DirectoryEnumerator: Handle non-null-terminated strings in CaseInsensitiveCompare

std::string_view instances aren't required to be null terminated. Given
this, we can make the functions a little safer by performing an explicit
bounded comparison on the range of characters, making the code more
generic with regards to handling the underlying string data.

include/nod/DirectoryEnumerator.hpp

@@ -6,20 +6,16 @@ namespace nod {
 
 struct CaseInsensitiveCompare {
   bool operator()(std::string_view lhs, std::string_view rhs) const {
-#if _WIN32
-    if (_stricmp(lhs.data(), rhs.data()) < 0)
-#else
-    if (strcasecmp(lhs.data(), rhs.data()) < 0)
-#endif
-      return true;
-    return false;
+    return std::lexicographical_compare(lhs.begin(), lhs.end(), rhs.begin(), rhs.end(), [](char lhs, char rhs) {
+      return std::tolower(static_cast<unsigned char>(lhs)) < std::tolower(static_cast<unsigned char>(rhs));
+    });
   }
 
 #if _WIN32
   bool operator()(std::wstring_view lhs, std::wstring_view rhs) const {
-    if (_wcsicmp(lhs.data(), rhs.data()) < 0)
-      return true;
-    return false;
+    return std::lexicographical_compare(lhs.begin(), lhs.end(), rhs.begin(), rhs.end(), [](wchar_t lhs, wchar_t rhs) {
+      return std::towlower(lhs) < std::towlower(rhs);
+    });
   }
 #endif
 };

include/nod/Util.hpp

@@ -1,7 +1,7 @@
 #pragma once
 
 #if _WIN32 && UNICODE
-#include <wctype.h>
+#include <cwctype>
 #include <direct.h>
 #ifndef WIN32_LEAN_AND_MEAN
 #define WIN32_LEAN_AND_MEAN 1
@@ -16,20 +16,19 @@
 #define WINDOWS_STORE 0
 #endif
 #else
-#include <ctype.h>
-#include <sys/file.h>
-#include <unistd.h>
+#include <cctype>
 #include <cerrno>
+#include <sys/file.h>
 #include <sys/param.h>
 #include <sys/statvfs.h>
-
+#include <unistd.h>
 #endif
 #include <sys/stat.h>
 
+#include <algorithm>
+#include <cstring>
 #include <string>
 #include <string_view>
-#include <cstring>
-#include <algorithm>
 #include "logvisor/logvisor.hpp"
 #ifdef _MSC_VER
 #pragma warning(disable : 4996)