C: implement native file system

classlib/src/main/java/org/teavm/classlib/fs/VirtualFile.java

@@ -15,6 +15,8 @@
  */
 package org.teavm.classlib.fs;
 
+import java.io.IOException;
+
 public interface VirtualFile {
     String getName();
 
@@ -22,19 +24,17 @@ public interface VirtualFile {
 
     boolean isFile();
 
-    VirtualFile[] listFiles();
+    String[] listFiles();
 
-    VirtualFile getChildFile(String fileName);
+    VirtualFileAccessor createAccessor(boolean readable, boolean writable, boolean append);
 
-    VirtualFileAccessor createAccessor();
+    boolean createFile(String fileName) throws IOException;
 
-    VirtualFile createFile(String fileName);
+    boolean createDirectory(String fileName);
 
-    VirtualFile createDirectory(String fileName);
+    boolean delete();
 
-    void delete();
+    boolean adopt(VirtualFile file, String fileName);
-
-    void adopt(VirtualFile targetDir, String fileName);
 
     boolean canRead();
 
@@ -42,9 +42,9 @@ public interface VirtualFile {
 
     long lastModified();
 
-    void setLastModified(long lastModified);
+    boolean setLastModified(long lastModified);
 
-    void setReadOnly(boolean readOnly);
+    boolean setReadOnly(boolean readOnly);
 
     int length();
 }

classlib/src/main/java/org/teavm/classlib/fs/VirtualFileAccessor.java

@@ -22,7 +22,11 @@ public interface VirtualFileAccessor {
 
     void write(int pos, byte[] buffer, int offset, int limit) throws IOException;
 
-    int size();
+    int size() throws IOException;
 
     void resize(int size) throws IOException;
+
+    void close() throws IOException;
+
+    void flush() throws IOException;
 }

classlib/src/main/java/org/teavm/classlib/fs/VirtualFileSystem.java

@@ -16,7 +16,7 @@
 package org.teavm.classlib.fs;
 
 public interface VirtualFileSystem {
-    VirtualFile getRootFile();
-
     String getUserDir();
+
+    VirtualFile getFile(String path);
 }

classlib/src/main/java/org/teavm/classlib/fs/VirtualFileSystemProvider.java

@@ -15,8 +15,20 @@
  */
 package org.teavm.classlib.fs;
 
+import org.teavm.classlib.PlatformDetector;
+import org.teavm.classlib.fs.c.CFileSystem;
+import org.teavm.classlib.fs.memory.InMemoryVirtualFileSystem;
+
 public final class VirtualFileSystemProvider {
-    private static VirtualFileSystem instance = new InMemoryVirtualFileSystem();
+    private static VirtualFileSystem instance;
+
+    static {
+        if (PlatformDetector.isC()) {
+            instance = new CFileSystem();
+        } else {
+            instance = new InMemoryVirtualFileSystem();
+        }
+    }
 
     private VirtualFileSystemProvider() {
     }

classlib/src/main/java/org/teavm/classlib/fs/c/CFileSystem.java

@@ -0,0 +1,173 @@
+/*
+ *  Copyright 2019 Alexey Andreev.
+ *
+ *  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.
+ */
+package org.teavm.classlib.fs.c;
+
+import java.lang.ref.ReferenceQueue;
+import java.lang.ref.WeakReference;
+import java.util.HashMap;
+import java.util.Map;
+import org.teavm.classlib.fs.VirtualFile;
+import org.teavm.classlib.fs.VirtualFileSystem;
+import org.teavm.classlib.impl.c.Memory;
+import org.teavm.classlib.impl.c.StringList;
+import org.teavm.interop.Address;
+import org.teavm.interop.Import;
+import org.teavm.interop.Unmanaged;
+
+public class CFileSystem implements VirtualFileSystem {
+    private Map<String, Entry> cache = new HashMap<>();
+    private ReferenceQueue<? super CVirtualFile> referenceQueue = new ReferenceQueue<>();
+
+    @Override
+    public String getUserDir() {
+        Address resultPtr = Memory.malloc(Address.sizeOf());
+        int length = workDirectory(resultPtr);
+        Address result = resultPtr.getAddress();
+        Memory.free(resultPtr);
+
+        int realLength = length > 0 ? length : -length - 1;
+        char[] chars = new char[realLength];
+        Memory.memcpy(Address.ofData(chars), result, chars.length * 2);
+        Memory.free(result);
+
+        String s = new String(chars);
+        if (length < 0) {
+            throw new RuntimeException(s);
+        } else {
+            return s;
+        }
+    }
+
+    @Override
+    public VirtualFile getFile(String path) {
+        return getByPath(path);
+    }
+
+    CVirtualFile getByPath(String path) {
+        Entry entry = cache.get(path);
+        if (entry == null || entry.get() == null) {
+            entry = new Entry(new CVirtualFile(this, path), referenceQueue);
+            cache.put(path, entry);
+        }
+        while (true) {
+            Entry staleEntry = (Entry) referenceQueue.poll();
+            if (staleEntry == null) {
+                break;
+            }
+            if (!staleEntry.path.equals(path)) {
+                cache.remove(staleEntry.path);
+            }
+        }
+        return entry.get();
+    }
+
+    static class Entry extends WeakReference<CVirtualFile> {
+        String path;
+
+        Entry(CVirtualFile referent, ReferenceQueue<? super CVirtualFile> q) {
+            super(referent, q);
+            this.path = referent.path;
+        }
+    }
+
+    @Import(name = "teavm_file_homeDirectory")
+    @Unmanaged
+    public static native int homeDirectory(Address resultPtr);
+
+    @Import(name = "teavm_file_workDirectory")
+    @Unmanaged
+    static native int workDirectory(Address resultPtr);
+
+    @Import(name = "teavm_file_isDir")
+    @Unmanaged
+    static native boolean isDir(char[] name, int nameSize);
+
+    @Import(name = "teavm_file_isFile")
+    @Unmanaged
+    static native boolean isFile(char[] name, int nameSize);
+
+    @Import(name = "teavm_file_canRead")
+    @Unmanaged
+    static native boolean canRead(char[] name, int nameSize);
+
+    @Import(name = "teavm_file_canWrite")
+    @Unmanaged
+    static native boolean canWrite(char[] name, int nameSize);
+
+    @Import(name = "teavm_file_setReadonly")
+    @Unmanaged
+    static native boolean setReadonly(char[] name, int nameSize, boolean readonly);
+
+    @Import(name = "teavm_file_listFiles")
+    @Unmanaged
+    static native StringList listFiles(char[] name, int nameSize);
+
+    @Import(name = "teavm_file_createDirectory")
+    @Unmanaged
+    static native boolean createDirectory(char[] name, int nameSize);
+
+    @Import(name = "teavm_file_createFile")
+    @Unmanaged
+    static native int createFile(char[] name, int nameSize);
+
+    @Import(name = "teavm_file_delete")
+    @Unmanaged
+    static native boolean delete(char[] name, int nameSize);
+
+    @Import(name = "teavm_file_rename")
+    @Unmanaged
+    static native boolean rename(char[] name, int nameSize, char[] newName, int newNameSize);
+
+    @Import(name = "teavm_file_length")
+    @Unmanaged
+    static native int length(char[] name, int nameSize);
+
+    @Import(name = "teavm_file_lastModified")
+    @Unmanaged
+    static native long lastModified(char[] name, int nameSize);
+
+    @Import(name = "teavm_file_setLastModified")
+    @Unmanaged
+    static native boolean setLastModified(char[] name, int nameSize, long lastModified);
+
+    @Import(name = "teavm_file_open")
+    @Unmanaged
+    static native long open(char[] name, int nameSize, int mode);
+
+    @Import(name = "teavm_file_close")
+    @Unmanaged
+    static native boolean close(long file);
+
+    @Import(name = "teavm_file_flush")
+    @Unmanaged
+    static native boolean flush(long file);
+
+    @Import(name = "teavm_file_seek")
+    @Unmanaged
+    static native boolean seek(long file, int where, int offset);
+
+    @Import(name = "teavm_file_tell")
+    @Unmanaged
+    static native int tell(long file);
+
+    @Import(name = "teavm_file_read")
+    @Unmanaged
+    static native int read(long file, byte[] data, int offset, int count);
+
+    @Import(name = "teavm_file_write")
+    @Unmanaged
+    static native int write(long file, byte[] data, int offset, int count);
+}

classlib/src/main/java/org/teavm/classlib/fs/c/CVirtualFile.java

@@ -0,0 +1,180 @@
+/*
+ *  Copyright 2019 Alexey Andreev.
+ *
+ *  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.
+ */
+package org.teavm.classlib.fs.c;
+
+import java.io.IOException;
+import java.util.ArrayList;
+import java.util.Collections;
+import java.util.List;
+import org.teavm.classlib.fs.VirtualFile;
+import org.teavm.classlib.fs.VirtualFileAccessor;
+import org.teavm.classlib.impl.c.Memory;
+import org.teavm.classlib.impl.c.StringList;
+import org.teavm.interop.Address;
+
+public class CVirtualFile implements VirtualFile {
+    CFileSystem fileSystem;
+    String path;
+
+    public CVirtualFile(CFileSystem fileSystem, String path) {
+        this.fileSystem = fileSystem;
+        this.path = path;
+    }
+
+    @Override
+    public String getName() {
+        return path.substring(path.lastIndexOf('/') + 1);
+    }
+
+    @Override
+    public boolean isDirectory() {
+        char[] chars = path.toCharArray();
+        return CFileSystem.isDir(chars, chars.length);
+    }
+
+    @Override
+    public boolean isFile() {
+        char[] chars = path.toCharArray();
+        return CFileSystem.isFile(chars, chars.length);
+    }
+
+    @Override
+    public String[] listFiles() {
+        char[] chars = path.toCharArray();
+        StringList list = CFileSystem.listFiles(chars, chars.length);
+        if (list == null) {
+            return null;
+        }
+
+        List<String> files = new ArrayList<>();
+        while (list != null) {
+            if (list.data != null) {
+                chars = new char[list.length];
+                Address data = list.data.toAddress();
+                for (int i = 0; i < chars.length; ++i) {
+                    chars[i] = data.add(i * 2).getChar();
+                }
+                Memory.free(data);
+                String name = new String(chars);
+                if (!name.equals(".") && !name.equals("..")) {
+                    files.add(name);
+                }
+            }
+            StringList next = list.next;
+            Memory.free(list.toAddress());
+            list = next;
+        }
+        Collections.reverse(files);
+
+        return files.toArray(new String[0]);
+    }
+
+    @Override
+    public VirtualFileAccessor createAccessor(boolean readable, boolean writable, boolean append) {
+        char[] chars = path.toCharArray();
+        int mode = 0;
+        if (readable) {
+            mode |= 1;
+        }
+        if (writable) {
+            mode |= 2;
+        }
+        if (append) {
+            mode |= 4;
+        }
+        long file = CFileSystem.open(chars, chars.length, mode);
+        if (file == 0) {
+            return null;
+        }
+        return new CVirtualFileAccessor(file, append ? -1 : 0);
+    }
+
+    @Override
+    public boolean createFile(String fileName) throws IOException {
+        String newPath = constructPath(path, fileName);
+        char[] chars = newPath.toCharArray();
+        int result = CFileSystem.createFile(chars, chars.length);
+        switch (result) {
+            case 0:
+                return true;
+            case 1:
+                return false;
+            default:
+                throw new IOException("Could not create file " + fileName);
+        }
+    }
+
+    @Override
+    public boolean createDirectory(String fileName) {
+        String newPath = constructPath(path, fileName);
+        char[] chars = newPath.toCharArray();
+        return CFileSystem.createDirectory(chars, chars.length);
+    }
+
+    @Override
+    public boolean delete() {
+        char[] chars = path.toCharArray();
+        return CFileSystem.delete(chars, chars.length);
+    }
+
+    @Override
+    public boolean adopt(VirtualFile file, String fileName) {
+        char[] chars = ((CVirtualFile) file).path.toCharArray();
+        String newPath = constructPath(path, fileName);
+        char[] newPathChars = newPath.toCharArray();
+        return CFileSystem.rename(chars, chars.length, newPathChars, newPathChars.length);
+    }
+
+    @Override
+    public boolean canRead() {
+        char[] chars = path.toCharArray();
+        return CFileSystem.canRead(chars, chars.length);
+    }
+
+    @Override
+    public boolean canWrite() {
+        char[] chars = path.toCharArray();
+        return CFileSystem.canWrite(chars, chars.length);
+    }
+
+    @Override
+    public long lastModified() {
+        char[] chars = path.toCharArray();
+        return CFileSystem.lastModified(chars, chars.length);
+    }
+
+    @Override
+    public boolean setLastModified(long lastModified) {
+        char[] chars = path.toCharArray();
+        return CFileSystem.setLastModified(chars, chars.length, lastModified);
+    }
+
+    @Override
+    public boolean setReadOnly(boolean readOnly) {
+        char[] chars = path.toCharArray();
+        return CFileSystem.setReadonly(chars, chars.length, readOnly);
+    }
+
+    @Override
+    public int length() {
+        char[] chars = path.toCharArray();
+        return CFileSystem.length(chars, chars.length);
+    }
+
+    private static String constructPath(String parent, String child) {
+        return parent.endsWith("/") ? parent + child : parent + "/" + child;
+    }
+}

