stdio-common/_itoa.c

   1 /* Internal function for converting integers to ASCII.
   2    Copyright (C) 1994-2022 Free Software Foundation, Inc.
   3    This file is part of the GNU C Library.
   4
   5    The GNU C Library is free software; you can redistribute it and/or
   6    modify it under the terms of the GNU Lesser General Public
   7    License as published by the Free Software Foundation; either
   8    version 2.1 of the License, or (at your option) any later version.
   9
  10    The GNU C Library is distributed in the hope that it will be useful,
  11    but WITHOUT ANY WARRANTY; without even the implied warranty of
  12    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  13    Lesser General Public License for more details.
  14
  15    You should have received a copy of the GNU Lesser General Public
  16    License along with the GNU C Library; if not, see
  17    <https://www.gnu.org/licenses/>.  */
  18
  19 #include <gmp-mparam.h>
  20 #include <gmp.h>
  21 #include <limits.h>
  22 #include <stdlib/gmp-impl.h>
  23 #include <stdlib/longlong.h>
  24
  25 #include <_itoa.h>
  26
  27
  28 /* Canonize environment.  For some architectures not all values might
  29    be defined in the GMP header files.  */
  30 #ifndef UMUL_TIME
  31 # define UMUL_TIME 1
  32 #endif
  33 #ifndef UDIV_TIME
  34 # define UDIV_TIME 3
  35 #endif
  36
  37 /* Control memory layout.  */
  38 #ifdef PACK
  39 # undef PACK
  40 # define PACK __attribute__ ((packed))
  41 #else
  42 # define PACK
  43 #endif
  44
  45
  46 /* Declare local types.  */
  47 struct base_table_t
  48 {
  49 #if (UDIV_TIME > 2 * UMUL_TIME)
  50   mp_limb_t base_multiplier;
  51 #endif
  52   char flag;
  53   char post_shift;
  54 #if BITS_PER_MP_LIMB == 32
  55   struct
  56     {
  57       char normalization_steps;
  58       char ndigits;
  59       mp_limb_t base PACK;
  60 #if UDIV_TIME > 2 * UMUL_TIME
  61       mp_limb_t base_ninv PACK;
  62 #endif
  63     } big;
  64 #endif
  65 };
  66
  67 /* To reduce the memory needed we include some fields of the tables
  68    only conditionally.  */
  69 #if UDIV_TIME > 2 * UMUL_TIME
  70 # define SEL1(X) X,
  71 # define SEL2(X) ,X
  72 #else
  73 # define SEL1(X)
  74 # define SEL2(X)
  75 #endif
  76
  77
  78 /* We do not compile _itoa if we always can use _itoa_word.  */
  79 #if _ITOA_NEEDED
  80 /* Local variables.  */
  81 const struct base_table_t _itoa_base_table[] attribute_hidden =
  82 {
  83 # if BITS_PER_MP_LIMB == 64
  84   /*  2 */ {SEL1(0ull) 1, 1},
  85   /*  3 */ {SEL1(0xaaaaaaaaaaaaaaabull) 0, 1},
  86   /*  4 */ {SEL1(0ull) 1, 2},
  87   /*  5 */ {SEL1(0xcccccccccccccccdull) 0, 2},
  88   /*  6 */ {SEL1(0xaaaaaaaaaaaaaaabull) 0, 2},
  89   /*  7 */ {SEL1(0x2492492492492493ull) 1, 3},
  90   /*  8 */ {SEL1(0ull) 1, 3},
  91   /*  9 */ {SEL1(0xe38e38e38e38e38full) 0, 3},
  92   /* 10 */ {SEL1(0xcccccccccccccccdull) 0, 3},
  93   /* 11 */ {SEL1(0x2e8ba2e8ba2e8ba3ull) 0, 1},
  94   /* 12 */ {SEL1(0xaaaaaaaaaaaaaaabull) 0, 3},
  95   /* 13 */ {SEL1(0x4ec4ec4ec4ec4ec5ull) 0, 2},
  96   /* 14 */ {SEL1(0x2492492492492493ull) 1, 4},
  97   /* 15 */ {SEL1(0x8888888888888889ull) 0, 3},
  98   /* 16 */ {SEL1(0ull) 1, 4},
  99   /* 17 */ {SEL1(0xf0f0f0f0f0f0f0f1ull) 0, 4},
 100   /* 18 */ {SEL1(0xe38e38e38e38e38full) 0, 4},
 101   /* 19 */ {SEL1(0xd79435e50d79435full) 0, 4},
 102   /* 20 */ {SEL1(0xcccccccccccccccdull) 0, 4},
