Adds a utility to check whether a file contains only US ASCII characters into ardor3d-extras

1 files changed, 74 insertions, 0 deletions

diff --git a/ardor3d-extras/src/main/java/com/ardor3d/extension/model/util/FileHelper.java b/ardor3d-extras/src/main/java/com/ardor3d/extension/model/util/FileHelper.java
new file mode 100644
index 0000000..5f8ae2b
--- /dev/null
+++ b/ardor3d-extras/src/main/java/com/ardor3d/extension/model/util/FileHelper.java
@@ -0,0 +1,74 @@
+/**
+ * Copyright (c) 2008-2016 Ardor Labs, Inc.
+ *
+ * This file is part of Ardor3D.
+ *
+ * Ardor3D is free software: you can redistribute it and/or modify it
+ * under the terms of its license which may be found in the accompanying
+ * LICENSE file or at <http://www.ardor3d.com/LICENSE>.
+ */
+
+package com.ardor3d.extension.model.util;
+
+import java.io.BufferedReader;
+import java.io.DataInputStream;
+import java.io.FileInputStream;
+import java.io.InputStreamReader;
+import java.nio.ByteBuffer;
+import java.nio.CharBuffer;
+import java.nio.charset.CharacterCodingException;
+import java.nio.charset.CharsetDecoder;
+import java.nio.charset.StandardCharsets;
+
+public class FileHelper {
+
+    /**
+     * Tests whether or not the specified string is pure ASCII. Uses the method discussed at:
+     *
+     * <pre>
+     * http://www.rgagnon.com/javadetails/java-0536.html
+     * http://stackoverflow.com/questions/3585053/in-java-is-it-possible-to-check-if-a-string-is-only-ascii
+     * </pre>
+     *
+     * @param string
+     *            String to test.
+     * @return Logical-true if pure ASCII, else logical-false.
+     */
+    public boolean isStringPureAscii(final String string) {
+        final byte bytearray[] = string.getBytes();
+        final CharsetDecoder d = StandardCharsets.US_ASCII.newDecoder();
+        try {
+            final CharBuffer r = d.decode(ByteBuffer.wrap(bytearray));
+            r.toString();
+        } catch (final CharacterCodingException e) {
+            return false;
+        }
+        return true;
+    }
+
+    /**
+     * Tests whether or not the file with the specified filename is pure ASCII. The method used is to read the file a
+     * line at a time and test if each line is ASCII.
+     *
+     * @param filename
+     *            File name.
+     * @return Logical-true if pure ASCII, else logical-false.
+     */
+    public boolean isFilePureAscii(final String filename) {
+        try (final FileInputStream fstream = new FileInputStream(filename);
+                final DataInputStream in = new DataInputStream(fstream);
+                final BufferedReader br = new BufferedReader(new InputStreamReader(in))) {
+            String strLine;
+            // read file a line at a time
+            while ((strLine = br.readLine()) != null) {
+                final boolean isAscii = isStringPureAscii(strLine);
+                if (!isAscii) {
+                    return false;
+                }
+            }
+        } catch (final Exception e) {
+            return false;
+        }
+        return true;
+    }
+}