. /include/boost/capy /read_until.hpp
100.00% Lines (65/65) 100.00% Functions (12/12)
[ ] prev/next file n p prev/next uncovered line
TLA Baseline Branch
Line Hits Code Line Hits Code
1   // 1   //
2   // Copyright (c) 2025 Vinnie Falco (vinnie.falco@gmail.com) 2   // Copyright (c) 2025 Vinnie Falco (vinnie.falco@gmail.com)
3   // 3   //
4   // Distributed under the Boost Software License, Version 1.0. (See accompanying 4   // Distributed under the Boost Software License, Version 1.0. (See accompanying
5   // file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt) 5   // file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
6   // 6   //
7   // Official repository: https://github.com/cppalliance/capy 7   // Official repository: https://github.com/cppalliance/capy
8   // 8   //
9   9  
10   #ifndef BOOST_CAPY_READ_UNTIL_HPP 10   #ifndef BOOST_CAPY_READ_UNTIL_HPP
11   #define BOOST_CAPY_READ_UNTIL_HPP 11   #define BOOST_CAPY_READ_UNTIL_HPP
12   12  
13   #include <boost/capy/detail/config.hpp> 13   #include <boost/capy/detail/config.hpp>
14   #include <boost/capy/buffers.hpp> 14   #include <boost/capy/buffers.hpp>
15   #include <boost/capy/cond.hpp> 15   #include <boost/capy/cond.hpp>
16   #include <coroutine> 16   #include <coroutine>
17   #include <boost/capy/error.hpp> 17   #include <boost/capy/error.hpp>
18   #include <boost/capy/io_result.hpp> 18   #include <boost/capy/io_result.hpp>
19   #include <boost/capy/io_task.hpp> 19   #include <boost/capy/io_task.hpp>
20   #include <boost/capy/concept/dynamic_buffer.hpp> 20   #include <boost/capy/concept/dynamic_buffer.hpp>
21   #include <boost/capy/concept/match_condition.hpp> 21   #include <boost/capy/concept/match_condition.hpp>
22   #include <boost/capy/concept/read_stream.hpp> 22   #include <boost/capy/concept/read_stream.hpp>
23   #include <boost/capy/ex/io_env.hpp> 23   #include <boost/capy/ex/io_env.hpp>
24   24  
25   #include <algorithm> 25   #include <algorithm>
26   #include <cstddef> 26   #include <cstddef>
27   #include <optional> 27   #include <optional>
28   #include <stop_token> 28   #include <stop_token>
29   #include <string_view> 29   #include <string_view>
30   #include <type_traits> 30   #include <type_traits>
31   31  
32   namespace boost { 32   namespace boost {
33   namespace capy { 33   namespace capy {
34   34  
35   namespace detail { 35   namespace detail {
36   36  
37   // Linearize a buffer sequence into a string 37   // Linearize a buffer sequence into a string
38   inline 38   inline
39   std::string 39   std::string
HITCBC 40   2 linearize_buffers(ConstBufferSequence auto const& data) 40   2 linearize_buffers(ConstBufferSequence auto const& data)
41   { 41   {
HITCBC 42   2 std::string linear; 42   2 std::string linear;
HITCBC 43   2 linear.reserve(buffer_size(data)); 43   2 linear.reserve(buffer_size(data));
HITCBC 44   2 auto const end_ = end(data); 44   2 auto const end_ = end(data);
HITCBC 45   6 for(auto it = begin(data); it != end_; ++it) 45   6 for(auto it = begin(data); it != end_; ++it)
HITCBC 46   8 linear.append( 46   8 linear.append(
HITCBC 47   4 static_cast<char const*>(it->data()), 47   4 static_cast<char const*>(it->data()),
48   it->size()); 48   it->size());
HITCBC 49   4 return linear; 49   4 return linear;
50   } // LCOV_EXCL_LINE gcov brace artifact (linearize_buffers is exercised) 50   } // LCOV_EXCL_LINE gcov brace artifact (linearize_buffers is exercised)
51   51  
52   // Search buffer using a MatchCondition, with single-buffer optimization 52   // Search buffer using a MatchCondition, with single-buffer optimization