classlib/src/main/java/org/teavm/classlib/fs/c/CVirtualFileAccessor.java

@@ -0,0 +1,95 @@
+/*
+ *  Copyright 2019 Alexey Andreev.
+ *
+ *  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.
+ */
+package org.teavm.classlib.fs.c;
+
+import java.io.IOException;
+import org.teavm.classlib.fs.VirtualFileAccessor;
+
+public class CVirtualFileAccessor implements VirtualFileAccessor {
+    private long file;
+    private int position;
+
+    public CVirtualFileAccessor(long file, int position) {
+        this.file = file;
+        this.position = position;
+    }
+
+    @Override
+    public int read(int pos, byte[] buffer, int offset, int limit) throws IOException {
+        ensurePosition(pos);
+        int bytesRead = CFileSystem.read(file, buffer, offset, limit);
+        position += bytesRead;
+        return bytesRead;
+    }
+
+    @Override
+    public void write(int pos, byte[] buffer, int offset, int limit) throws IOException {
+        ensurePosition(pos);
+        int bytesWritten = CFileSystem.write(file, buffer, offset, limit);
+        if (bytesWritten < limit) {
+            throw new IOException();
+        }
+        position += bytesWritten;
+    }
+
+    @Override
+    public int size() throws IOException {
+        if (!CFileSystem.seek(file, 2, 0)) {
+            throw new IOException();
+        }
+        position = CFileSystem.tell(file);
+        return position;
+    }
+
+    @Override
+    public void resize(int size) throws IOException {
+        if (!CFileSystem.seek(file, 2, 0)) {
+            throw new IOException();
+        }
+        position = CFileSystem.tell(file);
+        if (position < size) {
+            byte[] zeros = new byte[4096];
+            while (position < size) {
+                write(position, zeros, 0, Math.min(zeros.length, size - position));
+            }
+        }
+    }
+
+    @Override
+    public void close() throws IOException {
+        long file = this.file;
+        this.file = 0;
+        if (!CFileSystem.close(file)) {
+            throw new IOException();
+        }
+    }
+
+    @Override
+    public void flush() throws IOException {
+        if (!CFileSystem.flush(file)) {
+            throw new IOException();
+        }
+    }
+
+    private void ensurePosition(int pos) throws IOException {
+        if (position != pos) {
+            if (!CFileSystem.seek(file, 0, pos)) {
+                throw new IOException();
+            }
+            position = pos;
+        }
+    }
+}

classlib/src/main/java/org/teavm/classlib/fs/memory/AbstractInMemoryVirtualFile.java

@@ -1,5 +1,5 @@
 /*
- *  Copyright 2017 Alexey Andreev.
+ *  Copyright 2019 Alexey Andreev.
  *
  *  Licensed under the Apache License, Version 2.0 (the "License");
  *  you may not use this file except in compliance with the License.
@@ -13,9 +13,12 @@
  *  See the License for the specific language governing permissions and
  *  limitations under the License.
  */
-package org.teavm.classlib.fs;
+package org.teavm.classlib.fs.memory;
 
-public abstract class AbstractInMemoryVirtualFile implements VirtualFile {
+import java.io.IOException;
+import org.teavm.classlib.fs.VirtualFileAccessor;
+
+public abstract class AbstractInMemoryVirtualFile {
     String name;
     InMemoryVirtualDirectory parent;
     long lastModified = System.currentTimeMillis();
@@ -25,44 +28,71 @@ public abstract class AbstractInMemoryVirtualFile implements VirtualFile {
         this.name = name;
     }
 
-    @Override
     public String getName() {
         return name;
     }
 
-    @Override
+    public boolean delete() {
-    public void delete() {
+        if (parent == null || (isDirectory() && listFiles().length > 0)) {
+            return false;
+        }
+
+        if (parent != null && !parent.canWrite()) {
+            return false;
+        }
+
         parent.children.remove(name);
         parent.modify();
         parent = null;
+        return true;
     }
 
-    @Override
+    public abstract boolean isDirectory();
+
+    public abstract boolean isFile();
+
+    public abstract String[] listFiles();
+
     public boolean canRead() {
         return true;
     }
 
-    @Override
     public boolean canWrite() {
         return !readOnly;
     }
 
-    @Override
     public long lastModified() {
         return lastModified;
     }
 
-    @Override
+    public boolean setLastModified(long lastModified) {
-    public void setLastModified(long lastModified) {
+        if (readOnly) {
+            return false;
+        }
         this.lastModified = lastModified;
+        return true;
     }
 
-    @Override
+    public boolean setReadOnly(boolean readOnly) {
-    public void setReadOnly(boolean readOnly) {
         this.readOnly = readOnly;
+        return true;
     }
 
     void modify() {
         lastModified = System.currentTimeMillis();
     }
+
+    public abstract AbstractInMemoryVirtualFile getChildFile(String fileName);
+
+    public abstract VirtualFileAccessor createAccessor(boolean readable, boolean writable, boolean append);
+
+    public abstract InMemoryVirtualFile createFile(String fileName) throws IOException;
+
+    public abstract InMemoryVirtualDirectory createDirectory(String fileName);
+
+    public abstract boolean adopt(AbstractInMemoryVirtualFile file, String fileName);
+
+    public int length() {
+        return 0;
+    }
 }

classlib/src/main/java/org/teavm/classlib/fs/memory/InMemoryVirtualDirectory.java

@@ -1,5 +1,5 @@
 /*
- *  Copyright 2017 Alexey Andreev.
+ *  Copyright 2019 Alexey Andreev.
  *
  *  Licensed under the Apache License, Version 2.0 (the "License");
  *  you may not use this file except in compliance with the License.
@@ -13,13 +13,15 @@
  *  See the License for the specific language governing permissions and
  *  limitations under the License.
  */
-package org.teavm.classlib.fs;
+package org.teavm.classlib.fs.memory;
 
+import java.io.IOException;
 import java.util.LinkedHashMap;
 import java.util.Map;
+import org.teavm.classlib.fs.VirtualFileAccessor;
 
 public class InMemoryVirtualDirectory extends AbstractInMemoryVirtualFile {
-    final Map<String, VirtualFile> children = new LinkedHashMap<>();
+    final Map<String, AbstractInMemoryVirtualFile> children = new LinkedHashMap<>();
 
     InMemoryVirtualDirectory(String name) {
         super(name);
@@ -36,46 +38,61 @@ public class InMemoryVirtualDirectory extends AbstractInMemoryVirtualFile {
     }
 
     @Override
-    public VirtualFile[] listFiles() {
+    public String[] listFiles() {
-        return children.values().toArray(new VirtualFile[0]);
+        return children.keySet().toArray(new String[0]);
     }
 
     @Override
-    public VirtualFile getChildFile(String fileName) {
+    public AbstractInMemoryVirtualFile getChildFile(String fileName) {
         return children.get(fileName);
     }
 
     @Override
-    public VirtualFileAccessor createAccessor() {
+    public VirtualFileAccessor createAccessor(boolean readable, boolean writable, boolean append) {
-        throw new UnsupportedOperationException();
+        return null;
     }
 
     @Override
-    public VirtualFile createFile(String fileName) {
+    public InMemoryVirtualFile createFile(String fileName) throws IOException {
+        if (!canWrite()) {
+            throw new IOException("Directory is read-only");
+        }
+        if (children.containsKey(fileName)) {
+            return null;
+        }
         InMemoryVirtualFile file = new InMemoryVirtualFile(fileName);
         adoptFile(file);
         return file;
     }
 
     @Override
-    public VirtualFile createDirectory(String fileName) {
+    public InMemoryVirtualDirectory createDirectory(String fileName) {
+        if (!canWrite() || getChildFile(fileName) != null) {
+            return null;
+        }
         InMemoryVirtualDirectory file = new InMemoryVirtualDirectory(fileName);
         adoptFile(file);
         return file;
     }
 
     @Override
-    public void adopt(VirtualFile file, String fileName) {
+    public boolean adopt(AbstractInMemoryVirtualFile file, String fileName) {
-        AbstractInMemoryVirtualFile typedFile = (AbstractInMemoryVirtualFile) file;
+        if (!canWrite()) {
-        typedFile.parent.children.remove(typedFile.name);
+            return false;
-        typedFile.parent = this;
+        }
-        children.put(fileName, typedFile);
+        if (!file.parent.canWrite()) {
-        typedFile.name = fileName;
+            return false;
+        }
+        file.parent.children.remove(file.name);
+        file.parent = this;
+        children.put(fileName, file);
+        file.name = fileName;
+        return true;
     }
 
     @Override
     public int length() {
-        throw new UnsupportedOperationException();
+        return 0;
     }
 
     private void adoptFile(AbstractInMemoryVirtualFile file) {

classlib/src/main/java/org/teavm/classlib/fs/memory/InMemoryVirtualFile.java

@@ -1,5 +1,5 @@
 /*
- *  Copyright 2017 Alexey Andreev.
+ *  Copyright 2019 Alexey Andreev.
  *
  *  Licensed under the Apache License, Version 2.0 (the "License");
  *  you may not use this file except in compliance with the License.
@@ -13,10 +13,11 @@
  *  See the License for the specific language governing permissions and
  *  limitations under the License.
  */
-package org.teavm.classlib.fs;
+package org.teavm.classlib.fs.memory;
 
 import java.io.IOException;
 import java.util.Arrays;
+import org.teavm.classlib.fs.VirtualFileAccessor;
 
 public class InMemoryVirtualFile extends AbstractInMemoryVirtualFile {
     byte[] data = new byte[0];
@@ -37,31 +38,31 @@ public class InMemoryVirtualFile extends AbstractInMemoryVirtualFile {
     }
 
     @Override
-    public VirtualFile[] listFiles() {
+    public String[] listFiles() {
+        return null;
+    }
+
+    @Override
+    public AbstractInMemoryVirtualFile getChildFile(String fileName) {
         throw new UnsupportedOperationException();
     }
 
     @Override
-    public VirtualFile getChildFile(String fileName) {
+    public VirtualFileAccessor createAccessor(boolean readable, boolean writable, boolean append) {
-        throw new UnsupportedOperationException();
-    }
-
-    @Override
-    public VirtualFileAccessor createAccessor() {
         if (parent == null) {
             return null;
         }
 
         return new VirtualFileAccessor() {
             @Override
-            public int read(int pos, byte[] buffer, int offset, int limit) throws IOException {
+            public int read(int pos, byte[] buffer, int offset, int limit) {
                 limit = Math.max(0, Math.min(size - pos, limit));
                 System.arraycopy(data, pos, buffer, offset, limit);
                 return limit;
             }
 
