stdio-common/_itoa.c

   1 /* Internal function for converting integers to ASCII.
   2    Copyright (C) 1994-2024 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 /* Mark symbols hidden in static PIE for early self relocation to work.
  20    Note: string.h may have ifuncs which cannot be hidden on i686.  */
  21 #if BUILD_PIE_DEFAULT
  22 # pragma GCC visibility push(hidden)
  23 #endif
  24 #include <gmp-mparam.h>
  25 #include <gmp.h>
  26 #include <limits.h>
  27 #include <stdlib/gmp-impl.h>
  28 #include <stdlib/longlong.h>
  29
  30 #include <_itoa.h>
  31
  32
  33 /* Canonize environment.  For some architectures not all values might
  34    be defined in the GMP header files.  */
  35 #ifndef UMUL_TIME
  36 # define UMUL_TIME 1
  37 #endif
  38 #ifndef UDIV_TIME
  39 # define UDIV_TIME 3
  40 #endif
  41
  42 /* Control memory layout.  */
  43 #ifdef PACK
  44 # undef PACK
  45 # define PACK __attribute__ ((packed))
  46 #else
  47 # define PACK
  48 #endif
  49
  50
  51 /* Declare local types.  */
  52 struct base_table_t
  53 {
  54 #if (UDIV_TIME > 2 * UMUL_TIME)
  55   mp_limb_t base_multiplier;
  56 #endif
  57   char flag;
  58   char post_shift;
  59 #if BITS_PER_MP_LIMB == 32
  60   struct
  61     {
  62       char normalization_steps;
  63       char ndigits;
  64       mp_limb_t base PACK;
  65 #if UDIV_TIME > 2 * UMUL_TIME
  66       mp_limb_t base_ninv PACK;
  67 #endif
  68     } big;
  69 #endif
  70 };
  71
  72 /* To reduce the memory needed we include some fields of the tables
  73    only conditionally.  */
  74 #if UDIV_TIME > 2 * UMUL_TIME
  75 # define SEL1(X) X,
  76 # define SEL2(X) ,X
  77 #else
  78 # define SEL1(X)
  79 # define SEL2(X)
  80 #endif
  81
  82
  83 /* We do not compile _itoa if we always can use _itoa_word.  */
  84 #if _ITOA_NEEDED
  85 /* Local variables.  */
  86 const struct base_table_t _itoa_base_table[] attribute_hidden =
  87 {
  88 # if BITS_PER_MP_LIMB == 64
  89   /*  2 */ {SEL1(0ull) 1, 1},
  90   /*  3 */ {SEL1(0xaaaaaaaaaaaaaaabull) 0, 1},
  91   /*  4 */ {SEL1(0ull) 1, 2},
  92   /*  5 */ {SEL1(0xcccccccccccccccdull) 0, 2},
  93   /*  6 */ {SEL1(0xaaaaaaaaaaaaaaabull) 0, 2},
  94   /*  7 */ {SEL1(0x2492492492492493ull) 1, 3},
  95   /*  8 */ {SEL1(0ull) 1, 3},
  96   /*  9 */ {SEL1(0xe38e38e38e38e38full) 0, 3},
  97   /* 10 */ {SEL1(0xcccccccccccccccdull) 0, 3},
  98   /* 11 */ {SEL1(0x2e8ba2e8ba2e8ba3ull) 0, 1},
  99   /* 12 */ {SEL1(0xaaaaaaaaaaaaaaabull) 0, 3},
 100   /* 13 */ {SEL1(0x4ec4ec4ec4ec4ec5ull) 0, 2},
 101   /* 14 */ {SEL1(0x2492492492492493ull) 1, 4},
 102   /* 15 */ {SEL1(0x8888888888888889ull) 0, 3},
 103   /* 16 */ {SEL1(0ull) 1, 4},
 104   /* 17 */ {SEL1(0xf0f0f0f0f0f0f0f1ull) 0, 4},
 105   /* 18 */ {SEL1(0xe38e38e38e38e38full) 0, 4},
 106   /* 19 */ {SEL1(0xd79435e50d79435full) 0, 4},
 107   /* 20 */ {SEL1(0xcccccccccccccccdull) 0, 4},
 108   /* 21 */ {SEL1(0x8618618618618619ull) 1, 5},
 109   /* 22 */ {SEL1(0x2e8ba2e8ba2e8ba3ull) 0, 2},
 110   /* 23 */ {SEL1(0x642c8590b21642c9ull) 1, 5},
 111   /* 24 */ {SEL1(0xaaaaaaaaaaaaaaabull) 0, 4},
 112   /* 25 */ {SEL1(0x47ae147ae147ae15ull) 1, 5},
 113   /* 26 */ {SEL1(0x4ec4ec4ec4ec4ec5ull) 0, 3},
 114   /* 27 */ {SEL1(0x97b425ed097b425full) 0, 4},
 115   /* 28 */ {SEL1(0x2492492492492493ull) 1, 5},
 116   /* 29 */ {SEL1(0x1a7b9611a7b9611bull) 1, 5},
