eccodes/src/grib_bits_ibmpow_opt.c

/*
 * (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.
 */

int grib_decode_long_array(const unsigned char* p, long* bitp, long bitsPerValue,
                           size_t n_vals, long* val)
{
    long i               = 0;
    unsigned long lvalue = 0;

    if (bitsPerValue % 8) {
        int j = 0;
        for (i = 0; i < n_vals; i++) {
            lvalue = 0;
            for (j = 0; j < bitsPerValue; j++) {
                lvalue <<= 1;
                if (grib_get_bit(p, *bitp))
                    lvalue += 1;
                *bitp += 1;
            }
            val[i] = lvalue;
        }
    }
    else {
        int bc;
        int l    = bitsPerValue / 8;
        size_t o = *bitp / 8;

        for (i = 0; i < n_vals; i++) {
            lvalue = 0;
            lvalue <<= 8;
            lvalue |= p[o++];

            for (bc = 1; bc < l; bc++) {
                lvalue <<= 8;
                lvalue |= p[o++];
            }
            val[i] = lvalue;
        }
        *bitp += bitsPerValue * n_vals;
    }

    return 0;
}

int grib_decode_double_array(const unsigned char* p, long* bitp, long bitsPerValue,
                             double reference_value, double s, double d,
                             size_t n_vals, double* val)
{
    long i               = 0;
    unsigned long lvalue = 0;
    double x;

    if (bitsPerValue % 8) {
        int j = 0;
        for (i = 0; i < n_vals; i++) {
            lvalue = 0;
            for (j = 0; j < bitsPerValue; j++) {
                lvalue <<= 1;
                if (grib_get_bit(p, *bitp))
                    lvalue += 1;
                *bitp += 1;
            }
            x      = ((lvalue * s) + reference_value) * d;
            val[i] = (double)x;
        }
    }
    else {
        int bc;
        int l    = bitsPerValue / 8;
        size_t o = 0;

        for (i = 0; i < n_vals; i++) {
            lvalue = 0;
            lvalue <<= 8;
            lvalue |= p[o++];

            for (bc = 1; bc < l; bc++) {
                lvalue <<= 8;
                lvalue |= p[o++];
            }
            x      = ((lvalue * s) + reference_value) * d;
            val[i] = (double)x;
        }
    }

    return 0;
}

/* code from grib_bits_fast_big_endian_simple.c */
int grib_decode_double_array_complex(const unsigned char* p, long* bitp, long nbits, double reference_value, double s, double* d, size_t size, double* val)
{
    long i                   = 0;
    long countOfLeftmostBits = 0, leftmostBits = 0;
    long startBit;
    long remainingBits = nbits;
    long* pp           = (long*)p;
    int inited         = 0;
    unsigned long uval = 0;

    startBit      = *bitp;
    remainingBits = nbits;
    if (startBit >= max_nbits) {
        pp += startBit / max_nbits;
        startBit %= max_nbits;
    }

    if ((max_nbits % nbits == 0) && (*bitp % nbits == 0)) {
        for (i = 0; i < size; i++) {
            if (startBit == max_nbits) {
                startBit = 0;
                pp++;
            }

            val[i] = VALUE(*pp, startBit, remainingBits);
            val[i] = ((((val[i]) * s) + reference_value) * d[i / 2]);
            startBit += remainingBits;
            remainingBits = nbits;
        }
    }
    else {
        for (i = 0; i < size; i++) {
            countOfLeftmostBits = startBit + remainingBits;
            if (countOfLeftmostBits > max_nbits) {
                countOfLeftmostBits = max_nbits - startBit;
                remainingBits -= countOfLeftmostBits;
                leftmostBits = (VALUE(*pp, startBit, countOfLeftmostBits)) << remainingBits;
                startBit     = 0;
                pp++;
            }
            else
                leftmostBits = 0;

            val[i] = leftmostBits + (VALUE(*pp, startBit, remainingBits));
            val[i] = ((((val[i]) * s) + reference_value) * d[i / 2]);
            startBit += remainingBits;
            remainingBits = nbits;
        }
    }

    *bitp += size * nbits;

    return GRIB_SUCCESS;
}

int grib_encode_long_array(size_t n_vals, const long* val, long bits_per_value, unsigned char* p, long* off)
{
    size_t i                   = 0;
    unsigned long unsigned_val = 0;
    unsigned char* encoded     = p;
    if (bits_per_value % 8) {
        for (i = 0; i < n_vals; i++) {
            unsigned_val = val[i];
            grib_encode_unsigned_longb(encoded, unsigned_val, off, bits_per_value);
        }
    }
    else {
        for (i = 0; i < n_vals; i++) {
            int blen     = 0;
            blen         = bits_per_value;
            unsigned_val = val[i];
            while (blen >= 8) {
                blen -= 8;
                *encoded = (unsigned_val >> blen);
                encoded++;
                *off += 8;
            }
        }
    }
    return GRIB_SUCCESS;
}

