clean up path logic a bit

1 files changed, 49 insertions, 0 deletions

diff --git a/lib/nes/common/path-view.cc b/lib/nes/common/path-view.cc
new file mode 100644
index 0000000..47f198b
--- /dev/null
+++ b/lib/nes/common/path-view.cc
@@ -0,0 +1,49 @@
+#include "nes/common/path-view.hh"
+
+namespace nes
+{
+	auto path_view::iterator::operator*() const -> std::string_view
+	{
+		return current_ ? std::string_view{ current_, component_length_ } : "";
+	}
+
+	auto path_view::iterator::operator++() -> iterator&
+	{
+		// Move forward to next component
+		current_ += component_length_;
+		remaining_ -= component_length_;
+
+		// Skip over '/'.
+		while (remaining_ > 0 && *current_ == '/')
+		{
+			current_ += 1;
+			remaining_ -= 1;
+		}
+
+		// Scan until end of component to find its length.
+		component_length_ = 0;
+		while (component_length_ < remaining_ && current_[component_length_] != '/')
+		{
+			component_length_ += 1;
+		}
+
+		return *this;
+	}
+
+	auto path_view::iterator::operator++(int) -> iterator
+	{
+		auto const res = *this;
+		++*this;
+		return res;
+	}
+
+	auto path_view::begin() const -> iterator
+	{
+		return ++iterator{ path_.data(), 0, static_cast<u32>(path_.size()) };
+	}
+
+	auto path_view::end() const -> iterator
+	{
+		return iterator{ path_.data() + path_.size(), 0, 0 };
+	}
+} // namespace nes
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