 103   /* 21 */ {SEL1(0x8618618618618619ull) 1, 5},
 104   /* 22 */ {SEL1(0x2e8ba2e8ba2e8ba3ull) 0, 2},
 105   /* 23 */ {SEL1(0x642c8590b21642c9ull) 1, 5},
 106   /* 24 */ {SEL1(0xaaaaaaaaaaaaaaabull) 0, 4},
 107   /* 25 */ {SEL1(0x47ae147ae147ae15ull) 1, 5},
 108   /* 26 */ {SEL1(0x4ec4ec4ec4ec4ec5ull) 0, 3},
 109   /* 27 */ {SEL1(0x97b425ed097b425full) 0, 4},
 110   /* 28 */ {SEL1(0x2492492492492493ull) 1, 5},
 111   /* 29 */ {SEL1(0x1a7b9611a7b9611bull) 1, 5},
 112   /* 30 */ {SEL1(0x8888888888888889ull) 0, 4},
 113   /* 31 */ {SEL1(0x0842108421084211ull) 1, 5},
 114   /* 32 */ {SEL1(0ull) 1, 5},
 115   /* 33 */ {SEL1(0x0f83e0f83e0f83e1ull) 0, 1},
 116   /* 34 */ {SEL1(0xf0f0f0f0f0f0f0f1ull) 0, 5},
 117   /* 35 */ {SEL1(0xea0ea0ea0ea0ea0full) 0, 5},
 118   /* 36 */ {SEL1(0xe38e38e38e38e38full) 0, 5}
 119 # endif
 120 # if BITS_PER_MP_LIMB == 32
 121   /*  2 */ {SEL1(0ul) 1, 1, {0, 31, 0x80000000ul SEL2(0xfffffffful)}},
 122   /*  3 */ {SEL1(0xaaaaaaabul) 0, 1, {0, 20, 0xcfd41b91ul SEL2(0x3b563c24ul)}},
 123   /*  4 */ {SEL1(0ul) 1, 2, {1, 15, 0x40000000ul SEL2(0xfffffffful)}},
 124   /*  5 */ {SEL1(0xcccccccdul) 0, 2, {1, 13, 0x48c27395ul SEL2(0xc25c2684ul)}},
 125   /*  6 */ {SEL1(0xaaaaaaabul) 0, 2, {0, 12, 0x81bf1000ul SEL2(0xf91bd1b6ul)}},
 126   /*  7 */ {SEL1(0x24924925ul) 1, 3, {1, 11, 0x75db9c97ul SEL2(0x1607a2cbul)}},
 127   /*  8 */ {SEL1(0ul) 1, 3, {1, 10, 0x40000000ul SEL2(0xfffffffful)}},
 128   /*  9 */ {SEL1(0x38e38e39ul) 0, 1, {0, 10, 0xcfd41b91ul SEL2(0x3b563c24ul)}},
 129   /* 10 */ {SEL1(0xcccccccdul) 0, 3, {2, 9, 0x3b9aca00ul SEL2(0x12e0be82ul)}},
 130   /* 11 */ {SEL1(0xba2e8ba3ul) 0, 3, {0, 9, 0x8c8b6d2bul SEL2(0xd24cde04ul)}},
 131   /* 12 */ {SEL1(0xaaaaaaabul) 0, 3, {3, 8, 0x19a10000ul SEL2(0x3fa39ab5ul)}},
 132   /* 13 */ {SEL1(0x4ec4ec4ful) 0, 2, {2, 8, 0x309f1021ul SEL2(0x50f8ac5ful)}},
 133   /* 14 */ {SEL1(0x24924925ul) 1, 4, {1, 8, 0x57f6c100ul SEL2(0x74843b1eul)}},
 134   /* 15 */ {SEL1(0x88888889ul) 0, 3, {0, 8, 0x98c29b81ul SEL2(0xad0326c2ul)}},
 135   /* 16 */ {SEL1(0ul) 1, 4, {3, 7, 0x10000000ul SEL2(0xfffffffful)}},
 136   /* 17 */ {SEL1(0xf0f0f0f1ul) 0, 4, {3, 7, 0x18754571ul SEL2(0x4ef0b6bdul)}},
 137   /* 18 */ {SEL1(0x38e38e39ul) 0, 2, {2, 7, 0x247dbc80ul SEL2(0xc0fc48a1ul)}},
 138   /* 19 */ {SEL1(0xaf286bcbul) 1, 5, {2, 7, 0x3547667bul SEL2(0x33838942ul)}},
 139   /* 20 */ {SEL1(0xcccccccdul) 0, 4, {1, 7, 0x4c4b4000ul SEL2(0xad7f29abul)}},
 140   /* 21 */ {SEL1(0x86186187ul) 1, 5, {1, 7, 0x6b5a6e1dul SEL2(0x313c3d15ul)}},
 141   /* 22 */ {SEL1(0xba2e8ba3ul) 0, 4, {0, 7, 0x94ace180ul SEL2(0xb8cca9e0ul)}},
 142   /* 23 */ {SEL1(0xb21642c9ul) 0, 4, {0, 7, 0xcaf18367ul SEL2(0x42ed6de9ul)}},
 143   /* 24 */ {SEL1(0xaaaaaaabul) 0, 4, {4, 6, 0x0b640000ul SEL2(0x67980e0bul)}},
 144   /* 25 */ {SEL1(0x51eb851ful) 0, 3, {4, 6, 0x0e8d4a51ul SEL2(0x19799812ul)}},
 145   /* 26 */ {SEL1(0x4ec4ec4ful) 0, 3, {3, 6, 0x1269ae40ul SEL2(0xbce85396ul)}},
 146   /* 27 */ {SEL1(0x2f684bdbul) 1, 5, {3, 6, 0x17179149ul SEL2(0x62c103a9ul)}},
 147   /* 28 */ {SEL1(0x24924925ul) 1, 5, {3, 6, 0x1cb91000ul SEL2(0x1d353d43ul)}},
 148   /* 29 */ {SEL1(0x8d3dcb09ul) 0, 4, {2, 6, 0x23744899ul SEL2(0xce1deceaul)}},
 149   /* 30 */ {SEL1(0x88888889ul) 0, 4, {2, 6, 0x2b73a840ul SEL2(0x790fc511ul)}},
 150   /* 31 */ {SEL1(0x08421085ul) 1, 5, {2, 6, 0x34e63b41ul SEL2(0x35b865a0ul)}},
