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

include/boost/http_proto/field.hpp

@@ -12,6 +12,7 @@
 
 #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 +22,7 @@ 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 +398,7 @@ 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

@@ -74,7 +74,7 @@ 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 +98,7 @@ class fields_view_base
     */
     struct value_type
     {
-        field id;
+        boost::optional<field> id;
         std::string name;
         std::string value;
 

src/detail/header.cpp

@@ -1250,7 +1250,8 @@ 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

@@ -493,7 +493,7 @@ struct field_table
         }
     }
 
-    field
+    optional<field>
     string_to_field(
         core::string_view s) const noexcept
     {
@@ -505,13 +505,13 @@ 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 +558,7 @@ to_string(field f)
     return v.begin()[static_cast<unsigned>(f)];
 }
 
-field
+optional<field>
 string_to_field(
     core::string_view s) noexcept
 {

src/fields_base.cpp

@@ -562,15 +562,23 @@ shrink_to_fit() noexcept
 //
 //------------------------------------------------
 
-std::size_t
+auto
 fields_base::
 erase(
-    field id)
+    iterator it) noexcept -> iterator
 {
-    // Precondition violation
-    if(id == field::unknown)
-        detail::throw_logic_error();
+    auto const id = it->id.value_or(
+        detail::header::unknown_field);
+    raw_erase(it.i_);
+    h_.on_erase(id);
+    return it;
+}
 
+std::size_t
+fields_base::
+erase(
+    field id) noexcept
+{
     auto const i0 = h_.find(id);
     if(i0 == h_.count)
         return 0;
@@ -587,7 +595,7 @@ erase(
         return 0;
     auto const ft = h_.tab();
     auto const id = ft[i0].id;
-    if(id == field::unknown)
+    if(id == detail::header::unknown_field)
         return erase_all_impl(i0, name);
     return erase_all_impl(i0, id);
 }
@@ -701,14 +709,15 @@ set(
         h_.size = static_cast<
             offset_type>(h_.size + dn);
     }
-    auto const id = it->id;
+    auto const id = it->id.value_or(
+        detail::header::unknown_field);
     if(h_.is_special(id))
     {
         // replace first char of name
         // with null to hide metadata
         char saved = h_.buf[pos0];
         auto& e = h_.tab()[i];
-        e.id = field::unknown;
+        e.id = detail::header::unknown_field;
         h_.buf[pos0] = '\0';
         h_.on_erase(id);
         h_.buf[pos0] = saved; // restore
@@ -726,10 +735,6 @@ set(
     core::string_view value,
     system::error_code& ec)
 {
-    // Precondition violation
-    if(id == field::unknown)
-        detail::throw_logic_error();
-
     auto rv = verify_field_value(value);
     if(rv.has_error())
     {
@@ -801,7 +806,7 @@ set(
         }
         // VFALCO simple algorithm but
         // costs one extra memmove
-        if(id != field::unknown)
+        if(id != detail::header::unknown_field)
             erase_all_impl(i0, id);
         else
             erase_all_impl(i0, name);
@@ -865,7 +870,7 @@ copy_impl(
 void
 fields_base::
 insert_unchecked_impl(
-    field id,
+    optional<field> id,
     core::string_view name,
     core::string_view value,
     std::size_t before,
@@ -954,20 +959,20 @@ insert_unchecked_impl(
             ! value.empty());
     e.vn = static_cast<
         offset_type>(value.size());
-    e.id = id;
+    e.id = id.value_or(
+        detail::header::unknown_field);
 
     // update container
     h_.count++;
     h_.size = static_cast<
         offset_type>(h_.size + n);
-    if( id != field::unknown)
-        h_.on_insert(id, value);
+    h_.on_insert(e.id, value);
 }
 
 void
 fields_base::
 insert_impl(
-    field id,
+    optional<field> id,
     core::string_view name,
     core::string_view value,
     std::size_t before,
@@ -992,17 +997,6 @@ insert_impl(
         rv->has_obs_fold);
 }
 
-// erase i and update metadata
-void
-fields_base::
-erase_impl(
-    std::size_t i,
-    field id) noexcept
-{
-    raw_erase(i);
-    h_.on_erase(id);
-}
-
 //------------------------------------------------
 
 void
@@ -1038,7 +1032,7 @@ erase_all_impl(
     field id) noexcept
 {
     BOOST_ASSERT(
-        id != field::unknown);
+        id != detail::header::unknown_field);
     std::size_t n = 1;
     std::size_t i = h_.count - 1;
     auto const ft = h_.tab();
@@ -1059,7 +1053,7 @@ erase_all_impl(
 }
 
 // erase all fields with name
-// when id == field::unknown
+// when id == detail::header::unknown_field
 std::size_t
 fields_base::
 erase_all_impl(