field does not have unkown value

Author: ashtum

include/boost/http_proto/detail/header.hpp

@@ -63,6 +63,10 @@ struct header
         std::numeric_limits<
             offset_type>::max();
 
+    static constexpr
+    field unknown_field =
+        static_cast<field>(0);
+
     struct entry
     {
         offset_type np;   // name pos
@@ -212,7 +216,6 @@ struct header
     static std::size_t
     count_crlf(core::string_view s) noexcept;
 
-    BOOST_HTTP_PROTO_DECL
     void parse(
         std::size_t,
         header_limits const&,

include/boost/http_proto/field.hpp

@@ -1,5 +1,6 @@
 //
 // Copyright (c) 2021 Vinnie Falco (vinnie.falco@gmail.com)
+// Copyright (c) 2025 Mohammad Nejati
 //
 // Distributed under the Boost Software License, Version 1.0. (See accompanying
 // file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
@@ -12,6 +13,7 @@
 
 #include <boost/http_proto/detail/config.hpp>
 #include <boost/core/detail/string_view.hpp>
+#include <boost/optional.hpp>
 #include <cstdint>
 #include <iosfwd>
 #include <type_traits>
@@ -21,9 +23,7 @@ namespace http_proto {
 
 enum class field : unsigned short
 {
-    unknown = 0,    // must be zero
-
-    a_im,
+    a_im = 1,
     accept,
     accept_additions,
     accept_charset,
@@ -399,7 +399,7 @@ to_string(field f);
         @ref field::unknown if there is no match.
 */
 BOOST_HTTP_PROTO_DECL
-field
+boost::optional<field>
 string_to_field(
     core::string_view s) noexcept;
 

include/boost/http_proto/fields_base.hpp

@@ -203,8 +203,7 @@ class fields_base
         @par Exception Safety
         Strong guarantee.
 
-        @param id The field name constant,
-        which may not be @ref field::unknown.
+        @param id The field name constant.
 
         @param value A value, which must be semantically
         valid for the message.
@@ -252,8 +251,7 @@ class fields_base
         @par Exception Safety
         Strong guarantee.
 
-        @param id The field name constant,
-        which may not be @ref field::unknown.
+        @param id The field name constant.
 
         @param value A value, which must be semantically
         valid for the message.
@@ -271,10 +269,6 @@ class fields_base
         core::string_view value,
         system::error_code& ec)
     {
-        // Precondition violation
-        if(id == field::unknown)
-            detail::throw_logic_error();
-
         insert_impl(
             id,
             to_string(id),
@@ -411,8 +405,7 @@ class fields_base
 
         @param before Position to insert before.
 
-        @param id The field name constant,
-        which may not be @ref field::unknown.
+        @param id The field name constant.
 
         @param value A value, which must be semantically
         valid for the message.
@@ -468,8 +461,7 @@ class fields_base
 
         @param before Position to insert before.
 
-        @param id The field name constant,
-        which may not be @ref field::unknown.
+        @param id The field name constant.
 
         @param value A value, which must be semantically
         valid for the message.
@@ -488,10 +480,6 @@ class fields_base
         core::string_view value,
         system::error_code& ec)
     {
-        // Precondition violation
-        if(id == field::unknown)
-            detail::throw_logic_error();
-
         insert_impl(
             id,
             to_string(id),
@@ -630,18 +618,15 @@ class fields_base
         @par Exception Safety
         Throws nothing.
 
-        @return An iterator to the inserted
-        element.
+        @return An iterator to one past the
+        removed element.
 
         @param it An iterator to the element
         to erase.
     */
+    BOOST_HTTP_PROTO_DECL
     iterator
-    erase(iterator it) noexcept
-    {
-        erase_impl(it.i_, it->id);
-        return it;
-    }
+    erase(iterator it) noexcept;
 
     /** Erase headers
 
@@ -661,12 +646,11 @@ class fields_base
 
         @return The number of headers erased.
 