             @Override
-            public void write(int pos, byte[] buffer, int offset, int limit) throws IOException {
+            public void write(int pos, byte[] buffer, int offset, int limit) {
                 expandData(pos + limit);
                 System.arraycopy(buffer, offset, data, pos, limit);
                 size = pos + limit;
@@ -74,27 +75,35 @@ public class InMemoryVirtualFile extends AbstractInMemoryVirtualFile {
             }
 
             @Override
-            public void resize(int size) throws IOException {
+            public void resize(int size) {
                 expandData(size);
                 InMemoryVirtualFile.this.size = size;
                 modify();
             }
+
+            @Override
+            public void close() {
+            }
+
+            @Override
+            public void flush() {
+            }
         };
     }
 
     @Override
-    public VirtualFile createFile(String fileName) {
+    public InMemoryVirtualFile createFile(String fileName) throws IOException {
+        throw new IOException("Can't create file " + fileName + " since parent path denotes regular file");
+    }
+
+    @Override
+    public InMemoryVirtualDirectory createDirectory(String fileName) {
         throw new UnsupportedOperationException();
     }
 
     @Override
-    public VirtualFile createDirectory(String fileName) {
+    public boolean adopt(AbstractInMemoryVirtualFile file, String fileName) {
-        throw new UnsupportedOperationException();
+        return false;
-    }
-
-    @Override
-    public void adopt(VirtualFile file, String fileName) {
-        throw new UnsupportedOperationException();
     }
 
     @Override

classlib/src/main/java/org/teavm/classlib/fs/memory/InMemoryVirtualFileSystem.java

@@ -1,5 +1,5 @@
 /*
- *  Copyright 2017 Alexey Andreev.
+ *  Copyright 2019 Alexey Andreev.
  *
  *  Licensed under the Apache License, Version 2.0 (the "License");
  *  you may not use this file except in compliance with the License.
@@ -13,15 +13,18 @@
  *  See the License for the specific language governing permissions and
  *  limitations under the License.
  */
-package org.teavm.classlib.fs;
+package org.teavm.classlib.fs.memory;
+
+import org.teavm.classlib.fs.VirtualFile;
+import org.teavm.classlib.fs.VirtualFileSystem;
 
 public class InMemoryVirtualFileSystem implements VirtualFileSystem {
-    private InMemoryVirtualDirectory root = new InMemoryVirtualDirectory("");
+    InMemoryVirtualDirectory root = new InMemoryVirtualDirectory("");
     private String userDir = "/";
 
     @Override
-    public VirtualFile getRootFile() {
+    public VirtualFile getFile(String path) {
-        return root;
+        return new VirtualFileImpl(this, path);
     }
 
     @Override

classlib/src/main/java/org/teavm/classlib/fs/memory/VirtualFileImpl.java

@@ -0,0 +1,153 @@
+/*
+ *  Copyright 2019 Alexey Andreev.
+ *
+ *  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.
+ */
+package org.teavm.classlib.fs.memory;
+
+import java.io.IOException;
+import org.teavm.classlib.fs.VirtualFile;
+import org.teavm.classlib.fs.VirtualFileAccessor;
+
+public class VirtualFileImpl implements VirtualFile {
+    private InMemoryVirtualFileSystem fs;
+    private String path;
+
+    public VirtualFileImpl(InMemoryVirtualFileSystem fs, String path) {
+        this.fs = fs;
+        this.path = path;
+    }
+
+    @Override
+    public String getName() {
+        return path.substring(path.lastIndexOf('/') + 1);
+    }
+
+    @Override
+    public boolean isDirectory() {
+        AbstractInMemoryVirtualFile inMemory = findInMemory();
+        return inMemory != null && inMemory.isDirectory();
+    }
+
+    @Override
+    public boolean isFile() {
+        AbstractInMemoryVirtualFile inMemory = findInMemory();
+        return inMemory != null && inMemory.isFile();
+    }
+
+    @Override
+    public String[] listFiles() {
+        AbstractInMemoryVirtualFile inMemory = findInMemory();
+        return inMemory != null ? inMemory.listFiles() : null;
+    }
+
+    @Override
+    public VirtualFileAccessor createAccessor(boolean readable, boolean writable, boolean append) {
+        AbstractInMemoryVirtualFile inMemory = findInMemory();
+        return inMemory != null ? inMemory.createAccessor(readable, writable, append) : null;
+    }
+
+    @Override
+    public boolean createFile(String fileName) throws IOException {
+        AbstractInMemoryVirtualFile inMemory = findInMemory();
+        if (inMemory == null) {
+            throw new IOException("Directory does not exist");
+        }
+        return inMemory.createFile(fileName) != null;
+    }
+
+    @Override
+    public boolean createDirectory(String fileName) {
+        AbstractInMemoryVirtualFile inMemory = findInMemory();
+        return inMemory != null && inMemory.createDirectory(fileName) != null;
+    }
+
+    @Override
+    public boolean delete() {
+        AbstractInMemoryVirtualFile inMemory = findInMemory();
+        return inMemory != null && inMemory.delete();
+    }
+
+    @Override
+    public boolean adopt(VirtualFile file, String fileName) {
+        AbstractInMemoryVirtualFile inMemory = findInMemory();
+        if (inMemory == null) {
+            return false;
+        }
+        AbstractInMemoryVirtualFile fileInMemory = ((VirtualFileImpl) file).findInMemory();
+        if (fileInMemory == null) {
+            return false;
+        }
+        return inMemory.adopt(fileInMemory, fileName);
+    }
+
+    @Override
+    public boolean canRead() {
+        AbstractInMemoryVirtualFile inMemory = findInMemory();
+        return inMemory != null && inMemory.canRead();
+    }
+
+    @Override
+    public boolean canWrite() {
+        AbstractInMemoryVirtualFile inMemory = findInMemory();
+        return inMemory != null && inMemory.canWrite();
+    }
+
+    @Override
+    public long lastModified() {
+        AbstractInMemoryVirtualFile inMemory = findInMemory();
+        return inMemory != null ? inMemory.lastModified() : 0;
+    }
+
+    @Override
+    public boolean setLastModified(long lastModified) {
+        AbstractInMemoryVirtualFile inMemory = findInMemory();
+        return inMemory != null && inMemory.setLastModified(lastModified);
+    }
+
+    @Override
+    public boolean setReadOnly(boolean readOnly) {
+        AbstractInMemoryVirtualFile inMemory = findInMemory();
+        return inMemory != null && inMemory.setReadOnly(readOnly);
+    }
+
+    @Override
+    public int length() {
+        AbstractInMemoryVirtualFile inMemory = findInMemory();
+        return inMemory != null ? inMemory.length() : 0;
+    }
+
+    AbstractInMemoryVirtualFile findInMemory() {
+        AbstractInMemoryVirtualFile file = fs.root;
+        int i = 0;
+        if (path.startsWith("/")) {
+            i++;
+        }
+
+        while (i < path.length()) {
+            int next = path.indexOf('/', i);
+            if (next < 0) {
+                next = path.length();
+            }
+
+            file = file.getChildFile(path.substring(i, next));
+            if (file == null) {
+                break;
+            }
+
+            i = next + 1;
+        }
+
+        return file;
+    }
+}

classlib/src/main/java/org/teavm/classlib/impl/c/CharPtr.java

@@ -0,0 +1,22 @@
+/*
+ *  Copyright 2019 Alexey Andreev.
+ *
+ *  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.
+ */
+package org.teavm.classlib.impl.c;
+
+import org.teavm.interop.Structure;
+
+public class CharPtr extends Structure {
+    public char value;
+}

classlib/src/main/java/org/teavm/classlib/impl/c/Memory.java

@@ -0,0 +1,41 @@
+/*
+ *  Copyright 2019 Alexey Andreev.
+ *
+ *  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.
+ */
+package org.teavm.classlib.impl.c;
+
+import org.teavm.interop.Address;
+import org.teavm.interop.Import;
+import org.teavm.interop.Unmanaged;
+import org.teavm.interop.c.Include;
+
+public final class Memory {
+    private Memory() {
+    }
+
+    @Include("stdlib.h")
+    @Import(name = "malloc")
+    @Unmanaged
+    public static native Address malloc(int size);
+
+    @Include("stdlib.h")
+    @Import(name = "free")
+    @Unmanaged
+    public static native void free(Address address);
+
+    @Include("string.h")
+    @Import(name = "memcpy")
+    @Unmanaged
+    public static native void memcpy(Address target, Address source, int size);
+}

classlib/src/main/java/org/teavm/classlib/impl/c/StringList.java

@@ -0,0 +1,24 @@
+/*
+ *  Copyright 2019 Alexey Andreev.
+ *
+ *  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.
+ */
+package org.teavm.classlib.impl.c;
+
+import org.teavm.interop.Structure;
+
+public class StringList extends Structure {
+    public CharPtr data;
+    public int length;
+    public StringList next;
+}

classlib/src/main/java/org/teavm/classlib/impl/tz/DateTimeZoneProvider.java

@@ -27,6 +27,7 @@ import org.teavm.backend.javascript.spi.GeneratedBy;
 import org.teavm.classlib.impl.Base46;
 import org.teavm.classlib.impl.CharFlow;
 import org.teavm.interop.Import;
+import org.teavm.interop.Unmanaged;
 import org.teavm.jso.JSBody;
 import org.teavm.platform.metadata.ResourceMap;
 
@@ -190,6 +191,7 @@ public final class DateTimeZoneProvider {
 
     @JSBody(params = "instant", script = "return new Date(instant).getTimezoneOffset();")
     @Import(module = "teavm", name = "getNativeOffset")
+    @Unmanaged
     private static native int getNativeOffset(double instant);
 
     private static native ResourceMap<ResourceMap<TimeZoneResource>> getResource();

classlib/src/main/java/org/teavm/classlib/java/io/TFile.java

@@ -258,16 +258,10 @@ public class TFile implements Serializable, Comparable<TFile> {
 
     public String[] list() {
         VirtualFile virtualFile = findVirtualFile();
-        if (virtualFile == null || !virtualFile.isDirectory()) {
+        if (virtualFile == null) {
             return null;
         }
-        VirtualFile[] entries = virtualFile.listFiles();
+        return virtualFile.listFiles();
-        String[] names = new String[entries.length];
-        for (int i = 0; i < entries.length; ++i) {
-            names[i] = entries[i].getName();
-        }
-
-        return names;
     }
 
     public String[] list(TFilenameFilter filter) {
@@ -289,13 +283,16 @@ public class TFile implements Serializable, Comparable<TFile> {
 
     public TFile[] listFiles() {
         VirtualFile virtualFile = findVirtualFile();
-        if (virtualFile == null || !virtualFile.isDirectory()) {
+        if (virtualFile == null) {
+            return null;
+        }
+        String[] entries = virtualFile.listFiles();
+        if (entries == null) {
             return null;
         }
-        VirtualFile[] entries = virtualFile.listFiles();
         TFile[] files = new TFile[entries.length];
         for (int i = 0; i < entries.length; ++i) {
-            files[i] = new TFile(this, entries[i].getName());
+            files[i] = new TFile(this, entries[i]);
         }
 
         return files;
@@ -336,7 +333,11 @@ public class TFile implements Serializable, Comparable<TFile> {
     }
 
     public boolean exists() {
-        return findVirtualFile() != null;
+        VirtualFile virtualFile = findVirtualFile();
+        if (virtualFile == null) {
+            return false;
+        }
+        return virtualFile.isDirectory() || virtualFile.isFile();
     }
 
     public long lastModified() {
@@ -349,21 +350,24 @@ public class TFile implements Serializable, Comparable<TFile> {
             throw new IllegalArgumentException();
         }
         VirtualFile file = findVirtualFile();
-        if (file == null || !file.canWrite()) {
+        if (file == null) {
             return false;
         }
 