53   template<MatchCondition M> 53   template<MatchCondition M>
54   std::size_t 54   std::size_t
HITCBC 55   263 search_buffer_for_match( 55   263 search_buffer_for_match(
56   ConstBufferSequence auto const& data, 56   ConstBufferSequence auto const& data,
57   M const& match, 57   M const& match,
58   std::size_t* hint = nullptr) 58   std::size_t* hint = nullptr)
59   { 59   {
60   // Fast path: single buffer - no linearization needed 60   // Fast path: single buffer - no linearization needed
HITCBC 61   263 if(buffer_length(data) == 1) 61   263 if(buffer_length(data) == 1)
62   { 62   {
HITCBC 63   262 auto const& buf = *begin(data); 63   262 auto const& buf = *begin(data);
HITCBC 64   786 return match(std::string_view( 64   786 return match(std::string_view(
HITCBC 65   262 static_cast<char const*>(buf.data()), 65   262 static_cast<char const*>(buf.data()),
HITCBC 66   262 buf.size()), hint); 66   262 buf.size()), hint);
67   } 67   }
68   // Multiple buffers - linearize 68   // Multiple buffers - linearize
HITCBC 69   1 return match(linearize_buffers(data), hint); 69   1 return match(linearize_buffers(data), hint);
70   } 70   }
71   71  
72   // Implementation coroutine for read_until with MatchCondition 72   // Implementation coroutine for read_until with MatchCondition
73   template<class Stream, class B, MatchCondition M> 73   template<class Stream, class B, MatchCondition M>
74   io_task<std::size_t> 74   io_task<std::size_t>
HITCBC 75   136 read_until_match_impl( 75   136 read_until_match_impl(
76   Stream& stream, 76   Stream& stream,
77   B& buffers, 77   B& buffers,
78   M match, 78   M match,
79   std::size_t initial_amount) 79   std::size_t initial_amount)
80   { 80   {
81   std::size_t amount = initial_amount; 81   std::size_t amount = initial_amount;
82   82  
83   for(;;) 83   for(;;)
84   { 84   {
85   // Check max_size before preparing 85   // Check max_size before preparing
86   if(buffers.size() >= buffers.max_size()) 86   if(buffers.size() >= buffers.max_size())
87   co_return {error::not_found, 0}; 87   co_return {error::not_found, 0};
88   88  
89   // Prepare space, respecting max_size 89   // Prepare space, respecting max_size
90   std::size_t const available = buffers.max_size() - buffers.size(); 90   std::size_t const available = buffers.max_size() - buffers.size();
91   std::size_t const to_prepare = (std::min)(amount, available); 91   std::size_t const to_prepare = (std::min)(amount, available);
92   if(to_prepare == 0) 92   if(to_prepare == 0)
93   co_return {error::not_found, 0}; 93   co_return {error::not_found, 0};
94   94  
95   auto mb = buffers.prepare(to_prepare); 95   auto mb = buffers.prepare(to_prepare);
96   auto [ec, n] = co_await stream.read_some(mb); 96   auto [ec, n] = co_await stream.read_some(mb);
97   buffers.commit(n); 97   buffers.commit(n);
98   98  
99   if(!ec) 99   if(!ec)
100   { 100   {
101   auto pos = search_buffer_for_match(buffers.data(), match); 101   auto pos = search_buffer_for_match(buffers.data(), match);
102   if(pos != std::string_view::npos) 102   if(pos != std::string_view::npos)
103   co_return {{}, pos}; 103   co_return {{}, pos};
104   } 104   }
105   105  
106   if(ec == cond::eof) 106   if(ec == cond::eof)
107   co_return {error::eof, buffers.size()}; 107   co_return {error::eof, buffers.size()};
108   if(ec) 108   if(ec)
109   co_return {ec, buffers.size()}; 109   co_return {ec, buffers.size()};
110   110  
111   // Grow buffer size for next iteration 111   // Grow buffer size for next iteration
