BEGIN LICENSE BLOCK *****
Version: EPL 2.0/GPL 2.0/LGPL 2.1
The contents of this file are subject to the Eclipse Public
License Version 2.0 (the "License"); you may not use this file
except in compliance with the License. You may obtain a copy of
the License at http://www.eclipse.org/legal/epl-v20.html
Software distributed under the License is distributed on an "AS
IS" basis, WITHOUT WARRANTY OF ANY KIND, either express or
implied. See the License for the specific language governing
rights and limitations under the License.
Copyright (C) 2001-2004 Jan Arne Petersen 
Copyright (C) 2002 Benoit Cerrina 
Copyright (C) 2004 Anders Bengtsson 
Copyright (C) 2004 Stefan Matthias Aust 
Copyright (C) 2005 Charles O Nutter 
Copyright (C) 2006 Miguel Covarrubias 
Copyright (C) 2006 Thomas E Enebo 
Alternatively, the contents of this file may be used under the terms of
either of the GNU General Public License Version 2 or later (the "GPL"),
or the GNU Lesser General Public License Version 2.1 or later (the "LGPL"),
in which case the provisions of the GPL or the LGPL are applicable instead
of those above. If you wish to allow use of your version of this file only
under the terms of either the GPL or the LGPL, and not to allow others to
use your version of this file under the terms of the EPL, indicate your
decision by deleting the provisions above and replace them with the notice
and other provisions required by the GPL or the LGPL. If you do not delete
the provisions above, a recipient may use your version of this file under
the terms of any one of the EPL, the GPL or the LGPL.
END LICENSE BLOCK /***** BEGIN LICENSE BLOCK *****
 * Version: EPL 2.0/GPL 2.0/LGPL 2.1
 *
 * The contents of this file are subject to the Eclipse Public
 * License Version 2.0 (the "License"); you may not use this file
 * except in compliance with the License. You may obtain a copy of
 * the License at http://www.eclipse.org/legal/epl-v20.html
 *
 * Software distributed under the License is distributed on an "AS
 * IS" basis, WITHOUT WARRANTY OF ANY KIND, either express or
 * implied. See the License for the specific language governing
 * rights and limitations under the License.
 *
 * Copyright (C) 2001-2004 Jan Arne Petersen <jpetersen@uni-bonn.de>
 * Copyright (C) 2002 Benoit Cerrina <b.cerrina@wanadoo.fr>
 * Copyright (C) 2004 Anders Bengtsson <ndrsbngtssn@yahoo.se>
 * Copyright (C) 2004 Stefan Matthias Aust <sma@3plus4.de>
 * Copyright (C) 2005 Charles O Nutter <headius@headius.com>
 * Copyright (C) 2006 Miguel Covarrubias <mlcovarrubias@gmail.com>
 * Copyright (C) 2006 Thomas E Enebo <enebo@acm.org>
 *
 * Alternatively, the contents of this file may be used under the terms of
 * either of the GNU General Public License Version 2 or later (the "GPL"),
 * or the GNU Lesser General Public License Version 2.1 or later (the "LGPL"),
 * in which case the provisions of the GPL or the LGPL are applicable instead
 * of those above. If you wish to allow use of your version of this file only
 * under the terms of either the GPL or the LGPL, and not to allow others to
 * use your version of this file under the terms of the EPL, indicate your
 * decision by deleting the provisions above and replace them with the notice
 * and other provisions required by the GPL or the LGPL. If you do not delete
 * the provisions above, a recipient may use your version of this file under
 * the terms of any one of the EPL, the GPL or the LGPL.
 ***** END LICENSE BLOCK *****/

package org.jruby;

import org.jruby.anno.JRubyMethod;
import org.jruby.anno.JRubyModule;
import org.jruby.runtime.CallSite;
import org.jruby.runtime.JavaSites.ComparableSites;
import org.jruby.runtime.ThreadContext;
import org.jruby.runtime.builtin.IRubyObject;

import static org.jruby.runtime.Helpers.invokedynamic;

