integer_to_string.hpp

新版本TR1的stl

/* /////////////////////////////////////////////////////////////////////////
 * File:        stlsoft/conversion/integer_to_string.hpp
 *
 * Purpose:     Very efficient integer to string conversion functions.
 *
 * Created:     7th April 2002
 * Updated:     12th March 2007
 *
 * Home:        http://stlsoft.org/
 *
 * Copyright (c) 2002-2007, Matthew Wilson and Synesis Software
 * 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(s) of Matthew Wilson and Synesis Software nor the names of
 *   any 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, THE
 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
 * ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER 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.
 *
 * ////////////////////////////////////////////////////////////////////// */


/** \file stlsoft/conversion/integer_to_string.hpp
 *
 * \brief [C++ only] Very efficient integer to string conversion functions
 *   (\ref group__library__conversion "Conversion" Library).
 */

#ifndef STLSOFT_INCL_STLSOFT_CONVERSION_HPP_INTEGER_TO_STRING
#define STLSOFT_INCL_STLSOFT_CONVERSION_HPP_INTEGER_TO_STRING

#ifndef STLSOFT_DOCUMENTATION_SKIP_SECTION
# define STLSOFT_VER_STLSOFT_CONVERSION_HPP_INTEGER_TO_STRING_MAJOR     4
# define STLSOFT_VER_STLSOFT_CONVERSION_HPP_INTEGER_TO_STRING_MINOR     1
# define STLSOFT_VER_STLSOFT_CONVERSION_HPP_INTEGER_TO_STRING_REVISION  1
# define STLSOFT_VER_STLSOFT_CONVERSION_HPP_INTEGER_TO_STRING_EDIT      77
#endif /* !STLSOFT_DOCUMENTATION_SKIP_SECTION */

/* /////////////////////////////////////////////////////////////////////////
 * Includes
 */

#ifndef STLSOFT_INCL_STLSOFT_H_STLSOFT
# include <stlsoft/stlsoft.h>
#endif /* !STLSOFT_INCL_STLSOFT_H_STLSOFT */
#ifndef STLSOFT_CF_NEGATIVE_MODULUS_POSITIVE_GIVES_NEGATIVE_RESULT
# ifndef STLSOFT_INCL_STLSOFT_UTIL_H_LIMIT_TRAITS
#  include <stlsoft/util/limit_traits.h>
# endif /* !STLSOFT_INCL_STLSOFT_UTIL_H_LIMIT_TRAITS */
# ifndef STLSOFT_INCL_STLSOFT_UTIL_HPP_SIGN_TRAITS
#  include <stlsoft/util/sign_traits.hpp>
# endif /* !STLSOFT_INCL_STLSOFT_UTIL_HPP_SIGN_TRAITS */
# ifndef STLSOFT_INCL_STLSOFT_META_HPP_IS_SAME_TYPE
#  include <stlsoft/meta/is_same_type.hpp>
# endif /* !STLSOFT_INCL_STLSOFT_META_HPP_IS_SAME_TYPE */
#endif /* !STLSOFT_CF_NEGATIVE_MODULUS_POSITIVE_GIVES_NEGATIVE_RESULT */
#ifdef STLSOFT_UNITTEST
# ifndef STLSOFT_INCL_STLSOFT_UTIL_H_LIMIT_TRAITS
#  include <stlsoft/util/limit_traits.h>
# endif /* !STLSOFT_INCL_STLSOFT_UTIL_H_LIMIT_TRAITS */
# include <stdio.h>
# include <string.h>
#endif /* STLSOFT_UNITTEST */

/* /////////////////////////////////////////////////////////////////////////
 * Namespace
 */

#ifndef _STLSOFT_NO_NAMESPACE
namespace stlsoft
{
#endif /* _STLSOFT_NO_NAMESPACE */

/* /////////////////////////////////////////////////////////////////////////
 * Macros
 */

#ifdef __STLSOFT_INTEGER_TO_STRING_OPTIMISE_64BIT
# error __STLSOFT_INTEGER_TO_STRING_OPTIMISE_64BIT is no longer supported. Instead, define STLSOFT_INTEGER_TO_STRING_OPTIMISE_64BIT
#endif /* __STLSOFT_INTEGER_TO_STRING_OPTIMISE_64BIT */

