sort.cpp

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#include "pfc.h"

#if defined(_M_IX86) || defined(_M_IX64)
#include <intrin.h>
#define PFC_HAVE_RDTSC
#endif

namespace pfc {

void swap_void(void * item1,void * item2,t_size width)
{
    unsigned char * ptr1 = (unsigned char*)item1, * ptr2 = (unsigned char*)item2;
    t_size n;
    unsigned char temp;
    for(n=0;n<width;n++)
    {
        temp = *ptr2;
        *ptr2 = *ptr1;
        *ptr1 = temp;
        ptr1++;
        ptr2++;
    }
}

void reorder(reorder_callback & p_callback,const t_size * p_order,t_size p_count)
{
    t_size done_size = bit_array_bittable::g_estimate_size(p_count);
    pfc::array_hybrid_t<unsigned char,1024> done;
    done.set_size(done_size);
    pfc::memset_t(done,(unsigned char)0);
    t_size n;
    for(n=0;n<p_count;n++)
    {
        t_size next = p_order[n];
        if (next!=n && !bit_array_bittable::g_get(done,n))
        {
            t_size prev = n;
            do
            {
                PFC_ASSERT(!bit_array_bittable::g_get(done,next));
                PFC_ASSERT(next>n);
                PFC_ASSERT(n<p_count);
                p_callback.swap(prev,next);
                bit_array_bittable::g_set(done,next,true);
                prev = next;
                next = p_order[next];
            } while(next!=n);
            //bit_array_bittable::g_set(done,n,true);
        }
    }
}

void reorder_void(void * data,t_size width,const t_size * order,t_size num,void (*swapfunc)(void * item1,void * item2,t_size width))
{
    unsigned char * base = (unsigned char *) data;
    t_size done_size = bit_array_bittable::g_estimate_size(num);
    pfc::array_hybrid_t<unsigned char,1024> done;
    done.set_size(done_size);
    pfc::memset_t(done,(unsigned char)0);
    t_size n;
    for(n=0;n<num;n++)
    {
        t_size next = order[n];
        if (next!=n && !bit_array_bittable::g_get(done,n))
        {
            t_size prev = n;
            do
            {
                PFC_ASSERT(!bit_array_bittable::g_get(done,next));
                PFC_ASSERT(next>n);
                PFC_ASSERT(n<num);
                swapfunc(base+width*prev,base+width*next,width);
                bit_array_bittable::g_set(done,next,true);
                prev = next;
                next = order[next];
            } while(next!=n);
            //bit_array_bittable::g_set(done,n,true);
        }
    }
}

namespace {

class sort_callback_impl_legacy : public sort_callback
{
public:
    sort_callback_impl_legacy(
        void * p_base,t_size p_width, 
        int (*p_comp)(const void *, const void *),
        void (*p_swap)(void *, void *, t_size)
        ) :
    m_base((char*)p_base), m_width(p_width),
    m_comp(p_comp), m_swap(p_swap)
    {
    }


    int compare(t_size p_index1, t_size p_index2) const
    {
        return m_comp(m_base + p_index1 * m_width, m_base + p_index2 * m_width);
    }
    
    void swap(t_size p_index1, t_size p_index2)
    {
        m_swap(m_base + p_index1 * m_width, m_base + p_index2 * m_width, m_width);
    }

private:
    char * m_base;
    t_size m_width;
    int (*m_comp)(const void *, const void *);
    void (*m_swap)(void *, void *, t_size);
};
}

void sort_void_ex (
    void *base,
    t_size num,
    t_size width,
    int (*comp)(const void *, const void *),
    void (*swap)(void *, void *, t_size) )
{
    sort_callback_impl_legacy cb(base,width,comp,swap);
    sort(cb,num);
}

static void squaresort(pfc::sort_callback & p_callback,t_size const p_base,t_size const p_count) {
    const t_size max = p_base + p_count;
    for(t_size walk = p_base + 1; walk < max; ++walk) {
        for(t_size prev = p_base; prev < walk; ++prev) {
            p_callback.swap_check(prev,walk);
        }
    }
}


inline static void __sort_2elem_helper(pfc::sort_callback & p_callback,t_size & p_elem1,t_size & p_elem2) {
    if (p_callback.compare(p_elem1,p_elem2) > 0) pfc::swap_t(p_elem1,p_elem2);
}


