/*
 * (C) Copyright 2005- ECMWF.
 *
 * This software is licensed under the terms of the Apache Licence Version 2.0
 * which can be obtained at http://www.apache.org/licenses/LICENSE-2.0.
 *
 * In applying this licence, ECMWF does not waive the privileges and immunities granted to it by
 * virtue of its status as an intergovernmental organisation nor does it submit to any jurisdiction.
 */

#include "grib_api_internal.h"
#include "grib_optimize_decimal_factor.h"
#include <math.h>
/*
   This is used by make_class.pl

   START_CLASS_DEF
   CLASS      = accessor
   SUPER      = grib_accessor_class_data_simple_packing
   IMPLEMENTS = unpack_double
   IMPLEMENTS = pack_double
   IMPLEMENTS = value_count
   IMPLEMENTS = init
   MEMBERS= const char*  GRIBEX_sh_bug_present
   MEMBERS= const char*  ieee_floats
   MEMBERS= const char*  laplacianOperatorIsSet
   MEMBERS= const char*  laplacianOperator
   MEMBERS= const char*  sub_j
   MEMBERS= const char*  sub_k
   MEMBERS= const char*  sub_m
   MEMBERS= const char*  pen_j
   MEMBERS= const char*  pen_k
   MEMBERS= const char*  pen_m
   END_CLASS_DEF

 */


/* START_CLASS_IMP */

/*

Don't edit anything between START_CLASS_IMP and END_CLASS_IMP
Instead edit values between START_CLASS_DEF and END_CLASS_DEF
or edit "accessor.class" and rerun ./make_class.pl

*/

static int pack_double(grib_accessor*, const double* val, size_t* len);
static int unpack_double(grib_accessor*, double* val, size_t* len);
static int value_count(grib_accessor*, long*);
static void init(grib_accessor*, const long, grib_arguments*);
static void init_class(grib_accessor_class*);

typedef struct grib_accessor_data_complex_packing
{
    grib_accessor att;
    /* Members defined in gen */
    /* Members defined in values */
    int carg;
    const char* seclen;
    const char* offsetdata;
    const char* offsetsection;
    int dirty;
    /* Members defined in data_simple_packing */
    int edition;
    const char* units_factor;
    const char* units_bias;
    const char* changing_precision;
    const char* number_of_values;
    const char* bits_per_value;
    const char* reference_value;
    const char* binary_scale_factor;
    const char* decimal_scale_factor;
    const char* optimize_scaling_factor;
    /* Members defined in data_complex_packing */
    const char* GRIBEX_sh_bug_present;
    const char* ieee_floats;
    const char* laplacianOperatorIsSet;
    const char* laplacianOperator;
    const char* sub_j;
    const char* sub_k;
    const char* sub_m;
    const char* pen_j;
    const char* pen_k;
    const char* pen_m;
} grib_accessor_data_complex_packing;

extern grib_accessor_class* grib_accessor_class_data_simple_packing;

static grib_accessor_class _grib_accessor_class_data_complex_packing = {
    &grib_accessor_class_data_simple_packing,   /* super                     */
    "data_complex_packing",                     /* name                      */
    sizeof(grib_accessor_data_complex_packing), /* size                      */
    0,                                          /* inited */
    &init_class,                                /* init_class */
    &init,                                      /* init                      */
    0,                                          /* post_init                      */
    0,                                          /* free mem                       */
    0,                                          /* describes himself         */
    0,                                          /* get length of section     */
    0,                                          /* get length of string      */
    &value_count,                               /* get number of values      */
    0,                                          /* get number of bytes      */
    0,                                          /* get offset to bytes           */
    0,                                          /* get native type               */
    0,                                          /* get sub_section                */
    0,                                          /* grib_pack procedures long      */
    0,                                          /* grib_pack procedures long      */
    0,                                          /* grib_pack procedures long      */
    0,                                          /* grib_unpack procedures long    */
    &pack_double,                               /* grib_pack procedures double    */
    &unpack_double,                             /* grib_unpack procedures double  */
    0,                                          /* grib_pack procedures string    */
    0,                                          /* grib_unpack procedures string  */
    0,                                          /* grib_pack array procedures string    */
    0,                                          /* grib_unpack array procedures string  */
    0,                                          /* grib_pack procedures bytes     */
    0,                                          /* grib_unpack procedures bytes   */
    0,                                          /* pack_expression */
    0,                                          /* notify_change   */
    0,                                          /* update_size   */
    0,                                          /* preferred_size   */
    0,                                          /* resize   */
    0,                                          /* nearest_smaller_value */
    0,                                          /* next accessor    */
    0,                                          /* compare vs. another accessor   */
    0,                                          /* unpack only ith value          */
    0,                                          /* unpack a subarray         */
    0,                                          /* clear          */
    0,                                          /* clone accessor          */
};


