Don't emulate posix read, do mmap instead

native/src/main/java/com/hippo/UriArchiveAccessor.java

@@ -31,96 +31,39 @@ import java.io.FileNotFoundException;
 import java.io.IOException;
 import java.io.OutputStream;
 
-public class UriArchiveAccessor implements AutoCloseable {
-    public static int OPEN_OK = 1;
-    public static int OPEN_ERR = 2;
-    private final OsReadableFile osf;
+public class UriArchiveAccessor {
+    ParcelFileDescriptor pfd;
+    FileDescriptor fd;
+    long archiveAddr;
+    Context ctx;
+    Uri uri;
 
-    public UriArchiveAccessor(Context ctx, Uri uri) throws FileNotFoundException {
-        osf = new OsReadableFile(ctx, uri);
+    public UriArchiveAccessor(Context ctx, Uri uri) {
+        this.ctx = ctx;
+        this.uri = uri;
     }
 
-    public int open() {
-        return openArchive(osf);
+    public int open() throws Exception {
+        pfd = ctx.getContentResolver().openFileDescriptor(uri, "r");
+        fd = pfd.getFileDescriptor();
+        archiveAddr = Os.mmap(0, pfd.getStatSize(), OsConstants.PROT_READ, OsConstants.MAP_PRIVATE, fd, 0);
+        return openArchive(archiveAddr, pfd.getStatSize());
     }
 
     public void extractTargetIndexToOutputStream(int index, OutputStream os) {
         extracttoOutputStream(index, os);
     }
 
-    private native int openArchive(OsReadableFile osf);
+    private native int openArchive(long addr, long size);
 
     private native void extracttoOutputStream(int index, OutputStream os);
 
     private native void closeArchive();
 
-    @Override
-    public void close() throws IOException {
+    public void close() throws Exception {
         closeArchive();
-        osf.close();
-    }
-
-    static class OsReadableFile {
-        ParcelFileDescriptor pfd;
-        FileDescriptor fd;
-
-        public OsReadableFile(Context ctx, Uri uri) throws FileNotFoundException {
-            pfd = ctx.getContentResolver().openFileDescriptor(uri, "r");
-            fd = pfd.getFileDescriptor();
-        }
-
-        public int read(byte[] b, int off, int len) throws IOException, ErrnoException {
-            return Os.read(fd, b, off, len);
-        }
-
-        public int read(byte[] b) throws IOException, ErrnoException {
-            return read(b, 0, b.length);
-        }
-
-        public long length() throws IOException, ErrnoException {
-            return Os.fstat(fd).st_size;
-        }
-
-        public long seek(long pos, int whence) throws IOException, ErrnoException {
-            try {
-                return Os.lseek(fd, pos, whence);
-            } catch (Exception e) {
-                e.printStackTrace();
-                return -30;
-            }
-        }
-
-        public void rewind() throws IOException, ErrnoException {
-            Os.lseek(fd, 0, OsConstants.SEEK_SET);
-        }
-
-        public long skip(long n) throws IOException, ErrnoException {
-            long pos;
-            long len;
-            long newpos;
-
-            if (n <= 0) {
-                return 0;
-            }
-            pos = Os.lseek(fd, 0L, OsConstants.SEEK_CUR);
-            len = length();
-            newpos = pos + n;
-            if (newpos > len) {
-                newpos = len;
-            }
-            seek(newpos, OsConstants.SEEK_SET);
-
-            /* return the actual number of bytes skipped */
-            return newpos - pos;
-        }
-
-        public void close() throws IOException {
-            pfd.close();
-            try {
-                Os.close(fd);
-            } catch (ErrnoException e) {
-                throw new IOException("An ErrnoException occurs", e);
-            }
-        }
+        Os.munmap(archiveAddr, pfd.getStatSize());
+        pfd.close();
+        Os.close(fd);
     }
 }