Merge #13671: Remove the boost/algorithm/string/case_conv.hpp dependency

b193d5a443 Removes the Boost case_conv.hpp dependency. (251)
7a208d9fad Implements custom tolower and toupper functions. (251)
e2ba043b8d Implements ParseNetwork unit test. (251)

Pull request description:

  This pull request removes the `boost/algorithm/string/case_conv.hpp` dependency from the project.

  `boost/algorithm/string/case_conv.hpp` is included for the `boost::to_lower` and `boost::to_upper` template functions.

  We can replace the calls to these functions with straightforward alternative implementations that use the C++ Standard Library, because the functions are called with `std::string` objects that use standard 7-bit ASCII characters as argument.

  The refactored implementation should work without the explicit `static_cast<unsigned char>` cast and `unsigned char` lambda return type. Both have been added defensively and to be explicit. Especially in case of the former, behaviour is undefined (potentially result in a crash) if the `std::toupper` argument is not an `unsigned char`.

  A potential alternative, maybe even preferred, implementation to address the `boost::to_lower` function call in `ParseNetwork(std::string)` could have been:

  ```c++
  if (net == "ipv4" || net == "IPv4") return NET_IPV4;
  if (net == "ipv6" || net == "IPv6") return NET_IPV6;
  ```
  This alternative implementation would however change the external behaviour of `ParseNetwork(std::string)`.

  This pull requests includes a unit test to validate the implementation of `ParseNetwork(std::string)`  prior and after the removal of the `case_conv.hpp` dependency.

  `boost/algorithm/string/case_conv.hpp` has been removed from the `EXPECTED_BOOST_INCLUDES` in `test/lint/lint-includes.sh` because it is no longer required.

Tree-SHA512: d803ae709f2368a3efb223097384a722436955bce0c44a1a5cffd0abb3164be0cce85ba0e9ebd9408166df3f1a95ea0c0d29e3a2534af2fae206c0419d67fde9

src/test/netbase_tests.cpp

@@ -302,4 +302,22 @@ BOOST_AUTO_TEST_CASE(netbase_getgroup)
     BOOST_CHECK(CreateInternal("baz.net").GetGroup() == internal_group);
 }
 
+BOOST_AUTO_TEST_CASE(netbase_parsenetwork)
+{
+    BOOST_CHECK_EQUAL(ParseNetwork("ipv4"), NET_IPV4);
+    BOOST_CHECK_EQUAL(ParseNetwork("ipv6"), NET_IPV6);
+    BOOST_CHECK_EQUAL(ParseNetwork("onion"), NET_ONION);
+    BOOST_CHECK_EQUAL(ParseNetwork("tor"), NET_ONION);
+
+    BOOST_CHECK_EQUAL(ParseNetwork("IPv4"), NET_IPV4);
+    BOOST_CHECK_EQUAL(ParseNetwork("IPv6"), NET_IPV6);
+    BOOST_CHECK_EQUAL(ParseNetwork("ONION"), NET_ONION);
+    BOOST_CHECK_EQUAL(ParseNetwork("TOR"), NET_ONION);
+
+    BOOST_CHECK_EQUAL(ParseNetwork(":)"), NET_UNROUTABLE);
+    BOOST_CHECK_EQUAL(ParseNetwork("tÖr"), NET_UNROUTABLE);
+    BOOST_CHECK_EQUAL(ParseNetwork("\xfe\xff"), NET_UNROUTABLE);
+    BOOST_CHECK_EQUAL(ParseNetwork(""), NET_UNROUTABLE);
+}
+
 BOOST_AUTO_TEST_SUITE_END()

src/test/util_tests.cpp

@@ -1217,4 +1217,43 @@ BOOST_AUTO_TEST_CASE(test_DirIsWritable)
     fs::remove(tmpdirname);
 }
 
+BOOST_AUTO_TEST_CASE(test_ToLower)
+{
+    BOOST_CHECK_EQUAL(ToLower('@'), '@');
+    BOOST_CHECK_EQUAL(ToLower('A'), 'a');
+    BOOST_CHECK_EQUAL(ToLower('Z'), 'z');
+    BOOST_CHECK_EQUAL(ToLower('['), '[');
+    BOOST_CHECK_EQUAL(ToLower(0), 0);
+    BOOST_CHECK_EQUAL(ToLower(255), 255);
+
+    std::string testVector;
+    Downcase(testVector);
+    BOOST_CHECK_EQUAL(testVector, "");
+
+    testVector = "#HODL";
+    Downcase(testVector);
+    BOOST_CHECK_EQUAL(testVector, "#hodl");
+
+    testVector = "\x00\xfe\xff";
+    Downcase(testVector);
+    BOOST_CHECK_EQUAL(testVector, "\x00\xfe\xff");
+}
+
+BOOST_AUTO_TEST_CASE(test_ToUpper)
+{
+    BOOST_CHECK_EQUAL(ToUpper('`'), '`');
+    BOOST_CHECK_EQUAL(ToUpper('a'), 'A');
+    BOOST_CHECK_EQUAL(ToUpper('z'), 'Z');
+    BOOST_CHECK_EQUAL(ToUpper('{'), '{');
+    BOOST_CHECK_EQUAL(ToUpper(0), 0);
+    BOOST_CHECK_EQUAL(ToUpper(255), 255);
+}
+
+BOOST_AUTO_TEST_CASE(test_Capitalize)
+{
+    BOOST_CHECK_EQUAL(Capitalize(""), "");
+    BOOST_CHECK_EQUAL(Capitalize("bitcoin"), "Bitcoin");
+    BOOST_CHECK_EQUAL(Capitalize("\x00\xfe\xff"), "\x00\xfe\xff");
+}
+
 BOOST_AUTO_TEST_SUITE_END()