use platform-specific NSString for case changes on OS X/iOS

refs #309

common/platform_default.cpp

@@ -0,0 +1,25 @@
+#include <mbgl/platform/platform.hpp>
+
+#include <locale>
+
+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 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;
+}
+
+}
+}

common/platform_nsstring.mm

@@ -0,0 +1,21 @@
+#import <Foundation/Foundation.h>
+
+#include <mbgl/platform/platform.hpp>
+
+namespace mbgl {
+namespace platform {
+
+std::string uppercase(const std::string &string) {
+    NSString *nsstring = [[NSString alloc] initWithBytesNoCopy:const_cast<char *>(string.data()) length:string.size() encoding:NSUTF8StringEncoding freeWhenDone:NO];
+    nsstring = [nsstring uppercaseString];
+    return { [nsstring cStringUsingEncoding:NSUTF8StringEncoding], [nsstring lengthOfBytesUsingEncoding:NSUTF8StringEncoding] };
+}
+
+std::string lowercase(const std::string &string) {
+    NSString *nsstring = [[NSString alloc] initWithBytesNoCopy:const_cast<char *>(string.data()) length:string.size() encoding:NSUTF8StringEncoding freeWhenDone:NO];
+    nsstring = [nsstring lowercaseString];
+    return { [nsstring cStringUsingEncoding:NSUTF8StringEncoding], [nsstring lengthOfBytesUsingEncoding:NSUTF8StringEncoding] };
+}
+
+}
+}

include/mbgl/platform/platform.hpp

@@ -28,6 +28,12 @@ std::shared_ptr<Request> request_http(const std::string &url,
                                       std::function<void(Response *)> callback,
                                       std::shared_ptr<uv::loop> loop = nullptr);
 
+// Uppercase a string, potentially using platform-specific routines.
+std::string uppercase(const std::string &string);
+
+// Lowercase a string, potentially using platform-specific routines.
+std::string lowercase(const std::string &string);
+
 // Cancels an HTTP request.
 void cancel_request_http(const std::shared_ptr<Request> &req);
 

linux/mapboxgl-app.gyp

@@ -12,6 +12,7 @@
         './main.cpp',
         '../common/settings_json.cpp',
         '../common/settings_json.hpp',
+        '../common/platform_default.cpp',
         '../common/glfw_view.hpp',
         '../common/glfw_view.cpp',
         '../common/curl_request.cpp',

macosx/mapboxgl-app.gyp

@@ -12,6 +12,7 @@
         './main.mm',
         '../common/settings_nsuserdefaults.hpp',
         '../common/settings_nsuserdefaults.mm',
+        '../common/platform_nsstring.mm',
         '../common/glfw_view.hpp',
         '../common/glfw_view.cpp',
         '../common/foundation_request.h',

src/renderer/symbol_bucket.cpp

@@ -75,11 +75,10 @@ std::vector<SymbolFeature> SymbolBucket::processFeatures(const VectorTileLayer &
         if (text) {
             std::string u8string = util::replaceTokens(properties.text.field, feature.properties);
 
-            auto &convert = std::use_facet<std::ctype<char>>(std::locale());
             if (properties.text.transform == TextTransformType::Uppercase) {
-                convert.toupper(&u8string[0], &u8string[0] + u8string.size());
+                u8string = platform::uppercase(u8string);
             } else if (properties.text.transform == TextTransformType::Lowercase) {
-                convert.tolower(&u8string[0], &u8string[0] + u8string.size());
+                u8string = platform::lowercase(u8string);
             }
 
             ft.label = ucs4conv.convert(u8string);