Refactoring InputStream.

1 files changed, 411 insertions, 0 deletions

diff --git a/src/HTML5/Parser/StringInputStream.php b/src/HTML5/Parser/StringInputStream.php
new file mode 100644
index 0000000..3d6b96e
--- /dev/null
+++ b/src/HTML5/Parser/StringInputStream.php
@@ -0,0 +1,411 @@
+<?php
+namespace HTML5\Parser;
+
+/*
+ *
+ * Based on code from html5lib:
+
+Copyright 2009 Geoffrey Sneddon <http://gsnedders.com/>
+
+Permission is hereby granted, free of charge, to any person obtaining a
+copy of this software and associated documentation files (the
+"Software"), to deal in the Software without restriction, including
+without limitation the rights to use, copy, modify, merge, publish,
+distribute, sublicense, and/or sell copies of the Software, and to
+permit persons to whom the Software is furnished to do so, subject to
+the following conditions:
+
+The above copyright notice and this permission notice shall be included
+in all copies or substantial portions of the Software.
+
+THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS
+OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
+MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.
+IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY
+CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT,
+TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE
+SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
+
+*/
+
+// Some conventions:
+// - /* */ indicates verbatim text from the HTML 5 specification
+//   MPB: Not sure which version of the spec. Moving from HTML5lib to 
+//   HTML5-PHP, I have been using this version:
+//   http://www.w3.org/TR/2012/CR-html5-20121217/Overview.html#contents
+//
+// - // indicates regular comments
+
+class StringInputStream implements InputStream {
+  /**
+   * The string data we're parsing.
+   */
+  private $data;
+
+  /**
+   * The current integer byte position we are in $data
+   */
+  private $char;
+
+  /**
+   * Length of $data; when $char === $data, we are at the end-of-file.
+   */
+  private $EOF;
+
+  /**
+   * Parse errors.
+   */
+  public $errors = array();
+
+  /**
+   * Create a new InputStream wrapper.
+   *
+   * @param $data Data to parse
+   */
+  public function __construct($data, $encoding = 'UTF-8') {
+
+    $data = $this->convertToUTF8($data, $encoding);
+    $this->checkForIllegalCodepoints($data);
+
+    $data = $this->replaceLinefeeds($data);
+
+    $this->data = $data;
+    $this->char = 0;
+    $this->EOF  = strlen($data);
+  }
+
+  /**
+   * Convert data from the given encoding to UTF-8.
+   *
+   * This has not yet been tested with charactersets other than UTF-8. 
+   * It should work with ISO-8859-1/-13 and standard Latin Win charsets.
+   *
+   * @param string $data
+   *   The data to convert.
+   * @param string $encoding
+   *   A valid encoding. Examples: http://www.php.net/manual/en/mbstring.supported-encodings.php
+   */
+  protected function convertToUTF8($data, $encoding = 'UTF-8') {
+    /* Given an encoding, the bytes in the input stream must be
+    converted to Unicode characters for the tokeniser, as
+    described by the rules for that encoding, except that the
+    leading U+FEFF BYTE ORDER MARK character, if any, must not
+    be stripped by the encoding layer (it is stripped by the rule below).
+
+    Bytes or sequences of bytes in the original byte stream that
+    could not be converted to Unicode characters must be converted
+    to U+FFFD REPLACEMENT CHARACTER code points. */
+
+    // XXX currently assuming input data is UTF-8; once we
+    // build encoding detection this will no longer be the case
+    //
+    // We previously had an mbstring implementation here, but that
+    // implementation is heavily non-conforming, so it's been
+    // omitted.
+    if (function_exists('iconv') && $encoding != 'auto') {
+      // iconv has the following behaviors:
+      // - Overlong representations are ignored.
+      // - Beyond Plane 16 is replaced with a lower char.
+      // - Incomplete sequences generate a warning.
+      $data = @iconv($encoding, 'UTF-8//IGNORE', $data);
+    }
+    // MPB: Testing the newer mb_convert_encoding(). This might need
+    // to be removed again.
+    elseif (function_exists('mb_convert_encoding')) {
+      // mb library has the following behaviors:
+      // - UTF-16 surrogates result in FALSE.
+      // - Overlongs and outside Plane 16 result in empty strings.
+      $data = mb_convert_encoding($data, 'UTF-8', $encoding);
+    }
+    else {
+      // we can make a conforming native implementation
+      throw new Exception('Not implemented, please install mbstring or iconv');
+    }
+
+    /* One leading U+FEFF BYTE ORDER MARK character must be
+    ignored if any are present. */
+    if (substr($data, 0, 3) === "\xEF\xBB\xBF") {
+      $data = substr($data, 3);
+    }
+
+    return $data;
+  }
+
+  /**
+   * Replace linefeed characters according to the spec.
