stdio-common/_itoa.c

   1 /* Internal function for converting integers to ASCII.
   2    Copyright (C) 1994-2017 Free Software Foundation, Inc.
   3    This file is part of the GNU C Library.
   4    Contributed by Torbjorn Granlund <tege@matematik.su.se>
   5    and Ulrich Drepper <drepper@gnu.org>.
   6
   7    The GNU C Library is free software; you can redistribute it and/or
   8    modify it under the terms of the GNU Lesser General Public
   9    License as published by the Free Software Foundation; either
  10    version 2.1 of the License, or (at your option) any later version.
  11
  12    The GNU C Library is distributed in the hope that it will be useful,
  13    but WITHOUT ANY WARRANTY; without even the implied warranty of
  14    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  15    Lesser General Public License for more details.
  16
  17    You should have received a copy of the GNU Lesser General Public
  18    License along with the GNU C Library; if not, see
  19    <http://www.gnu.org/licenses/>.  */
  20
  21 #include <gmp-mparam.h>
  22 #include <gmp.h>
  23 #include <limits.h>
  24 #include <stdlib/gmp-impl.h>
  25 #include <stdlib/longlong.h>
  26
  27 #include <_itoa.h>
  28
  29
  30 /* Canonize environment.  For some architectures not all values might
  31    be defined in the GMP header files.  */
  32 #ifndef UMUL_TIME
  33 # define UMUL_TIME 1
  34 #endif
  35 #ifndef UDIV_TIME
  36 # define UDIV_TIME 3
  37 #endif
  38
  39 /* Control memory layout.  */
  40 #ifdef PACK
  41 # undef PACK
  42 # define PACK __attribute__ ((packed))
  43 #else
  44 # define PACK
  45 #endif
  46
  47
  48 /* Declare local types.  */
  49 struct base_table_t
  50 {
  51 #if (UDIV_TIME > 2 * UMUL_TIME)
  52   mp_limb_t base_multiplier;
  53 #endif
  54   char flag;
  55   char post_shift;
  56 #if BITS_PER_MP_LIMB == 32
  57   struct
  58     {
  59       char normalization_steps;
  60       char ndigits;
  61       mp_limb_t base PACK;
  62 #if UDIV_TIME > 2 * UMUL_TIME
  63       mp_limb_t base_ninv PACK;
  64 #endif
  65     } big;
  66 #endif
  67 };
  68
  69 /* To reduce the memory needed we include some fields of the tables
  70    only conditionally.  */
  71 #if UDIV_TIME > 2 * UMUL_TIME
  72 # define SEL1(X) X,
  73 # define SEL2(X) ,X
  74 #else
  75 # define SEL1(X)
  76 # define SEL2(X)
  77 #endif
  78
  79
  80 /* We do not compile _itoa if we always can use _itoa_word.  */
  81 #if _ITOA_NEEDED
  82 /* Local variables.  */
  83 const struct base_table_t _itoa_base_table[] attribute_hidden =
  84 {
  85 # if BITS_PER_MP_LIMB == 64
  86   /*  2 */ {SEL1(0ull) 1, 1},
  87   /*  3 */ {SEL1(0xaaaaaaaaaaaaaaabull) 0, 1},
  88   /*  4 */ {SEL1(0ull) 1, 2},
  89   /*  5 */ {SEL1(0xcccccccccccccccdull) 0, 2},
  90   /*  6 */ {SEL1(0xaaaaaaaaaaaaaaabull) 0, 2},
  91   /*  7 */ {SEL1(0x2492492492492493ull) 1, 3},
  92   /*  8 */ {SEL1(0ull) 1, 3},
  93   /*  9 */ {SEL1(0xe38e38e38e38e38full) 0, 3},
  94   /* 10 */ {SEL1(0xcccccccccccccccdull) 0, 3},
  95   /* 11 */ {SEL1(0x2e8ba2e8ba2e8ba3ull) 0, 1},
  96   /* 12 */ {SEL1(0xaaaaaaaaaaaaaaabull) 0, 3},
  97   /* 13 */ {SEL1(0x4ec4ec4ec4ec4ec5ull) 0, 2},
  98   /* 14 */ {SEL1(0x2492492492492493ull) 1, 4},
  99   /* 15 */ {SEL1(0x8888888888888889ull) 0, 3},
 100   /* 16 */ {SEL1(0ull) 1, 4},
 101   /* 17 */ {SEL1(0xf0f0f0f0f0f0f0f1ull) 0, 4},
 102   /* 18 */ {SEL1(0xe38e38e38e38e38full) 0, 4},