/* /////////////////////////////////////////////////////////////////////////
 * Constants
 */

#if 0
namespace constants
{
    enum
    {
        buffer_width = 21   //!< Sufficient for sprintf()-ing 8/16/32/64 bit signed/unsigned integers
    };

} // namespace int2str
#endif /* 0 */

/* /////////////////////////////////////////////////////////////////////////
 * Helper Functions
 */

#ifndef STLSOFT_DOCUMENTATION_SKIP_SECTION

/** \brief Provides an indexable sequence of digit characters
 *
 * \ingroup group__library__conversion
 */
template <ss_typename_param_k C>
#ifdef STLSOFT_CF_TEMPLATE_TYPE_REQUIRED_IN_ARGS
inline C const* get_digit_character(C * )
#else /* ? STLSOFT_CF_TEMPLATE_TYPE_REQUIRED_IN_ARGS */
inline C const* get_digit_character()
#endif /* STLSOFT_CF_TEMPLATE_TYPE_REQUIRED_IN_ARGS */
{
    static C const  s_characters[19] =
    {
            '9'
        ,   '8'
        ,   '7'
        ,   '6'
        ,   '5'
        ,   '4'
        ,   '3'
        ,   '2'
        ,   '1'
        ,   '0'
        ,   '1'
        ,   '2'
        ,   '3'
        ,   '4'
        ,   '5'
        ,   '6'
        ,   '7'
        ,   '8'
        ,   '9'
    };
#if 0
    static C const  *s_mid  =   s_characters + 9;

    return s_mid;
#else /* ? 0 */
    return s_characters + 9;
#endif /* 0 */
}

#endif /* !STLSOFT_DOCUMENTATION_SKIP_SECTION */

/* /////////////////////////////////////////////////////////////////////////
 * Functions
 */

#ifndef STLSOFT_DOCUMENTATION_SKIP_SECTION

/** \brief Highly efficient conversion of unsigned integers to string
 *
 * \ingroup group__library__conversion
 *
 * \note The function does not check that cchBuf is sufficient for conversion
 * of the particular integer type, except for a debug version
 * <code>assert()</code>. It is the programmer's responsibility to ensure that
 * the supplied buffer is large enough for the conversion. This can be done
 * with the use of the printf_traits templates.
 *
 * \param buf A buffer of sufficient space within which to convert the integer
 * \param cchBuf The number of characters available in \c buf
 * \param i The integer to convert
 */
template<   ss_typename_param_k C
        ,   ss_typename_param_k I
        >
inline C const* unsigned_integer_to_string(C *buf, ss_size_t cchBuf, I i)
{
    C   *psz    =   buf + cchBuf - 1;  // Set pointer to last character.

    *psz = 0;   // Set the terminating null character.

    do
    {
#if defined(STLSOFT_COMPILER_IS_MSVC)
        typedef I           rem_t;
#else /* ? compiler */
        typedef ss_uint_t   rem_t;
#endif /* compiler */

        rem_t   lsd = static_cast<rem_t>(i % 10);   // Determine the least significant digit.

        i = static_cast<I>(i / 10);                 // Deal with next most significant.

        --psz;                                      // Move back.

#ifdef STLSOFT_CF_TEMPLATE_TYPE_REQUIRED_IN_ARGS
        *psz = get_digit_character(static_cast<C*>(NULL))[lsd];
#else /* ? STLSOFT_CF_TEMPLATE_TYPE_REQUIRED_IN_ARGS */
        *psz = get_digit_character<C>()[lsd];
#endif /* STLSOFT_CF_TEMPLATE_TYPE_REQUIRED_IN_ARGS */

    } while(i != 0);