+   */
+  protected function replaceLinefeeds($data) {
+    /* U+000D CARRIAGE RETURN (CR) characters and U+000A LINE FEED
+    (LF) characters are treated specially. Any CR characters
+    that are followed by LF characters must be removed, and any
+    CR characters not followed by LF characters must be converted
+    to LF characters. Thus, newlines in HTML DOMs are represented
+    by LF characters, and there are never any CR characters in the
+    input to the tokenization stage. */
+    $crlfTable = array(
+        "\0" =>  "\xEF\xBF\xBD",
+        "\r\n" => "\n",
+        "\r" => "\n",
+    );
+    return strtr($data, $crlfTable);
+  }
+
+  /**
+   * Checks for Unicode code points that are not valid in a document.
+   *
+   * This stores a parse error for each error that is found.
+   */
+  protected function checkForIllegalCodepoints($data) {
+    if (!function_exists('preg_match_all')) {
+      throw \Exception('The PCRE library is not loaded or is not available.');
+    }
+
+    /* All U+0000 NULL characters in the input must be replaced
+    by U+FFFD REPLACEMENT CHARACTERs. Any occurrences of such
+    characters is a parse error. */
+    for ($i = 0, $count = substr_count($data, "\0"); $i < $count; $i++) {
+      $this->errors[] = array(
+        'type' => Tokenizer::PARSEERROR,
+        'data' => 'null-character'
+      );
+    }
+
+    /* Any occurrences of any characters in the ranges U+0001 to
+    U+0008, U+000B,  U+000E to U+001F,  U+007F  to U+009F,
+    U+D800 to U+DFFF , U+FDD0 to U+FDEF, and
+    characters U+FFFE, U+FFFF, U+1FFFE, U+1FFFF, U+2FFFE, U+2FFFF,
+    U+3FFFE, U+3FFFF, U+4FFFE, U+4FFFF, U+5FFFE, U+5FFFF, U+6FFFE,
+    U+6FFFF, U+7FFFE, U+7FFFF, U+8FFFE, U+8FFFF, U+9FFFE, U+9FFFF,
+    U+AFFFE, U+AFFFF, U+BFFFE, U+BFFFF, U+CFFFE, U+CFFFF, U+DFFFE,
+    U+DFFFF, U+EFFFE, U+EFFFF, U+FFFFE, U+FFFFF, U+10FFFE, and
+    U+10FFFF are parse errors. (These are all control characters
+    or permanently undefined Unicode characters.) */
+    // Check PCRE is loaded.
+    $count = preg_match_all(
+      '/(?:
+        [\x01-\x08\x0B\x0E-\x1F\x7F] # U+0001 to U+0008, U+000B,  U+000E to U+001F and U+007F
+      |
+        \xC2[\x80-\x9F] # U+0080 to U+009F
+      |
+        \xED(?:\xA0[\x80-\xFF]|[\xA1-\xBE][\x00-\xFF]|\xBF[\x00-\xBF]) # U+D800 to U+DFFFF
+      |
+        \xEF\xB7[\x90-\xAF] # U+FDD0 to U+FDEF
+      |
+        \xEF\xBF[\xBE\xBF] # U+FFFE and U+FFFF
+      |
+        [\xF0-\xF4][\x8F-\xBF]\xBF[\xBE\xBF] # U+nFFFE and U+nFFFF (1 <= n <= 10_{16})
+      )/x',
+      $data,
+      $matches
+    );
+    for ($i = 0; $i < $count; $i++) {
+      $this->errors[] = array(
+        'type' => Tokenizer::PARSEERROR,
+        'data' => 'invalid-codepoint'
+      );
+    }
+  }
+
+
+  /**
+   * Returns the current line that the tokenizer is at.
+   */
+  public function currentLine() {
+    if (empty($this->EOF) || $this->char == 0) {
+      return 1;
+    }
+    // Add one to $this->char because we want the number for the next
+    // byte to be processed.
+    return substr_count($this->data, "\n", 0, min($this->char, $this->EOF)) + 1;
+  }
+
+  /**
+   * @deprecated
+   */
+  public function getCurrentLine() {
+    return currentLine();
+  }
+
+  /**
+   * Returns the current column of the current line that the tokenizer is at.
+   *
+   * Newlines are column 0. The first char after a newline is column 1.
+   *
+   * @return int
+   *   The column number.
+   */
+  public function columnOffset() {
+
+    // Short circuit for the first char.
+    if ($this->char == 0) {
+      return 0;
+    }
+    // strrpos is weird, and the offset needs to be negative for what we
+    // want (i.e., the last \n before $this->char). This needs to not have
+    // one (to make it point to the next character, the one we want the
+    // position of) added to it because strrpos's behaviour includes the
+    // final offset byte.
