kwpcf.php

<?php

// Project Kaeru KWPCF builder
// Written by James Daniel
// github.com/jaames / rakujira.jp

// ---- USAGE ----

// create a new kaeruPrecache instance:
//
// $precache = new kaeruPrecache;

// open a buffer, this is where the precache data will be written:
//
// $precache->openBuffer("test.kwpcf");
//
// or you can pass in null to write to an in-memory buffer instead:
//
// $precache->openBuffer(null);

// add a resource entry to the cache:
//   "url" is the external reference to the resource,
//   "file" is the file path to the resource, which will be opened and embedded into the cache
//
// $precache->addEntry([
//   "url" => "http://example.com/path/to/image.gif",
//   "file" => "./image.gif"
// ]);

// get the buffer content (if using an in-memory buffer)
//
// $precache->getBuffer();

// close the buffer when finished
//
// $precache->closeBuffer();


class kaeruPrecache {
  var $buffer = false;
  
  // open up a buffer to write to
  function openBuffer($path) {
    // if $path is not given then use an in-memory file buffer
    if (is_null($path)) {
      $this->buffer = fopen("php://memory", "r+");
    }
    // else open $path as the buffer
    else {
      $this->buffer = fopen($path, "w+");
    }
  } 
  
  // close the buffer once finished
  function closeBuffer() {
    if ($this->buffer) {
      fclose($this->buffer);
      $this->buffer = false;
    }
  } 
  
  // get buffer contents
  function getBuffer() {
    if ($this->buffer) {
      return stream_get_contents($this->buffer, -1, 0);
    }
  }
  
  // add an entry to the precache buffer
  function addEntry($args) {
    if ($this->buffer && isset($args["url"]) && isset($args["file"])) {
      // write the entry header and URL
      // (header is "KPCF" followed by the length of the entry (not counting the 8-byte header) as uint32 LE)
      // (following the header is the URL, which is always null-padded to 512 bytes)
      fwrite($this->buffer, pack("a4Va512", "KPCF", filesize($args["file"]) + 512, $args["url"]));
      // write the entry embed
      fwrite($this->buffer, file_get_contents($args["file"])); 
    }
  }
  
  function __destruct() {
    // should, hopefully, auto-close the buffer when finished
    $this->closeBuffer();
  }
  
}