/* Cydia - iPhone UIKit Front-End for Debian APT
 * Copyright (C) 2008-2011  Jay Freeman (saurik)
*/

/* Modified BSD License {{{ */
/*
 *        Redistribution and use in source and binary
 * forms, with or without modification, are permitted
 * provided that the following conditions are met:
 *
 * 1. Redistributions of source code must retain the
 *    above copyright notice, this list of conditions
 *    and the following disclaimer.
 * 2. Redistributions in binary form must reproduce the
 *    above copyright notice, this list of conditions
 *    and the following disclaimer in the documentation
 *    and/or other materials provided with the
 *    distribution.
 * 3. The name of the author may not be used to endorse
 *    or promote products derived from this software
 *    without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS''
 * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING,
 * BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF
 * MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
 * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR BE
 * LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
 * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
 * SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
 * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF
 * LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR
 * TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN
 * ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF
 * ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
*/
/* }}} */

#include "CyteKit/UCPlatform.h"

#include "Menes/radixSortWithSelector.h"

#include <objc/runtime.h>

struct RadixItem_ {
    size_t index;
    uint32_t key;
};

@implementation NSMutableArray (MenesRadixSortWithSelector)

- (void) radixSortUsingFunction:(MenesRadixSortFunction)function withContext:(void *)argument {
    size_t count([self count]);
    struct RadixItem_ *swap(new RadixItem_[count * 2]);

    for (size_t i(0); i != count; ++i) {
        RadixItem_ &item(swap[i]);
        item.index = i;

        id object([self objectAtIndex:i]);
        item.key = function(object, argument);
    }

    struct RadixItem_ *lhs(swap), *rhs(swap + count);

    static const size_t width = 32;
    static const size_t bits = 11;
    static const size_t slots = 1 << bits;
    static const size_t passes = (width + (bits - 1)) / bits;

    size_t *hist(new size_t[slots]);

    for (size_t pass(0); pass != passes; ++pass) {
        memset(hist, 0, sizeof(size_t) * slots);

        for (size_t i(0); i != count; ++i) {
            uint32_t key(lhs[i].key);
            key >>= pass * bits;
            key &= _not(uint32_t) >> width - bits;
            ++hist[key];
        }

        size_t offset(0);
        for (size_t i(0); i != slots; ++i) {
            size_t local(offset);
            offset += hist[i];
            hist[i] = local;
        }

        for (size_t i(0); i != count; ++i) {
            uint32_t key(lhs[i].key);
            key >>= pass * bits;
            key &= _not(uint32_t) >> width - bits;
            rhs[hist[key]++] = lhs[i];
        }

        RadixItem_ *tmp(lhs);
        lhs = rhs;
        rhs = tmp;
    }

    delete [] hist;

    const void **values(new const void *[count]);
    for (size_t i(0); i != count; ++i)
        values[i] = [self objectAtIndex:lhs[i].index];
    CFArrayReplaceValues((CFMutableArrayRef) self, CFRangeMake(0, count), values, count);
    delete [] values;

    delete [] swap;
}

- (void) radixSortUsingSelector:(SEL)selector {
    if ([self count] == 0)
        return;

    IMP imp(class_getMethodImplementation([[self lastObject] class], selector));
    [self radixSortUsingFunction:reinterpret_cast<MenesRadixSortFunction>(imp) withContext:selector];
}

@end