    STLSOFT_ASSERT(!(psz < buf));

    return psz;
}


/** \brief Highly efficient conversion of unsigned integers to string
 *
 * \ingroup group__library__conversion
 *
 * \note The function does not check that cchBuf is sufficient for conversion
 * of the particular integer type, except for a debug version
 * <code>assert()</code>. It is the programmer's responsibility to ensure that
 * the supplied buffer is large enough for the conversion. This can be done
 * with the use of the printf_traits templates.
 *
 * \param buf A buffer of sufficient space within which to convert the integer
 * \param cchBuf The number of characters available in \c buf
 * \param i The integer to convert
 * \param cchRes Receives the number of characters written
 */
template<   ss_typename_param_k C
        ,   ss_typename_param_k I
        >
inline C const* unsigned_integer_to_string(C* buf, ss_size_t cchBuf, I i, ss_size_t& cchRes)
{
    C const* psz = unsigned_integer_to_string<C, I>(buf, cchBuf, i);

    cchRes = cchBuf - (psz - (buf - 1));

    return psz;
}


/** \brief Highly efficient conversion of signed integers to string
 *
 * \ingroup group__library__conversion
 *
 * \note The function does not check that cchBuf is sufficient for conversion
 * of the particular integer type, except for a debug version
 * <code>assert()</code>. It is the programmer's responsibility to ensure that
 * the supplied buffer is large enough for the conversion. This can be done
 * with the use of the printf_traits templates.
 *
 * \param buf A buffer of sufficient space within which to convert the integer
 * \param cchBuf The number of characters available in \c buf
 * \param i The integer to convert
 */
template<   ss_typename_param_k C
        ,   ss_typename_param_k I
        >
inline C const* signed_integer_to_string(C *buf, ss_size_t cchBuf, I i)
{
#ifndef STLSOFT_CF_NEGATIVE_MODULUS_POSITIVE_GIVES_NEGATIVE_RESULT
// If the compiler does not evaluate -9 % 10 to equal -9, then we need to work
// with it as if an unsigned, and prepend the -ve
    typedef limit_traits<I>                                 limit_traits_t;
    typedef sign_traits<I>                                  sign_traits_t;
    typedef ss_typename_type_k sign_traits_t::signed_type   signed_type_t;  
    typedef ss_typename_type_k sign_traits_t::unsigned_type unsigned_type_t;    

    // If this fires, something has happened to invoke this function on an
    // unsigned type.
    STLSOFT_STATIC_ASSERT((0 != is_same_type<signed_type_t, I>::value));

    C const* psz;

    if(i == limit_traits_t::minimum())
    {
        STLSOFT_ASSERT(i == -i);

        // Special case of the (signed) minimum, since the maximum -ve value
        // of a signed integer cannot be negated.
        //
        // We instead take the equivalent value as an unsigned integer,
        // convert that (as unsigned), and prepend a '-'

        psz = unsigned_integer_to_string(buf, cchBuf, static_cast<unsigned_type_t>(limit_traits_t::minimum()));

        *const_cast<C*>(--psz) = C('-');
    }
    else
    {
        // Just using the unsigned version here for the absence of
        // sign. Perversely, The invoked function is still a signed
        // specialisation.
        psz = unsigned_integer_to_string(buf, cchBuf, i);

        if(i < 0)
        {
            *const_cast<C*>(--psz) = C('-');
        }
    }

    return psz;
#else /* ? STLSOFT_CF_NEGATIVE_MODULUS_POSITIVE_GIVES_NEGATIVE_RESULT */
// Compiler evaluates -9 % 10 to equal -9, so use the full -ve algorithm. This
// is chosen because it is more efficient on most compilers than calling the
// unsigned peer and converting.

#if defined(STLSOFT_COMPILER_IS_MSVC)
    typedef I           rem_t;
#else /* ? compiler */
    typedef ss_sint_t   rem_t;
#endif /* compiler */

    C   *psz    =   buf + cchBuf - 1;  // Set pointer to last character.

    *psz = 0;   // Set the terminating null character.

    if(i < 0)
    {
        do
        {
            rem_t   lsd = static_cast<rem_t>(i % 10);   // Determine the least significant digit.

            i = static_cast<I>(i / 10);                 // Deal with next most significant.

            --psz;                                      // Move back.

