bigint check

src/main/java/org/apache/xmlbeans/impl/util/MathUtil.java

@@ -155,4 +155,21 @@ public static Integer parseAsInteger(String s) {
         }
         return Integer.parseInt(s);
     }
+
+    /**
+     * @param value BigDecimal to convert
+     * @return valid BigInteger
+     * @throws IllegalArgumentException if the input has an absolute exponent that is too large to safely convert
+     * @throws NullPointerException if string is null
+     */
+    public static BigInteger toBigInteger(BigDecimal value) {
+        BigDecimal normalized = value.stripTrailingZeros();
+        int integerDigits = normalized.precision() - normalized.scale();
+        if (integerDigits > MAX_NUMBER_LENGTH || normalized.scale() < -MAX_NUMBER_LENGTH) {
+            throw new IllegalArgumentException(
+                    "BigDecimal magnitude too large to convert safely: approx "
+                            + integerDigits + " integer digits (limit " + MAX_NUMBER_LENGTH + ")");
+        }
+        return normalized.toBigInteger();
+    }
 }

src/main/java/org/apache/xmlbeans/impl/values/JavaDecimalHolder.java

@@ -156,7 +156,7 @@ protected int value_hash_code() {
             }
         }
 
-        BigInteger intval = _value.toBigInteger();
+        BigInteger intval = MathUtil.toBigInteger(_value);
 
         if (intval.compareTo(_maxlong) > 0 ||
             intval.compareTo(_minlong) < 0) {

src/main/java/org/apache/xmlbeans/impl/values/JavaIntHolder.java

@@ -20,6 +20,7 @@
 import org.apache.xmlbeans.XmlErrorCodes;
 import org.apache.xmlbeans.XmlObject;
 import org.apache.xmlbeans.impl.schema.BuiltinSchemaTypeSystem;
+import org.apache.xmlbeans.impl.util.MathUtil;
 import org.apache.xmlbeans.impl.util.XsTypeConverter;
 
 import java.math.BigDecimal;
@@ -77,7 +78,7 @@ public int getIntValue() {
 
     // setters
     protected void set_BigDecimal(BigDecimal v) {
-        set_BigInteger(v.toBigInteger());
+        set_BigInteger(MathUtil.toBigInteger(v));
     }
 
     protected void set_BigInteger(BigInteger v) {

src/main/java/org/apache/xmlbeans/impl/values/JavaIntegerHolder.java

@@ -74,7 +74,7 @@ public BigInteger getBigIntegerValue() {
 
     // setters
     protected void set_BigDecimal(BigDecimal v) {
-        _value = v.toBigInteger();
+        _value = MathUtil.toBigInteger(v);
     }
 
     protected void set_BigInteger(BigInteger v) {

src/main/java/org/apache/xmlbeans/impl/values/JavaIntegerHolderEx.java

@@ -21,6 +21,7 @@
 import org.apache.xmlbeans.XmlPositiveInteger;
 import org.apache.xmlbeans.impl.common.QNameHelper;
 import org.apache.xmlbeans.impl.common.ValidationContext;
+import org.apache.xmlbeans.impl.util.MathUtil;
 
 import java.math.BigInteger;
 
@@ -152,7 +153,7 @@ private static BigInteger getBigIntegerValue(XmlObject o) {
         SchemaType s = o.schemaType();
         switch (s.getDecimalSize()) {
             case SchemaType.SIZE_BIG_DECIMAL:
-                return ((XmlObjectBase) o).getBigDecimalValue().toBigInteger();
+                return MathUtil.toBigInteger(((XmlObjectBase) o).getBigDecimalValue());
             case SchemaType.SIZE_BIG_INTEGER:
                 return ((XmlObjectBase) o).getBigIntegerValue();
             default:

src/main/java/org/apache/xmlbeans/impl/values/JavaLongHolder.java

@@ -20,6 +20,7 @@
 import org.apache.xmlbeans.XmlErrorCodes;
 import org.apache.xmlbeans.XmlObject;
 import org.apache.xmlbeans.impl.schema.BuiltinSchemaTypeSystem;
+import org.apache.xmlbeans.impl.util.MathUtil;
 import org.apache.xmlbeans.impl.util.XsTypeConverter;
 
 import java.math.BigDecimal;
@@ -72,7 +73,7 @@ public long getLongValue() {
 
     // setters
     protected void set_BigDecimal(BigDecimal v) {
-        set_BigInteger(v.toBigInteger());
+        set_BigInteger(MathUtil.toBigInteger(v));
     }
 
     protected void set_BigInteger(BigInteger v) {

src/main/java/org/apache/xmlbeans/impl/values/XmlObjectBase.java

@@ -20,6 +20,7 @@
 import org.apache.xmlbeans.impl.schema.SchemaTypeImpl;
 import org.apache.xmlbeans.impl.schema.SchemaTypeVisitorImpl;
 import org.apache.xmlbeans.impl.util.LongUTFDataInputStream;
+import org.apache.xmlbeans.impl.util.MathUtil;
 import org.apache.xmlbeans.impl.validator.Validator;
 import org.w3c.dom.Node;
 import org.xml.sax.ContentHandler;
@@ -1346,7 +1347,7 @@ public BigDecimal getBigDecimalValue() {
     // numerics: integral
     public BigInteger getBigIntegerValue() {
         BigDecimal bd = getBigDecimalValue();
-        return bd == null ? null : bd.toBigInteger();
+        return bd == null ? null : MathUtil.toBigInteger(bd);
     }
 
     public byte getByteValue() {

src/test/java/org/apache/xmlbeans/impl/util/TestMathUtil.java

@@ -0,0 +1,39 @@
+/* ====================================================================
+   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.xmlbeans.impl.util;
+
+import org.junit.jupiter.api.Test;
+
+import java.math.BigDecimal;
+import java.math.BigInteger;
+
+import static org.junit.jupiter.api.Assertions.assertEquals;
+import static org.junit.jupiter.api.Assertions.assertThrows;
+
+public class TestMathUtil {
+    @Test
+    public void testToBigInteger() {
+        BigInteger expected = new BigInteger("1234567890");
+        assertEquals(expected, MathUtil.toBigInteger(new BigDecimal(expected)));
+    }
+
+    @Test
+    public void testToBigIntegerBigExponent() {
+        BigDecimal expected = new BigDecimal("1E+2000");
+        assertThrows(IllegalArgumentException.class, () -> MathUtil.toBigInteger(expected));
+    }
+}