-        file.setLastModified(time);
+        return file.setLastModified(time);
-        return true;
     }
 
     public boolean setReadOnly() {
         VirtualFile file = findVirtualFile();
-        if (file == null || !file.canWrite()) {
+        if (file == null) {
             return false;
         }
-        file.setReadOnly(true);
+        return file.setReadOnly(true);
-        return true;
+    }
+
+    public boolean setWritable(boolean writable) {
+        VirtualFile file = findVirtualFile();
+        return file.setReadOnly(!writable);
     }
 
     public long length() {
@@ -376,51 +380,35 @@ public class TFile implements Serializable, Comparable<TFile> {
         if (parentVirtualFile == null) {
             throw new IOException("Can't create file " + getPath() + " since parent directory does not exist");
         }
-        if (!parentVirtualFile.isDirectory() || !parentVirtualFile.canWrite()) {
-            throw new IOException("Can't create file " + getPath() + " since parent path denotes regular file");
-        }
 
-        if (parentVirtualFile.getChildFile(getName()) != null) {
+        return parentVirtualFile.createFile(getName());
-            return false;
-        }
-
-        return parentVirtualFile.createFile(getName()) != null;
     }
 
     public boolean mkdir() {
         VirtualFile virtualFile = findParentFile();
-        if (virtualFile == null || !virtualFile.isDirectory() || !virtualFile.canWrite()) {
+        return virtualFile != null && virtualFile.createDirectory(getName());
-            return false;
-        }
-
-        return virtualFile.createDirectory(getName()) != null;
     }
 
     public boolean mkdirs() {
         String path = getCanonicalPathImpl();
-        if (path.startsWith("/")) {
-            path = path.substring(1);
-        }
 
-        VirtualFile virtualFile = fs().getRootFile();
+        int i = path.indexOf('/');
-        int i = 0;
+        if (i < 0) {
+            return false;
+        }
+        i++;
         while (i < path.length()) {
             int next = path.indexOf('/', i);
             if (next < 0) {
                 next = path.length();
             }
 
-            String name = path.substring(i, next);
+            VirtualFile parent = fs().getFile(path.substring(0, i));
-            VirtualFile child = virtualFile.getChildFile(name);
+            if (!parent.createDirectory(path.substring(i, next))) {
-            if (child == null) {
+                VirtualFile child = fs().getFile(path.substring(0, next));
-                if (!virtualFile.canWrite()) {
+                if (!child.isDirectory()) {
                     return false;
                 }
-                virtualFile = virtualFile.createDirectory(name);
-            } else if (child.isFile()) {
-                return false;
-            } else {
-                virtualFile = child;
             }
 
             i = next + 1;
@@ -431,18 +419,7 @@ public class TFile implements Serializable, Comparable<TFile> {
 
     public boolean delete() {
         VirtualFile virtualFile = findVirtualFile();
-        if (virtualFile == null || virtualFile == fs().getRootFile()
+        return virtualFile.delete();
-                || (virtualFile.isDirectory() && virtualFile.listFiles().length > 0)) {
-            return false;
-        }
-
-        VirtualFile parentVirtualFile = findParentFile();
-        if (parentVirtualFile != null && !parentVirtualFile.canWrite()) {
-            return false;
-        }
-
-        virtualFile.delete();
-        return true;
     }
 
     public void deleteOnExit() {
@@ -451,7 +428,7 @@ public class TFile implements Serializable, Comparable<TFile> {
 
     public boolean renameTo(TFile dest) {
         VirtualFile targetDir = dest.findParentFile();
-        if (targetDir == null || !targetDir.isDirectory()) {
+        if (targetDir == null) {
             return false;
         }
 
@@ -460,8 +437,7 @@ public class TFile implements Serializable, Comparable<TFile> {
             return false;
         }
 
-        targetDir.adopt(virtualFile, dest.getName());
+        return targetDir.adopt(virtualFile, dest.getName());
-        return true;
     }
 
     public URI toURI() {
@@ -589,7 +565,7 @@ public class TFile implements Serializable, Comparable<TFile> {
                 separatorIndex++;
             }
             if (separatorIndex > 0) {
-                name = name.substring(separatorIndex, name.length());
+                name = name.substring(separatorIndex);
             }
 
             if (!dirPath.isEmpty() && dirPath.charAt(dirPath.length() - 1) == separatorChar) {
@@ -602,28 +578,7 @@ public class TFile implements Serializable, Comparable<TFile> {
     }
 
     VirtualFile findVirtualFile() {
-        String path = getCanonicalPathImpl();
+        return fs().getFile(getCanonicalPathImpl());
-        if (path.startsWith("/")) {
-            path = path.substring(1);
-        }
-
-        VirtualFile virtualFile = fs().getRootFile();
-        int i = 0;
-        while (i < path.length()) {
-            int next = path.indexOf('/', i);
-            if (next < 0) {
-                next = path.length();
-            }
-
-            virtualFile = virtualFile.getChildFile(path.substring(i, next));
-            if (virtualFile == null) {
-                return null;
-            }
-
-            i = next + 1;
-        }
-
-        return virtualFile;
     }
 
     VirtualFile findParentFile() {
@@ -631,6 +586,6 @@ public class TFile implements Serializable, Comparable<TFile> {
         if (path.isEmpty() || path.equals("/")) {
             return null;
         }
-        return new TFile(getCanonicalPathImpl()).getParentFile().findVirtualFile();
+        return new TFile(path).getParentFile().findVirtualFile();
     }
 }

classlib/src/main/java/org/teavm/classlib/java/io/TFileInputStream.java

@@ -33,7 +33,7 @@ public class TFileInputStream extends InputStream {
             throw new FileNotFoundException();
         }
 
-        accessor = virtualFile.createAccessor();
+        accessor = virtualFile.createAccessor(true, false, false);
         if (accessor == null) {
             throw new FileNotFoundException();
         }

classlib/src/main/java/org/teavm/classlib/java/io/TFileOutputStream.java

@@ -43,28 +43,23 @@ public class TFileOutputStream extends OutputStream {
         if (file.getName().isEmpty()) {
             throw new FileNotFoundException("Invalid file name");
         }
-        VirtualFile virtualFile = file.findVirtualFile();
+        VirtualFile parentVirtualFile = file.findParentFile();
-        if (virtualFile == null) {
+        if (parentVirtualFile != null) {
-            VirtualFile parentVirtualFile = file.findParentFile();
+            try {
-            if (parentVirtualFile != null && parentVirtualFile.isDirectory()) {
+                parentVirtualFile.createFile(file.getName());
-                virtualFile = parentVirtualFile.createFile(file.getName());
+            } catch (IOException e) {
+                throw new FileNotFoundException();
             }
         }
-        if (virtualFile == null || virtualFile.isDirectory()) {
-            throw new FileNotFoundException();
-        }
 
-        if (!virtualFile.canWrite()) {
+        VirtualFile virtualFile = file.findVirtualFile();
-            throw new FileNotFoundException("File is read-only");
+        accessor = virtualFile.createAccessor(false, true, append);
-        }
-
-        accessor = virtualFile.createAccessor();
         if (accessor == null) {
             throw new FileNotFoundException();
         }
 
         if (append) {
-            pos = accessor.size();
+            pos = -1;
         }
     }
 
@@ -74,23 +69,28 @@ public class TFileOutputStream extends OutputStream {
         if (off < 0 || len < 0 || off > b.length - len) {
             throw new IndexOutOfBoundsException();
         }
-        ensureOpened();
+        ensurePos();
         accessor.write(pos, b, off, len);
         pos += len;
     }
 
     @Override
     public void flush() throws IOException {
+        ensureOpened();
+        accessor.flush();
     }
 
     @Override
     public void close() throws IOException {
+        if (accessor != null) {
+            accessor.close();
+        }
         accessor = null;
     }
 
     @Override
     public void write(int b) throws IOException {
-        ensureOpened();
+        ensurePos();
         byte[] buffer = { (byte) b };
         accessor.write(pos, buffer, 0, 1);
         pos++;
@@ -101,4 +101,11 @@ public class TFileOutputStream extends OutputStream {
             throw new IOException("This stream is already closed");
         }
     }
+
+    private void ensurePos() throws IOException {
+        ensureOpened();
+        if (pos < 0) {
+            pos = accessor.size();
+        }
+    }
 }

classlib/src/main/java/org/teavm/classlib/java/io/TRandomAccessFile.java

@@ -30,6 +30,7 @@ import org.teavm.classlib.java.lang.TNullPointerException;
 
 public class TRandomAccessFile implements DataInput, DataOutput, Closeable {
     private boolean readOnly;
+    private boolean autoFlush;
     private VirtualFileAccessor accessor;
     private int pos;
     private byte[] buff;
@@ -44,8 +45,10 @@ public class TRandomAccessFile implements DataInput, DataOutput, Closeable {
                 readOnly = true;
                 break;
             case "rw":
+                break;
             case "rwd":
             case "rws":
+                autoFlush = true;
                 break;
             default:
                 throw new IllegalArgumentException("Invalid mode: " + mode);
@@ -56,10 +59,11 @@ public class TRandomAccessFile implements DataInput, DataOutput, Closeable {
             throw new FileNotFoundException();
         }
 
-        accessor = virtualFile.createAccessor();
+        accessor = virtualFile.createAccessor(true, !readOnly, false);
         if (accessor == null) {
             throw new FileNotFoundException();
         }
+        buff = new byte[16];
     }
 
     @Override
@@ -281,20 +285,17 @@ public class TRandomAccessFile implements DataInput, DataOutput, Closeable {
 
     @Override
     public void write(int b) throws IOException {
-        if (readOnly) {
-            throw new IOException("This instance is read-only");
-        }
         ensureOpened();
         byte[] buffer = { (byte) b };
         accessor.write(pos, buffer, 0, 1);
+        if (autoFlush) {
+            accessor.flush();
+        }
         pos++;
     }
 
     @Override
     public void write(byte[] b) throws IOException {
-        if (readOnly) {
-            throw new IOException("This instance is read-only");
-        }
         write(b, 0, b.length);
     }
 
@@ -306,6 +307,9 @@ public class TRandomAccessFile implements DataInput, DataOutput, Closeable {
         }
         ensureOpened();
         accessor.write(pos, b, off, len);
+        if (autoFlush) {
+            accessor.flush();
+        }
         pos += len;
     }
 
@@ -456,7 +460,7 @@ public class TRandomAccessFile implements DataInput, DataOutput, Closeable {
         return new String(out, 0, s);
     }
 
-    static int writeShortToBuffer(int val, byte[] buffer, int offset) throws IOException {
+    static int writeShortToBuffer(int val, byte[] buffer, int offset) {
         buffer[offset++] = (byte) (val >> 8);
         buffer[offset++] = (byte) val;
         return offset;
@@ -478,7 +482,7 @@ public class TRandomAccessFile implements DataInput, DataOutput, Closeable {
         return utfCount;
     }
 
-    static int writeUTFBytesToBuffer(String str, byte[] buffer, int offset) throws IOException {
+    static int writeUTFBytesToBuffer(String str, byte[] buffer, int offset) {
         int length = str.length();
         for (int i = 0; i < length; i++) {
             int charValue = str.charAt(i);

classlib/src/main/java/org/teavm/classlib/java/lang/TCharacter.java

@@ -18,6 +18,7 @@ package org.teavm.classlib.java.lang;
 import org.teavm.classlib.impl.unicode.UnicodeHelper;
 import org.teavm.interop.DelegateTo;
 import org.teavm.interop.Import;
+import org.teavm.interop.Unmanaged;
 import org.teavm.interop.c.Include;
 import org.teavm.platform.Platform;
 import org.teavm.platform.metadata.StringResource;
@@ -244,6 +245,7 @@ public class TCharacter extends TObject implements TComparable<TCharacter> {
 
