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_itoa.c

/* Internal function for converting integers to ASCII.
   Copyright (C) 1994,1995,1996,1999,2000,2002 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, write to the Free
   Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA
   02111-1307 USA.  */

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

#include "_itoa.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


/* Local variables.  */
const struct base_table_t _itoa_base_table[] attribute_hidden =
{
#if BITS_PER_MP_LIMB == 64
  /*  2 */ {SEL1(0ul) 1, 1},
  /*  3 */ {SEL1(0xaaaaaaaaaaaaaaabul) 0, 1},
  /*  4 */ {SEL1(0ul) 1, 2},
  /*  5 */ {SEL1(0xcccccccccccccccdul) 0, 2},
  /*  6 */ {SEL1(0xaaaaaaaaaaaaaaabul) 0, 2},
  /*  7 */ {SEL1(0x2492492492492493ul) 1, 3},
  /*  8 */ {SEL1(0ul) 1, 3},
  /*  9 */ {SEL1(0xe38e38e38e38e38ful) 0, 3},
  /* 10 */ {SEL1(0xcccccccccccccccdul) 0, 3},
  /* 11 */ {SEL1(0x2e8ba2e8ba2e8ba3ul) 0, 1},
  /* 12 */ {SEL1(0xaaaaaaaaaaaaaaabul) 0, 3},
  /* 13 */ {SEL1(0x4ec4ec4ec4ec4ec5ul) 0, 2},
  /* 14 */ {SEL1(0x2492492492492493ul) 1, 4},
  /* 15 */ {SEL1(0x8888888888888889ul) 0, 3},
  /* 16 */ {SEL1(0ul) 1, 4},
  /* 17 */ {SEL1(0xf0f0f0f0f0f0f0f1ul) 0, 4},
  /* 18 */ {SEL1(0xe38e38e38e38e38ful) 0, 4},
  /* 19 */ {SEL1(0xd79435e50d79435ful) 0, 4},
  /* 20 */ {SEL1(0xcccccccccccccccdul) 0, 4},
  /* 21 */ {SEL1(0x8618618618618619ul) 1, 5},
  /* 22 */ {SEL1(0x2e8ba2e8ba2e8ba3ul) 0, 2},
  /* 23 */ {SEL1(0x642c8590b21642c9ul) 1, 5},
  /* 24 */ {SEL1(0xaaaaaaaaaaaaaaabul) 0, 4},
  /* 25 */ {SEL1(0x47ae147ae147ae15ul) 1, 5},
  /* 26 */ {SEL1(0x4ec4ec4ec4ec4ec5ul) 0, 3},
  /* 27 */ {SEL1(0x97b425ed097b425ful) 0, 4},
  /* 28 */ {SEL1(0x2492492492492493ul) 1, 5},
  /* 29 */ {SEL1(0x1a7b9611a7b9611bul) 1, 5},
  /* 30 */ {SEL1(0x8888888888888889ul) 0, 4},
  /* 31 */ {SEL1(0x0842108421084211ul) 1, 5},
  /* 32 */ {SEL1(0ul) 1, 5},
  /* 33 */ {SEL1(0x0f83e0f83e0f83e1ul) 0, 1},
  /* 34 */ {SEL1(0xf0f0f0f0f0f0f0f1ul) 0, 5},
  /* 35 */ {SEL1(0xea0ea0ea0ea0ea0ful) 0, 5},
  /* 36 */ {SEL1(0xe38e38e38e38e38ful) 0, 5}
#endif
#if BITS_PER_MP_LIMB == 32
  /*  2 */ {SEL1(0ul) 1, 1, {0, 31, 0x80000000ul SEL2(0xfffffffful)}},
  /*  3 */ {SEL1(0xaaaaaaabul) 0, 1, {0, 20, 0xcfd41b91ul SEL2(0x3b563c24ul)}},
  /*  4 */ {SEL1(0ul) 1, 2, {1, 15, 0x40000000ul SEL2(0xfffffffful)}},
  /*  5 */ {SEL1(0xcccccccdul) 0, 2, {1, 13, 0x48c27395ul SEL2(0xc25c2684ul)}},
  /*  6 */ {SEL1(0xaaaaaaabul) 0, 2, {0, 12, 0x81bf1000ul SEL2(0xf91bd1b6ul)}},
  /*  7 */ {SEL1(0x24924925ul) 1, 3, {1, 11, 0x75db9c97ul SEL2(0x1607a2cbul)}},
  /*  8 */ {SEL1(0ul) 1, 3, {1, 10, 0x40000000ul SEL2(0xfffffffful)}},
  /*  9 */ {SEL1(0x38e38e39ul) 0, 1, {0, 10, 0xcfd41b91ul SEL2(0x3b563c24ul)}},
  /* 10 */ {SEL1(0xcccccccdul) 0, 3, {2, 9, 0x3b9aca00ul SEL2(0x12e0be82ul)}},
  /* 11 */ {SEL1(0xba2e8ba3ul) 0, 3, {0, 9, 0x8c8b6d2bul SEL2(0xd24cde04ul)}},
  /* 12 */ {SEL1(0xaaaaaaabul) 0, 3, {3, 8, 0x19a10000ul SEL2(0x3fa39ab5ul)}},
  /* 13 */ {SEL1(0x4ec4ec4ful) 0, 2, {2, 8, 0x309f1021ul SEL2(0x50f8ac5ful)}},
  /* 14 */ {SEL1(0x24924925ul) 1, 4, {1, 8, 0x57f6c100ul SEL2(0x74843b1eul)}},
  /* 15 */ {SEL1(0x88888889ul) 0, 3, {0, 8, 0x98c29b81ul SEL2(0xad0326c2ul)}},
  /* 16 */ {SEL1(0ul) 1, 4, {3, 7, 0x10000000ul SEL2(0xfffffffful)}},
  /* 17 */ {SEL1(0xf0f0f0f1ul) 0, 4, {3, 7, 0x18754571ul SEL2(0x4ef0b6bdul)}},
  /* 18 */ {SEL1(0x38e38e39ul) 0, 2, {2, 7, 0x247dbc80ul SEL2(0xc0fc48a1ul)}},
  /* 19 */ {SEL1(0xaf286bcbul) 1, 5, {2, 7, 0x3547667bul SEL2(0x33838942ul)}},
  /* 20 */ {SEL1(0xcccccccdul) 0, 4, {1, 7, 0x4c4b4000ul SEL2(0xad7f29abul)}},
  /* 21 */ {SEL1(0x86186187ul) 1, 5, {1, 7, 0x6b5a6e1dul SEL2(0x313c3d15ul)}},
  /* 22 */ {SEL1(0xba2e8ba3ul) 0, 4, {0, 7, 0x94ace180ul SEL2(0xb8cca9e0ul)}},
  /* 23 */ {SEL1(0xb21642c9ul) 0, 4, {0, 7, 0xcaf18367ul SEL2(0x42ed6de9ul)}},
  /* 24 */ {SEL1(0xaaaaaaabul) 0, 4, {4, 6, 0x0b640000ul SEL2(0x67980e0bul)}},
  /* 25 */ {SEL1(0x51eb851ful) 0, 3, {4, 6, 0x0e8d4a51ul SEL2(0x19799812ul)}},
  /* 26 */ {SEL1(0x4ec4ec4ful) 0, 3, {3, 6, 0x1269ae40ul SEL2(0xbce85396ul)}},
  /* 27 */ {SEL1(0x2f684bdbul) 1, 5, {3, 6, 0x17179149ul SEL2(0x62c103a9ul)}},
  /* 28 */ {SEL1(0x24924925ul) 1, 5, {3, 6, 0x1cb91000ul SEL2(0x1d353d43ul)}},
  /* 29 */ {SEL1(0x8d3dcb09ul) 0, 4, {2, 6, 0x23744899ul SEL2(0xce1deceaul)}},
  /* 30 */ {SEL1(0x88888889ul) 0, 4, {2, 6, 0x2b73a840ul SEL2(0x790fc511ul)}},
  /* 31 */ {SEL1(0x08421085ul) 1, 5, {2, 6, 0x34e63b41ul SEL2(0x35b865a0ul)}},
  /* 32 */ {SEL1(0ul) 1, 5, {1, 6, 0x40000000ul SEL2(0xfffffffful)}},
  /* 33 */ {SEL1(0x3e0f83e1ul) 0, 3, {1, 6, 0x4cfa3cc1ul SEL2(0xa9aed1b3ul)}},
  /* 34 */ {SEL1(0xf0f0f0f1ul) 0, 5, {1, 6, 0x5c13d840ul SEL2(0x63dfc229ul)}},
  /* 35 */ {SEL1(0xd41d41d5ul) 1, 6, {1, 6, 0x6d91b519ul SEL2(0x2b0fee30ul)}},
  /* 36 */ {SEL1(0x38e38e39ul) 0, 3, {0, 6, 0x81bf1000ul SEL2(0xf91bd1b6ul)}}
#endif
};