 151   /* 32 */ {SEL1(0ul) 1, 5, {1, 6, 0x40000000ul SEL2(0xfffffffful)}},
 152   /* 33 */ {SEL1(0x3e0f83e1ul) 0, 3, {1, 6, 0x4cfa3cc1ul SEL2(0xa9aed1b3ul)}},
 153   /* 34 */ {SEL1(0xf0f0f0f1ul) 0, 5, {1, 6, 0x5c13d840ul SEL2(0x63dfc229ul)}},
 154   /* 35 */ {SEL1(0xd41d41d5ul) 1, 6, {1, 6, 0x6d91b519ul SEL2(0x2b0fee30ul)}},
 155   /* 36 */ {SEL1(0x38e38e39ul) 0, 3, {0, 6, 0x81bf1000ul SEL2(0xf91bd1b6ul)}}
 156 # endif
 157 };
 158 #endif
 159
 160 char *
 161 _itoa_word (_ITOA_WORD_TYPE value, char *buflim,
 162             unsigned int base, int upper_case)
 163 {
 164   const char *digits = (upper_case
 165                         ? _itoa_upper_digits
 166                         : _itoa_lower_digits);
 167
 168   switch (base)
 169     {
 170 #define SPECIAL(Base)                                                         \
 171     case Base:                                                                \
 172       do                                                                      \
 173         *--buflim = digits[value % Base];                                     \
 174       while ((value /= Base) != 0);                                           \
 175       break
 176
 177       SPECIAL (10);
 178       SPECIAL (16);
 179       SPECIAL (8);
 180     default:
 181       do
 182         *--buflim = digits[value % base];
 183       while ((value /= base) != 0);
 184     }
 185   return buflim;
 186 }
 187 #undef SPECIAL
 188
 189
 190 #if _ITOA_NEEDED
 191 char *
 192 _itoa (unsigned long long int value, char *buflim, unsigned int base,
 193        int upper_case)
 194 {
 195   const char *digits = (upper_case
 196                         ? _itoa_upper_digits
 197                         : _itoa_lower_digits);
 198   const struct base_table_t *brec = &_itoa_base_table[base - 2];
 199
 200   switch (base)
 201     {
 202 # define RUN_2N(BITS) \
 203       do                                                                      \
 204         {                                                                     \
 205           /* `unsigned long long int' always has 64 bits.  */                 \
 206           mp_limb_t work_hi = value >> (64 - BITS_PER_MP_LIMB);               \
 207                                                                               \
 208           if (BITS_PER_MP_LIMB == 32)                                         \
 209             {                                                                 \
 210               if (work_hi != 0)                                               \
 211                 {                                                             \
 212                   mp_limb_t work_lo;                                          \
 213                   int cnt;                                                    \
 214                                                                               \
 215                   work_lo = value & 0xfffffffful;                             \
 216                   for (cnt = BITS_PER_MP_LIMB / BITS; cnt > 0; --cnt)         \
 217                     {                                                         \
 218                       *--buflim = digits[work_lo & ((1ul << BITS) - 1)];      \
 219                       work_lo >>= BITS;                                       \
 220                     }                                                         \
