source: source/ariba/utility/vtypes/detail/vint_small.hpp @ 7468

// vint_small.hpp, created on 01.12.2008 by Sebastian Mies
// [The FreeBSD Licence]
//
// Copyright (c) 2008
//     Sebastian Mies, Institute of Telematics, UniversitÀt Karlsruhe (TH)
//     All rights reserved.
//
// Redistribution and use in source and binary forms, with or without
// modification, are permitted provided that the following conditions are
// met:
//
// * Redistributions of source code must retain the above copyright notice,
//   this list of conditions and the following disclaimer.
// * Redistributions 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.
// * Neither the name of the author nor the names of its contributors may 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,
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#ifndef VINT_SMALL_HPP_
#define VINT_SMALL_HPP_

#include<boost/mpl/if.hpp>
#include<boost/integer.hpp>

#include "helper.hpp"
#include <cmath>

#define NO_INT64

using boost::mpl::if_;
using boost::mpl::bool_;

namespace _vint {
namespace detail {
        template<size_t l, bool s> class vint_small;
}} // namespace _vint::detail

template<size_t l, bool s>
std::ostream& operator<<(std::ostream& os, const _vint::detail::vint_small<l, s>& v);

namespace _vint {
namespace detail {

/**
 * This class implements a integer wrapper for native integer types
 * and adapts it to integers which do not have a length divideable by
 * a power of 2. In this case bits are masked out to mimic the behaviour
 * of a real variable small integer.
 *
 * SIGNED values are currently unsupported!!!
 *
 * @autor Sebastian Mies
 */
template<size_t __length = 0, bool __sign = false>
class vint_small {
        friend std::ostream& operator<< <__length, __sign> (std::ostream&,
                        const vint_small<__length, __sign>&);
private:
        /* selection of integer type (beware: nasty mpl stuff :) */
typedef
#ifndef NO_INT64
        typename if_<
        bool_<(__length> 32 && __length <= 64)>,
        typename if_<bool_<__sign>, boost::int64_t, boost::uint64_t>::type,
#endif
#ifndef NO_INT32
        typename if_<
        bool_<(__length> 16 && __length <= 32)>,
        typename if_<bool_<__sign>, boost::int32_t, boost::uint32_t>::type,
#endif
        typename if_<
        bool_<(__length> 8 && __length <= 16)>,
        typename if_<bool_<__sign>, boost::int16_t, boost::uint16_t>::type,
        typename if_<
        bool_<(__length> 0 && __length <= 8)>,
        typename if_<bool_<__sign>, boost::int8_t, boost::uint8_t>::type,
        void
>       ::type
#ifndef NO_INT32
>       ::type
#endif
#ifndef NO_INT64
>       ::type
#endif
>       ::type type;

        /* THE actual value */
        type value;

        /* this method trims an integer if neccessary */
        finline void trim() {
                value &= (((type)1) << __length) - 1;
        }

        /* our internal small int */
        typedef vint_small<__length,__sign> _self;
public:
        finline vint_small() {
                value = 0;
        }

        finline vint_small( const type& value ) {
                this->value = value;
                trim();
        }

        finline vint_small(const char* text, int base = 10) {
                assign(std::string(text),base);
        }

        //-- conversion -----------------------------------------------------------

        template<class T>
        finline void convert_to( T& v, if_integral(T) ) const {
                v = (T)value;
        }

        finline std::string to_string(int base = 10,
                        int str_size = 0, char str_fill = '0') const {

                // convert to another base
                std::string s = "\0";
                int last_non_zero = 0;
                int last = 0;
                type _val = value;

                while (_val != 0) {
                        // divide by base
                        type rem = _val % base;
                        type _div = _val / base;

                        // set char
                        s += (char) rem;
                        if (rem != 0) last_non_zero = last;
                        last++;

                        // divided value as new
                        _val = _div;
                }
                last = last_non_zero + 1;

                // reverse
                for (int i = 0; i < last / 2; i++) {
                        char dummy = s[i];
                        s[i] = s[last - i - 1];
                        s[last - i - 1] = (int) dummy;
                }

                // convert string
                s.resize(last);
                for (int i = 0; i < last; i++)
                s[i] = ("0123456789ABCDEF")[(int) s[i]];

                // add leading zeros
                if (last < str_size) {
                        char zeros[str_size - last+1];
                        memset(zeros, str_fill, str_size - last);
                        zeros[str_size - last] = 0;
                        return std::string(zeros) + s;
                } else {
                        return s;
                }
        }

        std::string to_debug_string(int base = 10,
                        int str_size = 0, char str_fill = '0') const {
                std::ostringstream str;
                str << "vint_small(static,";
                str << "length=" << __length << ",";
                str << "mem=" << sizeof(*this) << ",";
                str << "val=" << to_string(base, str_size, str_fill) << ")";
                return str.str();
        }