112   if(n == buffer_size(mb)) 112   if(n == buffer_size(mb))
113   amount = amount / 2 + amount; 113   amount = amount / 2 + amount;
114   } 114   }
HITCBC 115   272 } 115   272 }
116   116  
117   template<class Stream, class B, MatchCondition M, bool OwnsBuffer> 117   template<class Stream, class B, MatchCondition M, bool OwnsBuffer>
118   struct read_until_awaitable 118   struct read_until_awaitable
119   { 119   {
120   Stream* stream_; 120   Stream* stream_;
121   M match_; 121   M match_;
122   std::size_t initial_amount_; 122   std::size_t initial_amount_;
123   std::optional<io_result<std::size_t>> immediate_; 123   std::optional<io_result<std::size_t>> immediate_;
124   std::optional<io_task<std::size_t>> inner_; 124   std::optional<io_task<std::size_t>> inner_;
125   125  
126   using storage_type = std::conditional_t<OwnsBuffer, B, B*>; 126   using storage_type = std::conditional_t<OwnsBuffer, B, B*>;
127   storage_type buffers_storage_; 127   storage_type buffers_storage_;
128   128  
HITCBC 129   136 B& buffers() noexcept 129   136 B& buffers() noexcept
130   { 130   {
131   if constexpr(OwnsBuffer) 131   if constexpr(OwnsBuffer)
HITCBC 132   126 return buffers_storage_; 132   126 return buffers_storage_;
133   else 133   else
HITCBC 134   10 return *buffers_storage_; 134   10 return *buffers_storage_;
135   } 135   }
136   136  
137   // Constructor for lvalue (pointer storage) 137   // Constructor for lvalue (pointer storage)
HITCBC 138   14 read_until_awaitable( 138   14 read_until_awaitable(
139   Stream& stream, 139   Stream& stream,
140   B* buffers, 140   B* buffers,
141   M match, 141   M match,
142   std::size_t initial_amount) 142   std::size_t initial_amount)
143   requires (!OwnsBuffer) 143   requires (!OwnsBuffer)
HITCBC 144   14 : stream_(std::addressof(stream)) 144   14 : stream_(std::addressof(stream))
HITCBC 145   14 , match_(std::move(match)) 145   14 , match_(std::move(match))
HITCBC 146   14 , initial_amount_(initial_amount) 146   14 , initial_amount_(initial_amount)
HITCBC 147   14 , buffers_storage_(buffers) 147   14 , buffers_storage_(buffers)
148   { 148   {
HITCBC 149   14 auto pos = search_buffer_for_match( 149   14 auto pos = search_buffer_for_match(
HITCBC 150   14 buffers_storage_->data(), match_); 150   14 buffers_storage_->data(), match_);
HITCBC 151   14 if(pos != std::string_view::npos) 151   14 if(pos != std::string_view::npos)
HITCBC 152   4 immediate_.emplace(io_result<std::size_t>{{}, pos}); 152   4 immediate_.emplace(io_result<std::size_t>{{}, pos});
HITCBC 153   14 } 153   14 }
154   154  
155   // Constructor for rvalue adapter (owned storage) 155   // Constructor for rvalue adapter (owned storage)
HITCBC 156   132 read_until_awaitable( 156   132 read_until_awaitable(
157   Stream& stream, 157   Stream& stream,
158   B&& buffers, 158   B&& buffers,
159   M match, 159   M match,
160   std::size_t initial_amount) 160   std::size_t initial_amount)
161   requires OwnsBuffer 161   requires OwnsBuffer
HITCBC 162   132 : stream_(std::addressof(stream)) 162   132 : stream_(std::addressof(stream))
HITCBC 163   132 , match_(std::move(match)) 163   132 , match_(std::move(match))
HITCBC 164   132 , initial_amount_(initial_amount) 164   132 , initial_amount_(initial_amount)
HITCBC 165   132 , buffers_storage_(std::move(buffers)) 165   132 , buffers_storage_(std::move(buffers))
166   { 166   {
HITCBC 167   132 auto pos = search_buffer_for_match( 167   132 auto pos = search_buffer_for_match(
HITCBC 168   132 buffers_storage_.data(), match_); 168   132 buffers_storage_.data(), match_);
