feat(cpp-object-oriented-modular-refactoring): step 11 - source-target-resolver

src/fesa/core/ascii.cpp

@@ -0,0 +1,49 @@
+#include "fesa/core/ascii.h"
+
+#include <charconv>
+#include <string>
+#include <system_error>
+
+namespace fesa {
+
+char AsciiLower(const char value) noexcept {
+  if (value >= 'A' && value <= 'Z') {
+    return static_cast<char>(value + ('a' - 'A'));
+  }
+  return value;
+}
+
+bool AsciiCaseInsensitiveEquals(const std::string_view lhs,
+                                const std::string_view rhs) noexcept {
+  if (lhs.size() != rhs.size()) {
+    return false;
+  }
+  for (std::size_t index = 0U; index < lhs.size(); ++index) {
+    if (AsciiLower(lhs[index]) != AsciiLower(rhs[index])) {
+      return false;
+    }
+  }
+  return true;
+}
+
+Result<std::int64_t> ParsePositiveSourceLabel(const std::string_view text) {
+  std::int64_t value = 0;
+  const char* const storage = text.empty() ? "" : text.data();
+  const char* const first = storage;
+  const char* const last = storage + text.size();
+  const auto parsed = std::from_chars(first, last, value, 10);
+  if (parsed.ec == std::errc{} && parsed.ptr == last && value > 0) {
+    return Result<std::int64_t>::Success(value);
+  }
+  const std::string identity{text};
+  return Result<std::int64_t>::Failure(Status::Failure(
+      FailureCategory::kInput,
+      {{Severity::kError,
+        "invalid-source-label",
+        {{}, 0U},
+        "SOURCE_LABEL",
+        identity,
+        "A source label must be a complete positive base-10 integer."}}));
+}
+
+}  // namespace fesa