grib_accessor_class* grib_accessor_class_data_complex_packing = &_grib_accessor_class_data_complex_packing;


static void init_class(grib_accessor_class* c)
{
    c->dump                   = (*(c->super))->dump;
    c->next_offset            = (*(c->super))->next_offset;
    c->string_length          = (*(c->super))->string_length;
    c->byte_count             = (*(c->super))->byte_count;
    c->byte_offset            = (*(c->super))->byte_offset;
    c->get_native_type        = (*(c->super))->get_native_type;
    c->sub_section            = (*(c->super))->sub_section;
    c->pack_missing           = (*(c->super))->pack_missing;
    c->is_missing             = (*(c->super))->is_missing;
    c->pack_long              = (*(c->super))->pack_long;
    c->unpack_long            = (*(c->super))->unpack_long;
    c->pack_string            = (*(c->super))->pack_string;
    c->unpack_string          = (*(c->super))->unpack_string;
    c->pack_string_array      = (*(c->super))->pack_string_array;
    c->unpack_string_array    = (*(c->super))->unpack_string_array;
    c->pack_bytes             = (*(c->super))->pack_bytes;
    c->unpack_bytes           = (*(c->super))->unpack_bytes;
    c->pack_expression        = (*(c->super))->pack_expression;
    c->notify_change          = (*(c->super))->notify_change;
    c->update_size            = (*(c->super))->update_size;
    c->preferred_size         = (*(c->super))->preferred_size;
    c->resize                 = (*(c->super))->resize;
    c->nearest_smaller_value  = (*(c->super))->nearest_smaller_value;
    c->next                   = (*(c->super))->next;
    c->compare                = (*(c->super))->compare;
    c->unpack_double_element  = (*(c->super))->unpack_double_element;
    c->unpack_double_subarray = (*(c->super))->unpack_double_subarray;
    c->clear                  = (*(c->super))->clear;
    c->make_clone             = (*(c->super))->make_clone;
}

/* END_CLASS_IMP */

typedef unsigned long (*encode_float_proc)(double);
typedef double (*decode_float_proc)(unsigned long);

static void init(grib_accessor* a, const long v, grib_arguments* args)
{
    grib_accessor_data_complex_packing* self = (grib_accessor_data_complex_packing*)a;
    grib_handle* gh                          = grib_handle_of_accessor(a);

    self->GRIBEX_sh_bug_present  = grib_arguments_get_name(gh, args, self->carg++);
    self->ieee_floats            = grib_arguments_get_name(gh, args, self->carg++);
    self->laplacianOperatorIsSet = grib_arguments_get_name(gh, args, self->carg++);
    self->laplacianOperator      = grib_arguments_get_name(gh, args, self->carg++);
    self->sub_j                  = grib_arguments_get_name(gh, args, self->carg++);
    self->sub_k                  = grib_arguments_get_name(gh, args, self->carg++);
    self->sub_m                  = grib_arguments_get_name(gh, args, self->carg++);
    self->pen_j                  = grib_arguments_get_name(gh, args, self->carg++);
    self->pen_k                  = grib_arguments_get_name(gh, args, self->carg++);
    self->pen_m                  = grib_arguments_get_name(gh, args, self->carg++);

    a->flags |= GRIB_ACCESSOR_FLAG_DATA;
}

static int value_count(grib_accessor* a, long* count)
{
    grib_accessor_data_complex_packing* self = (grib_accessor_data_complex_packing*)a;
    int ret                                  = 0;
    grib_handle* gh                          = grib_handle_of_accessor(a);

    long pen_j = 0;
    long pen_k = 0;
    long pen_m = 0;

