From f3269a49c474ffe4d382c3d60826ad1cfbb7cdc4 Mon Sep 17 00:00:00 2001
From: rtk0c <mail.tianyig@gmail.com>
Date: Fri, 25 Nov 2022 17:28:07 -0800
Subject: Changeset: 93 Branch comment: [] Port font and UTF-8 string utilities
 from p6503

---
 source/10-common/String.hpp | 79 +++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 79 insertions(+)
 create mode 100644 source/10-common/String.hpp

(limited to 'source/10-common/String.hpp')

diff --git a/source/10-common/String.hpp b/source/10-common/String.hpp
new file mode 100644
index 0000000..8d54bad
--- /dev/null
+++ b/source/10-common/String.hpp
@@ -0,0 +1,79 @@
+#pragma once
+
+#include <cstddef>
+#include <string>
+#include <string_view>
+
+class Utf8Iterator {
+public:
+	using iterator_category = std::bidirectional_iterator_tag;
+	using value_type = char32_t;
+	using difference_type = std::string_view::difference_type;
+	using pointer = const char32_t*;
+	using reference = const char32_t&;
+
+private:
+	std::string_view::iterator mIter;
+	mutable char32_t mCurrentCodePoint = 0;
+	mutable bool mDirty = true;
+
+public:
+	Utf8Iterator(std::string_view::iterator it);
+	~Utf8Iterator() = default;
+
+	Utf8Iterator(const Utf8Iterator& that) = default;
+	Utf8Iterator& operator=(const Utf8Iterator& that) = default;
+	Utf8Iterator(Utf8Iterator&& that) = default;
+	Utf8Iterator& operator=(Utf8Iterator&& that) = default;
+
+	Utf8Iterator& operator++();
+	Utf8Iterator operator++(int);
+	Utf8Iterator& operator--();
+	Utf8Iterator operator--(int);
+
+	char32_t operator*() const;
+	std::string_view::iterator AsInternal() const;
+
+	friend bool operator==(const Utf8Iterator& lhs, const Utf8Iterator& rhs);
+	friend bool operator!=(const Utf8Iterator& lhs, const Utf8Iterator& rhs);
+	friend bool operator==(const Utf8Iterator& lhs, std::string_view::iterator rhs);
+	friend bool operator!=(const Utf8Iterator& lhs, std::string_view::iterator rhs);
+
+private:
+	void UpdateCurrentValue() const;
+};
+
+class Utf8IterableString {
+private:
+	std::string_view mStr;
+
+public:
+	Utf8IterableString(std::string_view str);
+	Utf8Iterator begin() const;
+	Utf8Iterator end() const;
+};
+
+namespace Utils {
+
+std::u32string ConvertUtf8To32(std::string_view str);
+std::string ConvertUtf32To8(std::u32string_view str);
+
+/// Slice the given UTF-8 string into the given range, in codepoints.
+std::string_view SliceUtf8(std::string_view str, size_t begin, size_t end);
+
+/// Calculate the given UTF-8 string's number of codepoints.
+size_t CountUtf8Codepoints(std::string_view str);
+
+struct CodepointInfo {
+	size_t index;
+	size_t byteOffset;
+};
+
+/// Find info about the last codepoint in the given UTF-8 string.
+/// \param str A non-empty UTF-8 encoded string.
+CodepointInfo FindLastCodepoint(std::string_view str);
+/// Find info about the nth codepoint in the given UTF-8 string. If codepointIdx is larger than the length, info for the last codepoint will be returned.
+/// \param str A non-empty UTF-8 encoded string.
+CodepointInfo FindCodepoint(std::string_view str, size_t codepointIdx);
+
+} // namespace Utils
-- 
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