1 files changed, 31 insertions, 0 deletions
diff --git a/platform/darwin/src/string_nsstring.mm b/platform/darwin/src/string_nsstring.mm
new file mode 100644
index 0000000000..9bf199afc0
--- /dev/null
+++ b/platform/darwin/src/string_nsstring.mm
@@ -0,0 +1,31 @@
+#import <Foundation/Foundation.h>
+
+#include <mbgl/platform/platform.hpp>
+
+namespace mbgl {
+namespace platform {
+
+std::string uppercase(const std::string &string) {
+    NSString *original = [[NSString alloc] initWithBytesNoCopy:const_cast<char *>(string.data())
+                                                        length:string.size()
+                                                      encoding:NSUTF8StringEncoding
+                                                  freeWhenDone:NO];
+    NSString *uppercase = [original uppercaseString];
+    const std::string result{[uppercase cStringUsingEncoding : NSUTF8StringEncoding],
+                             [uppercase lengthOfBytesUsingEncoding:NSUTF8StringEncoding]};
+    return result;
+}
+
+std::string lowercase(const std::string &string) {
+    NSString *original = [[NSString alloc] initWithBytesNoCopy:const_cast<char *>(string.data())
+                                                        length:string.size()
+                                                      encoding:NSUTF8StringEncoding
+                                                  freeWhenDone:NO];
+    NSString *lowercase = [original lowercaseString];
+    const std::string result{[lowercase cStringUsingEncoding : NSUTF8StringEncoding],
+                             [lowercase lengthOfBytesUsingEncoding:NSUTF8StringEncoding]};
+    return result;
+}
+
+}
+}