1 files changed, 168 insertions, 0 deletions
diff --git a/pdf-as-lib/src/main/java/at/gv/egiz/pdfas/lib/util/StreamUtils.java b/pdf-as-lib/src/main/java/at/gv/egiz/pdfas/lib/util/StreamUtils.java
new file mode 100644
index 00000000..1590bef7
--- /dev/null
+++ b/pdf-as-lib/src/main/java/at/gv/egiz/pdfas/lib/util/StreamUtils.java
@@ -0,0 +1,168 @@
+
+package at.gv.egiz.pdfas.lib.util;
+
+import java.io.ByteArrayOutputStream;
+import java.io.IOException;
+import java.io.InputStream;
+import java.io.OutputStream;
+import java.io.PrintStream;
+
+public class StreamUtils {
+  
+  /**
+   * Compare the contents of two <code>InputStream</code>s.
+   * 
+   * @param is1 The 1st <code>InputStream</code> to compare.
+   * @param is2 The 2nd <code>InputStream</code> to compare.
+   * @return boolean <code>true</code>, if both streams contain the exactly the
+   * same content, <code>false</code> otherwise.
+   * @throws IOException An error occurred reading one of the streams.
+   */
+  public static boolean compareStreams(InputStream is1, InputStream is2) 
+    throws IOException {
+      
+    byte[] buf1 = new byte[256];
+    byte[] buf2 = new byte[256];
+    int length1;
+    int length2;
+  
+    try {
+      while (true) {
+        length1 = is1.read(buf1);
+        length2 = is2.read(buf2);
+        
+        if (length1 != length2) {
+          return false;
+        }
+        if (length1 <= 0) {
+          return true;
+        }
+        if (!compareBytes(buf1, buf2, length1)) {
+          return false;
+        }
+      }
+    } catch (IOException e) {
+      throw e;
+    } finally {
+      // close both streams
+      try {
+        is1.close();
+        is2.close();
+      } catch (IOException e) {
+        // ignore this
+      }
+    }
+  }
+  
+  /**
+   * Compare two byte arrays, up to a given maximum length.
+   * 
+   * @param b1 1st byte array to compare.
+   * @param b2 2nd byte array to compare.
+   * @param length The maximum number of bytes to compare.
+   * @return <code>true</code>, if the byte arrays are equal, <code>false</code>
+   * otherwise.
+   */
+  private static boolean compareBytes(byte[] b1, byte[] b2, int length) {
+    if (b1.length != b2.length) {
+      return false;
+    }
+  
+    for (int i = 0; i < b1.length && i < length; i++) {
+      if (b1[i] != b2[i]) {
+        return false;
+      }
+    }
+  
+    return true;
+  }
+
+  /**
+   * Reads a byte array from a stream.
+   * @param in The <code>InputStream</code> to read.
+   * @return The bytes contained in the given <code>InputStream</code>.
+   * @throws IOException on any exception thrown
+   */
+  public static byte[] readStream(InputStream in) throws IOException {
+
+    ByteArrayOutputStream out = new ByteArrayOutputStream();
+    copyStream(in, out, null);
+		  
+		/*  
+    ByteArrayOutputStream out = new ByteArrayOutputStream();
+    int b;
+    while ((b = in.read()) >= 0)
+      out.write(b);
+    
+    */
+    in.close();
+    return out.toByteArray();
+  }
+
+  /**
+   * Reads a <code>String</code> from a stream, using given encoding.
+   * @param in The <code>InputStream</code> to read.
+   * @param encoding The character encoding to use for converting the bytes
+   * of the <code>InputStream</code> into a <code>String</code>.
+   * @return The content of the given <code>InputStream</code> converted into
+   * a <code>String</code>.
+   * @throws IOException on any exception thrown
+   */
+  public static String readStream(InputStream in, String encoding) throws IOException {
+    ByteArrayOutputStream out = new ByteArrayOutputStream();
+    copyStream(in, out, null);
+
+    /*
+    ByteArrayOutputStream out = new ByteArrayOutputStream();
+    int b;
+    while ((b = in.read()) >= 0)
+      out.write(b);
+      */
+    in.close();
+    return out.toString(encoding);
+  }
+  
+  /**
+   * Reads all data (until EOF is reached) from the given source to the 
+   * destination stream. If the destination stream is null, all data is dropped.
+   * It uses the given buffer to read data and forward it. If the buffer is 
+   * null, this method allocates a buffer.
+   *
+   * @param source The stream providing the data.
+   * @param destination The stream that takes the data. If this is null, all
+   *                    data from source will be read and discarded.
+   * @param buffer The buffer to use for forwarding. If it is null, the method
+   *               allocates a buffer.
+   * @exception IOException If reading from the source or writing to the 
+   *                        destination fails.
+   */
+  private static void copyStream(InputStream source, OutputStream destination, byte[] buffer) throws IOException {
+    if (source == null) {
+      throw new NullPointerException("Argument \"source\" must not be null.");
+    }
+    if (buffer == null) {
+      buffer = new byte[8192];
+    }
+    
+    if (destination != null) {
+      int bytesRead;
+      while ((bytesRead = source.read(buffer)) >= 0) {
+        destination.write(buffer, 0, bytesRead);
+      }
+    } else {
+      while (source.read(buffer) >= 0);
+    }    
+  }
+  
+  /**
+   * Gets the stack trace of the <code>Throwable</code> passed in as a string.
+   * @param t The <code>Throwable</code>.
+   * @return a String representing the stack trace of the <code>Throwable</code>.
+   */
+  public static String getStackTraceAsString(Throwable t)
+  {
+    ByteArrayOutputStream stackTraceBIS = new ByteArrayOutputStream();
+    t.printStackTrace(new PrintStream(stackTraceBIS));
+    return new String(stackTraceBIS.toByteArray());
+  }
+}