 103   /* 19 */ {SEL1(0xd79435e50d79435full) 0, 4},
 104   /* 20 */ {SEL1(0xcccccccccccccccdull) 0, 4},
 105   /* 21 */ {SEL1(0x8618618618618619ull) 1, 5},
 106   /* 22 */ {SEL1(0x2e8ba2e8ba2e8ba3ull) 0, 2},
 107   /* 23 */ {SEL1(0x642c8590b21642c9ull) 1, 5},
 108   /* 24 */ {SEL1(0xaaaaaaaaaaaaaaabull) 0, 4},
 109   /* 25 */ {SEL1(0x47ae147ae147ae15ull) 1, 5},
 110   /* 26 */ {SEL1(0x4ec4ec4ec4ec4ec5ull) 0, 3},
 111   /* 27 */ {SEL1(0x97b425ed097b425full) 0, 4},
 112   /* 28 */ {SEL1(0x2492492492492493ull) 1, 5},
 113   /* 29 */ {SEL1(0x1a7b9611a7b9611bull) 1, 5},
 114   /* 30 */ {SEL1(0x8888888888888889ull) 0, 4},
 115   /* 31 */ {SEL1(0x0842108421084211ull) 1, 5},
 116   /* 32 */ {SEL1(0ull) 1, 5},
 117   /* 33 */ {SEL1(0x0f83e0f83e0f83e1ull) 0, 1},
 118   /* 34 */ {SEL1(0xf0f0f0f0f0f0f0f1ull) 0, 5},
 119   /* 35 */ {SEL1(0xea0ea0ea0ea0ea0full) 0, 5},
 120   /* 36 */ {SEL1(0xe38e38e38e38e38full) 0, 5}
 121 # endif
 122 # if BITS_PER_MP_LIMB == 32
 123   /*  2 */ {SEL1(0ul) 1, 1, {0, 31, 0x80000000ul SEL2(0xfffffffful)}},
 124   /*  3 */ {SEL1(0xaaaaaaabul) 0, 1, {0, 20, 0xcfd41b91ul SEL2(0x3b563c24ul)}},
 125   /*  4 */ {SEL1(0ul) 1, 2, {1, 15, 0x40000000ul SEL2(0xfffffffful)}},
 126   /*  5 */ {SEL1(0xcccccccdul) 0, 2, {1, 13, 0x48c27395ul SEL2(0xc25c2684ul)}},
 127   /*  6 */ {SEL1(0xaaaaaaabul) 0, 2, {0, 12, 0x81bf1000ul SEL2(0xf91bd1b6ul)}},
 128   /*  7 */ {SEL1(0x24924925ul) 1, 3, {1, 11, 0x75db9c97ul SEL2(0x1607a2cbul)}},
 129   /*  8 */ {SEL1(0ul) 1, 3, {1, 10, 0x40000000ul SEL2(0xfffffffful)}},
 130   /*  9 */ {SEL1(0x38e38e39ul) 0, 1, {0, 10, 0xcfd41b91ul SEL2(0x3b563c24ul)}},
 131   /* 10 */ {SEL1(0xcccccccdul) 0, 3, {2, 9, 0x3b9aca00ul SEL2(0x12e0be82ul)}},
 132   /* 11 */ {SEL1(0xba2e8ba3ul) 0, 3, {0, 9, 0x8c8b6d2bul SEL2(0xd24cde04ul)}},
 133   /* 12 */ {SEL1(0xaaaaaaabul) 0, 3, {3, 8, 0x19a10000ul SEL2(0x3fa39ab5ul)}},
 134   /* 13 */ {SEL1(0x4ec4ec4ful) 0, 2, {2, 8, 0x309f1021ul SEL2(0x50f8ac5ful)}},
 135   /* 14 */ {SEL1(0x24924925ul) 1, 4, {1, 8, 0x57f6c100ul SEL2(0x74843b1eul)}},
 136   /* 15 */ {SEL1(0x88888889ul) 0, 3, {0, 8, 0x98c29b81ul SEL2(0xad0326c2ul)}},
 137   /* 16 */ {SEL1(0ul) 1, 4, {3, 7, 0x10000000ul SEL2(0xfffffffful)}},
 138   /* 17 */ {SEL1(0xf0f0f0f1ul) 0, 4, {3, 7, 0x18754571ul SEL2(0x4ef0b6bdul)}},
 139   /* 18 */ {SEL1(0x38e38e39ul) 0, 2, {2, 7, 0x247dbc80ul SEL2(0xc0fc48a1ul)}},
 140   /* 19 */ {SEL1(0xaf286bcbul) 1, 5, {2, 7, 0x3547667bul SEL2(0x33838942ul)}},
 141   /* 20 */ {SEL1(0xcccccccdul) 0, 4, {1, 7, 0x4c4b4000ul SEL2(0xad7f29abul)}},
 142   /* 21 */ {SEL1(0x86186187ul) 1, 5, {1, 7, 0x6b5a6e1dul SEL2(0x313c3d15ul)}},
 143   /* 22 */ {SEL1(0xba2e8ba3ul) 0, 4, {0, 7, 0x94ace180ul SEL2(0xb8cca9e0ul)}},
 144   /* 23 */ {SEL1(0xb21642c9ul) 0, 4, {0, 7, 0xcaf18367ul SEL2(0x42ed6de9ul)}},
 145   /* 24 */ {SEL1(0xaaaaaaabul) 0, 4, {4, 6, 0x0b640000ul SEL2(0x67980e0bul)}},
 146   /* 25 */ {SEL1(0x51eb851ful) 0, 3, {4, 6, 0x0e8d4a51ul SEL2(0x19799812ul)}},
 147   /* 26 */ {SEL1(0x4ec4ec4ful) 0, 3, {3, 6, 0x1269ae40ul SEL2(0xbce85396ul)}},
 148   /* 27 */ {SEL1(0x2f684bdbul) 1, 5, {3, 6, 0x17179149ul SEL2(0x62c103a9ul)}},
 149   /* 28 */ {SEL1(0x24924925ul) 1, 5, {3, 6, 0x1cb91000ul SEL2(0x1d353d43ul)}},
 150   /* 29 */ {SEL1(0x8d3dcb09ul) 0, 4, {2, 6, 0x23744899ul SEL2(0xce1deceaul)}},
 151   /* 30 */ {SEL1(0x88888889ul) 0, 4, {2, 6, 0x2b73a840ul SEL2(0x790fc511ul)}},
 152   /* 31 */ {SEL1(0x08421085ul) 1, 5, {2, 6, 0x34e63b41ul SEL2(0x35b865a0ul)}},