-        @param id The field name constant,
-        which may not be @ref field::unknown.
+        @param id The field name constant.
     */
     BOOST_HTTP_PROTO_DECL
     std::size_t
-    erase(field id);
+    erase(field id) noexcept;
 
     /** Erase all matching fields
 
@@ -823,8 +807,7 @@ class fields_base
 
         @par Complexity
 
-        @param id The field name constant,
-        which may not be @ref field::unknown.
+        @param id The field name constant.
 
         @param value A value, which must be semantically
         valid for the message.
@@ -924,7 +907,7 @@ class fields_base
 
     void
     insert_unchecked_impl(
-        field id,
+        optional<field> id,
         core::string_view name,
         core::string_view value,
         std::size_t before,
@@ -933,7 +916,7 @@ class fields_base
     BOOST_HTTP_PROTO_DECL
     void
     insert_impl(
-        field id,
+        optional<field> id,
         core::string_view name,
         core::string_view value,
         std::size_t before,

include/boost/http_proto/fields_view_base.hpp

@@ -1,5 +1,6 @@
 //
 // Copyright (c) 2021 Vinnie Falco (vinnie.falco@gmail.com)
+// Copyright (c) 2025 Mohammad Nejati
 //
 // Distributed under the Boost Software License, Version 1.0. (See accompanying
 // file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
@@ -15,8 +16,6 @@
 #include <boost/url/grammar/recycled.hpp>
 #include <boost/url/grammar/type_traits.hpp>
 #include <boost/core/detail/string_view.hpp>
-#include <iterator>
-#include <memory>
 #include <string>
 
 namespace boost {
@@ -74,7 +73,7 @@ class fields_view_base
     /**@{*/
     struct reference
     {
-        field const id;
+        boost::optional<field> const id;
         core::string_view const name;
         core::string_view const value;
 
@@ -98,7 +97,7 @@ class fields_view_base
     */
     struct value_type
     {
-        field id;
+        boost::optional<field> id;
         std::string name;
         std::string value;
 

src/detail/header.cpp

@@ -71,6 +71,10 @@ operator-(
 
 //------------------------------------------------
 
+constexpr field header::unknown_field;
+
+//------------------------------------------------
+
 constexpr
 header::
 header(fields_tag) noexcept
@@ -1250,7 +1254,8 @@ parse_field(
         BOOST_ASSERT(h.buf != nullptr);
         remove_obs_fold(h.buf + h.size, it);
     }
-    auto id = string_to_field(rv->name);
+    auto id = string_to_field(rv->name)
+        .value_or(header::unknown_field);
     h.size = static_cast<header::offset_type>(it - h.cbuf);
 
     // add field table entry

src/field.cpp

@@ -1,5 +1,6 @@
 //
 // Copyright (c) 2021 Vinnie Falco (vinnie.falco@gmail.com)
+// Copyright (c) 2025 Mohammad Nejati
 //
 // Distributed under the Boost Software License, Version 1.0. (See accompanying
 // file LICENSE_1_0.txt or copy at http://www.boost.org/LICENSE_1_0.txt)
@@ -493,7 +494,7 @@ struct field_table
         }
     }
 
-    field
+    optional<field>
     string_to_field(
         core::string_view s) const noexcept
     {
@@ -505,13 +506,13 @@ struct field_table
             return static_cast<field>(i);
         i = map_[j][1];
         if(i == 0)
-            return field::unknown;
+            return boost::none;
         i += 255;
         s2 = by_name_[i];
 
         if(equals(s, s2))
             return static_cast<field>(i);
-        return field::unknown;
+        return boost::none;
     }
 
     //
@@ -558,7 +559,7 @@ to_string(field f)
     return v.begin()[static_cast<unsigned>(f)];
 }
 
-field
+boost::optional<field>
 string_to_field(
     core::string_view s) noexcept
 {