Improve size-in-bytes parser's use of BigInteger/BigDecimal

- use bitLength to see if we overflow Long - use BigInteger and BigDecimal to parse, instead of parseLong/parseDouble
lightbend · Jun 25, 2014 · 02867c8 · 02867c8
1 parent 6311ef8
commit 02867c8
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Showing 2 changed files with 13 additions and 13 deletions.
diff --git a/config/src/main/java/com/typesafe/config/impl/SimpleConfig.java b/config/src/main/java/com/typesafe/config/impl/SimpleConfig.java
@@ -624,12 +624,6 @@ static MemoryUnit parseUnit(String unit) {
         }
     }
 
-    private static boolean isValidLong(BigInteger v) {
-        BigInteger max = BigInteger.valueOf(Long.MAX_VALUE);
-        BigInteger min = BigInteger.valueOf(Long.MIN_VALUE);
-        return max.compareTo(v) >= 0 && min.compareTo(v) <= 0;
-    }
-
     /**
      * Parses a size-in-bytes string. If no units are specified in the string,
      * it is assumed to be in bytes. The returned value is in bytes. The purpose
@@ -673,14 +667,12 @@ public static long parseBytes(String input, ConfigOrigin originForException,
             // if the string is purely digits, parse as an integer to avoid
             // possible precision loss; otherwise as a double.
             if (numberString.matches("[0-9]+")) {
-                Long v = Long.parseLong(numberString);
-                result = units.bytes.multiply(BigInteger.valueOf(v));
+                result = units.bytes.multiply(new BigInteger(numberString));
             } else {
-                Double v = Double.parseDouble(numberString);
-                BigDecimal resultDecimal = (new BigDecimal(units.bytes)).multiply(BigDecimal.valueOf(v));
+                BigDecimal resultDecimal = (new BigDecimal(units.bytes)).multiply(new BigDecimal(numberString));
                 result = resultDecimal.toBigInteger();
             }
-            if (isValidLong(result))
+            if (result.bitLength() < 64)
                 return result.longValue();
             else
                 throw new ConfigException.BadValue(originForException, pathForException,

diff --git a/config/src/test/scala/com/typesafe/config/impl/UnitParserTest.scala b/config/src/test/scala/com/typesafe/config/impl/UnitParserTest.scala
@@ -59,7 +59,10 @@ class UnitParserTest extends TestUtils {
 
     @Test
     def parseMemorySizeInBytes(): Unit = {
-        def parseMem(s: String) = SimpleConfig.parseBytes(s, fakeOrigin(), "test")
+        def parseMem(s: String): Long = SimpleConfig.parseBytes(s, fakeOrigin(), "test")
+
+        assertEquals(Long.MaxValue, parseMem(s"${Long.MaxValue} bytes"))
+        assertEquals(Long.MinValue, parseMem(s"${Long.MinValue} bytes"))
 
         val oneMebis = List("1048576", "1048576b", "1048576bytes", "1048576byte",
             "1048576  b", "1048576  bytes",
@@ -123,13 +126,18 @@ class UnitParserTest extends TestUtils {
     // later on we'll want to check this with BigInteger version of getBytes
     @Test
     def parseHugeMemorySizes(): Unit = {
-        def parseMem(s: String) = SimpleConfig.parseBytes(s, fakeOrigin(), "test")
+        def parseMem(s: String): Long = SimpleConfig.parseBytes(s, fakeOrigin(), "test")
         def assertOutOfRange(s: String) = {
             val fail = intercept[ConfigException.BadValue] {
                 parseMem(s)
             }
             assertTrue("number was too big", fail.getMessage.contains("out of range"))
         }
+
+        import java.math.BigInteger
+        assertOutOfRange(s"${BigInteger.valueOf(Long.MaxValue).add(BigInteger.valueOf(1)).toString} bytes")
+        assertOutOfRange(s"${BigInteger.valueOf(Long.MinValue).subtract(BigInteger.valueOf(1)).toString} bytes")
+
         var result = 1024L * 1024 * 1024
         for (unit <- Seq("zebi", "yobi")) {
             val first = unit.substring(0, 1).toUpperCase()