/* Internal function for converting integers to ASCII.
   Copyright (C) 1994-2014 Free Software Foundation, Inc.
   This file is part of the GNU C Library.
   Contributed by Torbjorn Granlund <tege@matematik.su.se>
   and Ulrich Drepper <drepper@gnu.org>.

   The GNU C Library is free software; you can redistribute it and/or
   modify it under the terms of the GNU Lesser General Public
   License as published by the Free Software Foundation; either
   version 2.1 of the License, or (at your option) any later version.

   The GNU C Library is distributed in the hope that it will be useful,
   but WITHOUT ANY WARRANTY; without even the implied warranty of
   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
   Lesser General Public License for more details.

   You should have received a copy of the GNU Lesser General Public
   License along with the GNU C Library; if not, see
   <http://www.gnu.org/licenses/>.  */

#include <gmp-mparam.h>
#include <gmp.h>
#include <limits.h>
#include <stdlib/gmp-impl.h>
#include <stdlib/longlong.h>

#include <_itowa.h>


/* Canonize environment.  For some architectures not all values might
   be defined in the GMP header files.  */
#ifndef UMUL_TIME
# define UMUL_TIME 1
#endif
#ifndef UDIV_TIME
# define UDIV_TIME 3
#endif

/* Control memory layout.  */
#ifdef PACK
# undef PACK
# define PACK __attribute__ ((packed))
#else
# define PACK
#endif


/* Declare local types.  */
struct base_table_t
{
#if (UDIV_TIME > 2 * UMUL_TIME)
  mp_limb_t base_multiplier;
#endif
  char flag;
  char post_shift;
#if BITS_PER_MP_LIMB == 32
  struct
    {
      char normalization_steps;
      char ndigits;
      mp_limb_t base PACK;
#if UDIV_TIME > 2 * UMUL_TIME
      mp_limb_t base_ninv PACK;
#endif
    } big;
#endif
};

/* To reduce the memory needed we include some fields of the tables
   only conditionally.  */
#if UDIV_TIME > 2 * UMUL_TIME
# define SEL1(X) X,
# define SEL2(X) ,X
#else
# define SEL1(X)
# define SEL2(X)
#endif

/* Factor table for the different bases.  */
extern const struct base_table_t _itoa_base_table[] attribute_hidden;

/* Lower-case digits.  */
extern const wchar_t _itowa_lower_digits[] attribute_hidden;
/* Upper-case digits.  */
extern const wchar_t _itowa_upper_digits[] attribute_hidden;


#if _ITOA_NEEDED
wchar_t *
_itowa (value, buflim, base, upper_case)
     unsigned long long int value;
     wchar_t *buflim;
     unsigned int base;
     int upper_case;
{
  const wchar_t *digits = (upper_case
                           ? _itowa_upper_digits : _itowa_lower_digits);
  wchar_t *bp = buflim;
  const struct base_table_t *brec = &_itoa_base_table[base - 2];

  switch (base)
    {
# define RUN_2N(BITS) \
      do                                                                      \
        {                                                                     \
          /* `unsigned long long int' always has 64 bits.  */                 \
          mp_limb_t work_hi = value >> (64 - BITS_PER_MP_LIMB);               \
                                                                              \
          if (BITS_PER_MP_LIMB == 32)                                         \
            {                                                                 \
              if (work_hi != 0)                                               \
                {                                                             \
                  mp_limb_t work_lo;                                          \
                  int cnt;                                                    \
                                                                              \
                  work_lo = value & 0xfffffffful;                             \
                  for (cnt = BITS_PER_MP_LIMB / BITS; cnt > 0; --cnt)         \
                    {                                                         \
                      *--bp = digits[work_lo & ((1ul << BITS) - 1)];          \
                      work_lo >>= BITS;                                       \
                    }                                                         \
                  if (BITS_PER_MP_LIMB % BITS != 0)                           \
                    {                                                         \
                      work_lo                                                 \
                        |= ((work_hi                                          \
                             & ((1 << (BITS - BITS_PER_MP_LIMB%BITS))         \
                                - 1))                                         \
                            << BITS_PER_MP_LIMB % BITS);                      \
                      work_hi >>= BITS - BITS_PER_MP_LIMB % BITS;             \
                      if (work_hi == 0)                                       \
                        work_hi = work_lo;                                    \
                      else                                                    \
                        *--bp = digits[work_lo];                              \
                    }                                                         \
                }                                                             \
              else                                                            \
                work_hi = value & 0xfffffffful;                               \
            }                                                                 \
          do                                                                  \
            {                                                                 \
              *--bp = digits[work_hi & ((1 << BITS) - 1)];                    \
              work_hi >>= BITS;                                               \
            }                                                                 \
          while (work_hi != 0);                                               \
        }                                                                     \
      while (0)
    case 8:
      RUN_2N (3);
      break;