    *count = 0;

    if (a->length == 0)
        return 0;

    if ((ret = grib_get_long_internal(gh, self->pen_j, &pen_j)) != GRIB_SUCCESS)
        return ret;
    if ((ret = grib_get_long_internal(gh, self->pen_k, &pen_k)) != GRIB_SUCCESS)
        return ret;
    if ((ret = grib_get_long_internal(gh, self->pen_m, &pen_m)) != GRIB_SUCCESS)
        return ret;

    if (pen_j != pen_k || pen_j != pen_m) {
        grib_context_log(a->context, GRIB_LOG_ERROR, "pen_j=%ld, pen_k=%ld, pen_m=%ld\n", pen_j, pen_k, pen_m);
        Assert((pen_j == pen_k) && (pen_j == pen_m));
    }
    *count = (pen_j + 1) * (pen_j + 2);

    return ret;
}

static int unpack_double(grib_accessor* a, double* val, size_t* len)
{
    grib_accessor_data_complex_packing* self = (grib_accessor_data_complex_packing*)a;
    grib_handle* gh                          = grib_handle_of_accessor(a);

    size_t i       = 0;
    int ret        = GRIB_SUCCESS;
    long hcount    = 0;
    long lcount    = 0;
    long hpos      = 0;
    long lup       = 0;
    long mmax      = 0;
    long n_vals    = 0;
    double* scals  = NULL;
    double *pscals = NULL, *pval = NULL;

    double s                 = 0;
    double d                 = 0;
    double laplacianOperator = 0;
    unsigned char* buf       = NULL;
    unsigned char* hres      = NULL;
    unsigned char* lres      = NULL;
    unsigned long packed_offset;
    long lpos = 0;

    long maxv                  = 0;
    long GRIBEX_sh_bug_present = 0;
    long ieee_floats           = 0;

    long offsetdata           = 0;
    long bits_per_value       = 0;
    double reference_value    = 0;
    long binary_scale_factor  = 0;
    long decimal_scale_factor = 0;

    long sub_j = 0;
    long sub_k = 0;
    long sub_m = 0;
    long pen_j = 0;
    long pen_k = 0;
    long pen_m = 0;

    double operat = 0;
    int bytes;
    int err = 0;

    decode_float_proc decode_float = NULL;

    err = grib_value_count(a, &n_vals);
    if (err)
        return err;

    if (*len < n_vals) {
        *len = n_vals;
        return GRIB_ARRAY_TOO_SMALL;
    }

    if ((ret = grib_get_long_internal(gh, self->offsetdata, &offsetdata)) != GRIB_SUCCESS)
        return ret;
    if ((ret = grib_get_long_internal(gh, self->bits_per_value, &bits_per_value)) != GRIB_SUCCESS)
        return ret;
    if ((ret = grib_get_double_internal(gh, self->reference_value, &reference_value)) != GRIB_SUCCESS)
        return ret;
    if ((ret = grib_get_long_internal(gh, self->binary_scale_factor, &binary_scale_factor)) != GRIB_SUCCESS)
        return ret;

    if ((ret = grib_get_long_internal(gh, self->decimal_scale_factor, &decimal_scale_factor)) != GRIB_SUCCESS)
        return ret;

    if ((ret = grib_get_long_internal(gh, self->GRIBEX_sh_bug_present, &GRIBEX_sh_bug_present)) != GRIB_SUCCESS)
        return ret;

    /* ECC-774: don't use grib_get_long_internal */
    if ((ret = grib_get_long(gh, self->ieee_floats, &ieee_floats)) != GRIB_SUCCESS)
        return ret;

    if ((ret = grib_get_double_internal(gh, self->laplacianOperator, &laplacianOperator)) != GRIB_SUCCESS)
        return ret;
    if ((ret = grib_get_long_internal(gh, self->sub_j, &sub_j)) != GRIB_SUCCESS)
        return ret;
    if ((ret = grib_get_long_internal(gh, self->sub_k, &sub_k)) != GRIB_SUCCESS)
        return ret;
    if ((ret = grib_get_long_internal(gh, self->sub_m, &sub_m)) != GRIB_SUCCESS)
        return ret;
    if ((ret = grib_get_long_internal(gh, self->pen_j, &pen_j)) != GRIB_SUCCESS)
        return ret;
    if ((ret = grib_get_long_internal(gh, self->pen_k, &pen_k)) != GRIB_SUCCESS)
        return ret;
    if ((ret = grib_get_long_internal(gh, self->pen_m, &pen_m)) != GRIB_SUCCESS)
        return ret;

    self->dirty = 0;

    switch (ieee_floats) {
        case 0:
            decode_float = grib_long_to_ibm;
            bytes        = 4;
            break;
        case 1:
            decode_float = grib_long_to_ieee;
            bytes        = 4;
            break;
        case 2:
            decode_float = grib_long_to_ieee64;
            bytes        = 8;
            break;
        default:
            return GRIB_NOT_IMPLEMENTED;
    }