     @Import(module = "teavm", name = "towlower")
     @Include("wctype.h")
+    @Unmanaged
     private static native int toLowerCaseSystem(int codePoint);
 
     public static char toUpperCase(char ch) {
@@ -261,6 +263,7 @@ public class TCharacter extends TObject implements TComparable<TCharacter> {
 
     @Import(module = "teavm", name = "towupper")
     @Include("wctype.h")
+    @Unmanaged
     private static native int toUpperCaseSystem(int codePoint);
 
     public static int digit(char ch, int radix) {

classlib/src/main/java/org/teavm/classlib/java/lang/TConsoleOutputStreamStderr.java

@@ -19,6 +19,7 @@ import java.io.IOException;
 import org.teavm.classlib.java.io.TOutputStream;
 import org.teavm.interop.DelegateTo;
 import org.teavm.interop.Import;
+import org.teavm.interop.Unmanaged;
 import org.teavm.interop.c.Include;
 import org.teavm.jso.JSBody;
 
@@ -38,5 +39,6 @@ class TConsoleOutputStreamStderr extends TOutputStream {
 
     @Include("wchar.h")
     @Import(name = "putwchar", module = "teavm")
+    @Unmanaged
     static native void writeImpl(int b);
 }

classlib/src/main/java/org/teavm/classlib/java/lang/TDouble.java

@@ -18,6 +18,7 @@ package org.teavm.classlib.java.lang;
 import org.teavm.backend.javascript.spi.InjectedBy;
 import org.teavm.interop.Import;
 import org.teavm.interop.NoSideEffects;
+import org.teavm.interop.Unmanaged;
 import org.teavm.jso.JSBody;
 
 @NoSideEffects
@@ -233,21 +234,25 @@ public class TDouble extends TNumber implements TComparable<TDouble> {
     @JSBody(params = "v", script = "return isNaN(v);")
     @Import(module = "teavm", name = "isnan")
     @NoSideEffects
+    @Unmanaged
     public static native boolean isNaN(double v);
 
     @JSBody(script = "return NaN;")
     @Import(module = "teavm", name = "teavm_getNaN")
     @NoSideEffects
+    @Unmanaged
     private static native double getNaN();
 
     @JSBody(params = "v", script = "return !isFinite(v);")
     @Import(module = "teavm", name = "isinf")
     @NoSideEffects
+    @Unmanaged
     public static native boolean isInfinite(double v);
 
     @JSBody(params = "v", script = "return isFinite(v);")
     @Import(module = "teavm", name = "isfinite")
     @NoSideEffects
+    @Unmanaged
     public static native boolean isFinite(double v);
 
     public static long doubleToRawLongBits(double value) {
@@ -257,11 +262,13 @@ public class TDouble extends TNumber implements TComparable<TDouble> {
     @InjectedBy(DoubleGenerator.class)
     @Import(name = "teavm_reinterpretDoubleToLong")
     @NoSideEffects
+    @Unmanaged
     public static native long doubleToLongBits(double value);
 
     @InjectedBy(DoubleGenerator.class)
     @Import(name = "teavm_reinterpretLongToDouble")
     @NoSideEffects
+    @Unmanaged
     public static native double longBitsToDouble(long bits);
 
     public static String toHexString(double d) {

classlib/src/main/java/org/teavm/classlib/java/lang/TFloat.java

@@ -17,6 +17,7 @@ package org.teavm.classlib.java.lang;
 
 import org.teavm.interop.Import;
 import org.teavm.interop.NoSideEffects;
+import org.teavm.interop.Unmanaged;
 import org.teavm.jso.JSBody;
 
 public class TFloat extends TNumber implements TComparable<TFloat> {
@@ -97,21 +98,25 @@ public class TFloat extends TNumber implements TComparable<TFloat> {
     @JSBody(params = "v", script = "return isNaN(v);")
     @Import(module = "teavm", name = "isnan")
     @NoSideEffects
+    @Unmanaged
     public static native boolean isNaN(float v);
 
     @JSBody(params = "v", script = "return !isFinite(v);")
     @Import(module = "teavm", name = "isinf")
     @NoSideEffects
+    @Unmanaged
     public static native boolean isInfinite(float v);
 
     @JSBody(params = "v", script = "return isFinite(v);")
     @Import(module = "teavm", name = "isfinite")
     @NoSideEffects
+    @Unmanaged
     public static native boolean isFinite(float v);
 
     @JSBody(script = "return NaN;")
     @Import(module = "teavm", name = "teavm_getNaN")
     @NoSideEffects
+    @Unmanaged
     private static native float getNaN();
 
     public static float parseFloat(TString string) throws TNumberFormatException {
@@ -261,11 +266,13 @@ public class TFloat extends TNumber implements TComparable<TFloat> {
     @JSBody(params = "value", script = "return $rt_floatToIntBits(value);")
     @Import(name = "teavm_reinterpretFloatToInt")
     @NoSideEffects
+    @Unmanaged
     public static native int floatToIntBits(float value);
 
     @JSBody(params = "bits", script = "return $rt_intBitsToFloat(bits);")
     @Import(name = "teavm_reinterpretIntToFloat")
     @NoSideEffects
+    @Unmanaged
     public static native float intBitsToFloat(int bits);
 
     public static String toHexString(float f) {

classlib/src/main/java/org/teavm/classlib/java/lang/TMath.java

@@ -18,6 +18,7 @@ package org.teavm.classlib.java.lang;
 import org.teavm.backend.javascript.spi.GeneratedBy;
 import org.teavm.interop.Import;
 import org.teavm.interop.NoSideEffects;
+import org.teavm.interop.Unmanaged;
 
 @NoSideEffects
 public final class TMath extends TObject {
@@ -29,26 +30,32 @@ public final class TMath extends TObject {
 
     @GeneratedBy(MathNativeGenerator.class)
     @Import(module = "teavmMath", name = "sin")
+    @Unmanaged
     public static native double sin(double a);
 
     @GeneratedBy(MathNativeGenerator.class)
     @Import(module = "teavmMath", name = "cos")
+    @Unmanaged
     public static native double cos(double a);
 
     @GeneratedBy(MathNativeGenerator.class)
     @Import(module = "teavmMath", name = "tan")
+    @Unmanaged
     public static native double tan(double a);
 
     @GeneratedBy(MathNativeGenerator.class)
     @Import(module = "teavmMath", name = "asin")
+    @Unmanaged
     public static native double asin(double a);
 
     @GeneratedBy(MathNativeGenerator.class)
     @Import(module = "teavmMath", name = "acos")
+    @Unmanaged
     public static native double acos(double a);
 
     @GeneratedBy(MathNativeGenerator.class)
     @Import(module = "teavmMath", name = "atan")
+    @Unmanaged
     public static native double atan(double a);
 
     public static double toRadians(double angdeg) {
@@ -61,10 +68,12 @@ public final class TMath extends TObject {
 
     @GeneratedBy(MathNativeGenerator.class)
     @Import(module = "teavmMath", name = "exp")
+    @Unmanaged
     public static native double exp(double a);
 
     @GeneratedBy(MathNativeGenerator.class)
     @Import(module = "teavmMath", name = "log")
+    @Unmanaged
     public static native double log(double a);
 
     public static double log10(double a) {
@@ -73,6 +82,7 @@ public final class TMath extends TObject {
 
     @GeneratedBy(MathNativeGenerator.class)
     @Import(module = "teavmMath", name = "sqrt")
+    @Unmanaged
     public static native double sqrt(double a);
 
     public static double cbrt(double a) {
@@ -86,14 +96,17 @@ public final class TMath extends TObject {
 
     @GeneratedBy(MathNativeGenerator.class)
     @Import(module = "teavmMath", name = "ceil")
+    @Unmanaged
     public static native double ceil(double a);
 
     @GeneratedBy(MathNativeGenerator.class)
     @Import(module = "teavmMath", name = "floor")
+    @Unmanaged
     public static native double floor(double a);
 
     @GeneratedBy(MathNativeGenerator.class)
     @Import(module = "teavmMath", name = "pow")
+    @Unmanaged
     public static native double pow(double x, double y);
 
     public static double rint(double a) {
@@ -102,6 +115,7 @@ public final class TMath extends TObject {
 
     @GeneratedBy(MathNativeGenerator.class)
     @Import(module = "teavmMath", name = "atan2")
+    @Unmanaged
     public static native double atan2(double y, double x);
 
     public static int round(float a) {
@@ -114,6 +128,7 @@ public final class TMath extends TObject {
 
     @GeneratedBy(MathNativeGenerator.class)
     @Import(module = "teavmMath", name = "random")
+    @Unmanaged
     public static native double random();
 
     public static int min(int a, int b) {

classlib/src/main/java/org/teavm/classlib/java/lang/TSystem.java

@@ -19,6 +19,8 @@ import java.util.Enumeration;
 import java.util.Properties;
 import org.teavm.backend.javascript.spi.GeneratedBy;
 import org.teavm.classlib.PlatformDetector;
+import org.teavm.classlib.fs.c.CFileSystem;
+import org.teavm.classlib.impl.c.Memory;
 import org.teavm.classlib.java.io.TConsole;
 import org.teavm.classlib.java.io.TInputStream;
 import org.teavm.classlib.java.io.TPrintStream;
@@ -154,11 +156,28 @@ public final class TSystem extends TObject {
             defaults.put("line.separator", lineSeparator());
             defaults.put("java.io.tmpdir", "/tmp");
             defaults.put("java.vm.version", "1.8");
-            defaults.put("user.home", "/");
+            defaults.put("user.home", getHomeDir());
             properties = new Properties(defaults);
         }
     }
 
+    private static String getHomeDir() {
+        if (!PlatformDetector.isC()) {
+            return "/";
+        }
+
+        Address resultPtr = Memory.malloc(Address.sizeOf());
+        int length = CFileSystem.homeDirectory(resultPtr);
+        Address result = resultPtr.getAddress();
+        Memory.free(resultPtr);
+
+        char[] chars = new char[length];
+        Memory.memcpy(Address.ofData(chars), result, chars.length * 2);
+        Memory.free(result);
+
+        return new String(chars);
+    }
+
     public static String getProperty(@SuppressWarnings("unused") String key) {
         initPropertiesIfNeeded();
         return properties.getProperty(key);

classlib/src/main/java/org/teavm/classlib/java/util/TDate.java

@@ -21,6 +21,7 @@ import org.teavm.classlib.java.lang.TComparable;
 import org.teavm.classlib.java.lang.TSystem;
 import org.teavm.interop.Import;
 import org.teavm.interop.NoSideEffects;
+import org.teavm.interop.Unmanaged;
 import org.teavm.jso.core.JSDate;
 
 public class TDate implements TComparable<TDate> {
@@ -34,6 +35,7 @@ public class TDate implements TComparable<TDate> {
 
     @Import(name = "teavm_date_init")
     @NoSideEffects
+    @Unmanaged
     private static native void initLowLevel();
 
     public TDate() {
@@ -66,6 +68,7 @@ public class TDate implements TComparable<TDate> {
 
     @Import(name = "teavm_date_create")
     @NoSideEffects
+    @Unmanaged
     private static native long initDateLowLevel(int year, int month, int date, int hrs, int min, int sec);
 
     public TDate(String s) {
@@ -88,6 +91,7 @@ public class TDate implements TComparable<TDate> {
 
     @Import(name = "teavm_date_createUtc")
     @NoSideEffects
+    @Unmanaged
     private static native long initUtcDateLowLevel(int year, int month, int date, int hrs, int min, int sec);
 
     @Deprecated
@@ -105,6 +109,7 @@ public class TDate implements TComparable<TDate> {
 
     @Import(name = "teavm_date_parse")
     @NoSideEffects
+    @Unmanaged
     private static native long parseLowLevel(String s);
 
     @Deprecated
@@ -117,6 +122,7 @@ public class TDate implements TComparable<TDate> {
 