 221                   if (BITS_PER_MP_LIMB % BITS != 0)                           \
 222                     {                                                         \
 223                       work_lo                                                 \
 224                         |= ((work_hi                                          \
 225                              & ((1 << (BITS - BITS_PER_MP_LIMB%BITS))         \
 226                                 - 1))                                         \
 227                             << BITS_PER_MP_LIMB % BITS);                      \
 228                       work_hi >>= BITS - BITS_PER_MP_LIMB % BITS;             \
 229                       if (work_hi == 0)                                       \
 230                         work_hi = work_lo;                                    \
 231                       else                                                    \
 232                         *--buflim = digits[work_lo];                          \
 233                     }                                                         \
 234                 }                                                             \
 235               else                                                            \
 236                 work_hi = value & 0xfffffffful;                               \
 237             }                                                                 \
 238           do                                                                  \
 239             {                                                                 \
 240               *--buflim = digits[work_hi & ((1 << BITS) - 1)];                \
 241               work_hi >>= BITS;                                               \
 242             }                                                                 \
 243           while (work_hi != 0);                                               \
 244         }                                                                     \
 245       while (0)
 246     case 8:
 247       RUN_2N (3);
 248       break;
 249
 250     case 16:
 251       RUN_2N (4);
 252       break;
 253
 254     default:
 255       {
 256         char *bufend = buflim;
 257 # if BITS_PER_MP_LIMB == 64
 258         mp_limb_t base_multiplier = brec->base_multiplier;
 259         if (brec->flag)
 260           while (value != 0)
 261             {
 262               mp_limb_t quo, rem, x;
 263               mp_limb_t dummy __attribute__ ((unused));
 264
 265               umul_ppmm (x, dummy, value, base_multiplier);
 266               quo = (x + ((value - x) >> 1)) >> (brec->post_shift - 1);
 267               rem = value - quo * base;
 268               *--buflim = digits[rem];
 269               value = quo;
 270             }
 271         else
 272           while (value != 0)
 273             {
 274               mp_limb_t quo, rem, x;
 275               mp_limb_t dummy __attribute__ ((unused));
 276
 277               umul_ppmm (x, dummy, value, base_multiplier);
 278               quo = x >> brec->post_shift;
 279               rem = value - quo * base;
 280               *--buflim = digits[rem];
 281               value = quo;
 282             }
 283 # endif
 284 # if BITS_PER_MP_LIMB == 32
 285         mp_limb_t t[3];
 286         int n;
 287
 288         /* First convert x0 to 1-3 words in base s->big.base.
