1 files changed, 194 insertions, 0 deletions
diff --git a/smcc/src/main/java/at/gv/egiz/smcc/util/TransparentFileInputStream.java b/smcc/src/main/java/at/gv/egiz/smcc/util/TransparentFileInputStream.java
new file mode 100644
index 00000000..781f9137
--- /dev/null
+++ b/smcc/src/main/java/at/gv/egiz/smcc/util/TransparentFileInputStream.java
@@ -0,0 +1,194 @@
+/*
+* Copyright 2008 Federal Chancellery Austria and
+* Graz University of Technology
+*
+* 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 at.gv.egiz.smcc.util;
+
+import java.io.IOException;
+import java.io.InputStream;
+
+public abstract class TransparentFileInputStream extends InputStream {
+  
+  private final int chunkSize = 256;
+  
+  private byte[] buf = new byte[chunkSize];
+  private int start = 0;
+  private int end = 0;
+
+  private int offset = 0;
+  
+  private int length = -1;
+  
+  private int limit = -1;
+  
+  private int mark = -1;
+  
+  private int readlimit = -1; 
+  
+  public TransparentFileInputStream() {
+  }
+  
+  public TransparentFileInputStream(int length) {
+    this.length = length;
+  }
+
+  public void setLimit(int limit) {
+    this.limit = limit;
+  }
+
+  private int fill() throws IOException {
+    if (start == end && (limit < 0 || offset < limit)) {
+        int l;
+        if (limit > 0 && limit - offset < chunkSize) {
+          l = limit - offset;
+        } else if (length > 0) {
+          if (length - offset < chunkSize) {
+            l = length - offset;
+          } else {
+            l = chunkSize - 1;
+          }
+        } else {
+          l = chunkSize;
+        }
+        byte[] b = readBinary(offset, l);
+        offset += b.length;
+        if (mark < 0) {
+          start = 0;
+          end = b.length;
+          System.arraycopy(b, 0, buf, start, b.length);
+        } else {
+          if (end - mark + b.length > buf.length) {
+            // double buffer size
+            byte[] nbuf = new byte[buf.length * 2];
+            System.arraycopy(buf, mark, nbuf, 0, end - mark);
+            buf = nbuf;
+          } else {
+            System.arraycopy(buf, mark, buf, 0, end - mark);
+          }
+          start = start - mark;
+          end = end - mark + b.length;
+          mark = 0;
+          System.arraycopy(b, 0, buf, start, b.length);
+        }
+        if (l > b.length) {
+          // end of file reached
+          setLimit(offset);
+        }
+    }
+    return end - start;
+  }
+    
+  protected abstract byte[] readBinary(int offset, int len) throws IOException;
+  
+  @Override
+  public int read() throws IOException {
+    int b = (fill() > 0) ? 0xFF & buf[start++] : -1;
+    if (readlimit > 0 && start > readlimit) {
+      mark = -1;
+      readlimit = -1;
+    }
+    return b;
+  }
+  
+  @Override
+  public int read(byte[] b, int off, int len) throws IOException {
+    if (b == null) {
+      throw new NullPointerException();
+    } else if (off < 0 || len < 0 || len > b.length - off) {
+        throw new IndexOutOfBoundsException();
+    } else if (len == 0) {
+        return 0;
+    }
+
+    int count = 0;
+    int l;
+    while (count < len) {
+      if (fill() > 0) {
+        l = Math.min(end - start, len - count);
+        System.arraycopy(buf, start, b, off, l);
+        start += l;
+        off += l;
+        count += l;
+        if (readlimit > 0 && start > readlimit) {
+          mark = -1;
+          readlimit = -1;
+        }
+      } else {
+        return (count > 0) ? count : -1;
+      }
+    }
+
+    return count;
+
+  }
+
+  @Override
+  public synchronized void mark(int readlimit) {
+    this.readlimit = readlimit;
+    mark = start;
+  }
+
+  @Override
+  public boolean markSupported() {
+    return true;
+  }
+
+  @Override
+  public synchronized void reset() throws IOException {
+    if (mark < 0) {
+      throw new IOException();
+    } else {
+      start = mark;
+    }
+  }
+
+  @Override
+  public long skip(long n) throws IOException {
+
+    if (n <= 0) {
+      return 0;
+    }
+    
+    if (n <= end - start) {
+      start += n;
+      return n;
+    } else {
+      
+      mark = -1;
+      
+      long remaining = n - (end - start);
+      start = end;
+      
+      if (limit >= 0 && limit < offset + remaining) {
+        remaining -= limit - offset;
+        offset = limit;
+        return n - remaining;
+      }
+      
+      if (length >= 0 && length < offset + remaining) {
+        remaining -= length - offset;
+        offset = length;
+        return n - remaining; 
+      }
+      
+      offset += remaining;
+      
+      return n;
+      
+    }
+    
+  }
+  
+}