 153   /* 32 */ {SEL1(0ul) 1, 5, {1, 6, 0x40000000ul SEL2(0xfffffffful)}},
 154   /* 33 */ {SEL1(0x3e0f83e1ul) 0, 3, {1, 6, 0x4cfa3cc1ul SEL2(0xa9aed1b3ul)}},
 155   /* 34 */ {SEL1(0xf0f0f0f1ul) 0, 5, {1, 6, 0x5c13d840ul SEL2(0x63dfc229ul)}},
 156   /* 35 */ {SEL1(0xd41d41d5ul) 1, 6, {1, 6, 0x6d91b519ul SEL2(0x2b0fee30ul)}},
 157   /* 36 */ {SEL1(0x38e38e39ul) 0, 3, {0, 6, 0x81bf1000ul SEL2(0xf91bd1b6ul)}}
 158 # endif
 159 };
 160 #endif
 161
 162 char *
 163 _itoa_word (_ITOA_WORD_TYPE value, char *buflim,
 164             unsigned int base, int upper_case)
 165 {
 166   const char *digits = (upper_case
 167                         ? _itoa_upper_digits
 168                         : _itoa_lower_digits);
 169
 170   switch (base)
 171     {
 172 #define SPECIAL(Base)                                                         \
 173     case Base:                                                                \
 174       do                                                                      \
 175         *--buflim = digits[value % Base];                                     \
 176       while ((value /= Base) != 0);                                           \
 177       break
 178
 179       SPECIAL (10);
 180       SPECIAL (16);
 181       SPECIAL (8);
 182     default:
 183       do
 184         *--buflim = digits[value % base];
 185       while ((value /= base) != 0);
 186     }
 187   return buflim;
 188 }
 189 #undef SPECIAL
 190
 191
 192 #if _ITOA_NEEDED
 193 char *
 194 _itoa (unsigned long long int value, char *buflim, unsigned int base,
 195        int upper_case)
 196 {
 197   const char *digits = (upper_case
 198                         ? _itoa_upper_digits
 199                         : _itoa_lower_digits);
 200   const struct base_table_t *brec = &_itoa_base_table[base - 2];
 201
 202   switch (base)
 203     {
 204 # define RUN_2N(BITS) \
 205       do                                                                      \
 206         {                                                                     \
 207           /* `unsigned long long int' always has 64 bits.  */                 \
 208           mp_limb_t work_hi = value >> (64 - BITS_PER_MP_LIMB);               \
 209                                                                               \
 210           if (BITS_PER_MP_LIMB == 32)                                         \
 211             {                                                                 \
 212               if (work_hi != 0)                                               \
 213                 {                                                             \
 214                   mp_limb_t work_lo;                                          \
 215                   int cnt;                                                    \
 216                                                                               \
 217                   work_lo = value & 0xfffffffful;                             \
 218                   for (cnt = BITS_PER_MP_LIMB / BITS; cnt > 0; --cnt)         \
 219                     {                                                         \
 220                       *--buflim = digits[work_lo & ((1ul << BITS) - 1)];      \
 221                       work_lo >>= BITS;                                       \
 222                     }                                                         \