    case 16:
      RUN_2N (4);
      break;

    default:
      {
# if BITS_PER_MP_LIMB == 64
        mp_limb_t base_multiplier = brec->base_multiplier;
        if (brec->flag)
          while (value != 0)
            {
              mp_limb_t quo, rem, x;
              mp_limb_t dummy __attribute__ ((unused));

              umul_ppmm (x, dummy, value, base_multiplier);
              quo = (x + ((value - x) >> 1)) >> (brec->post_shift - 1);
              rem = value - quo * base;
              *--bp = digits[rem];
              value = quo;
            }
        else
          while (value != 0)
            {
              mp_limb_t quo, rem, x;
              mp_limb_t dummy __attribute__ ((unused));

              umul_ppmm (x, dummy, value, base_multiplier);
              quo = x >> brec->post_shift;
              rem = value - quo * base;
              *--bp = digits[rem];
              value = quo;
            }
# endif
# if BITS_PER_MP_LIMB == 32
        mp_limb_t t[3];
        int n;

        /* First convert x0 to 1-3 words in base s->big.base.
           Optimize for frequent cases of 32 bit numbers.  */
        if ((mp_limb_t) (value >> 32) >= 1)
          {
# if UDIV_TIME > 2 * UMUL_TIME || UDIV_NEEDS_NORMALIZATION
            int big_normalization_steps = brec->big.normalization_steps;
            mp_limb_t big_base_norm
              = brec->big.base << big_normalization_steps;
# endif
            if ((mp_limb_t) (value >> 32) >= brec->big.base)
              {
                mp_limb_t x1hi, x1lo, r;
                /* If you want to optimize this, take advantage of
                   that the quotient in the first udiv_qrnnd will
                   always be very small.  It might be faster just to
                   subtract in a tight loop.  */

# if UDIV_TIME > 2 * UMUL_TIME
                mp_limb_t x, xh, xl;

                if (big_normalization_steps == 0)
                  xh = 0;
                else
                  xh = (mp_limb_t) (value >> (64 - big_normalization_steps));
                xl = (mp_limb_t) (value >> (32 - big_normalization_steps));
                udiv_qrnnd_preinv (x1hi, r, xh, xl, big_base_norm,
                                   brec->big.base_ninv);

                xl = ((mp_limb_t) value) << big_normalization_steps;
                udiv_qrnnd_preinv (x1lo, x, r, xl, big_base_norm,
                                   brec->big.base_ninv);
                t[2] = x >> big_normalization_steps;

                if (big_normalization_steps == 0)
                  xh = x1hi;
                else
                  xh = ((x1hi << big_normalization_steps)
                        | (x1lo >> (32 - big_normalization_steps)));
                xl = x1lo << big_normalization_steps;
                udiv_qrnnd_preinv (t[0], x, xh, xl, big_base_norm,
                                   brec->big.base_ninv);
                t[1] = x >> big_normalization_steps;
# elif UDIV_NEEDS_NORMALIZATION
                mp_limb_t x, xh, xl;

