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1 files changed, 181 insertions, 0 deletions

diff --git a/zipstream.php b/zipstream.php
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+<?php
+
+#
+# ZipStream - Streamed, dynamically generated zip archives.
+# Paul Duncan <pabs@pablotron.org>
+#
+# Usage:
+#
+#   # create a new zip stream object
+#   $zs = new ZipStream();
+#
+#   # list of local files
+#   $files = array('foo.txt', 'bar.jpg');
+#
+#   # read and add each file to the archive
+#   foreach ($files as $path)
+#     $zs->add_file($path, file_get_contents($path));
+# 
+#   # write archive footer to stream
+#   $zs->finish();
+#
+class ZipStream {
+  var $files = array(),
+      $cdr_ofs = 0,
+      $ofs = 0; 
+
+  #
+  # add_file - add a file to the archive
+  #
+  # Parameters:
+  #   
+  #  $name - path of file in archive (including directory).
+  #  $data - contents of file
+  #  $time - last-modified timestamp of file (optional)
+  #
+  # Example:
+  #
+  #   $data = file_get_contents('foo.txt');
+  #   $zs->add_file('foo.txt', $data);
+  # 
+  function add_file($name, $data, $time = 0) {
+    # compress data
+    $zdata = substr(gzcompress($data), 2, -4);
+
+    # calculate header attributes
+    $crc  = crc32($data));
+    $zlen = strlen($zdata));
+    $nlen = strlen($name);
+    $len  = strlen($data));
+
+    # TODO: create unix timestamp
+
+    # build file header
+    $fields = array(              # (from V.A of APPNOTE.TXT)
+      array('V', 0x04034b50),     # local file header signature
+      array('v', 0x14),           # version needed to extract
+      array('v', 0x00),           # general purpose bit flag
+      array('v', 0x08),           # compresion method (deflate)
+      array('v', 0x08),           # file mod time (dos) FIXME
+      array('v', 0x08),           # file mod date (dos) FIXME
+      array('V', $crc),           # crc32 of data
+      array('V', $zlen),          # compressed data length
+      array('V', $len),           # uncompressed data length
+      array('v', $nlen),          # filename length
+      array('v', 0),              # extra data len
+    );
+
+    # pack fields
+    $ret = $this->pack_fields($fields) . $name . $zdata;
+    $full_len = strlen($ret);
+
+    # add to central directory record and increment offset
+    $this->add_to_cdr($name, $time, $crc, $zlen, $len, $full_len);
+
+    # print data
+    echo $ret;
+  }
+
+  #
+  # finish - Write zip footer to stream.
+  #
+  # Example:
+  #
+  #   # add a list of files to the archive
+  #   $files = array('foo.txt', 'bar.jpg');
+  #   foreach ($files as $path)
+  #     $zs->add_file($path, file_get_contents($path));
+  # 
+  #   # write footer to stream
+  #   $zs->finish();
+  # 
+  function finish() {
+    $this->add_cdr();
+    $this->clear();
+  }
+
+  function clear() {
+    $this->files = array(0;
+    $this->ofs = 0;
+    $this->cdr_ofs = 0;
+  }
+
+
+  ###################
+  # PRIVATE METHODS #
+  ###################
+
+  function add_to_cdr($name, $time, $crc, $zlen, $len, $full_len) {
+    $this->files[] = array($this->ofs, $name, $time, $crc32, $zlen, $len);
+    $this->ofs += $full_len;
+  }
+
+  function add_cdr_file($args) {
+    list ($name, $time, $crc32, $zlen, $len, $ofs) = $args;
+
+    $fields = array(              # (from V,F of APPNOTE.TXT)
+      array('V', 0x02014b50),     # central file header signature
+      array('v', 0x14),           # version needed to extract
+      array('v', 0x00),           # general purpose bit flag
+      array('v', 0x08),           # compresion method (deflate)
+      array('v', 0x08),           # file mod time (dos) FIXME
+      array('v', 0x08),           # file mod date (dos) FIXME
+      array('V', $crc),           # crc32 of data
+      array('V', $zlen),          # compressed data length
+      array('V', $len),           # uncompressed data length
+      array('v', $nlen),          # filename length
+      array('v', 0),              # extra data len
+      array('v', 0),              # file comment length
+      array('v', 0),              # disk number start
+      array('v', 0),              # internal file attributes
+      array('V', 0),              # external file attributes
+      array('V', $ofs),           # relative offset of local header
+    );
+
+    # pack fields and append name
+    $ret = $this->pack_fields($fields) . $name;
+
+    # increment cdr offset
+    $this->cdr_ofs += strlen($ret);
+  }
+
+  function add_cdr_eof() {
+    $num = count($this->files);
+    $cdr_len = $this->cdr_ofs;
+    $cdr_ofs = $this->ofs;
+
+    $fields = array(              # (from V,F of APPNOTE.TXT)
+      array('V', 0x06054b50),     # end of central file header signature
+      array('v', 0x00),           # disk number
+      array('v', 0x00),           # number of disk with cdr
+      array('v', $num),           # number of entries in the cdr on this disk
+      array('v', $num),           # number of entries in the cdr
+      array('V', $cdr_len),       # cdr size
+      array('V', $cdr_ofs),       # cdr ofs
+      array('v', 0x00),           # zip file comment length
+    );
+  }
+
+  function add_cdr() {
+    foreach ($this->files as $file)
+      $this->add_cdr_file($file);
+    $this->add_cdr_eof();
+  }
+
+  function pack_fields($fields) {
+    # populate format string and argument list
+    list ($pack_fmt, $args) = array('', array());
+    foreach ($fields as $field) {
+      $fmt .= $field[0];
+      $args[] = $field[1];
+    }
+
+    # prepend format string to argument list
+    array_unshift($args, $fmt);
+
+    # build output string from header and compressed data
+    return call_user_func('pack', $args));
+  }
+};
+
+?>