 223                   if (BITS_PER_MP_LIMB % BITS != 0)                           \
 224                     {                                                         \
 225                       work_lo                                                 \
 226                         |= ((work_hi                                          \
 227                              & ((1 << (BITS - BITS_PER_MP_LIMB%BITS))         \
 228                                 - 1))                                         \
 229                             << BITS_PER_MP_LIMB % BITS);                      \
 230                       work_hi >>= BITS - BITS_PER_MP_LIMB % BITS;             \
 231                       if (work_hi == 0)                                       \
 232                         work_hi = work_lo;                                    \
 233                       else                                                    \
 234                         *--buflim = digits[work_lo];                          \
 235                     }                                                         \
 236                 }                                                             \
 237               else                                                            \
 238                 work_hi = value & 0xfffffffful;                               \
 239             }                                                                 \
 240           do                                                                  \
 241             {                                                                 \
 242               *--buflim = digits[work_hi & ((1 << BITS) - 1)];                \
 243               work_hi >>= BITS;                                               \
 244             }                                                                 \
 245           while (work_hi != 0);                                               \
 246         }                                                                     \
 247       while (0)
 248     case 8:
 249       RUN_2N (3);
 250       break;
 251
 252     case 16:
 253       RUN_2N (4);
 254       break;
 255
 256     default:
 257       {
 258         char *bufend = buflim;
 259 # if BITS_PER_MP_LIMB == 64
 260         mp_limb_t base_multiplier = brec->base_multiplier;
 261         if (brec->flag)
 262           while (value != 0)
 263             {
 264               mp_limb_t quo, rem, x;
 265               mp_limb_t dummy __attribute__ ((unused));
 266
 267               umul_ppmm (x, dummy, value, base_multiplier);
 268               quo = (x + ((value - x) >> 1)) >> (brec->post_shift - 1);
 269               rem = value - quo * base;
 270               *--buflim = digits[rem];
 271               value = quo;
 272             }
 273         else
 274           while (value != 0)
 275             {
 276               mp_limb_t quo, rem, x;
 277               mp_limb_t dummy __attribute__ ((unused));
 278
 279               umul_ppmm (x, dummy, value, base_multiplier);
 280               quo = x >> brec->post_shift;
 281               rem = value - quo * base;
 282               *--buflim = digits[rem];
 283               value = quo;
 284             }
 285 # endif
 286 # if BITS_PER_MP_LIMB == 32
 287         mp_limb_t t[3];
 288         int n;
 289
 290         /* First convert x0 to 1-3 words in base s->big.base.
