<?php

require_once 'Fifo.php';

class ChunkIO extends Fifo
{
  /// 読み込みファイルハンドル
  private $fhin_;

  /// I/O サイズ
  private $chunk_size_;

  function __construct($fhin, $chunk_size = 10240)
  {
    $this->fhin_ = $fhin;
    if ($chunk_size) {
      $this->chunk_size_ = $chunk_size;
    }
  }


  ///
  /// @brief
  ///  最大 $chunk_size バイト読み込み
  ///
  /// @return
  /// 0 <  読み込んだバイト数
  /// 0	   EOF に達したが、バッファにデータが残っている。
  /// -1   EOF に達した。バッファが空になった。
  ///
  function chunkread() {
    $thisread = fread($this->fhin_, $this->chunk_size_);
    $len = strlen($thisread);
    if ($thisread === FALSE or $len == 0) {
      return 0 < $this->len() ? 0 : -1;
    }

    $this->append($thisread);

    //printf("%s: %d bytes in buffer\n", __METHOD__, $this->len_);

    return $len;
  }


  ///
  /// @brief
  ///  $str を検索する。
  ///
  /// @return
  ///	FALSE	EOF
  ///
  function read_until($str, &$found) {
    $len = strlen($str);

    $found = FALSE;
    $rtn = '';

    while (($pos = $this->strpos($str)) === FALSE) {
      if ($len < $this->len()) {
	$rtn .= $this->get($this->len() - $len);
      }

      switch ($this->chunkread()) {
      case -1: 			// buffer empty
	if ($rtn === '') {
	  return FALSE;
	} else {
	  return $rtn;
	}

      case 0:			// EOF
	$pos = $this->strpos($str);
	if ($pos === FALSE) {
	  return $rtn . $this->get();
	} else {
	  $found = TRUE;
	  $rtn .= $this->get($pos);
	  $this->get($len);
	  return $rtn;
	}
      }
    }

    // found $str
    $found = TRUE;
    $rtn .= $this->get($pos);
    $this->get($len);
    return $rtn;
 }


  function getline($delim = "\n")
  {
    return $this->read_until($delim, $found);
  }

		   

  ///
  /// @brief
  ///  $str を検索する。
  ///
  /// @return
  ///	FALSE	EOF
  ///
  function write_until($fhw, $str, &$found) {
    $len = strlen($str);
    $found = FALSE;
    $wrote = 0;

    while (($pos = $this->strpos($str)) === FALSE) {
      if ($len < $this->len()) {
	$wrote += fwrite($fhw, $this->get($this->len() - $len));
      }

      switch ($this->chunkread()) {
      case -1: 			// buffer empty
	return 0 < $wrote;

      case 0:			// EOF
	$pos = $this->strpos($str);
	if ($pos === FALSE) {
	  $wrote += fwrite($fhw, $this->get());
	  return 0 < $wrote;
	} else {
	  $found = TRUE;
	  $wrote += fwrite($fhw, $this->get($pos));
	  $this->get($len);
	  return 0 < $wrote;
	}
      }
    }

    // found $str
    $found = TRUE;
    $wrote += fwrite($fhw, $this->get($pos));
    $this->get($len);
    return 0 < $wrote; 
  }

}

// End of file