HITCBC 169   132 if(pos != std::string_view::npos) 169   132 if(pos != std::string_view::npos)
HITCBC 170   6 immediate_.emplace(io_result<std::size_t>{{}, pos}); 170   6 immediate_.emplace(io_result<std::size_t>{{}, pos});
HITCBC 171   132 } 171   132 }
172   172  
173   bool 173   bool
HITCBC 174   146 await_ready() const noexcept 174   146 await_ready() const noexcept
175   { 175   {
HITCBC 176   146 return immediate_.has_value(); 176   146 return immediate_.has_value();
177   } 177   }
178   178  
179   std::coroutine_handle<> 179   std::coroutine_handle<>
HITCBC 180   136 await_suspend(std::coroutine_handle<> h, io_env const* env) 180   136 await_suspend(std::coroutine_handle<> h, io_env const* env)
181   { 181   {
HITCBC 182   272 inner_.emplace(read_until_match_impl( 182   272 inner_.emplace(read_until_match_impl(
HITCBC 183   136 *stream_, buffers(), match_, initial_amount_)); 183   136 *stream_, buffers(), match_, initial_amount_));
HITCBC 184   136 return inner_->await_suspend(h, env); 184   136 return inner_->await_suspend(h, env);
185   } 185   }
186   186  
187   io_result<std::size_t> 187   io_result<std::size_t>
HITCBC 188   146 await_resume() 188   146 await_resume()
189   { 189   {
HITCBC 190   146 if(immediate_) 190   146 if(immediate_)
HITCBC 191   10 return *immediate_; 191   10 return *immediate_;
HITCBC 192   136 return inner_->await_resume(); 192   136 return inner_->await_resume();
193   } 193   }
194   }; 194   };
195 - template<ReadStream Stream, class B, MatchCondition M>  
196 - using read_until_return_t = read_until_awaitable<  
197 - Stream,  
198 - std::remove_reference_t<B>,  
199 - M,  
200 - !std::is_lvalue_reference_v<B&&>>;  
201 -  
202   195  
203   } // namespace detail 196   } // namespace detail
204   197  
205   /** Match condition that searches for a delimiter string. 198   /** Match condition that searches for a delimiter string.
206   199  
207   Satisfies @ref MatchCondition. Returns the position after the 200   Satisfies @ref MatchCondition. Returns the position after the
208   delimiter when found, or `npos` otherwise. Provides an overlap 201   delimiter when found, or `npos` otherwise. Provides an overlap
209   hint of `delim.size() - 1` to handle delimiters spanning reads. 202   hint of `delim.size() - 1` to handle delimiters spanning reads.
210   203  
211   @see MatchCondition, read_until 204   @see MatchCondition, read_until
212   */ 205   */
213   struct match_delim 206   struct match_delim
214   { 207   {
215   /** The delimiter string to search for. 208   /** The delimiter string to search for.
216   209  
217   @note The referenced characters must remain valid 210   @note The referenced characters must remain valid
218   for the lifetime of this object and any pending 211   for the lifetime of this object and any pending
219   read operation. 212   read operation.
220   */ 213   */
221   std::string_view delim; 214   std::string_view delim;
222   215  
223   /** Search for the delimiter in `data`. 216   /** Search for the delimiter in `data`.
224   217  
225   @param data The data to search. 218   @param data The data to search.
226   @param hint If non-null, receives the overlap hint 219   @param hint If non-null, receives the overlap hint
227   on miss. 220   on miss.
228   @return `0` if `delim` is empty; otherwise the position 221   @return `0` if `delim` is empty; otherwise the position
229   just past the delimiter, or `npos` if not found. 222   just past the delimiter, or `npos` if not found.