        //-- sub integers ---------------------------------------------------------

        finline bool get_bit(size_t index) const {
                return false;
        }

        finline void set_bit(size_t index, bool v) {
        }

        finline void set_subint(_self& v, size_t index) {
        }

        finline void set_subint(uintmax_t v, size_t index) {
        }

        finline _self get_subint(size_t index, size_t length) const {
        }

        finline uintmax_t get_subint(size_t index) const {
                return 0;
        }

        //-- assignment -----------------------------------------------------------

        template<typename T>
        finline void assign(const T& v, if_integral(T) ) {
                value = v;
        }

        finline void assign(const std::string& text, int base = 10) {
                int x;
                sscanf(text.c_str(), "%d", &x);
                value = x;
        }

        //-- compare operations ---------------------------------------------------

        finline int compare_to(const _self& v) const {
                return (int)(value-v.value);
        }

        template<class T>
        finline int compare_to(const T& v, if_integral(T) ) const {
                return (int)(value-v);
        }

        //-- integer arithmetic ---------------------------------------------------

        // addition
        template<class T>
        finline void add(const T& rhs, if_integral(T) ) {
                value += rhs; trim();
        }

        finline void add(const _self& rhs) {
                value += rhs.value; trim();
        }

        // subtraction
        template<class T>
        finline void sub(const T& rhs, if_integral(T) ) {
                value -= rhs; trim();
        }

        finline void sub(const _self& rhs) {
                value -= rhs.value; trim();
        }

        // multiplication
        template<class T>
        finline void mul(const T& rhs, if_integral(T) ) {
                value *= rhs; trim();
        }

        finline void mul(const _self& rhs) {
                value *= rhs.value; trim();
        }

        finline void mul(_self& res_l, _self& res_h, _self& rhs) {
                res_l.value = rhs.value * value;
                res_h.value = (rhs.value >> __length) * value;
        }

        // modulo
        template<class T>
        finline void mod(const T& rhs, if_integral(T) ) {
                value %= rhs; trim();
        }

        finline void mod( const _self& rhs ) {
                value %= rhs.value; trim();
        }

        finline void mod( _self& res, const _self& rhs ) {
                res.value = value % rhs.value; res.trim();
        }

        // exception to modulo
        template<class T>
        finline void mod( T& res, const T& rhs, if_integral(T) ) const {
                res = value % rhs;
        }

        // division
        template<class T>
        finline void div( const T& rhs, if_integral(T) ) {
                value /= rhs; trim();
        }

        finline void div( const _self& rhs ) {
                value /= rhs.value; trim();
        }

        finline void div( _self& res, const _self& rhs ) {
                res.value = value / rhs.value; res.trim();
        }

        // division with remainder
        template<class T>
        finline void divrem(_self& res_div, _self& res_rem, const T& rhs, if_integral(T)) {
                res_div.value = value / rhs;
                res_rem.value = value % rhs;
        }

        finline void divrem(_self& res_rem, const _self& rhs) {
                value = value / rhs.value;
                res_rem.value = value % rhs.value;
        }

        finline void divrem(_self& res_div, _self& res_rem, const _self& rhs) {
                res_div.value = value / rhs.value;
                res_rem.value = value % rhs.value;
        }

        // exception to division with remainder
        template<class T>
        finline void divrem(_self& res_div, T& res_rem, const T& rhs, if_integral(T)) {
                res_div.value = value / rhs;
                res_rem = value % rhs;
        }

        // logarithm to the base of 2
        finline uintmax_t log2() const {
                return ::log2(value);
        }

        //-- logical bit operations -----------------------------------------------

        finline void or_ (const _self& rhs) {value |= rhs.value;}
        finline void and_(const _self& rhs) {value &= rhs.value;}
        finline void xor_(const _self& rhs) {value ^= rhs.value;}
        finline void complement() {value = ~value; trim();}
        finline void lshift(size_t steps) {value <<= steps; trim();}
        finline void rshift(size_t steps) {value >>= steps; trim();}

        //-- integer dynamic ------------------------------------------------------

        //      inline vint<0, __sign> normalized() const { return value.normalized(); }

        //-- general information --------------------------------------------------

        finline size_t length() const {return __length;}
        finline void set_length(size_t length) {}
        finline bool is_unspecified() {return false;}

        finline _self max() const {return ~(type)0;}
        finline _self min() const {return (type)0;}
        finline _self zero() const {return (type)0;}
};

}} // namespace _vint::detail

template<size_t l, bool s>
std::ostream& operator<<(std::ostream& os, const _vint::detail::vint_small<l, s>& v) {
        return os << v.to_string();
}

#endif /* VINT_SMALL_HPP_ */