////////////////////////////////////////////////////////////////////////////////////////
//
//  IMPORTANT: READ BEFORE DOWNLOADING, COPYING, INSTALLING OR USING.
//
//  By downloading, copying, installing or using the software you agree to this license.
//  If you do not agree to this license, do not download, install,
//  copy or use the software.
//
//
//                           License Agreement
//                For Open Source Computer Vision Library
//
// Copyright (C) 2010-2012, Institute Of Software Chinese Academy Of Science, all rights reserved.
// Copyright (C) 2010-2012, Advanced Micro Devices, Inc., all rights reserved.
// Third party copyrights are property of their respective owners.
//
// @Authors
//    Shengen Yan,yanshengen@gmail.com
//
// Redistribution and use in source and binary forms, with or without modification,
// are permitted provided that the following conditions are met:
//
//   * Redistribution's of source code must retain the above copyright notice,
//     this list of conditions and the following disclaimer.
//
//   * Redistribution's 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.
//
//   * The name of the copyright holders may not be used to endorse or promote products
//     derived from this software without specific prior written permission.
//
// This software is provided by the copyright holders and contributors 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 Intel Corporation or contributors 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.
//

#ifdef DOUBLE_SUPPORT
#ifdef cl_amd_fp64
#pragma OPENCL EXTENSION cl_amd_fp64:enable
#elif defined (cl_khr_fp64)
#pragma OPENCL EXTENSION cl_khr_fp64:enable
#endif
#endif

#define noconvert

#ifdef HAVE_MASK
#define EXTRA_PARAMS , __global const uchar * mask, int mask_step, int mask_offset
#else
#define EXTRA_PARAMS
#endif

#if defined OP_SUM || defined OP_SUM_ABS || defined OP_SUM_SQR || defined OP_DOT
#ifdef OP_DOT
#define FUNC(a, b, c) a += b * c
#elif defined OP_SUM
#define FUNC(a, b) a += b
#elif defined OP_SUM_ABS
#define FUNC(a, b) a += b >= (dstT)(0) ? b : -b
#elif defined OP_SUM_SQR
#define FUNC(a, b) a += b * b
#endif
#define DECLARE_LOCAL_MEM \
    __local dstT localmem[WGS2_ALIGNED]
#define DEFINE_ACCUMULATOR \
    dstT accumulator = (dstT)(0)
#ifdef HAVE_MASK
#define REDUCE_GLOBAL \
    dstT temp = convertToDT(src[0]); \
    int mask_index = mad24(id / cols, mask_step, mask_offset + (id % cols)); \
    if (mask[mask_index]) \
        FUNC(accumulator, temp)
#elif defined OP_DOT
#define REDUCE_GLOBAL \
    int src2_index = mad24(id / cols, src2_step, src2_offset + (id % cols) * (int)sizeof(srcT)); \
    __global const srcT * src2 = (__global const srcT *)(src2ptr + src2_index); \
    dstT temp = convertToDT(src[0]), temp2 = convertToDT(src2[0]); \
    FUNC(accumulator, temp, temp2)
#else
#define REDUCE_GLOBAL \
    dstT temp = convertToDT(src[0]); \
    FUNC(accumulator, temp)
#endif
#define SET_LOCAL_1 \
    localmem[lid] = accumulator
#define REDUCE_LOCAL_1 \
    localmem[lid - WGS2_ALIGNED] += accumulator
#define REDUCE_LOCAL_2 \
    localmem[lid] += localmem[lid2]
#define CALC_RESULT \
    __global dstT * dst = (__global dstT *)(dstptr + (int)sizeof(dstT) * gid); \
    dst[0] = localmem[0]

#elif defined OP_COUNT_NON_ZERO
#define dstT int
#define DECLARE_LOCAL_MEM \
    __local dstT localmem[WGS2_ALIGNED]
#define DEFINE_ACCUMULATOR \
    dstT accumulator = (dstT)(0); \
    srcT zero = (srcT)(0), one = (srcT)(1)
#define REDUCE_GLOBAL \
    accumulator += src[0] == zero ? zero : one
#define SET_LOCAL_1 \
    localmem[lid] = accumulator
#define REDUCE_LOCAL_1 \
    localmem[lid - WGS2_ALIGNED] += accumulator
#define REDUCE_LOCAL_2 \
    localmem[lid] += localmem[lid2]
#define CALC_RESULT \
    __global dstT * dst = (__global dstT *)(dstptr + (int)sizeof(dstT) * gid); \
    dst[0] = localmem[0]

