1 files changed, 101 insertions, 0 deletions
diff --git a/platform/default/src/mbgl/i18n/collator.cpp b/platform/default/src/mbgl/i18n/collator.cpp
new file mode 100644
index 0000000000..f46accff8a
--- /dev/null
+++ b/platform/default/src/mbgl/i18n/collator.cpp
@@ -0,0 +1,101 @@
+#include <libnu/strcoll.h>
+#include <libnu/unaccent.h>
+#include <mbgl/i18n/collator.hpp>
+
+#include <cstring>
+#include <sstream>
+
+/*
+    The default implementation of Collator ignores locale.
+    Case sensitivity and collation order are based on
+    Default Unicode Collation Element Table (DUCET).
+
+    Diacritic-insensitivity is implemented with nunicode's
+    non-standard "unaccent" functionality, which is tailored
+    to European languages.
+
+    It would be possible to implement locale awareness using ICU,
+    but would require bundling locale data.
+*/
+
+namespace {
+std::string unaccent(const std::string& str) {
+    std::stringstream output;
+    char const *itr = str.c_str(), *nitr;
+    char const* end = itr + str.length();
+    char lo[5] = {0};
+
+    for (; itr < end; itr = nitr) {
+        uint32_t code_point = 0;
+        char const* buf = nullptr;
+
+        nitr = _nu_tounaccent(itr, end, nu_utf8_read, &code_point, &buf, nullptr);
+        if (buf != nullptr) {
+            do {
+                buf = NU_CASEMAP_DECODING_FUNCTION(buf, &code_point);
+                if (code_point == 0) break;
+                output.write(lo, nu_utf8_write(code_point, lo) - lo);
+            } while (code_point != 0);
+        } else {
+            output.write(itr, nitr - itr);
+        }
+    }
+
+    return output.str();
+}
+} // namespace
+
+namespace mbgl {
+namespace platform {
+
+class Collator::Impl {
+public:
+    Impl(bool caseSensitive_, bool diacriticSensitive_, optional<std::string>)
+        : caseSensitive(caseSensitive_)
+        , diacriticSensitive(diacriticSensitive_)
+    {}
+
+    bool operator==(const Impl& other) const {
+        return caseSensitive == other.caseSensitive && diacriticSensitive == other.diacriticSensitive;
+    }
+
+    int compare(const std::string& lhs, const std::string& rhs) const {
+        if (caseSensitive && diacriticSensitive) {
+            return nu_strcoll(lhs.c_str(), rhs.c_str(),
+                              nu_utf8_read, nu_utf8_read);
+        } else if (!caseSensitive && diacriticSensitive) {
+            return nu_strcasecoll(lhs.c_str(), rhs.c_str(),
+                                  nu_utf8_read, nu_utf8_read);
+        } else if (caseSensitive && !diacriticSensitive) {
+            return nu_strcoll(unaccent(lhs).c_str(), unaccent(rhs).c_str(), nu_utf8_read, nu_utf8_read);
+        } else {
+            return nu_strcasecoll(unaccent(lhs).c_str(), unaccent(rhs).c_str(), nu_utf8_read, nu_utf8_read);
+        }
+    }
+
+    std::string resolvedLocale() const {
+        return "";
+    }
+
+private:
+    bool caseSensitive;
+    bool diacriticSensitive;
+};
+
+int Collator::compare(const std::string& lhs, const std::string& rhs) const {
+    return impl->compare(lhs, rhs);
+}
+
+bool Collator::operator==(const Collator& other) const {
+    return *impl == *(other.impl);
+}
+
+std::string Collator::resolvedLocale() const {
+    return impl->resolvedLocale();
+}
+
+Collator::Collator(bool caseSensitive, bool diacriticSensitive, optional<std::string> locale)
+    : impl(std::make_shared<Impl>(caseSensitive, diacriticSensitive, std::move(locale))) {}
+
+} // namespace platform
+} // namespace mbgl