/* Lower-case digits.  */
extern const char _itoa_lower_digits[];
extern const char _itoa_lower_digits_internal[] attribute_hidden;
/* Upper-case digits.  */
extern const char _itoa_upper_digits[];
extern const char _itoa_upper_digits_internal[] attribute_hidden;


char *
_itoa (value, buflim, base, upper_case)
     unsigned long long int value;
     char *buflim;
     unsigned int base;
     int upper_case;
{
  const char *digits = (upper_case
                  ? INTUSE(_itoa_upper_digits)
                  : INTUSE(_itoa_lower_digits));
  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)       \
                {                                           \
                  *--buflim = 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                                      \
                  *--buflim = digits[work_lo];                    \
                }                                           \
            }                                               \
            else                                            \
            work_hi = value & 0xfffffffful;                             \
          }                                                 \
        do                                                  \
          {                                                 \
            *--buflim = 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, dummy;

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

            umul_ppmm (x, dummy, value, base_multiplier);
            quo = x >> brec->post_shift;
            rem = value - quo * base;
            *--buflim = 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, dummy;

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

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

            quo = ti / base;
            rem = ti % base;
            *--buflim = 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)
            {
              *--buflim = '0';
              ++ndig_for_this_limb;
            }
        }
      while (n != 0);
#endif
      }
      break;
    }

  return buflim;
}

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