1 files changed, 104 insertions, 0 deletions
diff --git a/src/org/tukaani/xz/SimpleInputStream.java b/src/org/tukaani/xz/SimpleInputStream.java
new file mode 100644
index 0000000..385b8e4
--- /dev/null
+++ b/src/org/tukaani/xz/SimpleInputStream.java
@@ -0,0 +1,104 @@
+/*
+ * SimpleInputStream
+ *
+ * Author: Lasse Collin <lasse.collin@tukaani.org>
+ *
+ * This file has been put into the public domain.
+ * You can do whatever you want with this file.
+ */
+
+package org.tukaani.xz;
+
+import java.io.InputStream;
+import java.io.IOException;
+import org.tukaani.xz.simple.SimpleFilter;
+
+class SimpleInputStream extends InputStream {
+    private static final int TMPBUF_SIZE = 4096;
+
+    private final InputStream in;
+    private final SimpleFilter simpleFilter;
+
+    private final byte[] tmpbuf = new byte[TMPBUF_SIZE];
+    private int pos = 0;
+    private int filtered = 0;
+    private int unfiltered = 0;
+
+    private boolean endReached = false;
+    private IOException exception = null;
+
+    static int getMemoryUsage() {
+        return 1 + TMPBUF_SIZE / 1024;
+    }
+
+    SimpleInputStream(InputStream in, SimpleFilter simpleFilter) {
+        this.in = in;
+        this.simpleFilter = simpleFilter;
+    }
+
+    public int read() throws IOException {
+        byte[] buf = new byte[1];
+        return read(buf, 0, 1) == -1 ? -1 : (buf[0] & 0xFF);
+    }
+
+    public int read(byte[] buf, int off, int len) throws IOException {
+        if (off < 0 || len < 0 || off + len < 0 || off + len > buf.length)
+            throw new IllegalArgumentException();
+
+        if (len == 0)
+            return 0;
+
+        if (exception != null)
+            throw exception;
+
+        try {
+            int size = 0;
+
+            while (true) {
+                // Copy filtered data into the caller-provided buffer.
+                int copySize = Math.min(filtered, len);
+                System.arraycopy(tmpbuf, pos, buf, off, copySize);
+                pos += copySize;
+                filtered -= copySize;
+                off += copySize;
+                len -= copySize;
+                size += copySize;
+
+                // If end of tmpbuf was reached, move the pending data to
+                // the beginning of the buffer so that more data can be
+                // copied into tmpbuf on the next loop iteration.
+                if (pos + filtered + unfiltered == TMPBUF_SIZE) {
+                    System.arraycopy(tmpbuf, pos, tmpbuf, 0,
+                                     filtered + unfiltered);
+                    pos = 0;
+                }
+
+                if (len == 0 || endReached)
+                    return size > 0 ? size : -1;
+
+                assert filtered == 0;
+
+                // Get more data into the temporary buffer.
+                int inSize = TMPBUF_SIZE - (pos + filtered + unfiltered);
+                inSize = in.read(tmpbuf, pos + filtered + unfiltered, inSize);
+
+                if (inSize == -1) {
+                    // Mark the remaining unfiltered bytes to be ready
+                    // to be copied out.
+                    endReached = true;
+                    filtered = unfiltered;
+                    unfiltered = 0;
+                } else {
+                    // Filter the data in tmpbuf.
+                    unfiltered += inSize;
+                    filtered = simpleFilter.code(tmpbuf, pos, unfiltered);
+                    assert filtered <= unfiltered;
+                    unfiltered -= filtered;
+                }
+            }
+        } catch (IOException e) {
+            exception = e;
+            throw e;
+        }
+    }
+}