#define U_BYTEORDER                    \
    static union                       \
    {                                  \
        unsigned long l;               \
        unsigned char c[sizeof(long)]; \
    } u_byteorder = { 1 }
#define IS_BIGENDIAN() (u_byteorder.c[sizeof(long) - 1])
#define GRIBPACK unsigned char
#define Error(x, y) fprintf(stderr, x, y)
#define restrict

#include "encode_double_array.c"

#undef U_BYTEORDER
#undef IS_BIGENDIAN
#undef GRIBPACK
#undef Error
#undef restrict

int grib_encode_double_array(size_t n_vals, const double* val, long bits_per_value, double reference_value, double d, double divisor, unsigned char* p, long* off)
{
    if (fabs(d - 1) > 0) /* d != 1 */
    {
        size_t i                   = 0;
        unsigned long unsigned_val = 0;
        unsigned char* encoded     = p;
        double x;

        if (bits_per_value % 8) {
            for (i = 0; i < n_vals; i++) {
                x            = (((val[i] * d) - reference_value) * divisor) + 0.5;
                unsigned_val = (unsigned long)x;
                grib_encode_unsigned_longb(encoded, unsigned_val, off, bits_per_value);
            }
        }
        else {
            for (i = 0; i < n_vals; i++) {
                int blen     = 0;
                blen         = bits_per_value;
                x            = ((((val[i] * d) - reference_value) * divisor) + 0.5);
                unsigned_val = (unsigned long)x;
                while (blen >= 8) {
                    blen -= 8;
                    *encoded = (unsigned_val >> blen);
                    encoded++;
                    *off += 8;
                }
            }
        }
    }
    else {
#if defined(_ARCH_PWR6)
        encode_double_array_unrolled(bits_per_value, 0, n_vals, p, val, reference_value, divisor, off);
#else
        encode_double_array_byte(bits_per_value, 0, n_vals, p, val, reference_value, divisor, off);
#endif
    }

    return GRIB_SUCCESS;
}

/* code from grib_bits_fast_big_endian_simple.c */
int grib_encode_double_array_complex(size_t n_vals, double* val, long nbits, double reference_value,
                                     double* scal, double d, double divisor, unsigned char* p, long* bitp)
{
    long* destination        = (long*)p;
    double* v                = val;
    long countOfLeftmostBits = 0, startBit = 0, remainingBits = 0, rightmostBits = 0;
    unsigned long uval = 0;
    size_t i           = 0;

    startBit      = *bitp;
    remainingBits = nbits;

    if (startBit >= max_nbits) {
        destination += startBit / max_nbits;
        startBit %= max_nbits;
    }

    if ((max_nbits % nbits == 0) && (*bitp % nbits == 0)) {
        for (i = 0; i < n_vals; i++) {
            uval = (unsigned long)(((((*v) * d * scal[i / 2]) - reference_value) * divisor) + 0.5);
            if (startBit == max_nbits) {
                startBit = 0;
                destination++;
            }

            rightmostBits = VALUE(uval, max_nbits - remainingBits, remainingBits);
            *destination  = ((*destination) & ~MASKVALUE(startBit, remainingBits)) + (rightmostBits << max_nbits - (remainingBits + startBit));
            startBit += remainingBits;
            remainingBits = nbits;

            v++;
        }
    }
    else {
        for (i = 0; i < n_vals; i++) {
            countOfLeftmostBits = startBit + remainingBits;
            uval                = (unsigned long)(((((*v) * d * scal[i / 2]) - reference_value) * divisor) + 0.5);
            if (countOfLeftmostBits > max_nbits) {
                countOfLeftmostBits = max_nbits - startBit;
                startBit            = max_nbits - remainingBits;
                remainingBits -= countOfLeftmostBits;
                *destination = (((*destination) >> countOfLeftmostBits) << countOfLeftmostBits) + (VALUE(uval, startBit, countOfLeftmostBits));
                startBit     = 0;
                destination++;
            }

            rightmostBits = VALUE(uval, max_nbits - remainingBits, remainingBits);
            *destination  = ((*destination) & ~MASKVALUE(startBit, remainingBits)) + (rightmostBits << max_nbits - (remainingBits + startBit));
            startBit += remainingBits;
            remainingBits = nbits;

            v++;
        }
    }

    *bitp += n_vals * nbits;

    return 0;
}