1 files changed, 214 insertions, 0 deletions
diff --git a/src/main/java/ch/obermuhlner/math/big/stream/BigFloatStream.java b/src/main/java/ch/obermuhlner/math/big/stream/BigFloatStream.java
new file mode 100644
index 0000000000..1c982302a6
--- /dev/null
+++ b/src/main/java/ch/obermuhlner/math/big/stream/BigFloatStream.java
@@ -0,0 +1,214 @@
+package ch.obermuhlner.math.big.stream;
+
+import java.util.Comparator;
+import java.util.Spliterator;
+import java.util.Spliterators.AbstractSpliterator;
+import java.util.function.Consumer;
+import java.util.stream.Stream;
+import java.util.stream.StreamSupport;
+
+import ch.obermuhlner.math.big.BigFloat;
+import ch.obermuhlner.math.big.BigFloat.Context;
+
+/**
+ * Provides constructor methods for streams of {@link BigFloat} elements. 
+ */
+public class BigFloatStream {
+
+    /**
+     * Returns a sequential ordered {@code Stream<BigFloat>} from {@code startInclusive}
+     * (inclusive) to {@code endExclusive} (exclusive) by an incremental {@code step}.
+     *
+     * <p>An equivalent sequence of increasing values can be produced
+     * sequentially using a {@code for} loop as follows:
+     * <pre>for (BigFloat i = startInclusive; i.isLessThan(endExclusive); i = i.add(step)) {
+    // ...
+}</pre>
+     *
+     * @param startInclusive the (inclusive) initial value
+     * @param endExclusive the exclusive upper bound
+     * @param step the step between elements
+     * @return a sequential {@code Stream<BigFloat>}
+     */
+    public static Stream<BigFloat> range(BigFloat startInclusive, BigFloat endExclusive, BigFloat step) {
+    	if (step.isZero()) {
+    		throw new IllegalArgumentException("invalid step: 0");
+    	}
+		if (endExclusive.subtract(startInclusive).signum() != step.signum()) {
+			return Stream.empty();
+		}
+    	return StreamSupport.stream(new BigFloatSpliterator(startInclusive, endExclusive, false, step), false);
+    }
+    
+    /**
+     * Returns a sequential ordered {@code Stream<BigFloat>} from {@code startInclusive}
+     * (inclusive) to {@code endExclusive} (exclusive) by an incremental {@code step}.
+     *
+     * <p>{@link Context#valueOf(long)} is used to convert the {@code long} values.</p>
+     *
+     * @param startInclusive the (inclusive) initial value
+     * @param endExclusive the exclusive upper bound
+     * @param step the step between elements
+     * @param context the {@link Context} used to convert the {@code long} values
+     * @return a sequential {@code Stream<BigFloat>}
+     * @see #range(BigFloat, BigFloat, BigFloat)
+     */
+    public static Stream<BigFloat> range(long startInclusive, long endExclusive, long step, Context context) {
+    	return range(context.valueOf(startInclusive), context.valueOf(endExclusive), context.valueOf(step));
+    }
+    
+    /**
+     * Returns a sequential ordered {@code Stream<BigFloat>} from {@code startInclusive}
+     * (inclusive) to {@code endExclusive} (exclusive) by an incremental {@code step}.
+     *
+     * <p>{@link Context#valueOf(double)} is used to convert the {@code double} values.</p>
+     *
+     * @param startInclusive the (inclusive) initial value
+     * @param endExclusive the exclusive upper bound
+     * @param step the step between elements
+     * @param context the {@link Context} used to convert the {@code double} values
+     * @return a sequential {@code Stream<BigFloat>}
+     * @see #range(BigFloat, BigFloat, BigFloat)
+     */
+    public static Stream<BigFloat> range(double startInclusive, double endExclusive, double step, Context context) {
+    	return range(context.valueOf(startInclusive), context.valueOf(endExclusive), context.valueOf(step));
+    }
+    
+    /**
+     * Returns a sequential ordered {@code Stream<BigFloat>} from {@code startInclusive}
+     * (inclusive) to {@code endInclusive} (inclusive) by an incremental {@code step}.
+     *
+     * <p>An equivalent sequence of increasing values can be produced
+     * sequentially using a {@code for} loop as follows:
+     * <pre>for (BigFloat i = startInclusive; i.isLessThanOrEqual(endInclusive); i = i.add(step)) {
+    //...
