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BigInteger Shrink Fix #277

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Merged
mperry merged 1 commit into from
Jun 16, 2016
Merged

BigInteger Shrink Fix #277

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47 changes: 23 additions & 24 deletions quickcheck/src/main/java/fj/test/Shrink.java
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Original file line number Diff line number Diff line change
Expand Up @@ -39,6 +39,8 @@
import static fj.data.Stream.nil;

import static java.lang.System.arraycopy;
import static java.math.BigInteger.ZERO;

import java.math.BigDecimal;
import java.math.BigInteger;
import java.sql.Time;
Expand Down Expand Up @@ -354,7 +356,7 @@ public static <A> Shrink<ArrayList<A>> shrinkArrayList(final Shrink<A> sa) {
* A shrink strategy for enum maps.
*
* @param sk The shrink strategy for keys.
* @param sv The shrink stratgey for values.
* @param sv The shrink strategy for values.
* @return A shrink strategy for enum maps.
*/
public static <K extends Enum<K>, V> Shrink<EnumMap<K, V>> shrinkEnumMap(final Shrink<K> sk, final Shrink<V> sv) {
Expand Down Expand Up @@ -385,7 +387,7 @@ public static <A extends Enum<A>> Shrink<EnumSet<A>> shrinkEnumSet(final Shrink<
* A shrink strategy for hash maps.
*
* @param sk The shrink strategy for keys.
* @param sv The shrink stratgey for values.
* @param sv The shrink strategy for values.
* @return A shrink strategy for hash maps.
*/
public static <K, V> Shrink<HashMap<K, V>> shrinkHashMap(final Shrink<K> sk, final Shrink<V> sv) {
Expand All @@ -406,7 +408,7 @@ public static <A> Shrink<HashSet<A>> shrinkHashSet(final Shrink<A> sa) {
* A shrink strategy for hash tables.
*
* @param sk The shrink strategy for keys.
* @param sv The shrink stratgey for values.
* @param sv The shrink strategy for values.
* @return A shrink strategy for hash tables.
*/
@SuppressWarnings("UseOfObsoleteCollectionType")
Expand All @@ -430,7 +432,7 @@ public static <K, V> Shrink<Hashtable<K, V>> shrinkHashtable(final Shrink<K> sk,
* A shrink strategy for identity hash maps.
*
* @param sk The shrink strategy for keys.
* @param sv The shrink stratgey for values.
* @param sv The shrink strategy for values.
* @return A shrink strategy for identity hash maps.
*/
public static <K, V> Shrink<IdentityHashMap<K, V>> shrinkIdentityHashMap(final Shrink<K> sk, final Shrink<V> sv) {
Expand All @@ -441,7 +443,7 @@ public static <K, V> Shrink<IdentityHashMap<K, V>> shrinkIdentityHashMap(final S
* A shrink strategy for linked hash maps.
*
* @param sk The shrink strategy for keys.
* @param sv The shrink stratgey for values.
* @param sv The shrink strategy for values.
* @return A shrink strategy for linked hash maps.
*/
public static <K, V> Shrink<LinkedHashMap<K, V>> shrinkLinkedHashMap(final Shrink<K> sk, final Shrink<V> sv) {
Expand Down Expand Up @@ -514,7 +516,7 @@ public static <A> Shrink<Stack<A>> shrinkStack(final Shrink<A> sa) {
* A shrink strategy for tree maps.
*
* @param sk The shrink strategy for keys.
* @param sv The shrink stratgey for values.
* @param sv The shrink strategy for values.
* @return A shrink strategy for tree maps.
*/
public static <K, V> Shrink<TreeMap<K, V>> shrinkTreeMap(final Shrink<K> sk, final Shrink<V> sv) {
Expand Down Expand Up @@ -545,7 +547,7 @@ public static <A> Shrink<Vector<A>> shrinkVector(final Shrink<A> sa) {
* A shrink strategy for weak hash maps.
*
* @param sk The shrink strategy for keys.
* @param sv The shrink stratgey for values.
* @param sv The shrink strategy for values.
* @return A shrink strategy for weak hash maps.
*/
public static <K, V> Shrink<WeakHashMap<K, V>> shrinkWeakHashMap(final Shrink<K> sk, final Shrink<V> sv) {
Expand All @@ -570,7 +572,7 @@ public static <A> Shrink<ArrayBlockingQueue<A>> shrinkArrayBlockingQueue(final S
* A shrink strategy for concurrent hash maps.
*
* @param sk The shrink strategy for keys.
* @param sv The shrink stratgey for values.
* @param sv The shrink strategy for values.
* @return A shrink strategy for concurrent hash maps.
*/
public static <K, V> Shrink<ConcurrentHashMap<K, V>> shrinkConcurrentHashMap(final Shrink<K> sk, final Shrink<V> sv) {
Expand Down Expand Up @@ -676,23 +678,20 @@ public static <A> Shrink<SynchronousQueue<A>> shrinkSynchronousQueue(final Shrin
/**
* A shrink strategy for big integers.
*/
public static final Shrink<BigInteger> shrinkBigInteger =
shrinkP2(shrinkByte, shrinkArray(shrinkByte)).map(bs -> {
final byte[] x = new byte[bs._2().length() + 1];

for (int i = 0; i < bs._2().array().length; i++) {
x[i] = bs._2().get(i);
}

x[bs._2().length()] = bs._1();
public static final Shrink<BigInteger> shrinkBigInteger = shrink(i -> {
final Equal<BigInteger> eq = Equal.bigintEqual;
final BigInteger two = BigInteger.valueOf(2L);
if (eq.eq(i, ZERO)) {
return nil();
} else {
final Stream<BigInteger> is = cons(ZERO,
() -> iterate(x -> x.divide(two), i)
.takeWhile(x2 -> eq.notEq(x2, ZERO))
.map(i::subtract));

return new BigInteger(x);
}, i -> {
final byte[] b = i.toByteArray();
final Byte[] x = new Byte[b.length - 1];
arraycopy(b, 0, x, 0, b.length - 1);
return p(b[0], array(x));
});
return Ord.bigintOrd.isLessThan(i, ZERO) ? cons(i.negate(), () -> is) : is;
}
});

/**
* A shrink strategy for big decimals.
Expand Down