3 files changed, 35 insertions, 30 deletions

diff --git a/src/mbgl/programs/program_parameters.cpp b/src/mbgl/programs/program_parameters.cpp
index e76ec4be71..2c70062e08 100644
--- a/src/mbgl/programs/program_parameters.cpp
+++ b/src/mbgl/programs/program_parameters.cpp
@@ -1,7 +1,5 @@
 #include <mbgl/programs/program_parameters.hpp>
-
-#include <iomanip>
-#include <sstream>
+#include <mbgl/util/string.hpp>
 
 namespace mbgl {
 
@@ -9,14 +7,15 @@ ProgramParameters::ProgramParameters(const float pixelRatio,
                                      const bool overdraw,
                                      optional<std::string> cacheDir_)
     : defines([&] {
-          std::ostringstream ss;
-          ss.imbue(std::locale("C"));
-          ss.setf(std::ios_base::showpoint);
-          ss << "#define DEVICE_PIXEL_RATIO " << pixelRatio << std::endl;
+          std::string result;
+          result.reserve(32);
+          result += "#define DEVICE_PIXEL_RATIO ";
+          result += util::toString(pixelRatio, true);
+          result += "\n";
           if (overdraw) {
-              ss << "#define OVERDRAW_INSPECTOR" << std::endl;
+              result += "#define OVERDRAW_INSPECTOR\n";
           }
-          return ss.str();
+          return result;
       }()),
       cacheDir(std::move(cacheDir_)) {
 }
@@ -29,10 +28,15 @@ optional<std::string> ProgramParameters::cachePath(const char* name) const {
     if (!cacheDir) {
         return {};
     } else {
-        std::ostringstream ss;
-        ss << *cacheDir << "/com.mapbox.gl.shader." << name << "." << std::setfill('0')
-           << std::setw(sizeof(size_t) * 2) << std::hex << std::hash<std::string>()(defines) << ".pbf";
-        return ss.str();
+        std::string result;
+        result.reserve(cacheDir->length() + 64);
+        result += *cacheDir;
+        result += "/com.mapbox.gl.shader.";
+        result += name;
+        result += ".";
+        result += util::toHex(std::hash<std::string>()(defines));
+        result += ".pbf";
+        return result;
     }
 }
 
diff --git a/src/mbgl/shaders/shaders.cpp b/src/mbgl/shaders/shaders.cpp
index 2e5a318024..04cfda35cc 100644
--- a/src/mbgl/shaders/shaders.cpp
+++ b/src/mbgl/shaders/shaders.cpp
@@ -1,10 +1,9 @@
 #include <mbgl/shaders/shaders.hpp>
 #include <mbgl/shaders/preludes.hpp>
 #include <mbgl/programs/program_parameters.hpp>
+#include <mbgl/util/string.hpp>
 
 #include <cassert>
-#include <sstream>
-#include <iomanip>
 
 namespace mbgl {
 namespace shaders {
@@ -18,12 +17,12 @@ std::string vertexSource(const ProgramParameters& parameters, const char* vertex
 }
 
 std::string programIdentifier(const std::string& vertexSource, const std::string& fragmentSource) {
-    std::ostringstream ss;
-    ss << std::setfill('0') << std::setw(sizeof(size_t) * 2) << std::hex;
-    ss << std::hash<std::string>()(vertexSource);
-    ss << std::hash<std::string>()(fragmentSource);
-    ss << "v2";
-    return ss.str();
+    std::string result;
+    result.reserve(sizeof(size_t) * 2 * 2 + 2 + 1);
+    result += util::toHex(std::hash<std::string>()(vertexSource));
+    result += util::toHex(std::hash<std::string>()(fragmentSource));
+    result += "v2";
+    return result;
 }
 
 } // namespace shaders
diff --git a/src/mbgl/util/url.cpp b/src/mbgl/util/url.cpp
index a4263502ef..37a70007ca 100644
--- a/src/mbgl/util/url.cpp
+++ b/src/mbgl/util/url.cpp
@@ -1,8 +1,6 @@
 #include <mbgl/util/url.hpp>
 #include <mbgl/util/token.hpp>
 
-#include <iomanip>
-#include <sstream>
 #include <string>
 #include <cstdlib>
 #include <algorithm>
@@ -24,26 +22,30 @@ inline bool isSchemeCharacter(char c) {
     return isAlphaNumericCharacter(c) || c == '-' || c == '+' || c == '.';
 }
 
+inline char toLowerHex(char c) {
+    c &= 0x0F;
+    return '0' + c + (c > 9 ? 7 : 0);
+}
+
 } // namespace
 
 namespace mbgl {
 namespace util {
 
 std::string percentEncode(const std::string& input) {
-    std::ostringstream encoded;
-
-    encoded.fill('0');
-    encoded << std::hex;
+    std::string encoded;
 
     for (auto c : input) {
         if (isAlphaNumericCharacter(c) || c == '-' || c == '_' || c == '.' || c == '~') {
-            encoded << c;
+            encoded += c;
         } else {
-            encoded << '%' << std::setw(2) << int(c);
+            encoded += '%';
+            encoded += toLowerHex(c >> 4);
+            encoded += toLowerHex(c);
         }
     }
 
-    return encoded.str();
+    return encoded;
 }
 
 std::string percentDecode(const std::string& input) {