Upload files to "java/expression"

java/expression/Pow2.java

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+package expression;
+
+import java.math.BigDecimal;
+import java.math.BigInteger;
+import java.util.List;
+
+/**
+ * @author Doschennikov Nikita (me@fymio.us)
+ */
+public class Pow2 extends AbstractExpression {
+    private final AbstractExpression operand;
+
+    public Pow2(AbstractExpression operand) {
+        this.operand = operand;
+    }
+
+    private static int pow2(int n) {
+        if (n < 0) throw new ArithmeticException("pow₂ of negative number: " + n);
+        if (n >= 31) throw new OverflowException("pow₂");
+        return 1 << n;
+    }
+
+    @Override public int        evaluate(int x)               { return pow2(operand.evaluate(x)); }
+    @Override public int        evaluate(int x, int y, int z) { return pow2(operand.evaluate(x,y,z)); }
+    @Override public int        evaluate(List<Integer> vars)  { return pow2(operand.evaluate(vars)); }
+    @Override public BigInteger evaluateBi(List<BigInteger> vars) { throw new UnsupportedOperationException(); }
+    @Override public BigDecimal evaluateBd(List<BigDecimal> vars) { throw new UnsupportedOperationException(); }
+
+    @Override public String toString()     { return "pow₂(" + operand + ")"; }
+
+    @Override
+    public String toMiniString() {
+        if (operand instanceof AbstractBinaryOperation) {
+            return "pow₂(" + operand.toMiniString() + ")";
+        }
+        return "pow₂ " + operand.toMiniString();
+    }
+
+    @Override
+    public boolean equals(Object obj) {
+        if (this == obj) return true;
+        if (!(obj instanceof Pow2)) return false;
+        return operand.equals(((Pow2) obj).operand);
+    }
+
+    @Override public int hashCode() { return operand.hashCode() ^ 0x504F5732; }
+}

java/expression/Power.java

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+package expression;
+
+import java.math.BigDecimal;
+import java.math.BigInteger;
+
+/**
+ * @author Doschennikov Nikita (me@fymio.us)
+ */
+public class Power extends AbstractBinaryOperation {
+    public Power(AbstractExpression l, AbstractExpression r) { super(l, r); }
+
+    @Override protected String  getOperator()  { return "**"; }
+    @Override protected int     getPriority()  { return 3; }
+    @Override protected boolean isRightAssoc() { return true; }
+
+    @Override
+    protected int applyInt(int base, int exp) {
+        if (exp < 0) throw new ArithmeticException("negative exponent");
+        if (base == 0 && exp == 0) throw new ArithmeticException("zero to the power of zero");
+        if (exp == 0) return 1;
+        if (base == 0) return 0;
+        int result = 1;
+        int b = base;
+        int e = exp;
+        while (e > 0) {
+            if ((e & 1) == 1) {
+                result = checkedMul(result, b);
+            }
+            if (e > 1) b = checkedMul(b, b);
+            e >>= 1;
+        }
+        return result;
+    }
+
+    private static int checkedMul(int a, int b) {
+        if (a == 0 || b == 0) return 0;
+        if (a == Integer.MIN_VALUE && b == -1) throw new OverflowException("power");
+        if (b == Integer.MIN_VALUE && a == -1) throw new OverflowException("power");
+        int result = a * b;
+        if (result / a != b) throw new OverflowException("power");
+        return result;
+    }
+
+    @Override protected BigInteger applyBi(BigInteger a, BigInteger b) { return a.pow(b.intValueExact()); }
+    @Override protected BigDecimal applyBd(BigDecimal a, BigDecimal b) { return a.pow(b.intValueExact()); }
+}

java/expression/Reverse.java

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+package expression;
+
+import java.math.BigDecimal;
+import java.math.BigInteger;
+import java.util.List;
+
+/**
+ * @author Doschennikov Nikita (me@fymio.us)
+ */
+public class Reverse extends AbstractExpression {
+
+    private final AbstractExpression operand;
+
+    public Reverse(AbstractExpression operand) {
+        this.operand = operand;
+    }
+
+    private static int reverseInt(int n) {
+        boolean negative = n < 0;
+        long abs = Math.abs((long) n);
+        long reversed = 0;
+        while (abs > 0) {
+            reversed = reversed * 10 + (abs % 10);
+            abs /= 10;
+        }
+        long result = negative ? -reversed : reversed;
+        return (int) result;
+    }
+
+    @Override
+    public int evaluate(int x) {
+        return reverseInt(operand.evaluate(x));
+    }
+
+    @Override
+    public int evaluate(int x, int y, int z) {
+        return reverseInt(operand.evaluate(x, y, z));
+    }
+
+    @Override
+    public int evaluate(List<Integer> vars) {
+        return reverseInt(operand.evaluate(vars));
+    }
+
+    @Override
+    public BigInteger evaluateBi(List<BigInteger> vars) {
+        throw new UnsupportedOperationException(
+            "reverse not supported for BigInteger"
+        );
+    }
+
+    @Override
+    public BigDecimal evaluateBd(List<BigDecimal> vars) {
+        throw new UnsupportedOperationException(
+            "reverse not supported for BigDecimal"
+        );
+    }
+
+    @Override
+    public String toString() {
+        return "reverse(" + operand + ")";
+    }
+
+    @Override
+    public String toMiniString() {
+        if (operand instanceof AbstractBinaryOperation) {
+            return "reverse(" + operand.toMiniString() + ")";
+        }
+
+        return "reverse " + operand.toMiniString();
+    }
+
+    @Override
+    public boolean equals(Object obj) {
+        if (this == obj) return true;
+        if (!(obj instanceof Reverse)) return false;
+        return operand.equals(((Reverse) obj).operand);
+    }
+
+    @Override
+    public int hashCode() {
+        return operand.hashCode() ^ 0x52455645;
+    }
+}

java/expression/SetBit.java

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+package expression;
+
+import java.math.BigDecimal;
+import java.math.BigInteger;
+
+/**
+ * @author Doschennikov Nikita (me@fymio.us)
+ */
+public class SetBit extends AbstractBinaryOperation {
+
+    public SetBit(AbstractExpression l, AbstractExpression r) {
+        super(l, r);
+    }
+
+    @Override
+    protected String getOperator() {
+        return "set";
+    }
+
+    @Override
+    protected int getPriority() {
+        return 0;
+    }
+
+    @Override
+    protected boolean isRightAssoc() {
+        return true;
+    }
+
+    @Override
+    protected int applyInt(int a, int b) {
+        return a | (1 << b);
+    }
+
+    @Override
+    protected BigInteger applyBi(BigInteger a, BigInteger b) {
+        return a.setBit(b.intValueExact());
+    }
+
+    @Override
+    protected BigDecimal applyBd(BigDecimal a, BigDecimal b) {
+        throw new UnsupportedOperationException(
+            "set not supported for BigDecimal"
+        );
+    }
+}

java/expression/package-info.java

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+/**
+ * Tests for <a href="https://www.kgeorgiy.info/courses/prog-intro/homeworks.html#expressions">Expressions</a> homework
+ * of <a href="https://www.kgeorgiy.info/courses/prog-intro/">Introduction to Programming</a> course.
+ *
+ * @author Georgiy Korneev (kgeorgiy@kgeorgiy.info)
+ */
+package expression;