     @Import(name = "teavm_date_getYear")
     @NoSideEffects
+    @Unmanaged
     private static native int getYearLowLevel(long date);
 
     @Deprecated
@@ -132,6 +138,7 @@ public class TDate implements TComparable<TDate> {
 
     @Import(name = "teavm_date_setYear")
     @NoSideEffects
+    @Unmanaged
     private static native long setYearLowLevel(long date, int year);
 
     @Deprecated
@@ -144,6 +151,7 @@ public class TDate implements TComparable<TDate> {
 
     @Import(name = "teavm_date_getMonth")
     @NoSideEffects
+    @Unmanaged
     private static native int getMonthLowLevel(long date);
 
     @Deprecated
@@ -159,6 +167,7 @@ public class TDate implements TComparable<TDate> {
 
     @Import(name = "teavm_date_setMonth")
     @NoSideEffects
+    @Unmanaged
     private static native long setMonthLowLevel(long date, int month);
 
     @Deprecated
@@ -171,6 +180,7 @@ public class TDate implements TComparable<TDate> {
 
     @Import(name = "teavm_date_getDate")
     @NoSideEffects
+    @Unmanaged
     private static native int getDateLowLevel(long date);
 
     @Deprecated
@@ -186,6 +196,7 @@ public class TDate implements TComparable<TDate> {
 
     @Import(name = "teavm_date_setDate")
     @NoSideEffects
+    @Unmanaged
     private static native int setDateLowLevel(long target, int date);
 
     @Deprecated
@@ -197,6 +208,7 @@ public class TDate implements TComparable<TDate> {
     }
 
     @Import(name = "teavm_date_getDay")
+    @Unmanaged
     public static native int getDayLowLevel(long date);
 
     @Deprecated
@@ -224,6 +236,7 @@ public class TDate implements TComparable<TDate> {
 
     @Import(name = "teavm_date_setHours")
     @NoSideEffects
+    @Unmanaged
     private static native int setHoursLowLevel(long date, int hours);
 
     @Deprecated
@@ -236,6 +249,7 @@ public class TDate implements TComparable<TDate> {
 
     @Import(name = "teavm_date_getMinutes")
     @NoSideEffects
+    @Unmanaged
     private static native int getMinutesLowLevel(long date);
 
     @Deprecated
@@ -251,6 +265,7 @@ public class TDate implements TComparable<TDate> {
 
     @Import(name = "teavm_date_setMinutes")
     @NoSideEffects
+    @Unmanaged
     private static native int setMinutesLowLevel(long date, int minutes);
 
     @Deprecated
@@ -263,6 +278,7 @@ public class TDate implements TComparable<TDate> {
 
     @Import(name = "teavm_date_getSeconds")
     @NoSideEffects
+    @Unmanaged
     private static native int getSecondsLowLevel(long date);
 
     @Deprecated
@@ -278,6 +294,7 @@ public class TDate implements TComparable<TDate> {
 
     @Import(name = "teavm_date_setSeconds")
     @NoSideEffects
+    @Unmanaged
     private static native int setSecondsLowLevel(long date, int seconds);
 
     public long getTime() {

classlib/src/main/java/org/teavm/classlib/java/util/TRandom.java

@@ -20,6 +20,7 @@ import org.teavm.classlib.java.io.TSerializable;
 import org.teavm.classlib.java.lang.TMath;
 import org.teavm.classlib.java.lang.TObject;
 import org.teavm.interop.Import;
+import org.teavm.interop.Unmanaged;
 import org.teavm.jso.JSBody;
 
 public class TRandom extends TObject implements TSerializable {
@@ -82,6 +83,7 @@ public class TRandom extends TObject implements TSerializable {
     }
 
     @Import(name = "teavm_rand")
+    @Unmanaged
     private static native double crand();
 
     /**
@@ -119,5 +121,6 @@ public class TRandom extends TObject implements TSerializable {
 
     @JSBody(script = "return Math.random();")
     @Import(module = "teavmMath", name = "random")
+    @Unmanaged
     private static native double random();
 }

core/src/main/java/org/teavm/backend/c/CTarget.java

@@ -379,6 +379,7 @@ public class CTarget implements TeaVMTarget, TeaVMCHost {
         copyResource("stringhash.c", buildTarget);
         copyResource("references.c", buildTarget);
         copyResource("date.c", buildTarget);
+        copyResource("file.c", buildTarget);
         generateCallSites(buildTarget, context, classes.getClassNames());
         generateStrings(buildTarget, context);
 
@@ -681,6 +682,7 @@ public class CTarget implements TeaVMTarget, TeaVMCHost {
         files.add("callsites.c");
         files.add("references.c");
         files.add("date.c");
+        files.add("file.c");
 
         for (String className : classes.getClassNames()) {
             files.add(ClassGenerator.fileName(className) + ".c");

core/src/main/java/org/teavm/backend/c/intrinsic/AddressIntrinsic.java

@@ -101,7 +101,7 @@ public class AddressIntrinsic implements Intrinsic {
                 context.writer().print(")");
                 break;
             case "getChar":
-                context.writer().print("((int32_t) *(uchar16_t*) ");
+                context.writer().print("((int32_t) *(char16_t*) ");
                 context.emit(invocation.getArguments().get(0));
                 context.writer().print(")");
                 break;
@@ -136,9 +136,9 @@ public class AddressIntrinsic implements Intrinsic {
                 context.writer().print(")");
                 break;
             case "putChar":
-                context.writer().print("(*(uchar16_t*) ");
+                context.writer().print("(*(char16_t*) ");
                 context.emit(invocation.getArguments().get(0));
-                context.writer().print(" = (uchar16_t) ");
+                context.writer().print(" = (char16_t) ");
                 context.emit(invocation.getArguments().get(1));
                 context.writer().print(")");
                 break;
@@ -225,6 +225,7 @@ public class AddressIntrinsic implements Intrinsic {
             case BYTE:
                 return 1;
             case SHORT:
+            case CHARACTER:
                 return 2;
             case INTEGER:
             case FLOAT:

core/src/main/resources/org/teavm/backend/c/date.c

@@ -43,6 +43,23 @@ inline static int64_t teavm_date_timestamp(struct tm *t) {
     return (int64_t) (1000 * difftime(result, teavm_epochStart));
 }
 
+int64_t teavm_date_timeToTimestamp(time_t t) {
+    return (int64_t) (1000 * difftime(t, teavm_epochStart));
+}
+
+time_t teavm_date_timestampToTime(int64_t timestamp) {
+    struct tm t = {
+        .tm_year = 70,
+        .tm_mon = 0,
+        .tm_mday = 1,
+        .tm_hour = 0,
+        .tm_min = 0,
+        .tm_sec = timestamp / 1000,
+        .tm_isdst = -1
+    };
+    return timegm(&t) + timestamp % 1000;
+}
+
 inline static struct tm* teavm_date_decompose(int64_t timestamp, struct tm *t) {
     *t = teavm_epochStartTm;
     t->tm_sec += timestamp / 1000;

core/src/main/resources/org/teavm/backend/c/file.c

@@ -0,0 +1,309 @@
+#include "runtime.h"
+#include <stdlib.h>
+#include <errno.h>
+
+#ifdef __GNUC__
+#include <unistd.h>
+#include <sys/stat.h>
+#include <sys/types.h>
+#include <fcntl.h>
+#include <stdio.h>
+#include <dirent.h>
+#include <utime.h>
+#include <pwd.h>
+
+int32_t teavm_file_homeDirectory(char16_t** result) {
+    struct passwd *pw = getpwuid(getuid());
+    int32_t length;
+    *result = teavm_mbToChar16(pw->pw_dir, &length);
+    return length;
+}
+
+int32_t teavm_file_workDirectory(char16_t** result) {
+    long pathMax;
+    size_t size;
+    char *buf;
+    int32_t length;
+
+    pathMax = pathconf(".", _PC_PATH_MAX);
+    if (pathMax == -1) {
+        size = 1024;
+    } else if (pathMax > 10240) {
+        size = 10240;
+    } else {
+        size = pathMax;
+    }
+
+    buf = malloc(size);
+
+    while (1) {
+        if (getcwd(buf, size) != buf) {
+            if (errno != ERANGE) {
+                *result = teavm_mbToChar16(strerror(errno), &length);
+                return -1 - length;
+            }
+        } else {
+            *result = teavm_mbToChar16(buf, &length);
+            free(buf);
+            return length;
+        }
+        size *= 2;
+        char* newBuf = realloc(buf, size);
+        if (newBuf == NULL) {
+            *result = teavm_mbToChar16("Out of memory", &length);
+            free(buf);
+            return -1 - length;
+        }
+        buf = newBuf;
+    }
+}
+
+int32_t teavm_file_isFile(char16_t* name, int32_t nameSize) {
+    struct stat s;
+    char* mbName = teavm_char16ToMb(name, nameSize);
+    int statResult = stat(mbName, &s);
+    free(mbName);
+    if (statResult != 0) {
+        return 0;
+    }
+
+    return !S_ISDIR(s.st_mode);
+}
+
+int32_t teavm_file_isDir(char16_t* name, int32_t nameSize) {
+    struct stat s;
+    char* mbName = teavm_char16ToMb(name, nameSize);
+    int statResult = stat(mbName, &s);
+    free(mbName);
+    if (statResult != 0) {
+        return 0;
+    }
+
+    return S_ISDIR(s.st_mode);
+}
+
+int32_t teavm_file_canRead(char16_t* name, int32_t nameSize) {
+    char* mbName = teavm_char16ToMb(name, nameSize);
+    int result = access(mbName, R_OK);
+    free(mbName);
+    return result == 0;
+}
+
+int32_t teavm_file_canWrite(char16_t* name, int32_t nameSize) {
+    char* mbName = teavm_char16ToMb(name, nameSize);
+    int result = access(mbName, W_OK);
+    free(mbName);
+    return result == 0;
+}
+
+int32_t teavm_file_setReadonly(char16_t* name, int32_t nameSize, int32_t readonly) {
+    struct stat s;
+    char* mbName = teavm_char16ToMb(name, nameSize);
+    int statResult = stat(mbName, &s);
+    if (statResult != 0) {
+        free(mbName);
+        return 0;
+    }
+
+    mode_t mode = s.st_mode;
+    if (readonly) {
+        mode &= ~S_IWUSR;
+    } else {
+        mode |= S_IWUSR;
+    }
+    int result = chmod(mbName, mode);
+    free(mbName);
+    return result == 0;
+}
+
+TeaVM_StringList* teavm_file_listFiles(char16_t* name, int32_t nameSize) {
+    char* mbName = teavm_char16ToMb(name, nameSize);
+    DIR* dir = opendir(mbName);
+    free(mbName);
+    if (dir == NULL) {
+        return NULL;
+    }
+
+    TeaVM_StringList *strings = teavm_appendString(NULL, NULL, 0);
+
+    while (1) {
+        struct dirent* entry = readdir(dir);
+        if (entry == NULL) {
+            break;
+        }
+
+        int32_t len;
+        char16_t* name = teavm_mbToChar16(entry->d_name, &len);
+        if (name == NULL) {
+            teavm_disposeStringList(strings);
+            return NULL;
+        }
+
+        strings = teavm_appendString(strings, name, len);
+    }
+
+    closedir(dir);
+    return strings;
+}
+
+int32_t teavm_file_createDirectory(char16_t* name, int32_t nameSize) {
+    char* mbName = teavm_char16ToMb(name, nameSize);
+    int result = mkdir(mbName, S_IRUSR | S_IWUSR | S_IXUSR | S_IRGRP | S_IXGRP | S_IROTH | S_IXOTH);
+    free(mbName);
+    return result == 0;
+}
+
+int32_t teavm_file_createFile(char16_t* name, int32_t nameSize) {
+    char* mbName = teavm_char16ToMb(name, nameSize);
+    int result = open(mbName, O_RDWR | O_CREAT | O_EXCL, S_IRUSR | S_IWUSR | S_IRGRP | S_IROTH);
+    free(mbName);
+    if (result >= 0) {
+        close(result);
+        return 0;
+    } else if (errno == EEXIST) {
+        return 1;
+    } else {
+        return 2;
+    }
+}
+
+int32_t teavm_file_delete(char16_t* name, int32_t nameSize) {
+    char* mbName = teavm_char16ToMb(name, nameSize);
+    int result = remove(mbName);
+    free(mbName);
+    return result == 0;
+}
+
+int32_t teavm_file_rename(char16_t* name, int32_t nameSize, char16_t* newName, int32_t newNameSize) {
+    char* mbName = teavm_char16ToMb(name, nameSize);
+    char* newMbName = teavm_char16ToMb(newName, newNameSize);
+    int result = rename(mbName, newMbName);
+    free(mbName);
+    free(newMbName);
+    return result == 0;
+}
+
+int64_t teavm_file_lastModified(char16_t* name, int32_t nameSize) {
+    struct stat s;
+    char* mbName = teavm_char16ToMb(name, nameSize);
+    int statResult = stat(mbName, &s);
+    free(mbName);
+    if (statResult != 0) {
+        return 0;
+    }
+
+    return teavm_date_timeToTimestamp(s.st_mtime);
+}
+
+int32_t teavm_file_setLastModified(char16_t* name, int32_t nameSize, int64_t lastModified) {
+    struct stat s;
+    char* mbName = teavm_char16ToMb(name, nameSize);
+    int statResult = stat(mbName, &s);
+    if (statResult != 0) {
+        free(mbName);
+        return 0;
+    }
+
+    struct utimbuf newTime;
+    newTime.actime = s.st_atime;
+    newTime.modtime = teavm_date_timestampToTime(lastModified);
+
+    return utime(mbName, &newTime) == 0;
+}
+
+int32_t teavm_file_length(char16_t* name, int32_t nameSize) {
+    char* mbName = teavm_char16ToMb(name, nameSize);
+    FILE* file = fopen(mbName, "r");
+    free(mbName);
+
+    if (file == NULL) {
+        return 0;
+    }
+
+    if (fseek(file, 0, SEEK_END) != 0) {
+        fclose(file);
+        return 0;
+    }
+
+    long result = ftell(file);
+    fclose(file);
+    if (result < 0) {
+        return 0;
+    }
+    return (int32_t) result;
+}
+
+int64_t teavm_file_open(char16_t* name, int32_t nameSize, int32_t mode) {
+    char* mbName = teavm_char16ToMb(name, nameSize);
+    char* modeString;
+    switch (mode) {
+        case 1:
+            modeString = "r";
+            break;
+        case 2:
+            modeString = "w";
+            break;
+        case 3:
+            modeString = "w+";
+            break;
+        case 6:
+            modeString = "a";
+            break;
+        case 7:
+            modeString = "a+";
+            break;
+        default:
+            modeString = "";
+            break;
+    }
+    FILE* file = fopen(mbName, modeString);
+    if (file == NULL) {
+        return 0;
+    }
+
+    return (int64_t) (intptr_t) file;
+}
+
+int32_t teavm_file_close(int64_t file) {
+    FILE* handle = (FILE*) file;
+    return fclose(handle) == 0;
+}
+
+int32_t teavm_file_flush(int64_t file) {
+    FILE* handle = (FILE*) file;
+    return fflush(handle) == 0;
+}
+
+int32_t teavm_file_seek(int64_t file, int32_t where, int32_t offset) {
+    FILE* handle = (FILE*) file;
+    int whence;
+    switch (where) {
+        case 0:
+            whence = SEEK_SET;
+            break;
+        case 1:
+            whence = SEEK_CUR;
+            break;
+        case 2:
+            whence = SEEK_END;
+            break;
+    }
+    return fseek(handle, offset, whence) == 0;
+}
+
+int32_t teavm_file_tell(int64_t file) {
+    FILE* handle = (FILE*) file;
+    return (int32_t) ftell(handle);
+}
+
+int32_t teavm_file_read(int64_t file, int8_t* data, int32_t offset, int32_t size) {
+    FILE* handle = (FILE*) file;
+    return (int32_t) fread(data + offset, 1, size, handle);
+}
+
+int32_t teavm_file_write(int64_t file, int8_t* data, int32_t offset, int32_t size) {
+    FILE* handle = (FILE*) file;
+    return (int32_t) fwrite(data + offset, 1, size, handle);
+}
+
+#endif