#ifdef STLSOFT_CF_TEMPLATE_TYPE_REQUIRED_IN_ARGS
            *psz = get_digit_character(static_cast<C*>(NULL))[lsd];
#else /* ? STLSOFT_CF_TEMPLATE_TYPE_REQUIRED_IN_ARGS */
            *psz = get_digit_character<C>()[lsd];
#endif /* STLSOFT_CF_TEMPLATE_TYPE_REQUIRED_IN_ARGS */

        } while(i != 0);

        *(--psz) = C('-');              // Prepend the minus sign.
    }
    else
    {
        do
        {
            rem_t   lsd = static_cast<rem_t>(i % 10);   // Determine the least significant digit.

            i = static_cast<I>(i / 10);                 // Deal with next most significant.

            --psz;                                      // Move back.

#ifdef STLSOFT_CF_TEMPLATE_TYPE_REQUIRED_IN_ARGS
            *psz = get_digit_character(static_cast<C*>(NULL))[lsd];
#else /* ? STLSOFT_CF_TEMPLATE_TYPE_REQUIRED_IN_ARGS */
            *psz = get_digit_character<C>()[lsd];
#endif /* STLSOFT_CF_TEMPLATE_TYPE_REQUIRED_IN_ARGS */

        } while(i != 0);
    }

    STLSOFT_ASSERT(!(psz < buf));

    return psz;
#endif /* !STLSOFT_CF_NEGATIVE_MODULUS_POSITIVE_GIVES_NEGATIVE_RESULT */
}

/** \brief Highly efficient conversion of signed integers to string
 *
 * \ingroup group__library__conversion
 *
 * \note The function does not check that cchBuf is sufficient for conversion
 * of the particular integer type, except for a debug version
 * <code>assert()</code>. It is the programmer's responsibility to ensure that
 * the supplied buffer is large enough for the conversion. This can be done
 * with the use of the printf_traits templates.
 *
 * \param buf A buffer of sufficient space within which to convert the integer
 * \param cchBuf The number of characters available in \c buf
 * \param i The integer to convert
 * \param cchRes Receives the number of characters written
 */
template<   ss_typename_param_k C
        ,   ss_typename_param_k I
        >
inline C const* signed_integer_to_string(C* buf, ss_size_t cchBuf, I i, ss_size_t& cchRes)
{
    C const* psz = signed_integer_to_string<C, I>(buf, cchBuf, i);

    cchRes = cchBuf - (psz - (buf - 1));

    return psz;
}

#endif /* !STLSOFT_DOCUMENTATION_SKIP_SECTION */

/** \brief Highly efficient conversion of integer to string.
 *
 * \ingroup group__library__conversion
 */
template <ss_typename_param_k C>
inline C const* integer_to_string(C *buf, ss_size_t cchBuf, ss_sint8_t i)
{
    return signed_integer_to_string(buf, cchBuf, i);
}

/** \brief Highly efficient conversion of integer to string.
 *
 * \ingroup group__library__conversion
 */
template <ss_typename_param_k C>
inline C const* integer_to_string(C *buf, ss_size_t cchBuf, ss_uint8_t i)
{
    return unsigned_integer_to_string(buf, cchBuf, i);
}

/** \brief Highly efficient conversion of integer to string.
 *
 * \ingroup group__library__conversion
 */
template <ss_typename_param_k C>
inline C const* integer_to_string(C *buf, ss_size_t cchBuf, ss_sint16_t i)
{
    return signed_integer_to_string(buf, cchBuf, i);
}

/** \brief Highly efficient conversion of integer to string.
 *
 * \ingroup group__library__conversion
 */
template <ss_typename_param_k C>
inline C const* integer_to_string(C *buf, ss_size_t cchBuf, ss_uint16_t i)
{
    return unsigned_integer_to_string(buf, cchBuf, i);
}

/** \brief Highly efficient conversion of integer to string.
 *
 * \ingroup group__library__conversion
 */
template <ss_typename_param_k C>
inline C const* integer_to_string(C *buf, ss_size_t cchBuf, ss_sint32_t i)
{
    return signed_integer_to_string(buf, cchBuf, i);
}