#ifdef PFC_HAVE_RDTSC
static inline t_uint64 uniqueVal() {return __rdtsc();}
#else
static counter uniqueValCounter;
static counter::t_val uniqueVal() {
    return ++uniqueValCounter;
}
#endif

static t_size myrand(t_size count) {
    const uint64_t rm = (uint64_t)RAND_MAX + 1;
    uint64_t m = 1;
    uint64_t v = 0;
    for(;;) {
        v += rand() * m;
        m *= rm;
        if (m >= count) break;
    }
    v ^= uniqueVal();
    return (t_size)(v % count);
}

inline static t_size __pivot_helper(pfc::sort_callback & p_callback,t_size const p_base,t_size const p_count) {
    PFC_ASSERT(p_count > 2);
    
    //t_size val1 = p_base, val2 = p_base + (p_count / 2), val3 = p_base + (p_count - 1);
    
    t_size val1 = myrand(p_count), val2 = myrand(p_count-1), val3 = myrand(p_count-2);
    if (val2 >= val1) val2++;
    if (val3 >= val1) val3++;
    if (val3 >= val2) val3++;

    val1 += p_base; val2 += p_base; val3 += p_base;
    
    __sort_2elem_helper(p_callback,val1,val2);
    __sort_2elem_helper(p_callback,val1,val3);
    __sort_2elem_helper(p_callback,val2,val3);

    return val2;
}

static void newsort(pfc::sort_callback & p_callback,t_size const p_base,t_size const p_count) {
    if (p_count <= 4) {
        squaresort(p_callback,p_base,p_count);
        return;
    }

    t_size pivot = __pivot_helper(p_callback,p_base,p_count);

    {
        const t_size target = p_base + p_count - 1;
        if (pivot != target) {
            p_callback.swap(pivot,target); pivot = target;
        }
    }


    t_size partition = p_base;
    {
        bool asdf = false;
        for(t_size walk = p_base; walk < pivot; ++walk) {
            const int comp = p_callback.compare(walk,pivot);
            bool trigger = false;
            if (comp == 0) {
                trigger = asdf;
                asdf = !asdf;
            } else if (comp < 0) {
                trigger = true;
            }
            if (trigger) {
                if (partition != walk) p_callback.swap(partition,walk);
                partition++;
            }
        }
    }   
    if (pivot != partition) {
        p_callback.swap(pivot,partition); pivot = partition;
    }

    newsort(p_callback,p_base,pivot-p_base);
    newsort(p_callback,pivot+1,p_count-(pivot+1-p_base));
}

void sort(pfc::sort_callback & p_callback,t_size p_num) {
    srand((unsigned int)(uniqueVal() ^ p_num));
    newsort(p_callback,0,p_num);
}


void sort_void(void * base,t_size num,t_size width,int (*comp)(const void *, const void *) )
{
    sort_void_ex(base,num,width,comp,swap_void);
}




sort_callback_stabilizer::sort_callback_stabilizer(sort_callback & p_chain,t_size p_count)
: m_chain(p_chain)
{
    m_order.set_size(p_count);
    t_size n;
    for(n=0;n<p_count;n++) m_order[n] = n;
}

int sort_callback_stabilizer::compare(t_size p_index1, t_size p_index2) const
{
    int ret = m_chain.compare(p_index1,p_index2);
    if (ret == 0) ret = pfc::sgn_t((t_ssize)m_order[p_index1] - (t_ssize)m_order[p_index2]);
    return ret;
}

void sort_callback_stabilizer::swap(t_size p_index1, t_size p_index2)
{
    m_chain.swap(p_index1,p_index2);
    pfc::swap_t(m_order[p_index1],m_order[p_index2]);
}


void sort_stable(sort_callback & p_callback,t_size p_count)
{
    sort_callback_stabilizer cb(p_callback,p_count);
    sort(cb,p_count);
}

}