#elif defined OP_MIN_MAX_LOC || defined OP_MIN_MAX_LOC_MASK

#ifdef DEPTH_0
#define srcT uchar
#define MIN_VAL 0
#define MAX_VAL 255
#elif defined DEPTH_1
#define srcT char
#define MIN_VAL -128
#define MAX_VAL 127
#elif defined DEPTH_2
#define srcT ushort
#define MIN_VAL 0
#define MAX_VAL 65535
#elif defined DEPTH_3
#define srcT short
#define MIN_VAL -32768
#define MAX_VAL 32767
#elif defined DEPTH_4
#define srcT int
#define MIN_VAL INT_MIN
#define MAX_VAL INT_MAX
#elif defined DEPTH_5
#define srcT float
#define MIN_VAL (-FLT_MAX)
#define MAX_VAL FLT_MAX
#elif defined DEPTH_6
#define srcT double
#define MIN_VAL (-DBL_MAX)
#define MAX_VAL DBL_MAX
#endif

#define DECLARE_LOCAL_MEM \
    __local srcT localmem_min[WGS2_ALIGNED]; \
    __local srcT localmem_max[WGS2_ALIGNED]; \
    __local int localmem_minloc[WGS2_ALIGNED]; \
    __local int localmem_maxloc[WGS2_ALIGNED]
#define DEFINE_ACCUMULATOR \
    srcT minval = MAX_VAL; \
    srcT maxval = MIN_VAL; \
    int negative = -1; \
    int minloc = negative; \
    int maxloc = negative; \
    srcT temp; \
    int temploc
#define REDUCE_GLOBAL \
    temp = src[0]; \
    temploc = id; \
    srcT temp_minval = minval, temp_maxval = maxval; \
    minval = min(minval, temp); \
    maxval = max(maxval, temp); \
    minloc = (minval == temp_minval) ? (temp_minval == MAX_VAL) ? temploc : minloc : temploc; \
    maxloc = (maxval == temp_maxval) ? (temp_maxval == MIN_VAL) ? temploc : maxloc : temploc
#define SET_LOCAL_1 \
    localmem_min[lid] = minval; \
    localmem_max[lid] = maxval; \
    localmem_minloc[lid] = minloc; \
    localmem_maxloc[lid] = maxloc
#define REDUCE_LOCAL_1 \
    srcT oldmin = localmem_min[lid-WGS2_ALIGNED]; \
    srcT oldmax = localmem_max[lid-WGS2_ALIGNED]; \
    localmem_min[lid - WGS2_ALIGNED] = min(minval,localmem_min[lid-WGS2_ALIGNED]); \
    localmem_max[lid - WGS2_ALIGNED] = max(maxval,localmem_max[lid-WGS2_ALIGNED]); \
    srcT minv = localmem_min[lid - WGS2_ALIGNED], maxv = localmem_max[lid - WGS2_ALIGNED]; \
    localmem_minloc[lid - WGS2_ALIGNED] = (minv == minval) ? (minv == oldmin) ? \
        min(minloc, localmem_minloc[lid-WGS2_ALIGNED]) : minloc : localmem_minloc[lid-WGS2_ALIGNED]; \
    localmem_maxloc[lid - WGS2_ALIGNED] = (maxv == maxval) ? (maxv == oldmax) ? \
        min(maxloc, localmem_maxloc[lid-WGS2_ALIGNED]) : maxloc : localmem_maxloc[lid-WGS2_ALIGNED]
#define REDUCE_LOCAL_2 \
    srcT oldmin = localmem_min[lid]; \
    srcT oldmax = localmem_max[lid]; \
    localmem_min[lid] = min(localmem_min[lid], localmem_min[lid2]); \
    localmem_max[lid] = max(localmem_max[lid], localmem_max[lid2]); \
    srcT min1 = localmem_min[lid], min2 = localmem_min[lid2]; \
    localmem_minloc[lid] = (localmem_minloc[lid] == negative) ? localmem_minloc[lid2] : (localmem_minloc[lid2] == negative) ? \
        localmem_minloc[lid] : (min1 == min2) ? (min1 == oldmin) ? min(localmem_minloc[lid2],localmem_minloc[lid]) : \
        localmem_minloc[lid2] : localmem_minloc[lid]; \
    srcT max1 = localmem_max[lid], max2 = localmem_max[lid2]; \
    localmem_maxloc[lid] = (localmem_maxloc[lid] == negative) ? localmem_maxloc[lid2] : (localmem_maxloc[lid2] == negative) ? \
        localmem_maxloc[lid] : (max1 == max2) ? (max1 == oldmax) ? min(localmem_maxloc[lid2],localmem_maxloc[lid]) : \
        localmem_maxloc[lid2] : localmem_maxloc[lid]
#define CALC_RESULT \
    __global srcT * dstminval = (__global srcT *)(dstptr + (int)sizeof(srcT) * gid); \
    __global srcT * dstmaxval = (__global srcT *)(dstptr2 + (int)sizeof(srcT) * gid); \
    dstminval[0] = localmem_min[0]; \
    dstmaxval[0] = localmem_max[0]; \
    dstlocptr[gid] = localmem_minloc[0]; \
    dstlocptr2[gid] = localmem_maxloc[0]

