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libs/http/include/boost/http/zlib/inflate.hpp

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libs/http/include/boost/http/zlib/inflate.hpp
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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
207