Implementation of the Comparable module.
/** Implementation of the Comparable module.
 *
 */
@JRubyModule(name="Comparable")
public class RubyComparable {
    public static RubyModule createComparable(Ruby runtime) {
        RubyModule comparableModule = runtime.defineModule("Comparable");
        runtime.setComparable(comparableModule);

        comparableModule.defineAnnotatedMethods(RubyComparable.class);

        return comparableModule;
    }

    /*  ================
     *  Utility Methods
     *  ================
     */

    
rb_cmpint
/** rb_cmpint
     *
     */
    public static int cmpint(ThreadContext context, CallSite op_gt, CallSite op_lt, IRubyObject val, IRubyObject a, IRubyObject b) {
        if (val == context.nil) cmperr(a, b);
        if (val instanceof RubyFixnum) {
            final int asInt = RubyNumeric.fix2int((RubyFixnum) val);

            if (asInt > 0) {
                return 1;
            }

            if (asInt < 0) {
                return -1;
            }

            return 0;
        }
        if (val instanceof RubyBignum) return ((RubyBignum) val).signum() == -1 ? -1 : 1;

        RubyFixnum zero = RubyFixnum.zero(context.runtime);

        if (op_gt.call(context, val, val, zero).isTrue()) return 1;
        if (op_lt.call(context, val, val, zero).isTrue()) return -1;

        return 0;
    }

    public static int cmpint(ThreadContext context, IRubyObject val, IRubyObject a, IRubyObject b) {
        ComparableSites sites = sites(context);
        return cmpint(context, sites.op_gt, sites.op_lt, val, a, b);
    }

    public static int cmpAndCmpint(ThreadContext context, IRubyObject a, IRubyObject b) {
        IRubyObject cmpResult = sites(context).op_cmp.call(context, a, a, b);
        return cmpint(context, cmpResult, a, b);
    }

    public static int cmpAndCmpint(ThreadContext context, CallSite op_cmp, CallSite op_gt, CallSite op_lt, IRubyObject a, IRubyObject b) {
        IRubyObject cmpResult = op_cmp.call(context, a, a, b);
        return cmpint(context, op_gt, op_lt, cmpResult, a, b);
    }

    
rb_cmperr
/** rb_cmperr
     *
     */
    public static IRubyObject cmperr(IRubyObject recv, IRubyObject other) {
        IRubyObject target;
        if (other.isImmediate() || !(other.isNil() || other.isTrue() || other == recv.getRuntime().getFalse())) {
            target = other.inspect();
        } else {
            target = other.getType();
        }

        throw recv.getRuntime().newArgumentError("comparison of " + recv.getType() + " with " + target + " failed");
    }

    
rb_invcmp
/** rb_invcmp
     *
     */
    public static IRubyObject invcmp(final ThreadContext context, final IRubyObject recv, final IRubyObject other) {
        return invcmp(context, DEFAULT_INVCMP, recv, other);
    }

    private static final ThreadContext.RecursiveFunctionEx DEFAULT_INVCMP = new ThreadContext.RecursiveFunctionEx<IRubyObject>() {
        @Override
        public IRubyObject call(ThreadContext context, IRubyObject recv, IRubyObject other, boolean recur) {
            if (recur || !sites(context).respond_to_op_cmp.respondsTo(context, other, other)) return context.nil;
            return sites(context).op_cmp.call(context, other, other, recv);
        }
    };

    
rb_invcmp
/** rb_invcmp
     *
     */
    public static IRubyObject invcmp(final ThreadContext context, ThreadContext.RecursiveFunctionEx func, IRubyObject recv, IRubyObject other) {
        IRubyObject result = context.safeRecurse(func, recv, other, "<=>", true);

        if (result.isNil()) return result;
        return RubyFixnum.newFixnum(context.runtime, -cmpint(context, result, recv, other));
    }

    /*  ================
     *  Module Methods
     *  ================
     */

    
cmp_equal (cmp_eq inlined here)
/** cmp_equal (cmp_eq inlined here)
     *
     */
    @JRubyMethod(name = "==", required = 1)
    public static IRubyObject op_equal(ThreadContext context, IRubyObject recv, IRubyObject other) {
        return callCmpMethod(context, recv, other, context.fals);
    }

    @Deprecated
    public static IRubyObject op_equal19(ThreadContext context, IRubyObject recv, IRubyObject other) {
        return op_equal(context, recv, other);
    }

    private static IRubyObject callCmpMethod(final ThreadContext context, final IRubyObject recv, final IRubyObject other, IRubyObject returnValueOnError) {
        final Ruby runtime = context.runtime;

        if (recv == other) return context.tru;