+}
+</pre>
+     *
+     * @param startInclusive the (inclusive) initial value
+     * @param endInclusive the inclusive upper bound
+     * @param step the step between elements
+     * @return a sequential {@code Stream<BigFloat>}
+     */
+    public static Stream<BigFloat> rangeClosed(BigFloat startInclusive, BigFloat endInclusive, BigFloat step) {
+    	if (step.isZero()) {
+    		throw new IllegalArgumentException("invalid step: 0");
+    	}
+		if (endInclusive.subtract(startInclusive).signum() == -step.signum()) {
+			return Stream.empty();
+		}
+    	return StreamSupport.stream(new BigFloatSpliterator(startInclusive, endInclusive, true, step), false);
+    }
+    
+    /**
+     * Returns a sequential ordered {@code Stream<BigFloat>} from {@code startInclusive}
+     * (inclusive) to {@code endInclusive} (inclusive) by an incremental {@code step}.
+     *
+     * <p>{@link Context#valueOf(long)} is used to convert the {@code long} values.</p>
+     *
+     * @param startInclusive the (inclusive) initial value
+     * @param endInclusive the inclusive upper bound
+     * @param step the step between elements
+     * @param context the {@link Context} used to convert the {@code long} values
+     * @return a sequential {@code Stream<BigFloat>}
+     * @see #rangeClosed(BigFloat, BigFloat, BigFloat)
+     */
+    public static Stream<BigFloat> rangeClosed(long startInclusive, long endInclusive, long step, Context context) {
+    	return rangeClosed(context.valueOf(startInclusive), context.valueOf(endInclusive), context.valueOf(step));
+    }
+    
+    /**
+     * Returns a sequential ordered {@code Stream<BigFloat>} from {@code startInclusive}
+     * (inclusive) to {@code endInclusive} (inclusive) by an incremental {@code step}.
+     *
+     * <p>{@link Context#valueOf(double)} is used to convert the {@code double} values.</p>
+     *
+     * @param startInclusive the (inclusive) initial value
+     * @param endInclusive the inclusive upper bound
+     * @param step the step between elements
+     * @param context the {@link Context} used to convert the {@code double} values
+     * @return a sequential {@code Stream<BigFloat>}
+     * @see #rangeClosed(BigFloat, BigFloat, BigFloat)
+     */
+    public static Stream<BigFloat> rangeClosed(double startInclusive, double endInclusive, double step, Context context) {
+    	return rangeClosed(context.valueOf(startInclusive), context.valueOf(endInclusive), context.valueOf(step));
+    }
+
+    private static class BigFloatSpliterator extends AbstractSpliterator<BigFloat> {
+
+		private BigFloat value;
+		private BigFloat step;
+		private long count;
+
+		public BigFloatSpliterator(BigFloat startInclusive, BigFloat step, long count) {
+    		super(count,
+    				Spliterator.SIZED | Spliterator.SUBSIZED | Spliterator.DISTINCT | Spliterator.IMMUTABLE | Spliterator.NONNULL | Spliterator.ORDERED | Spliterator.SORTED);
+			
+    		this.value = startInclusive;
+			this.step = step;
+			this.count = count;
+		}
+    	
+		public BigFloatSpliterator(BigFloat startInclusive, BigFloat end, boolean inclusive, BigFloat step) {
+			this(startInclusive, step, estimatedCount(startInclusive, end, inclusive, step));
+		}
+		
+		private static long estimatedCount(BigFloat startInclusive, BigFloat end, boolean inclusive, BigFloat step) {
+			BigFloat count = end.subtract(startInclusive).divide(step);
+    		long result = count.toLong();
+    		if (count.getFractionalPart().signum() != 0) {
+    			result++;
+    		} else {
+    			if (inclusive) {
+    				result++;
+    			}
+    		}
+    		return result;
+		}
+
+		@Override
+		public Comparator<? super BigFloat> getComparator() {
+			if (step.signum() < 0) {
+				return Comparator.reverseOrder();
+			}
+			return null;
+		}
+		
+		@Override
+		public boolean tryAdvance(Consumer<? super BigFloat> action) {
+			if (count == 0) {
+				return false;
+			}
+			
+			action.accept(value);
+			value = value.add(step);
+			count--;
+			return true;
+		}
+		
+		@Override
+		public void forEachRemaining(Consumer<? super BigFloat> action) {
+			while (count > 0) {
+				action.accept(value);
+				value = value.add(step);
+				count--;
+			}
+		}
+		
+		@Override
+		public Spliterator<BigFloat> trySplit() {
+			long firstHalfCount = count / 2;
+			
+			if (firstHalfCount == 0) {
+				return null;
+			}
+			
+			long secondHalfCount = count - firstHalfCount;
+			
+			count = firstHalfCount;
+			BigFloat startSecondHalf = value.add(step.multiply(firstHalfCount));
+			
+			return new BigFloatSpliterator(startSecondHalf, step, secondHalfCount);
+		}
+    }
+}