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authorDan Goodliffe <dan.goodliffe@octal.co.uk>2022-08-22 14:51:38 +0100
committerDan Goodliffe <dan.goodliffe@octal.co.uk>2022-08-22 14:51:38 +0100
commitf9e95c2b7d2c50f6d12b9a67ce4ed897e032a300 (patch)
treefbe8e0802a988e2866f498051b4876a8e7dfc3dd /lib
parentEnable all cppchecks, no further fixes needed (diff)
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Create a string_view like thing for utf8 strings
utf8_string_view provides length and character iteration over a std::string_view containing utf8 data.
Diffstat (limited to 'lib')
-rw-r--r--lib/unicode.h65
1 files changed, 65 insertions, 0 deletions
diff --git a/lib/unicode.h b/lib/unicode.h
index dde1d3d..2945650 100644
--- a/lib/unicode.h
+++ b/lib/unicode.h
@@ -14,4 +14,69 @@ uint32_t get_codepoint(const char *);
#ifdef __cplusplus
}
+
+# include <string_view>
+# include <algorithm>
+
+struct utf8_string_view {
+ struct iter {
+ constexpr explicit iter(const char * p) : pos {p} { }
+
+ [[nodiscard]] auto
+ operator!=(const iter & other) const
+ {
+ return pos != other.pos;
+ }
+
+ auto &
+ operator++()
+ {
+ pos = next_char(pos);
+ return *this;
+ }
+
+ [[nodiscard]] auto
+ operator*() const
+ {
+ return get_codepoint(pos);
+ }
+
+ private:
+ const char * pos;
+ };
+
+ // cppcheck-suppress noExplicitConstructor; NOLINTNEXTLINE(hicpp-explicit-conversions)
+ template<typename... Args> constexpr utf8_string_view(Args &&... args) : str {std::forward<Args>(args)...} { }
+
+ [[nodiscard]] auto
+ begin() const
+ {
+ return iter {str.cbegin()};
+ }
+
+ [[nodiscard]] auto
+ end() const
+ {
+ return iter {str.cend()};
+ }
+
+ [[nodiscard]] size_t length() const;
+
+private:
+ std::string_view str;
+};
+template<> struct std::iterator_traits<utf8_string_view::iter> {
+ using difference_type = size_t;
+ using value_type = uint32_t;
+ using pointer = void;
+ using reference = void;
+ using iterator_category = std::forward_iterator_tag;
+};
+
+[[nodiscard]] inline size_t
+utf8_string_view::length() const
+{
+ return std::distance(begin(), end());
+}
+
#endif