                if (big_normalization_steps == 0)
                  xh = 0;
                else
                  xh = (mp_limb_t) (value >> 64 - big_normalization_steps);
                xl = (mp_limb_t) (value >> 32 - big_normalization_steps);
                udiv_qrnnd (x1hi, r, xh, xl, big_base_norm);

                xl = ((mp_limb_t) value) << big_normalization_steps;
                udiv_qrnnd (x1lo, x, r, xl, big_base_norm);
                t[2] = x >> big_normalization_steps;

                if (big_normalization_steps == 0)
                  xh = x1hi;
                else
                  xh = ((x1hi << big_normalization_steps)
                        | (x1lo >> 32 - big_normalization_steps));
                xl = x1lo << big_normalization_steps;
                udiv_qrnnd (t[0], x, xh, xl, big_base_norm);
                t[1] = x >> big_normalization_steps;
# else
                udiv_qrnnd (x1hi, r, 0, (mp_limb_t) (value >> 32),
                            brec->big.base);
                udiv_qrnnd (x1lo, t[2], r, (mp_limb_t) value, brec->big.base);
                udiv_qrnnd (t[0], t[1], x1hi, x1lo, brec->big.base);
# endif
                n = 3;
              }
            else
              {
# if UDIV_TIME > 2 * UMUL_TIME
                mp_limb_t x;

                value <<= brec->big.normalization_steps;
                udiv_qrnnd_preinv (t[0], x, (mp_limb_t) (value >> 32),
                                   (mp_limb_t) value, big_base_norm,
                                   brec->big.base_ninv);
                t[1] = x >> brec->big.normalization_steps;
# elif UDIV_NEEDS_NORMALIZATION
                mp_limb_t x;

                value <<= big_normalization_steps;
                udiv_qrnnd (t[0], x, (mp_limb_t) (value >> 32),
                            (mp_limb_t) value, big_base_norm);
                t[1] = x >> big_normalization_steps;
# else
                udiv_qrnnd (t[0], t[1], (mp_limb_t) (value >> 32),
                            (mp_limb_t) value, brec->big.base);
# endif
                n = 2;
              }
          }
        else
          {
            t[0] = value;
            n = 1;
          }

        /* Convert the 1-3 words in t[], word by word, to ASCII.  */
        do
          {
            mp_limb_t ti = t[--n];
            int ndig_for_this_limb = 0;

# if UDIV_TIME > 2 * UMUL_TIME
            mp_limb_t base_multiplier = brec->base_multiplier;
            if (brec->flag)
              while (ti != 0)
                {
                  mp_limb_t quo, rem, x;
                  mp_limb_t dummy __attribute__ ((unused));

                  umul_ppmm (x, dummy, ti, base_multiplier);
                  quo = (x + ((ti - x) >> 1)) >> (brec->post_shift - 1);
                  rem = ti - quo * base;
                  *--bp = digits[rem];
                  ti = quo;
                  ++ndig_for_this_limb;
                }
            else
              while (ti != 0)
                {
                  mp_limb_t quo, rem, x;
                  mp_limb_t dummy __attribute__ ((unused));

                  umul_ppmm (x, dummy, ti, base_multiplier);
                  quo = x >> brec->post_shift;
                  rem = ti - quo * base;
                  *--bp = digits[rem];
                  ti = quo;
                  ++ndig_for_this_limb;
                }
# else
            while (ti != 0)
              {
                mp_limb_t quo, rem;

                quo = ti / base;
                rem = ti % base;
                *--bp = digits[rem];
                ti = quo;
                ++ndig_for_this_limb;
              }
# endif
            /* If this wasn't the most significant word, pad with zeros.  */
            if (n != 0)
              while (ndig_for_this_limb < brec->big.ndigits)
                {
                  *--bp = '0';
                  ++ndig_for_this_limb;
                }
          }
        while (n != 0);
# endif
      }
      break;
    }

  return bp;
}
#endif