diff --git a/tools/aapt/Android.bp b/tools/aapt/Android.bp
index cc10db9..cecd95a 100644
--- a/tools/aapt/Android.bp
+++ b/tools/aapt/Android.bp
@@ -97,6 +97,7 @@
         "ResourceTable.cpp",
         "SourcePos.cpp",
         "StringPool.cpp",
+        "Utils.cpp",
         "WorkQueue.cpp",
         "XMLNode.cpp",
         "ZipEntry.cpp",
diff --git a/tools/aapt/Package.cpp b/tools/aapt/Package.cpp
index 965655b..a7ff5fa 100644
--- a/tools/aapt/Package.cpp
+++ b/tools/aapt/Package.cpp
@@ -8,6 +8,7 @@
 #include "OutputSet.h"
 #include "ResourceTable.h"
 #include "ResourceFilter.h"
+#include "Utils.h"
 
 #include <androidfw/misc.h>
 
@@ -226,7 +227,7 @@
             fprintf(stderr, "warning: null file being processed.\n");
         } else {
             String8 storagePath(entry.getPath());
-            storagePath.convertToResPath();
+            convertToResPath(storagePath);
             if (!processFile(bundle, zip, storagePath, entry.getFile())) {
                 return UNKNOWN_ERROR;
             }
diff --git a/tools/aapt/Resource.cpp b/tools/aapt/Resource.cpp
index 4ca3a68..9c944e0 100644
--- a/tools/aapt/Resource.cpp
+++ b/tools/aapt/Resource.cpp
@@ -15,6 +15,7 @@
 #include "ResourceTable.h"
 #include "StringPool.h"
 #include "Symbol.h"
+#include "Utils.h"
 #include "WorkQueue.h"
 #include "XMLNode.h"
 
@@ -321,7 +322,7 @@
             str++;
         }
         String8 resPath = it.getPath();
-        resPath.convertToResPath();
+        convertToResPath(resPath);
         status_t result = table->addEntry(SourcePos(it.getPath(), 0),
                         String16(assets->getPackage()),
                         type16,
diff --git a/tools/aapt/ResourceTable.cpp b/tools/aapt/ResourceTable.cpp
index 3abb89a..b6a17eb 100644
--- a/tools/aapt/ResourceTable.cpp
+++ b/tools/aapt/ResourceTable.cpp
@@ -11,6 +11,7 @@
 #include "ResourceFilter.h"
 #include "ResourceIdCache.h"
 #include "SdkConstants.h"
+#include "Utils.h"
 
 #include <algorithm>
 #include <androidfw/ResourceTypes.h>
@@ -4803,7 +4804,7 @@
     String8 resPath = String8::format("res/%s/%s.xml",
             newFile->getGroupEntry().toDirName(target->getResourceType()).c_str(),
             String8(resourceName).c_str());
-    resPath.convertToResPath();
+    convertToResPath(resPath);
 
     // Add a resource table entry.
     addEntry(SourcePos(),
@@ -4927,7 +4928,7 @@
         String8 resPath = String8::format("res/%s/%s.xml",
                 newFile->getGroupEntry().toDirName(target->getResourceType()).c_str(),
                 String8(resourceName).c_str());
-        resPath.convertToResPath();
+        convertToResPath(resPath);
 
         // Add a resource table entry.
         if (bundle->getVerbose()) {
diff --git a/tools/aapt/Utils.cpp b/tools/aapt/Utils.cpp
new file mode 100644
index 0000000..36b018e
--- /dev/null
+++ b/tools/aapt/Utils.cpp
@@ -0,0 +1,38 @@
+/*
+ * Copyright (C) 2005 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+#include "Utils.h"
+
+#include <utils/Compat.h>
+
+// Separator used by resource paths. This is not platform dependent contrary
+// to OS_PATH_SEPARATOR.
+#define RES_PATH_SEPARATOR '/'
+
+using android::String8;
+
+void convertToResPath([[maybe_unused]] String8& s) {
+#if OS_PATH_SEPARATOR != RES_PATH_SEPARATOR
+    size_t len = s.length();
+    if (len > 0) {
+        char* buf = s.lockBuffer(len);
+        for (char* end = buf + len; buf < end; ++buf) {
+            if (*buf == OS_PATH_SEPARATOR) *buf = RES_PATH_SEPARATOR;
+        }
+        s.unlockBuffer(len);
+    }
+#endif
+}
diff --git a/tools/aapt/Utils.h b/tools/aapt/Utils.h
new file mode 100644
index 0000000..8eb5941
--- /dev/null
+++ b/tools/aapt/Utils.h
@@ -0,0 +1,28 @@
+/*
+ * Copyright (C) 2005 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+#pragma once
+
+// This file contains cruft that used to be in libutils' String8, that's only
+// used for aapt.
+
+#include <utils/String8.h>
+
+// Converts all separators in this string to /, the default path
+// separator.
+// If the default OS separator is backslash, this converts all
+// backslashes to slashes, in-place. Otherwise it does nothing.
+void convertToResPath(android::String8&);