230   */ 223   */
231   std::size_t 224   std::size_t
HITCBC 232   226 operator()( 225   226 operator()(
233   std::string_view data, 226   std::string_view data,
234   std::size_t* hint) const noexcept 227   std::size_t* hint) const noexcept
235   { 228   {
HITCBC 236   226 if(delim.empty()) 229   226 if(delim.empty())
HITCBC 237   2 return 0; 230   2 return 0;
HITCBC 238   224 auto pos = data.find(delim); 231   224 auto pos = data.find(delim);
HITCBC 239   224 if(pos != std::string_view::npos) 232   224 if(pos != std::string_view::npos)
HITCBC 240   27 return pos + delim.size(); 233   27 return pos + delim.size();
HITCBC 241   197 if(hint) 234   197 if(hint)
HITCBC 242   1 *hint = delim.size() > 1 ? delim.size() - 1 : 0; 235   1 *hint = delim.size() > 1 ? delim.size() - 1 : 0;
HITCBC 243   197 return std::string_view::npos; 236   197 return std::string_view::npos;
244   } 237   }
245   }; 238   };
246   239  
247   /** Asynchronously read until a match condition is satisfied. 240   /** Asynchronously read until a match condition is satisfied.
248   241  
249 - Reads data from `stream` and appends it to `dynbuf` via calling 242 + Reads data from the stream into the dynamic buffer until the match
250 - `stream.read_some` zero or more times and using the prepare/commit 243 + condition returns a valid position. Implemented using `read_some`.
251 - interface until: 244 + If the match condition is already satisfied by existing buffer
252 - 245 + data, returns immediately without I/O.
253 - @li either @c match returns a valid position,  
254 - @li or @c dynbuf.size() == @c dynbuf.max_size() ,  
255 - @li or a contingency on @c stream.read_some occurs.  
256 -  
257 - If the match condition is satisfied by data in `dynbuf.data()` upon entry,  
258 - no call to `stream.read_some` is performed.  
259 -  
260 -  
261 - @par Await-returns  
262 -  
263 - An object of type `io_result<std::size_t>` destructuring as `[ec, n]`.  
264 -  
265 - If `bool(ec)`, `n` is the position returned by the match condition  
266 - (bytes up to and including the matched delimiter).  
267 -  
268   246  
269 - Contingencies: 247 + @li The operation completes when:
  248 + @li The match condition returns a valid position
  249 + @li End-of-stream is reached (`cond::eof`)
  250 + @li The buffer's `max_size()` is reached (`cond::not_found`)
  251 + @li An error occurs
  252 + @li The operation is cancelled
270   253  
271 - @li The first contingency, reported from awaiting @c stream.read_some . 254 + @par Cancellation
272 - @li @c cond::not_found -- when @c dynbuf.size() == @c dynbuf.max_size() 255 + Supports cancellation via `stop_token` propagated through the
273 - and the match condition is not satisfied by data in @c dynbuf.data() . 256 + IoAwaitable protocol. When cancelled, returns with `cond::canceled`.
274   257  
275   @param stream The stream to read from. The caller retains ownership. 258   @param stream The stream to read from. The caller retains ownership.
276 - @param dynbuf The dynamic buffer to append data to. Must remain 259 + @param buffers The dynamic buffer to append data to. Must remain
277   valid until the operation completes. 260   valid until the operation completes.
278   @param match The match condition callable. Copied into the awaitable. 261   @param match The match condition callable. Copied into the awaitable.
279   @param initial_amount Initial bytes to read per iteration (default 262   @param initial_amount Initial bytes to read per iteration (default
280   2048). Grows by 1.5x when filled. 263   2048). Grows by 1.5x when filled.
281   264  
282 - 265 + @return An awaitable that await-returns `(error_code, std::size_t)`.
283 - 266 + On success, `n` is the position returned by the match condition
284 - 267 + (bytes up to and including the matched delimiter). Compare error
285 - @par Await-throws 268 + codes to conditions:
286 - 269 + @li `cond::eof` - EOF before match; `n` is buffer size
287 - Whatever operations on @c dunbuf throw. 270 + @li `cond::not_found` - `max_size()` reached before match
288 - 271 + @li `cond::canceled` - Operation was cancelled
289 - (Note: types modeling @c DynamicBufferParam provided by Capy throw  
290 - @c std::bad_alloc from member function  
291 - @c prepare .)  
292 -  
293 - @par Remarks  
294 - Supports _IoAwaitable cancellation_.  