    Assert(sub_j == sub_k);
    Assert(sub_j == sub_m);
    Assert(pen_j == pen_k);
    Assert(pen_j == pen_m);

    buf = (unsigned char*)gh->buffer->data;

    maxv = pen_j + 1;

    buf += grib_byte_offset(a);
    hres = buf;
    lres = buf;

    if (pen_j == sub_j) {
        n_vals = (pen_j + 1) * (pen_j + 2);
        d      = grib_power(-decimal_scale_factor, 10);
        grib_ieee_decode_array(a->context, buf, n_vals, bytes, val);
        if (d) {
            for (i = 0; i < n_vals; i++)
                val[i] *= d;
        }
        return 0;
    }

    packed_offset = grib_byte_offset(a) + bytes * (sub_k + 1) * (sub_k + 2);

    lpos = 8 * (packed_offset - offsetdata);

    s = grib_power(binary_scale_factor, 2);
    d = grib_power(-decimal_scale_factor, 10);

    scals = (double*)grib_context_malloc(a->context, maxv * sizeof(double));
    Assert(scals);

    scals[0] = 0;
    for (i = 1; i < maxv; i++) {
        operat = pow(i * (i + 1), laplacianOperator);
        if (operat != 0)
            scals[i] = (1.0 / operat);
        else {
            grib_context_log(a->context, GRIB_LOG_WARNING,
                             "COMPLEX_PACKING : problem with operator div by zero at index %d of %d \n",
                             i, maxv);
            scals[i] = 0;
        }
    }

    /*
    printf("UNPACKING LAPLACE=%.20f\n",laplacianOperator);
    printf("packed offset=%ld\n",packed_offset);
    for(i=0;i<maxv;i++)
        printf("scals[%d]=%g\n",i,scals[i]);*/

    i = 0;

    while (maxv > 0) {
        lup = mmax;
        if (sub_k >= 0) {
            for (hcount = 0; hcount < sub_k + 1; hcount++) {
                val[i++] = decode_float(grib_decode_unsigned_long(hres, &hpos, 8 * bytes));
                val[i++] = decode_float(grib_decode_unsigned_long(hres, &hpos, 8 * bytes));

                if (GRIBEX_sh_bug_present && hcount == sub_k) {
                    /*  bug in ecmwf data, last row (K+1)is scaled but should not */
                    val[i - 2] *= scals[lup];
                    val[i - 1] *= scals[lup];
                }
                lup++;
            }
            sub_k--;
        }

        pscals = scals + lup;
        pval   = val + i;
#if FAST_BIG_ENDIAN
        grib_decode_double_array_complex(lres,
                                         &lpos, bits_per_value,
                                         reference_value, s, pscals, (maxv - hcount) * 2, pval);
        i += (maxv - hcount) * 2;
#else
        (void)pscals; /* suppress gcc warning */
        (void)pval;   /* suppress gcc warning */
        for (lcount = hcount; lcount < maxv; lcount++) {
            val[i++] = d * (double)((grib_decode_unsigned_long(lres, &lpos, bits_per_value) * s) + reference_value) * scals[lup];
            val[i++] = d * (double)((grib_decode_unsigned_long(lres, &lpos, bits_per_value) * s) + reference_value) * scals[lup];
            /* These values should always be zero, but as they are packed,
               it is necessary to force them back to zero */
            if (mmax == 0)
                val[i - 1] = 0;
            lup++;
        }
#endif

        maxv--;
        hcount = 0;
        mmax++;
    }

    Assert(*len >= i);
    *len = i;

    grib_context_free(a->context, scals);

    return ret;
}

#define MAXVAL(a, b) a > b ? a : b

static double calculate_pfactor(grib_context* ctx, const double* spectralField, long fieldTruncation, long subsetTruncation)
{
    /*long n_vals = ((fieldTruncation+1)*(fieldTruncation+2));*/
    long loop, index, m, n = 0;
    double pFactor, zeps = 1.0e-15;
    long ismin = (subsetTruncation + 1), ismax = (fieldTruncation + 1);
    double *weights, range, *norms;
    double weightedSumOverX = 0.0, weightedSumOverY = 0.0, sumOfWeights = 0.0, x, y;
    double numerator = 0.0, denominator = 0.0, slope;

