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1 : //
2 : // Copyright (c) 2021 Vinnie Falco (vinnie.falco@gmail.com)
3 : // Copyright (c) 2025 Mohammad Nejati
4 : //
5 : // Distributed under the Boost Software License, Version 1.0. (See accompanying
6 : // file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
7 : //
8 : // Official repository: https://github.com/cppalliance/http
9 : //
10 :
11 : #ifndef BOOST_HTTP_ZLIB_INFLATE_HPP
12 : #define BOOST_HTTP_ZLIB_INFLATE_HPP
13 :
14 : #include <boost/http/detail/config.hpp>
15 : #include <boost/http/zlib/service.hpp>
16 : #include <boost/http/zlib/stream.hpp>
17 :
18 : #include <boost/capy/ex/execution_context.hpp>
19 :
20 : namespace boost {
21 : namespace http {
22 : namespace zlib {
23 :
24 : /** Provides the ZLib decompression API.
25 :
26 : This service interface exposes the ZLib inflate (decompression)
27 : functionality through a set of virtual functions. The inflate
28 : algorithm reverses the deflate compression, restoring the
29 : original uncompressed data.
30 :
31 : The windowBits parameter in init2() controls format detection:
32 : - 8..15: zlib format with specified window size
33 : - -8..-15: raw deflate format (no header/trailer)
34 : - 16+windowBits: gzip format only
35 : - 32+windowBits: auto-detect zlib or gzip format
36 :
37 : @code
38 : // Example: Basic decompression
39 : boost::http::datastore ctx;
40 : auto& inflate_svc = boost::http::zlib::install_inflate_service(ctx);
41 :
42 : boost::http::zlib::stream st = {};
43 : std::vector<unsigned char> compressed_data = get_compressed();
44 : std::vector<unsigned char> output(1024 * 1024); // 1MB buffer
45 :
46 : st.zalloc = nullptr;
47 : st.zfree = nullptr;
48 : st.opaque = nullptr;
49 :
50 : inflate_svc.init(st);
51 :
52 : st.avail_in = compressed_data.size();
53 : st.next_in = compressed_data.data();
54 : st.avail_out = output.size();
55 : st.next_out = output.data();
56 :
57 : inflate_svc.inflate(st, boost::http::zlib::finish);
58 : output.resize(st.total_out);
59 :
60 : inflate_svc.inflate_end(st);
61 : @endcode
62 :
63 : @code
64 : // Example: Auto-detect gzip or zlib format
65 : boost::http::zlib::stream st = {};
66 : st.zalloc = nullptr;
67 : st.zfree = nullptr;
68 :
69 : // Auto-detect format (32 + 15 for max window)
70 : inflate_svc.init2(st, 32 + 15);
71 :
72 : st.avail_in = compressed_data.size();
73 : st.next_in = compressed_data.data();
74 : st.avail_out = output.size();
75 : st.next_out = output.data();
76 :
77 : int result = inflate_svc.inflate(st, boost::http::zlib::no_flush);
78 : // Handle result...
79 :
80 : inflate_svc.inflate_end(st);
81 : @endcode
82 : */
83 : struct BOOST_SYMBOL_VISIBLE
84 : inflate_service
85 : : capy::execution_context::service
86 : {
87 : /** Return the ZLib version string. */
88 : virtual char const* version() const noexcept = 0;
89 :
90 : /** Initialize inflate decompression.
91 : @param st The stream to initialize.
92 : @return Zero on success, or an error code.
93 : */
94 : virtual int init(stream& st) const = 0;
95 :
96 : /** Initialize inflate decompression with extended parameters.
97 : @param st The stream to initialize.
98 : @param windowBits The base-2 logarithm of the window size.
99 : @return Zero on success, or an error code.
100 : */
101 : virtual int init2(stream& st, int windowBits) const = 0;
102 :
103 : /** Decompress data in the stream.
104 : @param st The stream containing data to decompress.
105 : @param flush The flush mode.
106 : @return Status code indicating decompression state.
107 : */
108 : virtual int inflate(stream& st, int flush) const = 0;
109 :
110 : /** Release all resources held by the inflate stream.
111 : @param st The stream to finalize.
112 : @return Zero on success, or an error code.
113 : */
114 : virtual int inflate_end(stream& st) const = 0;
115 :
116 : /** Set the decompression dictionary.
117 : @param st The stream.
118 : @param dict Pointer to the dictionary data.
119 : @param len Length of the dictionary.
120 : @return Zero on success, or an error code.
121 : */
122 : virtual int set_dict(stream& st, unsigned char const* dict, unsigned len) const = 0;
123 :
124 : /** Return the current decompression dictionary.
125 : @param st The stream.
126 : @param dest Destination buffer for the dictionary.
127 : @param len Pointer to variable receiving dictionary length.
128 : @return Zero on success, or an error code.
129 : */
130 : virtual int get_dict(stream& st, unsigned char* dest, unsigned* len) const = 0;
131 :
132 : /** Synchronize the decompression state.
133 : @param st The stream to synchronize.
134 : @return Zero on success, or an error code.
135 : */
136 : virtual int sync(stream& st) const = 0;
137 :
138 : /** Duplicate an inflate stream.
139 : @param dest The destination stream.
140 : @param src The source stream to duplicate.
141 : @return Zero on success, or an error code.
142 : */
143 : virtual int dup(stream& dest, stream& src) const = 0;
144 :
145 : /** Reset the inflate stream state.
146 : @param st The stream to reset.
147 : @return Zero on success, or an error code.
148 : */
149 : virtual int reset(stream& st) const = 0;
150 :
151 : /** Reset the inflate stream state with new window size.
152 : @param st The stream to reset.
153 : @param windowBits The base-2 logarithm of the window size.
154 : @return Zero on success, or an error code.
155 : */
156 : virtual int reset2(stream& st, int windowBits) const = 0;
157 :
158 : /** Insert bits into the input stream.
159 : @param st The stream.
160 : @param bits Number of bits to insert.
161 : @param value The bit pattern to insert.
162 : @return Zero on success, or an error code.
163 : */
164 : virtual int prime(stream& st, int bits, int value) const = 0;
165 :
166 : /** Return the current inflate mark.
167 : @param st The stream.
168 : @return The mark value, or -1 on error.
169 : */
170 : virtual long mark(stream& st) const = 0;
171 :
172 : /** Return the gzip header information.
173 : @param st The stream.
174 : @param header Pointer to gzip header structure.
175 : @return Zero on success, or an error code.
176 : */
177 : virtual int get_header(stream& st, void* header) const = 0;
178 :
179 : /** Initialize backward inflate decompression.
180 : @param st The stream to initialize.
181 : @param windowBits The base-2 logarithm of the window size.
182 : @param window Pointer to the window buffer.
183 : @return Zero on success, or an error code.
184 : */
185 : virtual int back_init(stream& st, int windowBits, unsigned char* window) const = 0;
186 :
187 : /** Release resources held by backward inflate stream.
188 : @param st The stream to finalize.
189 : @return Zero on success, or an error code.
190 : */
191 : virtual int back_end(stream& st) const = 0;
192 :
193 : /** Return ZLib compile-time flags.
194 : @return Bit flags indicating compile-time options.
195 : */
196 : virtual unsigned long compile_flags() const = 0;
197 :
198 : protected:
199 1 : void shutdown() override {}
200 : };
201 :
202 : } // zlib
203 : } // http
204 : } // boost
205 :
206 : #endif
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