        IRubyObject result = context.safeRecurse(CMP_RECURSIVE, other, recv, "<=>", true);

        // This is only to prevent throwing exceptions by cmperr - it has poor performance
        if ( result.isNil() ) return returnValueOnError;

        return RubyBoolean.newBoolean(runtime, cmpint(context, result, recv, other) == 0);
    }

    
cmp_gt
/** cmp_gt
     *
     */
    // <=> may return nil in many circumstances, e.g. 3 <=> NaN
    @JRubyMethod(name = ">", required = 1)
    public static RubyBoolean op_gt(ThreadContext context, IRubyObject recv, IRubyObject other) {
        IRubyObject result = sites(context).op_cmp.call(context, recv, recv, other);

        if (result.isNil()) cmperr(recv, other);

        return RubyBoolean.newBoolean(context.runtime, cmpint(context, result, recv, other) > 0);
    }

    
cmp_ge
/** cmp_ge
     *
     */
    @JRubyMethod(name = ">=", required = 1)
    public static RubyBoolean op_ge(ThreadContext context, IRubyObject recv, IRubyObject other) {
        IRubyObject result = sites(context).op_cmp.call(context, recv, recv, other);

        if (result.isNil()) cmperr(recv, other);

        return RubyBoolean.newBoolean(context.runtime, cmpint(context, result, recv, other) >= 0);
    }

    
cmp_lt
/** cmp_lt
     *
     */
    @JRubyMethod(name = "<", required = 1)
    public static RubyBoolean op_lt(ThreadContext context, IRubyObject recv, IRubyObject other) {
        IRubyObject result = sites(context).op_cmp.call(context, recv, recv, other);

        if (result.isNil()) cmperr(recv, other);

        return RubyBoolean.newBoolean(context.runtime, cmpint(context, result, recv, other) < 0);
    }

    public static RubyBoolean op_lt(ThreadContext context, CallSite cmp, IRubyObject recv, IRubyObject other) {
        IRubyObject result = cmp.call(context, recv, recv, other);

        if (result.isNil()) cmperr(recv, other);

        return RubyBoolean.newBoolean(context.runtime, cmpint(context, result, recv, other) < 0);
    }

    
cmp_le
/** cmp_le
     *
     */
    @JRubyMethod(name = "<=", required = 1)
    public static RubyBoolean op_le(ThreadContext context, IRubyObject recv, IRubyObject other) {
        IRubyObject result = sites(context).op_cmp.call(context, recv, recv, other);

        if (result.isNil()) cmperr(recv, other);

        return RubyBoolean.newBoolean(context.runtime, cmpint(context, result, recv, other) <= 0);
    }

    
cmp_between
/** cmp_between
     *
     */
    @JRubyMethod(name = "between?", required = 2)
    public static RubyBoolean between_p(ThreadContext context, IRubyObject recv, IRubyObject first, IRubyObject second) {
        return context.runtime.newBoolean(op_lt(context, recv, first).isFalse() && op_gt(context, recv, second).isFalse());
    }

    @JRubyMethod(name = "clamp")
    public static IRubyObject clamp(ThreadContext context, IRubyObject recv, IRubyObject min, IRubyObject max) {
        int c;

        ComparableSites sites = sites(context);
        CallSite op_gt = sites.op_gt;
        CallSite op_lt = sites.op_lt;
        CallSite op_cmp = sites.op_cmp;

        if (cmpAndCmpint(context, op_cmp, op_gt, op_lt, min, max) > 0) {
            throw context.runtime.newArgumentError("min argument must be smaller than max argument");
        }

        c = cmpAndCmpint(context, op_cmp, op_gt, op_lt, recv, min);
        if (c == 0) return recv;
        if (c < 0) return min;
        c = cmpAndCmpint(context, op_cmp, op_gt, op_lt, recv, max);
        if (c > 0) return max;
        return recv;
    }

    private static ComparableSites sites(ThreadContext context) {
        return context.sites.Comparable;
    }

    private static class CmpRecursive implements ThreadContext.RecursiveFunctionEx<IRubyObject> {
        @Override
        public IRubyObject call(ThreadContext context, IRubyObject other, IRubyObject self, boolean recur) {
            if (recur) return context.nil;
            return sites(context).op_cmp.call(context, self, self, other);
        }
    }

    private static final CmpRecursive CMP_RECURSIVE = new CmpRecursive();
}