1// Copyright (c) 2011 The Chromium Authors. All rights reserved.
2// Use of this source code is governed by a BSD-style license that can be
3// found in the LICENSE file.
4
5// Derived from:
6//   mozilla/netwerk/protocol/http/src/nsHttpChunkedDecoder.h
7// The license block is:
8/* ***** BEGIN LICENSE BLOCK *****
9 * Version: MPL 1.1/GPL 2.0/LGPL 2.1
10 *
11 * The contents of this file are subject to the Mozilla Public License Version
12 * 1.1 (the "License"); you may not use this file except in compliance with
13 * the License. You may obtain a copy of the License at
14 * http://www.mozilla.org/MPL/
15 *
16 * Software distributed under the License is distributed on an "AS IS" basis,
17 * WITHOUT WARRANTY OF ANY KIND, either express or implied. See the License
18 * for the specific language governing rights and limitations under the
19 * License.
20 *
21 * The Original Code is Mozilla.
22 *
23 * The Initial Developer of the Original Code is
24 * Netscape Communications.
25 * Portions created by the Initial Developer are Copyright (C) 2001
26 * the Initial Developer. All Rights Reserved.
27 *
28 * Contributor(s):
29 *   Darin Fisher <darin@netscape.com> (original author)
30 *
31 * Alternatively, the contents of this file may be used under the terms of
32 * either the GNU General Public License Version 2 or later (the "GPL"), or
33 * the GNU Lesser General Public License Version 2.1 or later (the "LGPL"),
34 * in which case the provisions of the GPL or the LGPL are applicable instead
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38 * decision by deleting the provisions above and replace them with the notice
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40 * the provisions above, a recipient may use your version of this file under
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42 *
43 * ***** END LICENSE BLOCK ***** */
44
45#ifndef NET_HTTP_HTTP_CHUNKED_DECODER_H_
46#define NET_HTTP_HTTP_CHUNKED_DECODER_H_
47
48#include <string>
49
50#include "net/base/net_export.h"
51
52namespace net {
53
54// From RFC2617 section 3.6.1, the chunked transfer coding is defined as:
55//
56//   Chunked-Body    = *chunk
57//                     last-chunk
58//                     trailer
59//                     CRLF
60//   chunk           = chunk-size [ chunk-extension ] CRLF
61//                     chunk-data CRLF
62//   chunk-size      = 1*HEX
63//   last-chunk      = 1*("0") [ chunk-extension ] CRLF
64//
65//   chunk-extension = *( ";" chunk-ext-name [ "=" chunk-ext-val ] )
66//   chunk-ext-name  = token
67//   chunk-ext-val   = token | quoted-string
68//   chunk-data      = chunk-size(OCTET)
69//   trailer         = *(entity-header CRLF)
70//
71// The chunk-size field is a string of hex digits indicating the size of the
72// chunk.  The chunked encoding is ended by any chunk whose size is zero,
73// followed by the trailer, which is terminated by an empty line.
74//
75// NOTE: This implementation does not bother to parse trailers since they are
76// not used on the web.
77//
78class NET_EXPORT_PRIVATE HttpChunkedDecoder {
79 public:
80  // The maximum length of |line_buf_| between calls to FilterBuff().
81  // Exposed for tests.
82  static const size_t kMaxLineBufLen;
83
84  HttpChunkedDecoder();
85
86  // Indicates that a previous call to FilterBuf encountered the final CRLF.
87  bool reached_eof() const { return reached_eof_; }
88
89  // Returns the number of bytes after the final CRLF.
90  int bytes_after_eof() const { return bytes_after_eof_; }
91
92  // Called to filter out the chunk markers from buf and to check for end-of-
93  // file.  This method modifies |buf| inline if necessary to remove chunk
94  // markers.  The return value indicates the final size of decoded data stored
95  // in |buf|.  Call reached_eof() after this method to check if end-of-file
96  // was encountered.
97  int FilterBuf(char* buf, int buf_len);
98
99 private:
100  // Scans |buf| for the next chunk delimiter.  This method returns the number
101  // of bytes consumed from |buf|.  If found, |chunk_remaining_| holds the
102  // value for the next chunk size.
103  int ScanForChunkRemaining(const char* buf, int buf_len);
104
105  // Converts string |start| of length |len| to a numeric value.
106  // |start| is a string of type "chunk-size" (hex string).
107  // If the conversion succeeds, returns true and places the result in |out|.
108  static bool ParseChunkSize(const char* start, int len, int* out);
109
110  // Indicates the number of bytes remaining for the current chunk.
111  int chunk_remaining_;
112
113  // A small buffer used to store a partial chunk marker.
114  std::string line_buf_;
115
116  // True if waiting for the terminal CRLF of a chunk's data.
117  bool chunk_terminator_remaining_;
118
119  // Set to true when FilterBuf encounters the last-chunk.
120  bool reached_last_chunk_;
121
122  // Set to true when FilterBuf encounters the final CRLF.
123  bool reached_eof_;
124
125  // The number of extraneous unfiltered bytes after the final CRLF.
126  int bytes_after_eof_;
127};
128
129}  // namespace net
130
131#endif  // NET_HTTP_HTTP_CHUNKED_DECODER_H_
132