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| author | crupest <crupest@outlook.com> | 2020-12-29 22:52:02 +0800 |
|---|---|---|
| committer | crupest <crupest@outlook.com> | 2020-12-29 22:52:02 +0800 |
| commit | 168c9a009eb68697c1b8328cfbf3a1a6ccae48f6 (patch) | |
| tree | 8d1e3be48cc45d7fb0770c4196ac041561efd544 /works/life/cpp-practicum/StringUtil.hpp | |
| parent | 9a7553406beef499f64d220131ac02465f524ee1 (diff) | |
| download | crupest-168c9a009eb68697c1b8328cfbf3a1a6ccae48f6.tar.gz crupest-168c9a009eb68697c1b8328cfbf3a1a6ccae48f6.tar.bz2 crupest-168c9a009eb68697c1b8328cfbf3a1a6ccae48f6.zip | |
import(life): ...
Diffstat (limited to 'works/life/cpp-practicum/StringUtil.hpp')
| -rw-r--r-- | works/life/cpp-practicum/StringUtil.hpp | 148 |
1 files changed, 148 insertions, 0 deletions
diff --git a/works/life/cpp-practicum/StringUtil.hpp b/works/life/cpp-practicum/StringUtil.hpp new file mode 100644 index 0000000..d7b6cc9 --- /dev/null +++ b/works/life/cpp-practicum/StringUtil.hpp @@ -0,0 +1,148 @@ +#pragma once
+#include "Base.hpp"
+
+#include <functional>
+#include <string>
+#include <string_view>
+
+namespace cru {
+using CodePoint = std::int32_t;
+constexpr CodePoint k_invalid_code_point = -1;
+
+class TextEncodeException : public std::runtime_error {
+public:
+ using runtime_error::runtime_error;
+};
+
+inline bool IsUtf16SurrogatePairCodeUnit(char16_t c) {
+ return c >= 0xD800 && c <= 0xDFFF;
+}
+
+inline bool IsUtf16SurrogatePairLeading(char16_t c) {
+ return c >= 0xD800 && c <= 0xDBFF;
+}
+
+inline bool IsUtf16SurrogatePairTrailing(char16_t c) {
+ return c >= 0xDC00 && c <= 0xDFFF;
+}
+
+CodePoint Utf8NextCodePoint(std::string_view str, Index current,
+ Index *next_position);
+
+CodePoint Utf16NextCodePoint(std::u16string_view str, Index current,
+ Index *next_position);
+CodePoint Utf16PreviousCodePoint(std::u16string_view str, Index current,
+ Index *previous_position);
+
+template <typename StringType>
+using NextCodePointFunctionType = CodePoint (*)(StringType, Index, Index *);
+
+template <typename StringType,
+ NextCodePointFunctionType<StringType> NextCodePointFunction>
+class CodePointIterator {
+public:
+ using difference_type = Index;
+ using value_type = CodePoint;
+ using pointer = void;
+ using reference = value_type;
+ using iterator_category = std::forward_iterator_tag;
+
+public:
+ struct past_end_tag_t {};
+
+ explicit CodePointIterator(StringType string)
+ : string_(std::move(string)), position_(0) {}
+ explicit CodePointIterator(StringType string, past_end_tag_t)
+ : string_(std::move(string)), position_(string_.size()) {}
+
+ CRU_DEFAULT_COPY(CodePointIterator)
+ CRU_DEFAULT_MOVE(CodePointIterator)
+
+ ~CodePointIterator() = default;
+
+public:
+ StringType GetString() const { return string_; }
+ Index GetPosition() const { return position_; }
+
+ bool IsPastEnd() const {
+ return position_ == static_cast<Index>(string_.size());
+ }
+
+public:
+ CodePointIterator begin() const { return *this; }
+ CodePointIterator end() const {
+ return CodePointIterator{string_, past_end_tag_t{}};
+ }
+
+public:
+ bool operator==(const CodePointIterator &other) const {
+ // You should compare iterator that iterate on the same string.
+ Expects(this->string_.data() == other.string_.data() &&
+ this->string_.size() == other.string_.size());
+ return this->position_ == other.position_;
+ }
+ bool operator!=(const CodePointIterator &other) const {
+ return !this->operator==(other);
+ }
+
+ CodePointIterator &operator++() {
+ Expects(!IsPastEnd());
+ Forward();
+ return *this;
+ }
+
+ CodePointIterator operator++(int) {
+ Expects(!IsPastEnd());
+ CodePointIterator old = *this;
+ Forward();
+ return old;
+ }
+
+ CodePoint operator*() const {
+ return NextCodePointFunction(string_, position_, &next_position_cache_);
+ }
+
+private:
+ void Forward() {
+ if (next_position_cache_ > position_) {
+ position_ = next_position_cache_;
+ } else {
+ NextCodePointFunction(string_, position_, &position_);
+ }
+ }
+
+private:
+ StringType string_;
+ Index position_;
+ mutable Index next_position_cache_;
+};
+
+using Utf8CodePointIterator =
+ CodePointIterator<std::string_view, &Utf8NextCodePoint>;
+
+using Utf16CodePointIterator =
+ CodePointIterator<std::u16string_view, &Utf16NextCodePoint>;
+
+void Utf8EncodeCodePointAppend(CodePoint code_point, std::string &str);
+void Utf16EncodeCodePointAppend(CodePoint code_point, std::u16string &str);
+
+std::string ToUtf8(std::u16string_view s);
+std::u16string ToUtf16(std::string_view s);
+
+// If given s is not a valid utf16 string, return value is UD.
+bool Utf16IsValidInsertPosition(std::u16string_view s, gsl::index position);
+
+// Return position after the character making predicate returns true or 0 if no
+// character doing so.
+gsl::index Utf16BackwardUntil(std::u16string_view str, gsl::index position,
+ const std::function<bool(CodePoint)> &predicate);
+// Return position before the character making predicate returns true or
+// str.size() if no character doing so.
+gsl::index Utf16ForwardUntil(std::u16string_view str, gsl::index position,
+ const std::function<bool(CodePoint)> &predicate);
+
+gsl::index Utf16PreviousWord(std::u16string_view str, gsl::index position,
+ bool *is_space = nullptr);
+gsl::index Utf16NextWord(std::u16string_view str, gsl::index position,
+ bool *is_space = nullptr);
+} // namespace cru
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