From d0d0b173b427322fe76c5a91abfd06dd1be3dade Mon Sep 17 00:00:00 2001
From: Shane Carr <shane@unicode.org>
Date: Fri, 26 May 2017 23:59:13 +0000
Subject: [PATCH] ICU-13205 Prevent exception from being thrown when parsing
 numbers with very large exponents.

X-SVN-Rev: 40141
---
 .../src/com/ibm/icu/text/DecimalFormat.java   | 27 +++++++++++++++++--
 .../icu/dev/test/format/NumberFormatTest.java | 27 +++++++++++++++++++
 2 files changed, 52 insertions(+), 2 deletions(-)

diff --git a/icu4j/main/classes/core/src/com/ibm/icu/text/DecimalFormat.java b/icu4j/main/classes/core/src/com/ibm/icu/text/DecimalFormat.java
index 17e0b9779c5..e1f5acef3d4 100644
--- a/icu4j/main/classes/core/src/com/ibm/icu/text/DecimalFormat.java
+++ b/icu4j/main/classes/core/src/com/ibm/icu/text/DecimalFormat.java
@@ -802,7 +802,7 @@ public class DecimalFormat extends NumberFormat {
     Number result = Parse.parse(text, parsePosition, pprops, symbols);
     // Backwards compatibility: return com.ibm.icu.math.BigDecimal
     if (result instanceof java.math.BigDecimal) {
-      result = new com.ibm.icu.math.BigDecimal((java.math.BigDecimal) result);
+      result = safeConvertBigDecimal((java.math.BigDecimal) result);
     }
     return result;
   }
@@ -820,7 +820,7 @@ public class DecimalFormat extends NumberFormat {
       Number number = result.getNumber();
       // Backwards compatibility: return com.ibm.icu.math.BigDecimal
       if (number instanceof java.math.BigDecimal) {
-        number = new com.ibm.icu.math.BigDecimal((java.math.BigDecimal) number);
+        number = safeConvertBigDecimal((java.math.BigDecimal) number);
         result = new CurrencyAmount(number, result.getCurrency());
       }
       return result;
@@ -2438,6 +2438,29 @@ public class DecimalFormat extends NumberFormat {
     formatter.export(exportedProperties);
   }
 
+  /**
+   * Converts a java.math.BigDecimal to a com.ibm.icu.math.BigDecimal with fallback for numbers
+   * outside of the range supported by com.ibm.icu.math.BigDecimal.
+   *
+   * @param number
+   * @return
+   */
+  private Number safeConvertBigDecimal(java.math.BigDecimal number) {
+    try {
+      return new com.ibm.icu.math.BigDecimal(number);
+    } catch (NumberFormatException e) {
+      if (number.signum() > 0 && number.scale() < 0) {
+        return Double.POSITIVE_INFINITY;
+      } else if (number.scale() < 0) {
+        return Double.NEGATIVE_INFINITY;
+      } else if (number.signum() < 0) {
+        return -0.0;
+      } else {
+        return 0.0;
+      }
+    }
+  }
+
   /**
    * Updates the property bag with settings from the given pattern.
    *
diff --git a/icu4j/main/tests/core/src/com/ibm/icu/dev/test/format/NumberFormatTest.java b/icu4j/main/tests/core/src/com/ibm/icu/dev/test/format/NumberFormatTest.java
index 8a2d81133a8..cf9a2adf78b 100644
--- a/icu4j/main/tests/core/src/com/ibm/icu/dev/test/format/NumberFormatTest.java
+++ b/icu4j/main/tests/core/src/com/ibm/icu/dev/test/format/NumberFormatTest.java
@@ -5284,6 +5284,33 @@ public class NumberFormatTest extends TestFmwk {
         expect2(df, 35.0, "$35.0");
     }
 
+    @Test
+    public void testParseVeryVeryLargeExponent() {
+        DecimalFormat df = new DecimalFormat();
+        ParsePosition ppos = new ParsePosition(0);
+
+        Object[][] cases = {
+                {"1.2E+1234567890", Double.POSITIVE_INFINITY},
+                {"1.2E+999999999", new com.ibm.icu.math.BigDecimal("1.2E+999999999")},
+                {"1.2E+1000000000", Double.POSITIVE_INFINITY},
+                {"-1.2E+999999999", new com.ibm.icu.math.BigDecimal("-1.2E+999999999")},
+                {"-1.2E+1000000000", Double.NEGATIVE_INFINITY},
+                {"1.2E-999999999", new com.ibm.icu.math.BigDecimal("1.2E-999999999")},
+                {"1.2E-1000000000", 0.0},
+                {"-1.2E-999999999", new com.ibm.icu.math.BigDecimal("-1.2E-999999999")},
+                {"-1.2E-1000000000", -0.0},
+
+        };
+
+        for (Object[] cas : cases) {
+            ppos.setIndex(0);
+            String input = (String) cas[0];
+            Number expected = (Number) cas[1];
+            Number actual = df.parse(input, ppos);
+            assertEquals(input, expected, actual);
+        }
+    }
+
     @Test
     public void testParseGroupingMode() {
         ULocale[] locales = {         // GROUPING   DECIMAL