295   272  
296   @par Example 273   @par Example
297   274  
298   @code 275   @code
299   task<> read_http_header( ReadStream auto& stream ) 276   task<> read_http_header( ReadStream auto& stream )
300   { 277   {
301   std::string header; 278   std::string header;
302   auto [ec, n] = co_await read_until( 279   auto [ec, n] = co_await read_until(
303   stream, 280   stream,
304   string_dynamic_buffer( &header ), 281   string_dynamic_buffer( &header ),
305   []( std::string_view data, std::size_t* hint ) { 282   []( std::string_view data, std::size_t* hint ) {
306   auto pos = data.find( "\r\n\r\n" ); 283   auto pos = data.find( "\r\n\r\n" );
307   if( pos != std::string_view::npos ) 284   if( pos != std::string_view::npos )
308   return pos + 4; 285   return pos + 4;
309   if( hint ) 286   if( hint )
310 - (*hint) = 3; // partial "\r\n\r" possible 287 + *hint = 3; // partial "\r\n\r" possible
311   return std::string_view::npos; 288   return std::string_view::npos;
312   } ); 289   } );
313   if( ec ) 290   if( ec )
314   detail::throw_system_error( ec ); 291   detail::throw_system_error( ec );
315   // header contains data through "\r\n\r\n" 292   // header contains data through "\r\n\r\n"
316   } 293   }
317   @endcode 294   @endcode
318   295  
319   @see read_some, MatchCondition, DynamicBufferParam 296   @see read_some, MatchCondition, DynamicBufferParam
320   */ 297   */
321   template<ReadStream Stream, class B, MatchCondition M> 298   template<ReadStream Stream, class B, MatchCondition M>
322   requires DynamicBufferParam<B&&> 299   requires DynamicBufferParam<B&&>
323 - detail::read_until_return_t<Stream, B, M> 300 + auto
HITCBC 324   146 read_until( 301   146 read_until(
325   Stream& stream, 302   Stream& stream,
326 - B&& dynbuf, 303 + B&& buffers,
327   M match, 304   M match,
328   std::size_t initial_amount = 2048) 305   std::size_t initial_amount = 2048)
329   { 306   {
HITCBC 330   146 constexpr bool is_lvalue = std::is_lvalue_reference_v<B&&>; 307   146 constexpr bool is_lvalue = std::is_lvalue_reference_v<B&&>;
331   using BareB = std::remove_reference_t<B>; 308   using BareB = std::remove_reference_t<B>;
332   309  
333   if constexpr(is_lvalue) 310   if constexpr(is_lvalue)
334   return detail::read_until_awaitable<Stream, BareB, M, false>( 311   return detail::read_until_awaitable<Stream, BareB, M, false>(
HITCBC 335 - 14 stream, std::addressof(dynbuf), std::move(match), initial_amount); 312 + 14 stream, std::addressof(buffers), std::move(match), initial_amount);
336   else 313   else
337   return detail::read_until_awaitable<Stream, BareB, M, true>( 314   return detail::read_until_awaitable<Stream, BareB, M, true>(
HITCBC 338 - 132 stream, std::move(dynbuf), std::move(match), initial_amount); 315 + 132 stream, std::move(buffers), std::move(match), initial_amount);
339   } 316   }
340   317  
341   /** Asynchronously read until a delimiter string is found. 318   /** Asynchronously read until a delimiter string is found.
342   319  
343   Reads data from the stream until the delimiter is found. This is 320   Reads data from the stream until the delimiter is found. This is
344   a convenience overload equivalent to calling `read_until` with 321   a convenience overload equivalent to calling `read_until` with
345   `match_delim{delim}`. If the delimiter already exists in the 322   `match_delim{delim}`. If the delimiter already exists in the
346   buffer, returns immediately without I/O. 323   buffer, returns immediately without I/O.