    /* Catch corner case. See GRIB-172 */
    if (ismax - ismin <= 1) {
        return 1; /* any value will do! we cannot do linear fit on a single point! */
    }

    /*
     * Setup the weights
     */
    range   = (double)(ismax - ismin + 1);
    weights = (double*)grib_context_malloc(ctx, (ismax + 1) * sizeof(double));
    for (loop = ismin; loop <= ismax; loop++)
        weights[loop] = range / (double)(loop - ismin + 1);

    /*
     * Compute norms
     * Handle values 2 at a time (real and imaginary parts).
     */
    norms = (double*)grib_context_malloc(ctx, (ismax + 1) * sizeof(double));
    for (loop = 0; loop < ismax + 1; loop++)
        norms[loop] = 0.0;

    /*
     * Form norms for the rows which contain part of the unscaled subset.
     */

    index = -2;
    for (m = 0; m < subsetTruncation; m++) {
        for (n = m; n <= fieldTruncation; n++) {
            index += 2;
            if (n >= subsetTruncation) {
                norms[n] = MAXVAL(norms[n], fabs(spectralField[index]));
                norms[n] = MAXVAL(norms[n], fabs(spectralField[index + 1]));
            }
        }
    }

    /*
     * Form norms for the rows which do not contain part of the unscaled subset.
     */

    for (m = subsetTruncation; m <= fieldTruncation; m++) {
        for (n = m; n <= fieldTruncation; n++) {
            index += 2;
            norms[n] = MAXVAL(norms[n], fabs(spectralField[index]));
            norms[n] = MAXVAL(norms[n], fabs(spectralField[index + 1]));
        }
    }

    /*
     * Ensure the norms have a value which is not too small in case of
     * problems with math functions (e.g. LOG).
     */
    for (loop = ismin; loop <= ismax; loop++) {
        norms[loop] = MAXVAL(norms[loop], zeps);
        if (norms[loop] == zeps)
            weights[loop] = 100.0 * zeps;
    }

    /*
     * Do linear fit to find the slope
     */
    for (loop = ismin; loop <= ismax; loop++) {
        x = log((double)(loop * (loop + 1)));
        Assert(norms[loop] > 0);
        y                = log(norms[loop]);
        weightedSumOverX = weightedSumOverX + x * weights[loop];
        weightedSumOverY = weightedSumOverY + y * weights[loop];
        sumOfWeights     = sumOfWeights + weights[loop];
    }
    weightedSumOverX = weightedSumOverX / sumOfWeights;
    weightedSumOverY = weightedSumOverY / sumOfWeights;

    /*
     * Perform a least square fit for the equation
     */

    for (loop = ismin; loop <= ismax; loop++) {
        x = log((double)(loop * (loop + 1)));
        y = log(norms[loop]);
        numerator =
            numerator + weights[loop] * (y - weightedSumOverY) * (x - weightedSumOverX);
        denominator =
            denominator + weights[loop] * ((x - weightedSumOverX) * (x - weightedSumOverX));
    }
    slope = numerator / denominator;

    grib_context_free(ctx, weights);
    grib_context_free(ctx, norms);

    pFactor = -slope;
    if (pFactor < -9999.9)
        pFactor = -9999.9;
    if (pFactor > 9999.9)
        pFactor = 9999.9;
    return pFactor;
}

static int pack_double(grib_accessor* a, const double* val, size_t* len)
{
    grib_accessor_data_complex_packing* self = (grib_accessor_data_complex_packing*)a;
    grib_handle* gh                          = grib_handle_of_accessor(a);

    size_t i      = 0;
    int ret       = GRIB_SUCCESS;
    long hcount   = 0;
    long lcount   = 0;
    long hpos     = 0;
    long lup      = 0;
    long mmax     = 0;
    long n_vals   = 0;
    double* scals = NULL;

    double s = 0;
    double d = 0;

    unsigned char* buf = NULL;

    size_t buflen = 0;
    size_t hsize  = 0;
    size_t lsize  = 0;

