test/java/math/BigInteger/BigIntegerTest.java

rev 11188 : 4026465: Provide more byte array constructors for BigInteger
Summary: Add two's complement and sign-magnitude constructors for byte arrays with offset and length.
Reviewed-by: TBD

@@ -21,11 +21,11 @@
  * questions.
  */
 
 /*
  * @test
- * @bug 4181191 4161971 4227146 4194389 4823171 4624738 4812225 4837946
+ * @bug 4181191 4161971 4227146 4194389 4823171 4624738 4812225 4837946 4026465
  * @summary tests methods in BigInteger
  * @run main/timeout=400 BigIntegerTest
  * @author madbot
  */
 

@@ -87,10 +87,70 @@
     static final int SIZE = 1000; // numbers per batch
 
     static Random rnd = new Random();
     static boolean failure = false;
 
+    public static void constructor() {
+        int failCount = 0;
+
+        byte[] magZeroLength = new byte[0];
+        for (int signum = -1; signum <= 1; signum++) {
+            BigInteger bi = new BigInteger(signum, magZeroLength);
+            if (bi.compareTo(BigInteger.ZERO) != 0) {
+                System.err.println("A: Zero length BigInteger != 0 for signum " + signum);
+                failCount++;
+            }
+        }
+
+        for (int signum = -1; signum <= 1; signum++) {
+            BigInteger bi = new BigInteger(signum, magZeroLength, 0, 0);
+            if (bi.compareTo(BigInteger.ZERO) != 0) {
+                System.err.println("B: Zero length BigInteger != 0 for signum " + signum);
+                failCount++;
+            }
+        }
+
+        byte[] magNonZeroLength = new byte[42];
+        rnd.nextBytes(magNonZeroLength);
+        for (int signum = -1; signum <= 1; signum++) {
+            BigInteger bi = new BigInteger(signum, magNonZeroLength, 0, 0);
+            if (bi.compareTo(BigInteger.ZERO) != 0) {
+                System.err.println("C: Zero length BigInteger != 0 for signum " + signum);
+                failCount++;
+            }
+        }
+
+        for (int i = 0; i < SIZE; i++) {
+            BigInteger reference = new BigInteger(rnd.nextInt(5000), rnd);
+
+            byte[] refArray = reference.toByteArray();
+            int refLen = refArray.length;
+            int factor = rnd.nextInt(5);
+            int objLen = refArray.length + factor*rnd.nextInt(refArray.length) + 1;
+            int offset = rnd.nextInt(objLen - refLen);
+            byte[] objArray = new byte[objLen];
+            System.arraycopy(refArray, 0, objArray, offset, refLen);
+
+            BigInteger twosComp = new BigInteger(objArray, offset, refLen);
+            if (twosComp.compareTo(reference) != 0) {
+                System.err.println("Two's-complement BigInteger not equal for offset " +
+                        offset + " and length " + refLen);
+                failCount++;
+            }
+
+            boolean isNegative = rnd.nextBoolean();
+            BigInteger signMag = new BigInteger(isNegative ? -1 : 1, objArray, offset, refLen);
+            if (signMag.compareTo(isNegative ? reference.negate() : reference) != 0) {
+                System.err.println("Sign-magnitude BigInteger not equal for offset " +
+                        offset + " and length " + refLen);
+                failCount++;
+            }
+        }
+
+        report("Constructor", failCount);
+    }
+
     public static void pow(int order) {
         int failCount1 = 0;
 
         for (int i=0; i<SIZE; i++) {
             // Test identity x^power == x*x*x ... *x

@@ -959,10 +1019,12 @@
         if (args.length >2)
             order3 = (int)((Integer.parseInt(args[2]))* 3.333);
         if (args.length >3)
             order4 = (int)((Integer.parseInt(args[3]))* 3.333);
 
+        constructor();
+
         prime();
         nextProbablePrime();
 
         arithmetic(order1);   // small numbers
         arithmetic(order3);   // Karatsuba range