347   324  
348   @li The operation completes when: 325   @li The operation completes when:
349   @li The delimiter string is found 326   @li The delimiter string is found
350   @li End-of-stream is reached (`cond::eof`) 327   @li End-of-stream is reached (`cond::eof`)
351   @li The buffer's `max_size()` is reached (`cond::not_found`) 328   @li The buffer's `max_size()` is reached (`cond::not_found`)
352   @li An error occurs 329   @li An error occurs
353   @li The operation is cancelled 330   @li The operation is cancelled
354   331  
355   @par Cancellation 332   @par Cancellation
356   Supports cancellation via `stop_token` propagated through the 333   Supports cancellation via `stop_token` propagated through the
357   IoAwaitable protocol. When cancelled, returns with `cond::canceled`. 334   IoAwaitable protocol. When cancelled, returns with `cond::canceled`.
358   335  
359   @param stream The stream to read from. The caller retains ownership. 336   @param stream The stream to read from. The caller retains ownership.
360   @param buffers The dynamic buffer to append data to. Must remain 337   @param buffers The dynamic buffer to append data to. Must remain
361   valid until the operation completes. 338   valid until the operation completes.
362   @param delim The delimiter string to search for. 339   @param delim The delimiter string to search for.
363   @param initial_amount Initial bytes to read per iteration (default 340   @param initial_amount Initial bytes to read per iteration (default
364   2048). Grows by 1.5x when filled. 341   2048). Grows by 1.5x when filled.
365   342  
366   @return An awaitable that await-returns `(error_code, std::size_t)`. 343   @return An awaitable that await-returns `(error_code, std::size_t)`.
367   On success, `n` is bytes up to and including the delimiter. 344   On success, `n` is bytes up to and including the delimiter.
368   Compare error codes to conditions: 345   Compare error codes to conditions:
369   @li `cond::eof` - EOF before delimiter; `n` is buffer size 346   @li `cond::eof` - EOF before delimiter; `n` is buffer size
370   @li `cond::not_found` - `max_size()` reached before delimiter 347   @li `cond::not_found` - `max_size()` reached before delimiter
371   @li `cond::canceled` - Operation was cancelled 348   @li `cond::canceled` - Operation was cancelled
372   349  
373   @par Example 350   @par Example
374   351  
375   @code 352   @code
376   task<std::string> read_line( ReadStream auto& stream ) 353   task<std::string> read_line( ReadStream auto& stream )
377   { 354   {
378   std::string line; 355   std::string line;
379   auto [ec, n] = co_await read_until( 356   auto [ec, n] = co_await read_until(
380   stream, string_dynamic_buffer( &line ), "\r\n" ); 357   stream, string_dynamic_buffer( &line ), "\r\n" );
381   if( ec == cond::eof ) 358   if( ec == cond::eof )
382   co_return line; // partial line at EOF 359   co_return line; // partial line at EOF
383   if( ec ) 360   if( ec )
384   detail::throw_system_error( ec ); 361   detail::throw_system_error( ec );
385   line.resize( n - 2 ); // remove "\r\n" 362   line.resize( n - 2 ); // remove "\r\n"
386   co_return line; 363   co_return line;
387   } 364   }
388   @endcode 365   @endcode
389   366  
390   @see read_until, match_delim, DynamicBufferParam 367   @see read_until, match_delim, DynamicBufferParam
391   */ 368   */
392   template<ReadStream Stream, class B> 369   template<ReadStream Stream, class B>
393   requires DynamicBufferParam<B&&> 370   requires DynamicBufferParam<B&&>
394 - detail::read_until_return_t<Stream, B, match_delim> 371 + auto
HITCBC 395   118 read_until( 372   118 read_until(
396   Stream& stream, 373   Stream& stream,
397   B&& buffers, 374   B&& buffers,
398   std::string_view delim, 375   std::string_view delim,
399   std::size_t initial_amount = 2048) 376   std::size_t initial_amount = 2048)
400   { 377   {
401   return read_until( 378   return read_until(
402   stream, 379   stream,
403   std::forward<B>(buffers), 380   std::forward<B>(buffers),
404   match_delim{delim}, 381   match_delim{delim},
HITCBC 405   118 initial_amount); 382   118 initial_amount);
406   } 383   }
407   384  
408   } // namespace capy 385   } // namespace capy
409   } // namespace boost 386   } // namespace boost
410   387  
411   #endif 388   #endif