From d57e1c5cef631944fdeed5e46805b3962e3324fd Mon Sep 17 00:00:00 2001
From: tastytea <tastytea@tastytea.de>
Date: Sun, 8 Nov 2020 14:35:09 +0100
Subject: [PATCH] Revert to ASCII-only case insensitivity for get_header().

boost::regex doesn't respected locale.
---
 CMakeLists.txt         |  1 -
 src/CMakeLists.txt     |  2 --
 src/types.cpp          | 30 +++++++++++++++++++-----------
 src/types.hpp          |  7 ++++---
 tests/test_headers.cpp | 37 ++++++++++++++++++++-----------------
 5 files changed, 43 insertions(+), 34 deletions(-)

diff --git a/CMakeLists.txt b/CMakeLists.txt
index 27d8e37..9d64249 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -10,7 +10,6 @@ project(curl_wrapper
   LANGUAGES CXX)
 
 find_package(CURL 7.52 REQUIRED)
-find_package(Boost 1.54 REQUIRED COMPONENTS regex)
 
 add_subdirectory(src)
 
diff --git a/src/CMakeLists.txt b/src/CMakeLists.txt
index 5fd64c4..423993c 100644
--- a/src/CMakeLists.txt
+++ b/src/CMakeLists.txt
@@ -18,7 +18,5 @@ else()
   target_link_libraries(${PROJECT_NAME} PUBLIC ${CURL_LIBRARIES})
 endif()
 
-target_link_libraries(${PROJECT_NAME} PRIVATE Boost::regex)
-
 target_include_directories(${PROJECT_NAME}
   PUBLIC "$<BUILD_INTERFACE:${PROJECT_SOURCE_DIR}/src>")
diff --git a/src/types.cpp b/src/types.cpp
index af89cfd..a59430e 100644
--- a/src/types.cpp
+++ b/src/types.cpp
@@ -16,25 +16,33 @@
 
 #include "types.hpp"
 
-#include <boost/regex.hpp>
-
+#include <algorithm>
+#include <cctype>
 #include <string>
 #include <string_view>
 
 namespace curl_wrapper
 {
 
-std::string answer::get_header(const std::string_view field) const
-{
-    const boost::regex re_field(string("^") + field.data()
-                                    + R"(:\s+([^\r\n]+))",
-                                boost::regex::icase);
-    boost::cmatch match;
+using std::tolower;
 
-    boost::regex_search(headers.c_str(), match, re_field);
-    if (match[1].matched)
+std::string_view answer::get_header(const std::string_view field) const
+{
+    const string searchstring{string(field) += ":"};
+    // clang-format off
+    auto it{std::search(headers.begin(), headers.end(), searchstring.begin(),
+                        searchstring.end(),
+                        [](unsigned char a, unsigned char b)
+                        { return tolower(a) == tolower(b); })};
+    // clang-format on
+
+    if (it != headers.end())
     {
-        return match[1].str();
+        auto pos{static_cast<size_t>(it - headers.begin())};
+        pos = headers.find(':', pos) + 1;
+        pos = headers.find_first_not_of(' ', pos);
+        const auto endpos{headers.find_first_of("\r\n", pos)};
+        return string_view(&headers[pos], endpos - pos);
     }
 
     return {};
diff --git a/src/types.hpp b/src/types.hpp
index 66fd0b6..08949e0 100644
--- a/src/types.hpp
+++ b/src/types.hpp
@@ -91,13 +91,14 @@ struct answer
     /*!
      *  @brief  Returns the value of a header field.
      *
-     *  @param  field Case insensitive, uses default locale.
+     *  @param  field Case insensitive, ASCII only.
      *
-     *  @return The value of the header field as std::string or {} if not found.
+     *  @return A std::string_view to the value of the header field or {} if not
+     *          found.
      *
      *  @since  INSERT_VERSION
      */
-    [[nodiscard]] string get_header(string_view field) const;
+    [[nodiscard]] string_view get_header(string_view field) const;
 };
 
 } // namespace curl_wrapper
diff --git a/tests/test_headers.cpp b/tests/test_headers.cpp
index 73a6822..06d279b 100644
--- a/tests/test_headers.cpp
+++ b/tests/test_headers.cpp
@@ -3,6 +3,7 @@
 #include <catch.hpp>
 
 #include <exception>
+#include <iostream>
 #include <locale>
 #include <string>
 
@@ -38,6 +39,7 @@ X-UmläÜt: 🙂
         }
         catch (const std::exception &e)
         {
+            std::cerr << "Exception: " << e.what() << '\n';
             exception = true;
         }
 
@@ -49,24 +51,25 @@ X-UmläÜt: 🙂
         }
     }
 
-    WHEN("We search for “X-UMLÄÜT”")
-    {
-        try
-        {
-            value = ret.get_header("X-UMLÄÜT");
-        }
-        catch (const std::exception &e)
-        {
-            exception = true;
-        }
+    // WHEN("We search for “X-UMLÄÜT”")
+    // {
+    //     try
+    //     {
+    //         value = ret.get_header("X-UMLÄÜT");
+    //     }
+    //     catch (const std::exception &e)
+    //     {
+    //         std::cerr << "Exception: " << e.what() << '\n';
+    //         exception = true;
+    //     }
 
-        THEN("No exception is thrown")
-        AND_THEN("The value is successfully extracted")
-        {
-            REQUIRE_FALSE(exception);
-            REQUIRE(value == "🙂");
-        }
-    }
+    //     THEN("No exception is thrown")
+    //     AND_THEN("The value is successfully extracted")
+    //     {
+    //         REQUIRE_FALSE(exception);
+    //         REQUIRE(value == "🙂");
+    //     }
+    // }
 }
 
 } // namespace curl_wrapper