    unsigned char* hres = NULL;
    unsigned char* lres = NULL;

    long lpos = 0;
    long maxv = 0;

    long offsetdata              = 0;
    long bits_per_value          = 0;
    double reference_value       = 0;
    long binary_scale_factor     = 0;
    long decimal_scale_factor    = 0;
    long optimize_scaling_factor = 0;
    long laplacianOperatorIsSet  = 0;

    double laplacianOperator   = 0;
    long sub_j                 = 0;
    long sub_k                 = 0;
    long sub_m                 = 0;
    long pen_j                 = 0;
    long pen_k                 = 0;
    long pen_m                 = 0;
    long GRIBEX_sh_bug_present = 0;
    long ieee_floats           = 0;
    double min                 = 0;
    double max                 = 0;
    double current_val         = 0;
    short mixmax_unset         = 0;
    int bytes;

    encode_float_proc encode_float = NULL;

    if (*len == 0)
        return GRIB_NO_VALUES;

    if ((ret = grib_get_long_internal(gh, self->offsetdata, &offsetdata)) != GRIB_SUCCESS)
        return ret;
    if ((ret = grib_get_long_internal(gh, self->bits_per_value, &bits_per_value)) != GRIB_SUCCESS)
        return ret;

    if ((ret = grib_get_long_internal(gh, self->decimal_scale_factor, &decimal_scale_factor)) != GRIB_SUCCESS)
        return ret;

    if ((ret = grib_get_long_internal(gh, self->optimize_scaling_factor, &optimize_scaling_factor)) != GRIB_SUCCESS)
        return ret;

    if ((ret = grib_get_long_internal(gh, self->GRIBEX_sh_bug_present, &GRIBEX_sh_bug_present)) != GRIB_SUCCESS)
        return ret;

    if ((ret = grib_get_long_internal(gh, self->ieee_floats, &ieee_floats)) != GRIB_SUCCESS)
        return ret;

    if ((ret = grib_get_long_internal(gh, self->laplacianOperatorIsSet, &laplacianOperatorIsSet)) != GRIB_SUCCESS)
        return ret;
    if ((ret = grib_get_double_internal(gh, self->laplacianOperator, &laplacianOperator)) != GRIB_SUCCESS)
        return ret;

    if ((ret = grib_get_long_internal(gh, self->sub_j, &sub_j)) != GRIB_SUCCESS)
        return ret;
    if ((ret = grib_get_long_internal(gh, self->sub_k, &sub_k)) != GRIB_SUCCESS)
        return ret;
    if ((ret = grib_get_long_internal(gh, self->sub_m, &sub_m)) != GRIB_SUCCESS)
        return ret;
    if ((ret = grib_get_long_internal(gh, self->pen_j, &pen_j)) != GRIB_SUCCESS)
        return ret;
    if ((ret = grib_get_long_internal(gh, self->pen_k, &pen_k)) != GRIB_SUCCESS)
        return ret;
    if ((ret = grib_get_long_internal(gh, self->pen_m, &pen_m)) != GRIB_SUCCESS)
        return ret;

    self->dirty = 1;

    switch (ieee_floats) {
        case 0:
            encode_float = grib_ibm_to_long;
            bytes        = 4;
            break;
        case 1:
            encode_float = grib_ieee_to_long;
            bytes        = 4;
            break;
        case 2:
            encode_float = grib_ieee64_to_long;
            bytes        = 8;
            break;
        default:
            return GRIB_NOT_IMPLEMENTED;
    }

    Assert(sub_j == sub_k);
    Assert(sub_j == sub_m);
    Assert(pen_j == pen_k);
    Assert(pen_j == pen_m);

    n_vals = (pen_j + 1) * (pen_j + 2);

    if (*len != n_vals) {
        grib_context_log(a->context, GRIB_LOG_ERROR, "COMPLEX_PACKING: wrong number of values, expected %ld - got %lu",
                n_vals, *len);
        return GRIB_INTERNAL_ERROR;
    }