 291            Optimize for frequent cases of 32 bit numbers.  */
 292         if ((mp_limb_t) (value >> 32) >= 1)
 293           {
 294 #  if UDIV_TIME > 2 * UMUL_TIME || UDIV_NEEDS_NORMALIZATION
 295             int big_normalization_steps = brec->big.normalization_steps;
 296             mp_limb_t big_base_norm
 297               = brec->big.base << big_normalization_steps;
 298 #  endif
 299             if ((mp_limb_t) (value >> 32) >= brec->big.base)
 300               {
 301                 mp_limb_t x1hi, x1lo, r;
 302                 /* If you want to optimize this, take advantage of
 303                    that the quotient in the first udiv_qrnnd will
 304                    always be very small.  It might be faster just to
 305                    subtract in a tight loop.  */
 306
 307 #  if UDIV_TIME > 2 * UMUL_TIME
 308                 mp_limb_t x, xh, xl;
 309
 310                 if (big_normalization_steps == 0)
 311                   xh = 0;
 312                 else
 313                   xh = (mp_limb_t) (value >> (64 - big_normalization_steps));
 314                 xl = (mp_limb_t) (value >> (32 - big_normalization_steps));
 315                 udiv_qrnnd_preinv (x1hi, r, xh, xl, big_base_norm,
 316                                    brec->big.base_ninv);
 317
 318                 xl = ((mp_limb_t) value) << big_normalization_steps;
 319                 udiv_qrnnd_preinv (x1lo, x, r, xl, big_base_norm,
 320                                    brec->big.base_ninv);
 321                 t[2] = x >> big_normalization_steps;
 322
 323                 if (big_normalization_steps == 0)
 324                   xh = x1hi;
 325                 else
 326                   xh = ((x1hi << big_normalization_steps)
 327                         | (x1lo >> (32 - big_normalization_steps)));
 328                 xl = x1lo << big_normalization_steps;
 329                 udiv_qrnnd_preinv (t[0], x, xh, xl, big_base_norm,
 330                                    brec->big.base_ninv);
 331                 t[1] = x >> big_normalization_steps;
 332 #  elif UDIV_NEEDS_NORMALIZATION
 333                 mp_limb_t x, xh, xl;
 334
 335                 if (big_normalization_steps == 0)
 336                   xh = 0;
 337                 else
 338                   xh = (mp_limb_t) (value >> 64 - big_normalization_steps);
 339                 xl = (mp_limb_t) (value >> 32 - big_normalization_steps);
 340                 udiv_qrnnd (x1hi, r, xh, xl, big_base_norm);
 341
 342                 xl = ((mp_limb_t) value) << big_normalization_steps;
 343                 udiv_qrnnd (x1lo, x, r, xl, big_base_norm);
 344                 t[2] = x >> big_normalization_steps;
 345
 346                 if (big_normalization_steps == 0)
 347                   xh = x1hi;
 348                 else
 349                   xh = ((x1hi << big_normalization_steps)
 350                         | (x1lo >> 32 - big_normalization_steps));
 351                 xl = x1lo << big_normalization_steps;
 352                 udiv_qrnnd (t[0], x, xh, xl, big_base_norm);
 353                 t[1] = x >> big_normalization_steps;
 354 #  else
 355                 udiv_qrnnd (x1hi, r, 0, (mp_limb_t) (value >> 32),
 356                             brec->big.base);
 357                 udiv_qrnnd (x1lo, t[2], r, (mp_limb_t) value, brec->big.base);
 358                 udiv_qrnnd (t[0], t[1], x1hi, x1lo, brec->big.base);
 359 #  endif
 360                 n = 3;
 361               }
 362             else
 363               {
 364 #  if UDIV_TIME > 2 * UMUL_TIME
 365                 mp_limb_t x;
 366
 367                 value <<= brec->big.normalization_steps;
 368                 udiv_qrnnd_preinv (t[0], x, (mp_limb_t) (value >> 32),
 369                                    (mp_limb_t) value, big_base_norm,