 289            Optimize for frequent cases of 32 bit numbers.  */
 290         if ((mp_limb_t) (value >> 32) >= 1)
 291           {
 292 #  if UDIV_TIME > 2 * UMUL_TIME || UDIV_NEEDS_NORMALIZATION
 293             int big_normalization_steps = brec->big.normalization_steps;
 294             mp_limb_t big_base_norm
 295               = brec->big.base << big_normalization_steps;
 296 #  endif
 297             if ((mp_limb_t) (value >> 32) >= brec->big.base)
 298               {
 299                 mp_limb_t x1hi, x1lo, r;
 300                 /* If you want to optimize this, take advantage of
 301                    that the quotient in the first udiv_qrnnd will
 302                    always be very small.  It might be faster just to
 303                    subtract in a tight loop.  */
 304
 305 #  if UDIV_TIME > 2 * UMUL_TIME
 306                 mp_limb_t x, xh, xl;
 307
 308                 if (big_normalization_steps == 0)
 309                   xh = 0;
 310                 else
 311                   xh = (mp_limb_t) (value >> (64 - big_normalization_steps));
 312                 xl = (mp_limb_t) (value >> (32 - big_normalization_steps));
 313                 udiv_qrnnd_preinv (x1hi, r, xh, xl, big_base_norm,
 314                                    brec->big.base_ninv);
 315
 316                 xl = ((mp_limb_t) value) << big_normalization_steps;
 317                 udiv_qrnnd_preinv (x1lo, x, r, xl, big_base_norm,
 318                                    brec->big.base_ninv);
 319                 t[2] = x >> big_normalization_steps;
 320
 321                 if (big_normalization_steps == 0)
 322                   xh = x1hi;
 323                 else
 324                   xh = ((x1hi << big_normalization_steps)
 325                         | (x1lo >> (32 - big_normalization_steps)));
 326                 xl = x1lo << big_normalization_steps;
 327                 udiv_qrnnd_preinv (t[0], x, xh, xl, big_base_norm,
 328                                    brec->big.base_ninv);
 329                 t[1] = x >> big_normalization_steps;
 330 #  elif UDIV_NEEDS_NORMALIZATION
 331                 mp_limb_t x, xh, xl;
 332
 333                 if (big_normalization_steps == 0)
 334                   xh = 0;
 335                 else
 336                   xh = (mp_limb_t) (value >> 64 - big_normalization_steps);
 337                 xl = (mp_limb_t) (value >> 32 - big_normalization_steps);
 338                 udiv_qrnnd (x1hi, r, xh, xl, big_base_norm);
 339
 340                 xl = ((mp_limb_t) value) << big_normalization_steps;
 341                 udiv_qrnnd (x1lo, x, r, xl, big_base_norm);
 342                 t[2] = x >> big_normalization_steps;
 343
 344                 if (big_normalization_steps == 0)
 345                   xh = x1hi;
 346                 else
 347                   xh = ((x1hi << big_normalization_steps)
 348                         | (x1lo >> 32 - big_normalization_steps));
 349                 xl = x1lo << big_normalization_steps;
 350                 udiv_qrnnd (t[0], x, xh, xl, big_base_norm);
 351                 t[1] = x >> big_normalization_steps;
 352 #  else
 353                 udiv_qrnnd (x1hi, r, 0, (mp_limb_t) (value >> 32),
 354                             brec->big.base);
 355                 udiv_qrnnd (x1lo, t[2], r, (mp_limb_t) value, brec->big.base);
 356                 udiv_qrnnd (t[0], t[1], x1hi, x1lo, brec->big.base);
 357 #  endif
 358                 n = 3;
 359               }
 360             else
 361               {
 362 #  if UDIV_TIME > 2 * UMUL_TIME
 363                 mp_limb_t x;
 364
 365                 value <<= brec->big.normalization_steps;
 366                 udiv_qrnnd_preinv (t[0], x, (mp_limb_t) (value >> 32),
 367                                    (mp_limb_t) value, big_base_norm,