    /* Data Quality checks */
    if (a->context->grib_data_quality_checks) {
        /* First value is the field's average */
        double min_val = val[0];
        double max_val = min_val;
        if ((ret = grib_util_grib_data_quality_check(gh, min_val, max_val)) != GRIB_SUCCESS)
            return ret;
    }

    if (pen_j == sub_j) {
        double* values;
        d = grib_power(decimal_scale_factor, 10);
        if (d) {
            values = (double*)grib_context_malloc_clear(a->context, sizeof(double) * n_vals);
            for (i = 0; i < n_vals; i++)
                values[i] = val[i] * d;
        }
        else {
            values = (double*)val;
        }
        buflen = n_vals * bytes;
        buf    = (unsigned char*)grib_context_malloc_clear(a->context, buflen);
        grib_ieee_encode_array(a->context, values, n_vals, bytes, buf);
        if (d)
            grib_context_free(a->context, values);
        grib_buffer_replace(a, buf, buflen, 1, 1);
        grib_context_free(a->context, buf);
        return 0;
    }

    if (!laplacianOperatorIsSet) {
        laplacianOperator = calculate_pfactor(a->context, val, pen_j, sub_j);
        if ((ret = grib_set_double_internal(gh, self->laplacianOperator, laplacianOperator)) != GRIB_SUCCESS)
            return ret;
        grib_get_double_internal(gh, self->laplacianOperator, &laplacianOperator);
    }

    hsize = bytes * (sub_k + 1) * (sub_k + 2);
    lsize = ((n_vals - ((sub_k + 1) * (sub_k + 2))) * bits_per_value) / 8;

    buflen = hsize + lsize;

    buf  = (unsigned char*)grib_context_malloc(a->context, buflen);
    hres = buf;
    lres = buf + hsize;

    maxv = pen_j + 1;

    lpos = 0;
    hpos = 0;

    scals = (double*)grib_context_malloc(a->context, maxv * sizeof(double));
    Assert(scals);

    scals[0] = 0;
    for (i = 1; i < maxv; i++)
        scals[i] = ((double)pow(i * (i + 1), laplacianOperator));

    mmax   = 0;
    maxv   = pen_j + 1;
    i      = 0;
    hcount = 0;
    sub_k  = sub_j;

    while (maxv > 0) {
        lup = mmax;

        if (sub_k >= 0) {
            i += 2 * (sub_k + 1);
            lup += sub_k + 1;
            hcount += sub_k + 1;
            sub_k--;
        }

        for (lcount = hcount; lcount < maxv; lcount++) {
            current_val = ((val[i++]) * scals[lup]);
            if (mixmax_unset == 0) {
                max          = current_val;
                min          = current_val;
                mixmax_unset = 1;
            }

            if (current_val > max)
                max = current_val;
            if (current_val < min)
                min = current_val;

            current_val = ((val[i++]) * scals[lup]);
            if (current_val > max)
                max = current_val;
            if (current_val < min)
                min = current_val;

            lup++;
        }
        maxv--;
        hcount = 0;
        mmax++;
    }

    if (optimize_scaling_factor) {
        ret = grib_optimize_decimal_factor(a, self->reference_value,
                                           max, min, bits_per_value, 0, 1,
                                           &decimal_scale_factor,
                                           &binary_scale_factor,
                                           &reference_value);
        if (ret != GRIB_SUCCESS) {
            grib_context_log(gh->context, GRIB_LOG_ERROR,
                             "unable to find nearest_smaller_value of %g for %s", min, self->reference_value);
            return GRIB_INTERNAL_ERROR;
        }
        d = grib_power(+decimal_scale_factor, 10);
    }
    else {
        d = grib_power(+decimal_scale_factor, 10);
        if (grib_get_nearest_smaller_value(gh, self->reference_value, d * min, &reference_value) != GRIB_SUCCESS) {
            grib_context_log(gh->context, GRIB_LOG_ERROR,
                             "unable to find nearest_smaller_value of %g for %s", d * min, self->reference_value);
            return GRIB_INTERNAL_ERROR;
        }
        binary_scale_factor = grib_get_binary_scale_fact(d * max, reference_value, bits_per_value, &ret);

        if (ret == GRIB_UNDERFLOW) {
            d                   = 0;
            binary_scale_factor = 0;
            reference_value     = 0;
        }
        else {
            if (ret != GRIB_SUCCESS) {
                grib_context_log(a->context, GRIB_LOG_ERROR, "COMPLEX_PACKING : Cannot compute binary_scale_factor");
                return ret;
            }
        }
    }
    s = grib_power(-binary_scale_factor, 2);

    i = 0;

    mmax   = 0;
    maxv   = pen_j + 1;
    hcount = 0;
    sub_k  = sub_j;