core/src/main/resources/org/teavm/backend/c/runtime.c

@@ -14,6 +14,7 @@
 #include <unistd.h>
 #include <sys/mman.h>
 #include <signal.h>
+#include <locale.h>
 #endif
 
 #ifdef _MSC_VER
@@ -64,6 +65,8 @@ void teavm_beforeInit() {
     srand(time(NULL));
 
     #ifdef __GNUC__
+        setlocale (LC_ALL, "");
+
         struct sigaction sigact;
         sigact.sa_flags = 0;
         sigact.sa_handler = NULL;
@@ -377,6 +380,42 @@ TeaVM_String* teavm_cToString(char* cstring) {
     return teavm_createString(charArray);
 }
 
+char16_t* teavm_mbToChar16(char* cstring, int32_t* length) {
+    size_t clen = strlen(cstring);
+    int32_t size = teavm_c16Size(cstring, clen);
+    char16_t* javaChars = malloc(sizeof(char16_t) * (size + 2));
+    mbstate_t state = {0};
+    for (int32_t i = 0; i < size; ++i) {
+        int32_t result = mbrtoc16(javaChars + i, cstring, clen, &state);
+        if (result == -1) {
+            break;
+        } else if ((int) result >= 0) {
+            clen -= result;
+            cstring += result;
+        }
+    }
+    *length = size;
+    return javaChars;
+}
+
+char* teavm_char16ToMb(char16_t* javaChars, int32_t length) {
+    size_t sz = teavm_mbSize(javaChars, length);
+    char* cchars = malloc(sz + 1);
+
+    int32_t j = 0;
+    char* dst = cchars;
+    mbstate_t state = {0};
+    for (int32_t i = 0; i < length; ++i) {
+        size_t result = c16rtomb(dst, javaChars[i], &state);
+        if (result == -1) {
+            break;
+        }
+        dst += result;
+    }
+    *dst = '\0';
+    return cchars;
+}
+
 TeaVM_Array* teavm_parseArguments(int argc, char** argv) {
     TeaVM_Array* array = teavm_allocateStringArray(argc - 1);
     TeaVM_String** arrayData = TEAVM_ARRAY_DATA(array, TeaVM_String*);
@@ -438,3 +477,25 @@ void teavm_afterInitClasses() {
         builder = next;
     }
 }
+
+void teavm_disposeStringList(TeaVM_StringList* list) {
+    while (list != NULL) {
+        TeaVM_StringList* next = list->next;
+        if (list->data != NULL) {
+            free(list->data);
+        }
+        free(list);
+        list = next;
+    }
+}
+TeaVM_StringList* teavm_appendString(TeaVM_StringList* list, char16_t* data, int32_t length) {
+    TeaVM_StringList* entry = malloc(sizeof(TeaVM_StringList));
+    if (entry == NULL) {
+        teavm_disposeStringList(list);
+        return NULL;
+    }
+    entry->data = data;
+    entry->length = length;
+    entry->next = list;
+    return entry;
+}

core/src/main/resources/org/teavm/backend/c/runtime.h

@@ -207,6 +207,8 @@ extern int32_t teavm_timeZoneOffset();
 
 extern char* teavm_stringToC(void*);
 extern TeaVM_String* teavm_cToString(char*);
+extern char16_t* teavm_mbToChar16(char*, int32_t*);
+extern char* teavm_char16ToMb(char16_t*, int32_t);
 static inline void teavm_free(void* s) {
     if (s != NULL) {
         free(s);
@@ -238,12 +240,12 @@ extern void teavm_waitFor(int64_t timeout);
 extern void teavm_interrupt();
 
 extern void teavm_outOfMemory();
-extern void teavm_printString(char* s);
+extern void teavm_printString(char*);
-extern void teavm_printInt(int32_t i);
+extern void teavm_printInt(int32_t);
 
-extern TeaVM_Array* teavm_parseArguments(int argc, char** argv);
+extern TeaVM_Array* teavm_parseArguments(int, char**);
 
-extern void teavm_registerStaticGcRoots(void***, int count);
+extern void teavm_registerStaticGcRoots(void***, int);
 
 extern TeaVM_String* teavm_registerString(TeaVM_String*);
 
@@ -279,9 +281,11 @@ extern TeaVM_Reference* teavm_reference_poll(TeaVM_ReferenceQueue*);
 extern void teavm_reference_init(TeaVM_Reference*, TeaVM_Object*, TeaVM_ReferenceQueue*);
 
 extern void teavm_date_init();
+extern int64_t teavm_date_timeToTimestamp(time_t);
+extern time_t teavm_date_timestampToTime(int64_t);
 extern int64_t teavm_date_create(int32_t,int32_t,int32_t,int32_t,int32_t,int32_t);
 extern int64_t teavm_date_createUtc(int32_t,int32_t,int32_t,int32_t,int32_t,int32_t);
-extern int64_t teavm_date_parse(char* s);
+extern int64_t teavm_date_parse(char*);
 extern int32_t teavm_date_getYear(int64_t);
 extern int64_t teavm_date_setYear(int64_t,int32_t);
 extern int32_t teavm_date_getMonth(int64_t);
@@ -296,3 +300,43 @@ extern int64_t teavm_date_setMinutes(int64_t,int32_t);
 extern int32_t teavm_date_getSeconds(int64_t);
 extern int64_t teavm_date_setSeconds(int64_t,int32_t);
 extern char* teavm_date_format(int64_t);
+
+#define TEAVM_SURROGATE_BIT_MASK 0xFC00
+#define TEAVM_SURROGATE_INV_BIT_MASK 0x03FF
+#define TEAVM_HIGH_SURROGATE_BITS 0xD800
+#define TEAVM_LOW_SURROGATE_BITS 0xDC00
+#define TEAVM_MIN_SUPPLEMENTARY_CODE_POINT 0x010000
+
+//extern int32_t teavm_utf8_encode(char16_t*, int32_t, char*);
+//extern int32_t teavm_utf8_decode(char*, int32_t, char16_t*);
+
+typedef struct TeaVM_StringList {
+    char16_t* data;
+    int32_t length;
+    struct TeaVM_StringList* next;
+} TeaVM_StringList;
+
+extern void teavm_disposeStringList(TeaVM_StringList*);
+extern TeaVM_StringList* teavm_appendString(TeaVM_StringList*, char16_t*, int32_t);
+
+extern int32_t teavm_file_homeDirectory(char16_t**);
+extern int32_t teavm_file_workDirectory(char16_t**);
+extern int32_t teavm_file_isFile(char16_t*, int32_t);
+extern int32_t teavm_file_isDir(char16_t*, int32_t);
+extern int32_t teavm_file_canRead(char16_t*, int32_t);
+extern int32_t teavm_file_canWrite(char16_t*, int32_t);
+extern TeaVM_StringList* teavm_file_listFiles(char16_t*, int32_t);
+extern int32_t teavm_file_createDirectory(char16_t*, int32_t);
+extern int32_t teavm_file_createFile(char16_t*, int32_t);
+extern int32_t teavm_file_delete(char16_t*, int32_t);
+extern int32_t teavm_file_rename(char16_t*, int32_t, char16_t*, int32_t);
+extern int64_t teavm_file_lastModified(char16_t*, int32_t);
+extern int32_t teavm_file_setLastModified(char16_t*, int32_t, int64_t);
+extern int32_t teavm_file_length(char16_t*, int32_t);
+extern int64_t teavm_file_open(char16_t*, int32_t, int32_t);
+extern int32_t teavm_file_close(int64_t);
+extern int32_t teavm_file_flush(int64_t);
+extern int32_t teavm_file_seek(int64_t, int32_t, int32_t);
+extern int32_t teavm_file_tell(int64_t);
+extern int32_t teavm_file_read(int64_t, int8_t*, int32_t, int32_t);
+extern int32_t teavm_file_write(int64_t, int8_t*, int32_t, int32_t);