#if defined OP_MIN_MAX_LOC_MASK
#undef DEFINE_ACCUMULATOR
#define DEFINE_ACCUMULATOR \
    srcT minval = MAX_VAL; \
    srcT maxval = MIN_VAL; \
    int negative = -1; \
    int minloc = negative; \
    int maxloc = negative; \
    srcT temp, temp_mask, zeroVal = (srcT)(0); \
    int temploc
#undef REDUCE_GLOBAL
#define REDUCE_GLOBAL \
    temp = src[0]; \
    temploc = id; \
    int mask_index = mad24(id / cols, mask_step, mask_offset + (id % cols) * (int)sizeof(uchar)); \
    __global const uchar * mask = (__global const uchar *)(maskptr + mask_index); \
    temp_mask = mask[0]; \
    srcT temp_minval = minval, temp_maxval = maxval; \
    minval = (temp_mask == zeroVal) ? minval : min(minval, temp); \
    maxval = (temp_mask == zeroVal) ? maxval : max(maxval, temp); \
    minloc = (temp_mask == zeroVal) ? minloc : (minval == temp_minval) ? (temp_minval == MAX_VAL) ? temploc : minloc : temploc; \
    maxloc = (temp_mask == zeroVal) ? maxloc : (maxval == temp_maxval) ? (temp_maxval == MIN_VAL) ? temploc : maxloc : temploc
#endif

#else
#error "No operation"
#endif

#ifdef OP_MIN_MAX_LOC
#undef EXTRA_PARAMS
#define EXTRA_PARAMS , __global uchar * dstptr2, __global int * dstlocptr, __global int * dstlocptr2
#elif defined OP_MIN_MAX_LOC_MASK
#undef EXTRA_PARAMS
#define EXTRA_PARAMS , __global uchar * dstptr2, __global int * dstlocptr, __global int * dstlocptr2, \
    __global const uchar * maskptr, int mask_step, int mask_offset
#elif defined OP_DOT
#undef EXTRA_PARAMS
#define EXTRA_PARAMS , __global uchar * src2ptr, int src2_step, int src2_offset
#endif

__kernel void reduce(__global const uchar * srcptr, int src_step, int src_offset, int cols,
                     int total, int groupnum, __global uchar * dstptr EXTRA_PARAMS)
{
    int lid = get_local_id(0);
    int gid = get_group_id(0);
    int  id = get_global_id(0);

    DECLARE_LOCAL_MEM;
    DEFINE_ACCUMULATOR;

    for (int grain = groupnum * WGS; id < total; id += grain)
    {
        int src_index = mad24(id / cols, src_step, src_offset + (id % cols) * (int)sizeof(srcT));
        __global const srcT * src = (__global const srcT *)(srcptr + src_index);
        REDUCE_GLOBAL;
    }

    if (lid < WGS2_ALIGNED)
    {
        SET_LOCAL_1;
    }
    barrier(CLK_LOCAL_MEM_FENCE);

    if (lid >= WGS2_ALIGNED && total >= WGS2_ALIGNED)
    {
        REDUCE_LOCAL_1;
    }
    barrier(CLK_LOCAL_MEM_FENCE);

    for (int lsize = WGS2_ALIGNED >> 1; lsize > 0; lsize >>= 1)
    {
        if (lid < lsize)
        {
           int lid2 = lsize + lid;
           REDUCE_LOCAL_2;
        }
        barrier(CLK_LOCAL_MEM_FENCE);
    }

    if (lid == 0)
    {
        CALC_RESULT;
    }
}