    while (maxv > 0) {
        lup = mmax;

        if (sub_k >= 0) {
            for (hcount = 0; hcount < sub_k + 1; hcount++) {
                if (GRIBEX_sh_bug_present && hcount == sub_k) {
                    /* _test(val[i]*d*scals[lup],1); */
                    grib_encode_unsigned_long(hres, encode_float((val[i++] * d) * scals[lup]), &hpos, 8 * bytes);
                    /* _test(val[i]*d*scals[lup],1); */
                    grib_encode_unsigned_long(hres, encode_float((val[i++] * d) * scals[lup]), &hpos, 8 * bytes);
                }
                else {
                    /* _test(val[i]*d,0); */
                    grib_encode_unsigned_long(hres, encode_float(val[i++]), &hpos, 8 * bytes);
                    /* _test(val[i]*d,0); */
                    grib_encode_unsigned_long(hres, encode_float(val[i++]), &hpos, 8 * bytes);
                }
                lup++;
            }
            sub_k--;
        }

#if FAST_BIG_ENDIAN
        grib_encode_double_array_complex((maxv - hcount) * 2, &(val[i]), bits_per_value, reference_value, &(scals[lup]), d, s, lres, &lpos);
        i += (maxv - hcount) * 2;
#else
        if (bits_per_value % 8) {
            for (lcount = hcount; lcount < maxv; lcount++) {
                current_val = (((((val[i++] * d) * scals[lup]) - reference_value) * s) + 0.5);
                if (current_val < 0)
                    grib_context_log(a->context, GRIB_LOG_ERROR,
                                     "COMPLEX_PACKING : negative coput before packing (%g)", current_val);
                grib_encode_unsigned_longb(lres, current_val, &lpos, bits_per_value);

                current_val = (((((val[i++] * d) * scals[lup]) - reference_value) * s) + 0.5);
                if (current_val < 0)
                    grib_context_log(a->context, GRIB_LOG_ERROR,
                                     "COMPLEX_PACKING : negative coput before packing (%g)", current_val);
                grib_encode_unsigned_longb(lres, current_val, &lpos, bits_per_value);
                lup++;
            }
        }
        else {
            for (lcount = hcount; lcount < maxv; lcount++) {
                current_val = (((((val[i++] * d) * scals[lup]) - reference_value) * s) + 0.5);
                if (current_val < 0)
                    grib_context_log(a->context, GRIB_LOG_ERROR,
                                     "COMPLEX_PACKING : negative coput before packing (%g)", current_val);
                grib_encode_unsigned_long(lres, current_val, &lpos, bits_per_value);

                current_val = (((((val[i++] * d) * scals[lup]) - reference_value) * s) + 0.5);
                if (current_val < 0)
                    grib_context_log(a->context, GRIB_LOG_ERROR,
                                     "COMPLEX_PACKING : negative coput before packing (%g)", current_val);
                grib_encode_unsigned_long(lres, current_val, &lpos, bits_per_value);
                lup++;
            }
        }
#endif

        maxv--;
        hcount = 0;
        mmax++;
    }

    if (((hpos / 8) != hsize) && ((lpos / 8) != lsize)) {
        grib_context_log(a->context, GRIB_LOG_ERROR,
                         "COMPLEX_PACKING : Mismatch in packing between high resolution and low resolution part");
        grib_context_free(a->context, buf);
        grib_context_free(a->context, scals);
        return GRIB_INTERNAL_ERROR;
    }

    buflen = ((hpos + lpos) / 8);

    if ((ret = grib_set_double_internal(gh, self->reference_value, reference_value)) != GRIB_SUCCESS)
        return ret;
    {
        /* Make sure we can decode it again */
        double ref = 1e-100;
        grib_get_double_internal(gh, self->reference_value, &ref);
        Assert(ref == reference_value);
    }

    if ((ret = grib_set_long_internal(gh, self->binary_scale_factor, binary_scale_factor)) != GRIB_SUCCESS)
        return ret;
    if ((ret = grib_set_long_internal(gh, self->decimal_scale_factor, decimal_scale_factor)) != GRIB_SUCCESS)
        return ret;

    grib_buffer_replace(a, buf, buflen, 1, 1);
    grib_context_free(a->context, buf);
    grib_context_free(a->context, scals);

    return ret;
}
