ByteCount.h

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/*******************************************************************************
 *
 * Copyright (c) 2008-2010 Michael Schulze <mschulze@ivs.cs.uni-magdeburg.de>
 *                    2010 Marcus Foerster <MarcusFoerster1@gmx.de>
 * All rights reserved.
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 *      distribution.
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#ifndef _ByteCount_h_
#define _ByteCount_h_

#include <stdint.h>

#include "boost/mpl/eval_if.hpp"
#include "boost/mpl/int.hpp"
#include "boost/mpl/plus.hpp"


template <typename ValueType, ValueType Value>
struct BitCount {
        typedef ValueType value_type;
        typedef boost::mpl::integral_c_tag tag;
        typedef BitCount type;

        static const uint16_t value = boost::mpl::eval_if_c<(Value != 0),
                                                            boost::mpl::plus<BitCount<ValueType, (Value >> 1)>,
                                                                             boost::mpl::int_<1>
                                                                            >,
                                                            boost::mpl::int_<0>
                                                           >::type::value;
};

template <>
struct BitCount<bool, true> {
        typedef bool value_type;
        typedef boost::mpl::integral_c_tag tag;
        typedef BitCount type;

        static const uint16_t value = 1;
};

template <>
struct BitCount<bool, false> {
        typedef bool value_type;
        typedef boost::mpl::integral_c_tag tag;
        typedef BitCount type;

        static const uint16_t value = 0;
};

#define BitCountSigned(stype)                                               \
    template <stype Value>                                                  \
    struct BitCount<stype, Value> {                                         \
                                                                            \
        typedef stype value_type;                                           \
                                                                            \
        typedef boost::mpl::integral_c_tag tag;                             \
                                                                            \
        typedef BitCount type;                                              \
                                                                            \
        static const uint16_t value = (Value < 0) ?                         \
                                      (sizeof(stype) * 8) :                 \
                                      BitCount<                             \
                                        uint64_t,                           \
                                        static_cast<uint64_t>(Value)        \
                                      >::value;                             \
    }

BitCountSigned(int8_t);
BitCountSigned(int16_t);
BitCountSigned(int32_t);
BitCountSigned(int64_t);

#undef BitCountSigned

template <typename ValueType, ValueType Value>
struct ByteCount {
    private:
        static const uint16_t bitCount = BitCount<ValueType, Value>::value;

    public:
        static const uint16_t value = (bitCount % 8 == 0) ?
                                          (bitCount / 8) :
                                          ((bitCount / 8) + 1);
};

// Runtime bit / byte count calculation

inline const uint16_t getBitCount(uint64_t value) {
    uint16_t result = 0;

    while (value > 0) {
        ++result;

        value >>= 1;
    }

    return (result);
}

static inline const uint16_t getBitCount(uint8_t value) {
    return (getBitCount(static_cast<uint64_t>(value)));
}

static inline const uint16_t getBitCount(uint16_t value) {
    return (getBitCount(static_cast<uint64_t>(value)));
}

static inline const uint16_t getBitCount(uint32_t value) {
    return (getBitCount(static_cast<uint64_t>(value)));
}

static inline const uint16_t getBitCount(bool value) {
    return ((value) ? 1 : 0);
}

static inline const uint16_t getBitCount(int8_t value) {
    return ((value < 0) ? sizeof(int8_t) : getBitCount(static_cast<uint64_t>(value)));
}
static inline const uint16_t getBitCount(int16_t value) {
    return ((value < 0) ? sizeof(int16_t) : getBitCount(static_cast<uint64_t>(value)));
}
static inline const uint16_t getBitCount(int32_t value) {
    return ((value < 0) ? sizeof(int32_t) : getBitCount(static_cast<uint64_t>(value)));
}
static inline const uint16_t getBitCount(int64_t value) {
    return ((value < 0) ? sizeof(int64_t) : getBitCount(static_cast<uint64_t>(value)));
}

inline const uint16_t bitCountToByteCount(const uint16_t value) {
    // Similar to
    //  return (((value % 8) == 0) ? (value / 8) : ((value / 8) + 1));
    //
    return (((value & 0x7) == 0) ? (value >> 3) : ((value >> 3) + 1));
}

#endif