use nunicode for proper to_upper/to_lower string conversions

1 files changed, 41 insertions, 14 deletions

diff --git a/platform/default/string_stdlib.cpp b/platform/default/string_stdlib.cpp
index 1acbfa8508..d2c02e2881 100644
--- a/platform/default/string_stdlib.cpp
+++ b/platform/default/string_stdlib.cpp
@@ -1,24 +1,51 @@
 #include <mbgl/platform/platform.hpp>
-
-#include <locale>
+#include <mbgl/util/utf.hpp>
+#define NU_WITH_TOUPPER
+#define NU_WITH_TOLOWER
+#define NU_WITH_UTF8_WRITER
+#include <libnu/libnu.h>
 
 namespace mbgl {
 namespace platform {
 
-std::string uppercase(const std::string& string) {
-    // TODO: Use a proper Unicode Special Casing-aware algorithm.
-    const auto &convert = std::use_facet<std::ctype<char>>(std::locale());
-    std::string converted = string;
-    convert.toupper(&converted[0], &converted[0] + converted.size());
-    return converted;
+std::string uppercase(const std::string& str)
+{
+    boost::u8_to_u32_iterator<std::string::const_iterator> itr(str.begin());
+    boost::u8_to_u32_iterator<std::string::const_iterator> end(str.end());
+    std::string output;
+    char buf[4];
+    for (; itr!=end; ++itr)
+    {
+        char const* up = nu_toupper(*itr);
+        if (up != 0) output.append(up);
+        else
+        {
+            std::memset(buf, 0, 4);
+            nu_utf8_write(*itr, buf);
+            output.append(buf);
+        }
+    }
+    return output;
 }
 
-std::string lowercase(const std::string& string) {
-    // TODO: Use a proper Unicode Special Casing-aware algorithm.
-    const auto &convert = std::use_facet<std::ctype<char>>(std::locale());
-    std::string converted = string;
-    convert.tolower(&converted[0], &converted[0] + converted.size());
-    return converted;
+std::string lowercase(const std::string& str)
+{
+    boost::u8_to_u32_iterator<std::string::const_iterator> itr(str.begin());
+    boost::u8_to_u32_iterator<std::string::const_iterator> end(str.end());
+    std::string output;
+    char buf[4];
+    for (; itr!=end; ++itr)
+    {
+        char const* up = nu_tolower(*itr);
+        if (up != 0) output.append(up);
+        else
+        {
+            std::memset(buf, 0, 4);
+            nu_utf8_write(*itr, buf);
+            output.append(buf);
+        }
+    }
+    return output;
 }
 
 }