 370                                    brec->big.base_ninv);
 371                 t[1] = x >> brec->big.normalization_steps;
 372 #  elif UDIV_NEEDS_NORMALIZATION
 373                 mp_limb_t x;
 374
 375                 value <<= big_normalization_steps;
 376                 udiv_qrnnd (t[0], x, (mp_limb_t) (value >> 32),
 377                             (mp_limb_t) value, big_base_norm);
 378                 t[1] = x >> big_normalization_steps;
 379 #  else
 380                 udiv_qrnnd (t[0], t[1], (mp_limb_t) (value >> 32),
 381                             (mp_limb_t) value, brec->big.base);
 382 #  endif
 383                 n = 2;
 384               }
 385           }
 386         else
 387           {
 388             t[0] = value;
 389             n = 1;
 390           }
 391
 392         /* Convert the 1-3 words in t[], word by word, to ASCII.  */
 393         do
 394           {
 395             mp_limb_t ti = t[--n];
 396             int ndig_for_this_limb = 0;
 397
 398 #  if UDIV_TIME > 2 * UMUL_TIME
 399             mp_limb_t base_multiplier = brec->base_multiplier;
 400             if (brec->flag)
 401               while (ti != 0)
 402                 {
 403                   mp_limb_t quo, rem, x;
 404                   mp_limb_t dummy __attribute__ ((unused));
 405
 406                   umul_ppmm (x, dummy, ti, base_multiplier);
 407                   quo = (x + ((ti - x) >> 1)) >> (brec->post_shift - 1);
 408                   rem = ti - quo * base;
 409                   *--buflim = digits[rem];
 410                   ti = quo;
 411                   ++ndig_for_this_limb;
 412                 }
 413             else
 414               while (ti != 0)
 415                 {
 416                   mp_limb_t quo, rem, x;
 417                   mp_limb_t dummy __attribute__ ((unused));
 418
 419                   umul_ppmm (x, dummy, ti, base_multiplier);
 420                   quo = x >> brec->post_shift;
 421                   rem = ti - quo * base;
 422                   *--buflim = digits[rem];
 423                   ti = quo;
 424                   ++ndig_for_this_limb;
 425                 }
 426 #  else
 427             while (ti != 0)
 428               {
 429                 mp_limb_t quo, rem;
 430
 431                 quo = ti / base;
 432                 rem = ti % base;
 433                 *--buflim = digits[rem];
 434                 ti = quo;
 435                 ++ndig_for_this_limb;
 436               }
 437 #  endif
 438             /* If this wasn't the most significant word, pad with zeros.  */
 439             if (n != 0)
 440               while (ndig_for_this_limb < brec->big.ndigits)
 441                 {
 442                   *--buflim = '0';
 443                   ++ndig_for_this_limb;
 444                 }
 445           }
 446         while (n != 0);
 447 # endif
 448         if (buflim == bufend)
 449           *--buflim = '0';
 450       }
 451       break;
 452     }
 453
 454   return buflim;
 455 }
 456 #endif
 457
 458 char *
 459 _fitoa_word (_ITOA_WORD_TYPE value, char *buf, unsigned int base,
 460              int upper_case)
 461 {
 462   char tmpbuf[sizeof (value) * 4];            /* Worst case length: base 2.  */
 463   char *cp = _itoa_word (value, tmpbuf + sizeof (value) * 4, base, upper_case);
 464   while (cp < tmpbuf + sizeof (value) * 4)
 465     *buf++ = *cp++;
 466   return buf;
 467 }
 468
 469 #if _ITOA_NEEDED
 470 char *
 471 _fitoa (unsigned long long value, char *buf, unsigned int base, int upper_case)
 472 {
 473   char tmpbuf[sizeof (value) * 4];            /* Worst case length: base 2.  */
 474   char *cp = _itoa (value, tmpbuf + sizeof (value) * 4, base, upper_case);
 475   while (cp < tmpbuf + sizeof (value) * 4)
 476     *buf++ = *cp++;
 477   return buf;
 478 }
 479 #endif