 368                                    brec->big.base_ninv);
 369                 t[1] = x >> brec->big.normalization_steps;
 370 #  elif UDIV_NEEDS_NORMALIZATION
 371                 mp_limb_t x;
 372
 373                 value <<= big_normalization_steps;
 374                 udiv_qrnnd (t[0], x, (mp_limb_t) (value >> 32),
 375                             (mp_limb_t) value, big_base_norm);
 376                 t[1] = x >> big_normalization_steps;
 377 #  else
 378                 udiv_qrnnd (t[0], t[1], (mp_limb_t) (value >> 32),
 379                             (mp_limb_t) value, brec->big.base);
 380 #  endif
 381                 n = 2;
 382               }
 383           }
 384         else
 385           {
 386             t[0] = value;
 387             n = 1;
 388           }
 389
 390         /* Convert the 1-3 words in t[], word by word, to ASCII.  */
 391         do
 392           {
 393             mp_limb_t ti = t[--n];
 394             int ndig_for_this_limb = 0;
 395
 396 #  if UDIV_TIME > 2 * UMUL_TIME
 397             mp_limb_t base_multiplier = brec->base_multiplier;
 398             if (brec->flag)
 399               while (ti != 0)
 400                 {
 401                   mp_limb_t quo, rem, x;
 402                   mp_limb_t dummy __attribute__ ((unused));
 403
 404                   umul_ppmm (x, dummy, ti, base_multiplier);
 405                   quo = (x + ((ti - x) >> 1)) >> (brec->post_shift - 1);
 406                   rem = ti - quo * base;
 407                   *--buflim = digits[rem];
 408                   ti = quo;
 409                   ++ndig_for_this_limb;
 410                 }
 411             else
 412               while (ti != 0)
 413                 {
 414                   mp_limb_t quo, rem, x;
 415                   mp_limb_t dummy __attribute__ ((unused));
 416
 417                   umul_ppmm (x, dummy, ti, base_multiplier);
 418                   quo = x >> brec->post_shift;
 419                   rem = ti - quo * base;
 420                   *--buflim = digits[rem];
 421                   ti = quo;
 422                   ++ndig_for_this_limb;
 423                 }
 424 #  else
 425             while (ti != 0)
 426               {
 427                 mp_limb_t quo, rem;
 428
 429                 quo = ti / base;
 430                 rem = ti % base;
 431                 *--buflim = digits[rem];
 432                 ti = quo;
 433                 ++ndig_for_this_limb;
 434               }
 435 #  endif
 436             /* If this wasn't the most significant word, pad with zeros.  */
 437             if (n != 0)
 438               while (ndig_for_this_limb < brec->big.ndigits)
 439                 {
 440                   *--buflim = '0';
 441                   ++ndig_for_this_limb;
 442                 }
 443           }
 444         while (n != 0);
 445 # endif
 446         if (buflim == bufend)
 447           *--buflim = '0';
 448       }
 449       break;
 450     }
 451
 452   return buflim;
 453 }
 454 #endif
 455
 456 char *
 457 _fitoa_word (_ITOA_WORD_TYPE value, char *buf, unsigned int base,
 458              int upper_case)
 459 {
 460   char tmpbuf[sizeof (value) * 4];            /* Worst case length: base 2.  */
 461   char *cp = _itoa_word (value, tmpbuf + sizeof (value) * 4, base, upper_case);
 462   while (cp < tmpbuf + sizeof (value) * 4)
 463     *buf++ = *cp++;
 464   return buf;
 465 }
 466
 467 #if _ITOA_NEEDED
 468 char *
 469 _fitoa (unsigned long long value, char *buf, unsigned int base, int upper_case)
 470 {
 471   char tmpbuf[sizeof (value) * 4];            /* Worst case length: base 2.  */
 472   char *cp = _itoa (value, tmpbuf + sizeof (value) * 4, base, upper_case);
 473   while (cp < tmpbuf + sizeof (value) * 4)
 474     *buf++ = *cp++;
 475   return buf;
 476 }
 477 #endif