core/src/main/resources/org/teavm/backend/c/utf8.c

@@ -0,0 +1,119 @@
+#include "runtime.h"
+#include <stdlib.h>
+
+#define teavm_utf8_encodeSingle16(ch, char* target) \
+    *target++ = (char) (0xE0 | (ch >> 12)); \
+    *target++ = (char) (0x80 | ((ch >> 6) & 0x3F)); \
+    *target++ = (char) (0x80 | (ch & 0x3F));
+
+int32_t teavm_utf8_encode(char16_t* source, int32_t sourceSize, char* target) {
+    char* initialTarget = target;
+    while (sourceSize-- > 0) {
+        char16_t ch = *source++;
+        if (ch < 0x80) {
+            **target++ = (char) ch;
+        } else if (ch < 0x800) {
+            *target++ = (char) (0xC0 | (ch >> 6));
+            *target++ = (char) (0x80 | (ch & 0x3F));
+        } else {
+            if (ch & TEAVM_SURROGATE_BIT_MASK == TEAVM_HIGH_SURROGATE_BITS) {
+                if (sourceSize-- == 0) {
+                    teavm_utf8_encodeSingle16(ch, target);
+                    break;
+                }
+
+                char16_t nextCh = *source;
+                if (ch & TEAVM_SURROGATE_BIT_MASK != TEAVM_LOW_SURROGATE_BITS) {
+                    teavm_utf8_encodeSingle16(ch, target);
+                    continue;
+                }
+                source++;
+                sourceSize--;
+
+                int32_t codePoint = (((ch & TEAVM_SURROGATE_BIT_INV_MASK) << 10) | (nextCh & SURROGATE_BIT_INV_MASK))
+                                + TEAVM_MIN_SUPPLEMENTARY_CODE_POINT;
+                *target++ = (char) (0xF0 | (codePoint >> 18));
+                *target++ = (char) (0x80 | ((codePoint >> 12) & 0x3F));
+                *target++ = (char) (0x80 | ((codePoint >> 6) & 0x3F));
+                *target++ = (char) (0x80 | (codePoint & 0x3F));
+            } else {
+                teavm_utf8_encodeSingle16(ch, target);
+            }
+        }
+    }
+    return (int32_t) (target - initialTarget);
+}
+
+int32_t teavm_utf8_decode(char* source, int32_t sourceSize, char16_t* target) {
+    char16_t* initialTarget = target;
+    while (sourceSize-- > 0) {
+        char b = *source++;
+        if ((b & 0x80) == 0) {
+            *target++ = (char16_t) b;
+        } else if ((b & 0xE0) == 0xC0) {
+            if (sourceSize-- == 0) {
+                *target++ = (char16_t) b;
+                break;
+            }
+
+            char b2 = *source;
+            if ((b2 & 0xC0) != 0x80) {
+                *target++ = (char16_t) b;
+                continue;
+            }
+            source++;
+            sourceSize--;
+
+           *target++ = (char16_t) ((((char16_t) b & 0x1F) << 6) | ((char16_t) b2 & 0x3F);
+        } else if ((b & 0xF0) == 0xE0) {
+            if (sourceSize < 2) {
+                *target++ = (char16_t) b;
+                continue;
+            }
+
+            char b2 = source[0];
+            char b3 = source[1];
+            if ((b2 & 0xC0) != 0x80 || (b3 & 0xC0) != 0x80) {
+                *target++ = (char16_t) b;
+                continue;
+            }
+            source += 2;
+            sourceSize -= 2;
+
+            char16_t c = (char16_t)
+                     ((((char16_t) b & 0x0F) << 12)
+                    | (((char16_t) b2 & 0x3F) << 6)
+                    | ((char16_t) b3 & 0x3F));
+            *target++ = c;
+        } else if ((b & 0xF8) == 0xF0) {
+            if (sourceSize < 3) {
+                *target++ = (char16_t) b;
+                continue;
+            }
+
+            char b2 = source[0];
+            char b3 = source[1];
+            char b4 = source[2];
+            if ((b2 & 0xC0) != 0x80 || (b3 & 0xC0) != 0x80 || (b4 & 0xC0) != 0x80) {
+                *target++ = (char16_t) b;
+                continue;
+            }
+            source += 3;
+            sourceSize -= 3;
+
+            int32_t code = (int32_t)
+                     ((((int32_t) b  & 0x07) << 18)
+                    | (((int32_t) b2 & 0x3f) << 12)
+                    | (((int32_t) b3 & 0x3F) << 6)
+                    | (((int32_t) b4 & 0x3F)));
+
+            *target++ = (char16_t) ((TEAVM_HIGH_SURROGATE_BITS | ((code - TEAVM_MIN_SUPPLEMENTARY_CODE_POINT) >> 10)
+                & SURROGATE_BIT_INV_MASK))
+            *target++ = (char16_t) (TEAVM_LOW_SURROGATE_BITS | code & TEAVM_SURROGATE_BIT_INV_MASK);
+        } else {
+            *target++ = (char16_t) b;
+        }
+    }
+
+    return (int32_t) (target - initialTarget);
+}

tests/src/test/java/org/teavm/classlib/java/io/FileOutputStreamTest.java

@@ -189,10 +189,11 @@ public class FileOutputStreamTest {
         f = new File(System.getProperty("user.home"), "output.tst");
         fos = new FileOutputStream(f.getPath());
         fos.write(fileString.getBytes());
+        fos.close();
         fis = new FileInputStream(f.getPath());
         byte[] rbytes = new byte[4000];
         fis.read(rbytes, 0, fileString.length());
-        assertTrue("Incorrect string returned", new String(rbytes, 0, fileString.length()).equals(fileString));
+        assertEquals("Incorrect string returned", fileString, new String(rbytes, 0, fileString.length()));
     }
 
     @Test
@@ -200,10 +201,11 @@ public class FileOutputStreamTest {
         f = new File(System.getProperty("user.home"), "output.tst");
         fos = new FileOutputStream(f.getPath());
         fos.write(fileString.getBytes(), 0, fileString.length());
+        fos.close();
         fis = new FileInputStream(f.getPath());
         byte[] rbytes = new byte[4000];
         fis.read(rbytes, 0, fileString.length());
-        assertTrue("Incorrect bytes written", new String(rbytes, 0, fileString.length()).equals(fileString));
+        assertEquals("Incorrect bytes written", fileString, new String(rbytes, 0, fileString.length()));
 
         // Regression test for HARMONY-285
         File file = new File("FileOutputStream.tmp");
@@ -224,6 +226,7 @@ public class FileOutputStreamTest {
         f = new File(System.getProperty("user.home"), "output.tst");
         fos = new FileOutputStream(f.getPath());
         fos.write('t');
+        fos.close();
         fis = new FileInputStream(f.getPath());
         assertEquals("Incorrect char written", 't', fis.read());
     }

tests/src/test/java/org/teavm/classlib/java/io/FileTest.java

@@ -1323,7 +1323,7 @@ public class FileTest {
             // it a new directory name.)
             if (baseDir.exists()) {
                 dirNumber++;
-                baseDir = new File(base, String.valueOf(dirNumber));
+                baseDir = new File(base, platformId + String.valueOf(dirNumber));
             } else {
                 dirExists = false;
             }

tools/junit/src/main/java/org/teavm/junit/CRunStrategy.java

@@ -56,10 +56,11 @@ class CRunStrategy implements TestRunStrategy {
             writeLines(compilerOutput);
 
             List<String> runtimeOutput = new ArrayList<>();
+            List<String> stdout = new ArrayList<>();
             outputFile.setExecutable(true);
-            runProcess(new ProcessBuilder(outputFile.getPath()).start(), runtimeOutput);
+            runProcess(new ProcessBuilder(outputFile.getPath()).start(), runtimeOutput, stdout);
-            if (!runtimeOutput.isEmpty() && runtimeOutput.get(runtimeOutput.size() - 1).equals("SUCCESS")) {
+            if (!stdout.isEmpty() && stdout.get(stdout.size() - 1).equals("SUCCESS")) {
-                writeLines(runtimeOutput.subList(0, runtimeOutput.size() - 1));
+                writeLines(runtimeOutput);
                 run.getCallback().complete();
             } else {
                 run.getCallback().error(new RuntimeException("Test failed:\n" + mergeLines(runtimeOutput)));
@@ -83,12 +84,13 @@ class CRunStrategy implements TestRunStrategy {
         }
     }
 
-    private boolean runCompiler(File inputDir, List<String> output) throws IOException, InterruptedException {
+    private boolean runCompiler(File inputDir, List<String> output)
+            throws IOException, InterruptedException {
         String command = new File(compilerCommand).getAbsolutePath();
-        return runProcess(new ProcessBuilder(command).directory(inputDir).start(), output);
+        return runProcess(new ProcessBuilder(command).directory(inputDir).start(), output, new ArrayList<>());
     }
 
-    private boolean runProcess(Process process, List<String> output) throws InterruptedException {
+    private boolean runProcess(Process process, List<String> output, List<String> stdout) throws InterruptedException {
         BufferedReader stdin = new BufferedReader(new InputStreamReader(process.getInputStream()));
         BufferedReader stderr = new BufferedReader(new InputStreamReader(process.getErrorStream()));
         ConcurrentLinkedQueue<String> lines = new ConcurrentLinkedQueue<>();
@@ -109,21 +111,18 @@ class CRunStrategy implements TestRunStrategy {
         thread.setDaemon(true);
         thread.start();
 
-        thread = new Thread(() -> {
+        try {
-            try {
+            while (true) {
-                while (true) {
+                String line = stdin.readLine();
-                    String line = stdin.readLine();
+                if (line == null) {
-                    if (line == null) {
+                    break;
-                        break;
-                    }
-                    lines.add(line);
                 }
-            } catch (IOException e) {
+                lines.add(line);
-                // do nothing
+                stdout.add(line);
             }
-        });
+        } catch (IOException e) {
-        thread.setDaemon(true);
+            // do nothing
-        thread.start();
+        }
 
         boolean result = process.waitFor() == 0;
         output.addAll(lines);

tools/junit/src/main/java/org/teavm/junit/TeaVMTestRunner.java

@@ -101,6 +101,7 @@ public class TeaVMTestRunner extends Runner implements Filterable {
     private static final String C_ENABLED = "teavm.junit.c";
     private static final String WASM_ENABLED = "teavm.junit.wasm";
     private static final String C_COMPILER = "teavm.junit.c.compiler";
+    private static final String C_LINE_NUMBERS = "teavm.junit.c.lineNumbers";
     private static final String MINIFIED = "teavm.junit.minified";
     private static final String OPTIMIZED = "teavm.junit.optimized";
     private static final String FAST_ANALYSIS = "teavm.junit.fastAnalysis";
@@ -607,10 +608,16 @@ public class TeaVMTestRunner extends Runner implements Filterable {
                 throw new RuntimeException(e);
             }
         };
-        return compileTest(method, configuration, CTarget::new, TestNativeEntryPoint.class.getName(), path, ".c",
+        return compileTest(method, configuration, this::createCTarget, TestNativeEntryPoint.class.getName(), path, ".c",
                 postBuild, true);
     }
 
+    private CTarget createCTarget() {
+        CTarget cTarget = new CTarget();
+        cTarget.setLineNumbersGenerated(Boolean.parseBoolean(System.getProperty(C_LINE_NUMBERS, "false")));
+        return cTarget;
+    }
+
     private CompileResult compileToWasm(Method method, TeaVMTestConfiguration<WasmTarget> configuration,
             File path) {
         return compileTest(method, configuration, WasmTarget::new, TestNativeEntryPoint.class.getName(), path,