1 files changed, 215 insertions, 0 deletions
diff --git a/src/main/java/org/apache/commons/math3/util/CompositeFormat.java b/src/main/java/org/apache/commons/math3/util/CompositeFormat.java
new file mode 100644
index 0000000..63dfd59
--- /dev/null
+++ b/src/main/java/org/apache/commons/math3/util/CompositeFormat.java
@@ -0,0 +1,215 @@
+/*
+ * Licensed to the Apache Software Foundation (ASF) under one or more
+ * contributor license agreements.  See the NOTICE file distributed with
+ * this work for additional information regarding copyright ownership.
+ * The ASF licenses this file to You 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 org.apache.commons.math3.util;
+
+import java.text.FieldPosition;
+import java.text.NumberFormat;
+import java.text.ParsePosition;
+import java.util.Locale;
+
+/** Base class for formatters of composite objects (complex numbers, vectors ...). */
+public class CompositeFormat {
+
+    /** Class contains only static methods. */
+    private CompositeFormat() {}
+
+    /**
+     * Create a default number format. The default number format is based on {@link
+     * NumberFormat#getInstance()} with the only customizing that the maximum number of fraction
+     * digits is set to 10.
+     *
+     * @return the default number format.
+     */
+    public static NumberFormat getDefaultNumberFormat() {
+        return getDefaultNumberFormat(Locale.getDefault());
+    }
+
+    /**
+     * Create a default number format. The default number format is based on {@link
+     * NumberFormat#getInstance(java.util.Locale)} with the only customizing that the maximum number
+     * of fraction digits is set to 10.
+     *
+     * @param locale the specific locale used by the format.
+     * @return the default number format specific to the given locale.
+     */
+    public static NumberFormat getDefaultNumberFormat(final Locale locale) {
+        final NumberFormat nf = NumberFormat.getInstance(locale);
+        nf.setMaximumFractionDigits(10);
+        return nf;
+    }
+
+    /**
+     * Parses <code>source</code> until a non-whitespace character is found.
+     *
+     * @param source the string to parse
+     * @param pos input/output parsing parameter. On output, <code>pos</code> holds the index of the
+     *     next non-whitespace character.
+     */
+    public static void parseAndIgnoreWhitespace(final String source, final ParsePosition pos) {
+        parseNextCharacter(source, pos);
+        pos.setIndex(pos.getIndex() - 1);
+    }
+
+    /**
+     * Parses <code>source</code> until a non-whitespace character is found.
+     *
+     * @param source the string to parse
+     * @param pos input/output parsing parameter.
+     * @return the first non-whitespace character.
+     */
+    public static char parseNextCharacter(final String source, final ParsePosition pos) {
+        int index = pos.getIndex();
+        final int n = source.length();
+        char ret = 0;
+
+        if (index < n) {
+            char c;
+            do {
+                c = source.charAt(index++);
+            } while (Character.isWhitespace(c) && index < n);
+            pos.setIndex(index);
+
+            if (index < n) {
+                ret = c;
+            }
+        }
+
+        return ret;
+    }
+
+    /**
+     * Parses <code>source</code> for special double values. These values include Double.NaN,
+     * Double.POSITIVE_INFINITY, Double.NEGATIVE_INFINITY.
+     *
+     * @param source the string to parse
+     * @param value the special value to parse.
+     * @param pos input/output parsing parameter.
+     * @return the special number.
+     */
+    private static Number parseNumber(
+            final String source, final double value, final ParsePosition pos) {
+        Number ret = null;
+
+        StringBuilder sb = new StringBuilder();
+        sb.append('(');
+        sb.append(value);
+        sb.append(')');
+
+        final int n = sb.length();
+        final int startIndex = pos.getIndex();
+        final int endIndex = startIndex + n;
+        if (endIndex < source.length()
+                && source.substring(startIndex, endIndex).compareTo(sb.toString()) == 0) {
+            ret = Double.valueOf(value);
+            pos.setIndex(endIndex);
+        }
+
+        return ret;
+    }
+
+    /**
+     * Parses <code>source</code> for a number. This method can parse normal, numeric values as well
+     * as special values. These special values include Double.NaN, Double.POSITIVE_INFINITY,
+     * Double.NEGATIVE_INFINITY.
+     *
+     * @param source the string to parse
+     * @param format the number format used to parse normal, numeric values.
+     * @param pos input/output parsing parameter.
+     * @return the parsed number.
+     */
+    public static Number parseNumber(
+            final String source, final NumberFormat format, final ParsePosition pos) {
+        final int startIndex = pos.getIndex();
+        Number number = format.parse(source, pos);
+        final int endIndex = pos.getIndex();
+
+        // check for error parsing number
+        if (startIndex == endIndex) {
+            // try parsing special numbers
+            final double[] special = {
+                Double.NaN, Double.POSITIVE_INFINITY, Double.NEGATIVE_INFINITY
+            };
+            for (int i = 0; i < special.length; ++i) {
+                number = parseNumber(source, special[i], pos);
+                if (number != null) {
+                    break;
+                }
+            }
+        }
+
+        return number;
+    }
+
+    /**
+     * Parse <code>source</code> for an expected fixed string.
+     *
+     * @param source the string to parse
+     * @param expected expected string
+     * @param pos input/output parsing parameter.
+     * @return true if the expected string was there
+     */
+    public static boolean parseFixedstring(
+            final String source, final String expected, final ParsePosition pos) {
+
+        final int startIndex = pos.getIndex();
+        final int endIndex = startIndex + expected.length();
+        if ((startIndex >= source.length())
+                || (endIndex > source.length())
+                || (source.substring(startIndex, endIndex).compareTo(expected) != 0)) {
+            // set index back to start, error index should be the start index
+            pos.setIndex(startIndex);
+            pos.setErrorIndex(startIndex);
+            return false;
+        }
+
+        // the string was here
+        pos.setIndex(endIndex);
+        return true;
+    }
+
+    /**
+     * Formats a double value to produce a string. In general, the value is formatted using the
+     * formatting rules of <code>format</code>. There are three exceptions to this:
+     *
+     * <ol>
+     *   <li>NaN is formatted as '(NaN)'
+     *   <li>Positive infinity is formatted as '(Infinity)'
+     *   <li>Negative infinity is formatted as '(-Infinity)'
+     * </ol>
+     *
+     * @param value the double to format.
+     * @param format the format used.
+     * @param toAppendTo where the text is to be appended
+     * @param pos On input: an alignment field, if desired. On output: the offsets of the alignment
+     *     field
+     * @return the value passed in as toAppendTo.
+     */
+    public static StringBuffer formatDouble(
+            final double value,
+            final NumberFormat format,
+            final StringBuffer toAppendTo,
+            final FieldPosition pos) {
+        if (Double.isNaN(value) || Double.isInfinite(value)) {
+            toAppendTo.append('(');
+            toAppendTo.append(value);
+            toAppendTo.append(')');
+        } else {
+            format.format(value, toAppendTo, pos);
+        }
+        return toAppendTo;
+    }
+}