+    $backwardFrom = $this->char - 1 - strlen($this->data);
+    $lastLine = strrpos($this->data, "\n", $backwardFrom);
+
+    // However, for here we want the length up until the next byte to be
+    // processed, so add one to the current byte ($this->char).
+    if ($lastLine !== FALSE) {
+      $findLengthOf = substr($this->data, $lastLine + 1, $this->char - 1 - $lastLine);
+    }
+    else {
+      // After a newline.
+      $findLengthOf = substr($this->data, 0, $this->char);
+    }
+
+    return self::countChars($findLengthOf);
+  }
+
+  /**
+   * Count the number of characters in a string.
+   *
+   * UTF-8 aware. This will try (in order) iconv,
+   * MB, libxml, and finally a custom counter.
+   *
+   * @todo Move this to a general utility class.
+   */
+  public static function countChars($string) {
+    // Get the length for the string we need.
+    if(function_exists('iconv_strlen')) {
+      return iconv_strlen($string, 'utf-8');
+    }
+    elseif(function_exists('mb_strlen')) {
+      return mb_strlen($string, 'utf-8');
+    }
+    elseif(function_exists('utf8_decod')) {
+      // MPB: Will this work? Won't certain decodes lead to two chars 
+      // extrapolated out of 2-byte chars?
+      return strlen(utf8_decode($string));
+    }
+    $count = count_chars($string);
+    // 0x80 = 0x7F - 0 + 1 (one added to get inclusive range)
+    // 0x33 = 0xF4 - 0x2C + 1 (one added to get inclusive range)
+    return array_sum(array_slice($count, 0, 0x80)) +
+         array_sum(array_slice($count, 0xC2, 0x33));
+  }
+
+  /**
+   * @deprecated
+   */
+  public function getColumnOffset() {
+    return $this->columnOffset();
+  }
+
+  /**
+   * Retrieve the currently consumed character.
+   * @note This performs bounds checking
+   */
+  public function char() {
+    // MPB: This appears to advance the pointer, which is not the same
+    // as "retrieving the currently consumed character". Calling char() 
+    // twice will return two different results.
+    if ($this->char++ < $this->EOF) {
+      return $this->data[$this->char - 1];
+    }
+    return FALSE;
+  }
+
+  /**
+   * Get all characters until EOF.
+   *
+   * This reads to the end of the file, and sets the read marker at the 
+   * end of the file.
+   *
+   * @note This performs bounds checking
+   */
+  public function remainingChars() {
+    if ($this->char < $this->EOF) {
+      $data = substr($this->data, $this->char);
+      $this->char = $this->EOF;
+      return $data;
+    }
+    return FALSE;
+  }
+
+  /**
+   * Read to a particular match (or until $max bytes are consumed).
+   *
+   * This operates on byte sequences, not characters.
+   *
+   * Matches as far as possible until we reach a certain set of bytes
+   * and returns the matched substring.
+   *
+   * @param string $bytes
+   *   Bytes to match.
+   * @param int $max
+   *   Maximum number of bytes to scan.
+   * @return mixed
+   *   Index or FALSE if no match is found. You should use strong 
+   *   equality when checking the result, since index could be 0.
+   */
+  public function charsUntil($bytes, $max = null) {
+    if ($this->char >= $this->EOF) {
+      return FALSE;
+    }
+
+    if ($max === 0 || $max) {
+      $len = strcspn($this->data, $bytes, $this->char, $max);
+    }
+    else {
+      $len = strcspn($this->data, $bytes, $this->char);
+    }
+
+    $string = (string) substr($this->data, $this->char, $len);
+    $this->char += $len;
+    return $string;
+  }
+
+  /**
+   * Returns the string so long as $bytes matches.
+   *
+   * Matches as far as possible with a certain set of bytes
+   * and returns the matched substring.
+   *
+   * @param string $bytes
+   *   A mask of bytes to match. If ANY byte in this mask matches the 
+   *   current char, the pointer advances and the char is part of the 
+   *   substring.
+   * @param int $max
+   *   The max number of chars to read.
+   */
+  public function charsWhile($bytes, $max = null) {
+    if ($this->char >= $this->EOF) {
+      return FALSE;
+    }
+
+    if ($max === 0 || $max) {
+      $len = strspn($this->data, $bytes, $this->char, $max);
+    }
+    else {
+      $len = strspn($this->data, $bytes, $this->char);
+    }
+    $string = (string) substr($this->data, $this->char, $len);
+    $this->char += $len;
+    return $string;
+  }
+
+  /**
+   * Unconsume one character.
+   */
+  public function unconsume() {
+    if ($this->char > 0 && $this->char <= $this->EOF) {
+      $this->char--;
+    }
+  }
+  public function unget() {
+    $this->unconsume();
+  }
+
+  public function peek() {
+    return $this->data[$this->char + 1];
+  }
+
+  public function position() {
+    return $this->char;
+  }
+}