 1];
+            $b = ord(self::BE ? $c1 : $c2);
+            if (!$b) {
+                $c = self::BE ? $c2 : $c1;
+                $b = ord($c);
+                if ($b < 0x80 && strpos($mask, $c) === false && $c1 !== "" && $c2 !== "") {
+                    $out .= $c;
+                    $this->posByte += 2;
+                    $this->posChar++;
+                } else {
+                    break;
+                }
+            } else {
+                break;
+            }
+        }
+        return $out;
+    }
+
     /** Implements backward seeking $distance characters */
     protected function seekBack(int $distance): int {
         if ($this->dirtyEOF && $distance) {