1<?php
2/***********************************************
3* File      :   stringstreamwrapper.php
4* Project   :   Z-Push
5* Descr     :   Wraps a string as a standard php stream
6*               The used method names are predefined and can not be altered.
7*
8* Created   :   24.11.2011
9*
10* Copyright 2007 - 2013, 2015 - 2016 Zarafa Deutschland GmbH
11*
12* This program is free software: you can redistribute it and/or modify
13* it under the terms of the GNU Affero General Public License, version 3,
14* as published by the Free Software Foundation.
15*
16* This program is distributed in the hope that it will be useful,
17* but WITHOUT ANY WARRANTY; without even the implied warranty of
18* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
19* GNU Affero General Public License for more details.
20*
21* You should have received a copy of the GNU Affero General Public License
22* along with this program.  If not, see <http://www.gnu.org/licenses/>.
23*
24* Consult LICENSE file for details
25************************************************/
26
27class StringStreamWrapper {
28    const PROTOCOL = "stringstream";
29
30    private $stringstream;
31    private $position;
32    private $stringlength;
33    private $truncateHtmlSafe;
34
35    /**
36     * Opens the stream
37     * The string to be streamed is passed over the context
38     *
39     * @param string    $path           Specifies the URL that was passed to the original function
40     * @param string    $mode           The mode used to open the file, as detailed for fopen()
41     * @param int       $options        Holds additional flags set by the streams API
42     * @param string    $opened_path    If the path is opened successfully, and STREAM_USE_PATH is set in options,
43     *                                  opened_path should be set to the full path of the file/resource that was actually opened.
44     *
45     * @access public
46     * @return boolean
47     */
48    public function stream_open($path, $mode, $options, &$opened_path) {
49        $contextOptions = stream_context_get_options($this->context);
50        if (!isset($contextOptions[self::PROTOCOL]['string']))
51            return false;
52
53        $this->position = 0;
54
55        // this is our stream!
56        $this->stringstream = $contextOptions[self::PROTOCOL]['string'];
57        $this->truncateHtmlSafe = (isset($contextOptions[self::PROTOCOL]['truncatehtmlsafe'])) ? $contextOptions[self::PROTOCOL]['truncatehtmlsafe'] : false;
58
59        $this->stringlength = strlen($this->stringstream);
60        ZLog::Write(LOGLEVEL_DEBUG, sprintf("StringStreamWrapper::stream_open(): initialized stream length: %d - HTML-safe-truncate: %s", $this->stringlength,  Utils::PrintAsString($this->truncateHtmlSafe)));
61
62        return true;
63    }
64
65    /**
66     * Reads from stream
67     *
68     * @param int $len      amount of bytes to be read
69     *
70     * @access public
71     * @return string
72     */
73    public function stream_read($len) {
74        $data = substr($this->stringstream, $this->position, $len);
75        $this->position += strlen($data);
76        return $data;
77    }
78
79    /**
80     * Writes data to the stream.
81     *
82     * @param string $data
83     * @return int
84     */
85    public function stream_write($data){
86        $l = strlen($data);
87        $this->stringstream = substr($this->stringstream, 0, $this->position) . $data . substr($this->stringstream, $this->position += $l);
88        $this->stringlength = strlen($this->stringstream);
89        return $l;
90    }
91
92    /**
93     * Stream "seek" functionality.
94     *
95     * @param int $offset
96     * @param int $whence
97     * @return boolean
98     */
99    public function stream_seek($offset, $whence = SEEK_SET) {
100        if ($whence == SEEK_CUR) {
101            $this->position += $offset;
102        }
103        else if ($whence == SEEK_END) {
104            $this->position = $this->stringlength + $offset;
105        }
106        else {
107            $this->position = $offset;
108        }
109        return true;
110    }
111
112    /**
113     * Returns the current position on stream
114     *
115     * @access public
116     * @return int
117     */
118    public function stream_tell() {
119        return $this->position;
120    }
121
122   /**
123     * Indicates if 'end of file' is reached
124     *
125     * @access public
126     * @return boolean
127     */
128    public function stream_eof() {
129        return ($this->position >= $this->stringlength);
130    }
131
132    /**
133     * Truncates the stream to the new size.
134     *
135     * @param int $new_size
136     * @return boolean
137     */
138    public function stream_truncate ($new_size) {
139        // cut the string!
140        $this->stringstream = Utils::Utf8_truncate($this->stringstream, $new_size, $this->truncateHtmlSafe);
141        $this->stringlength = strlen($this->stringstream);
142
143        if ($this->position > $this->stringlength) {
144            ZLog::Write(LOGLEVEL_WARN, sprintf("StringStreamWrapper->stream_truncate(): stream position (%d) ahead of new size of %d. Repositioning pointer to end of stream.", $this->position, $this->stringlength));
145            $this->position = $this->stringlength;
146        }
147        return true;
148    }
149
150    /**
151    * Retrieves information about a stream
152    *
153    * @access public
154    * @return array
155    */
156    public function stream_stat() {
157        return array(
158            7               => $this->stringlength,
159            'size'          => $this->stringlength,
160        );
161    }
162
163   /**
164     * Instantiates a StringStreamWrapper
165     *
166     * @param string    $string             The string to be wrapped
167     * @param boolean   $truncatehtmlsafe   Indicates if a truncation should be done html-safe - default: false
168     *
169     * @access public
170     * @return StringStreamWrapper
171     */
172     static public function Open($string, $truncatehtmlsafe = false) {
173        $context = stream_context_create(array(self::PROTOCOL => array('string' => &$string, 'truncatehtmlsafe' => $truncatehtmlsafe)));
174        return fopen(self::PROTOCOL . "://",'r', false, $context);
175    }
176}
177
178stream_wrapper_register(StringStreamWrapper::PROTOCOL, "StringStreamWrapper");
179