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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));
+ }
+};
+
+?>