 117   /* 30 */ {SEL1(0x8888888888888889ull) 0, 4},
 118   /* 31 */ {SEL1(0x0842108421084211ull) 1, 5},
 119   /* 32 */ {SEL1(0ull) 1, 5},
 120   /* 33 */ {SEL1(0x0f83e0f83e0f83e1ull) 0, 1},
 121   /* 34 */ {SEL1(0xf0f0f0f0f0f0f0f1ull) 0, 5},
 122   /* 35 */ {SEL1(0xea0ea0ea0ea0ea0full) 0, 5},
 123   /* 36 */ {SEL1(0xe38e38e38e38e38full) 0, 5}
 124 # endif
 125 # if BITS_PER_MP_LIMB == 32
 126   /*  2 */ {SEL1(0ul) 1, 1, {0, 31, 0x80000000ul SEL2(0xfffffffful)}},
 127   /*  3 */ {SEL1(0xaaaaaaabul) 0, 1, {0, 20, 0xcfd41b91ul SEL2(0x3b563c24ul)}},
 128   /*  4 */ {SEL1(0ul) 1, 2, {1, 15, 0x40000000ul SEL2(0xfffffffful)}},
 129   /*  5 */ {SEL1(0xcccccccdul) 0, 2, {1, 13, 0x48c27395ul SEL2(0xc25c2684ul)}},
 130   /*  6 */ {SEL1(0xaaaaaaabul) 0, 2, {0, 12, 0x81bf1000ul SEL2(0xf91bd1b6ul)}},
 131   /*  7 */ {SEL1(0x24924925ul) 1, 3, {1, 11, 0x75db9c97ul SEL2(0x1607a2cbul)}},
 132   /*  8 */ {SEL1(0ul) 1, 3, {1, 10, 0x40000000ul SEL2(0xfffffffful)}},
 133   /*  9 */ {SEL1(0x38e38e39ul) 0, 1, {0, 10, 0xcfd41b91ul SEL2(0x3b563c24ul)}},
 134   /* 10 */ {SEL1(0xcccccccdul) 0, 3, {2, 9, 0x3b9aca00ul SEL2(0x12e0be82ul)}},
 135   /* 11 */ {SEL1(0xba2e8ba3ul) 0, 3, {0, 9, 0x8c8b6d2bul SEL2(0xd24cde04ul)}},
 136   /* 12 */ {SEL1(0xaaaaaaabul) 0, 3, {3, 8, 0x19a10000ul SEL2(0x3fa39ab5ul)}},
 137   /* 13 */ {SEL1(0x4ec4ec4ful) 0, 2, {2, 8, 0x309f1021ul SEL2(0x50f8ac5ful)}},
 138   /* 14 */ {SEL1(0x24924925ul) 1, 4, {1, 8, 0x57f6c100ul SEL2(0x74843b1eul)}},
 139   /* 15 */ {SEL1(0x88888889ul) 0, 3, {0, 8, 0x98c29b81ul SEL2(0xad0326c2ul)}},
 140   /* 16 */ {SEL1(0ul) 1, 4, {3, 7, 0x10000000ul SEL2(0xfffffffful)}},
 141   /* 17 */ {SEL1(0xf0f0f0f1ul) 0, 4, {3, 7, 0x18754571ul SEL2(0x4ef0b6bdul)}},
 142   /* 18 */ {SEL1(0x38e38e39ul) 0, 2, {2, 7, 0x247dbc80ul SEL2(0xc0fc48a1ul)}},
 143   /* 19 */ {SEL1(0xaf286bcbul) 1, 5, {2, 7, 0x3547667bul SEL2(0x33838942ul)}},
 144   /* 20 */ {SEL1(0xcccccccdul) 0, 4, {1, 7, 0x4c4b4000ul SEL2(0xad7f29abul)}},
 145   /* 21 */ {SEL1(0x86186187ul) 1, 5, {1, 7, 0x6b5a6e1dul SEL2(0x313c3d15ul)}},
 146   /* 22 */ {SEL1(0xba2e8ba3ul) 0, 4, {0, 7, 0x94ace180ul SEL2(0xb8cca9e0ul)}},
 147   /* 23 */ {SEL1(0xb21642c9ul) 0, 4, {0, 7, 0xcaf18367ul SEL2(0x42ed6de9ul)}},
 148   /* 24 */ {SEL1(0xaaaaaaabul) 0, 4, {4, 6, 0x0b640000ul SEL2(0x67980e0bul)}},
 149   /* 25 */ {SEL1(0x51eb851ful) 0, 3, {4, 6, 0x0e8d4a51ul SEL2(0x19799812ul)}},
 150   /* 26 */ {SEL1(0x4ec4ec4ful) 0, 3, {3, 6, 0x1269ae40ul SEL2(0xbce85396ul)}},
 151   /* 27 */ {SEL1(0x2f684bdbul) 1, 5, {3, 6, 0x17179149ul SEL2(0x62c103a9ul)}},
 152   /* 28 */ {SEL1(0x24924925ul) 1, 5, {3, 6, 0x1cb91000ul SEL2(0x1d353d43ul)}},
 153   /* 29 */ {SEL1(0x8d3dcb09ul) 0, 4, {2, 6, 0x23744899ul SEL2(0xce1deceaul)}},
 154   /* 30 */ {SEL1(0x88888889ul) 0, 4, {2, 6, 0x2b73a840ul SEL2(0x790fc511ul)}},
 155   /* 31 */ {SEL1(0x08421085ul) 1, 5, {2, 6, 0x34e63b41ul SEL2(0x35b865a0ul)}},
 156   /* 32 */ {SEL1(0ul) 1, 5, {1, 6, 0x40000000ul SEL2(0xfffffffful)}},
 157   /* 33 */ {SEL1(0x3e0f83e1ul) 0, 3, {1, 6, 0x4cfa3cc1ul SEL2(0xa9aed1b3ul)}},
 158   /* 34 */ {SEL1(0xf0f0f0f1ul) 0, 5, {1, 6, 0x5c13d840ul SEL2(0x63dfc229ul)}},
 159   /* 35 */ {SEL1(0xd41d41d5ul) 1, 6, {1, 6, 0x6d91b519ul SEL2(0x2b0fee30ul)}},
 160   /* 36 */ {SEL1(0x38e38e39ul) 0, 3, {0, 6, 0x81bf1000ul SEL2(0xf91bd1b6ul)}}
 161 # endif
 162 };
 163 #endif
 164
 165 #if IS_IN (libc)
 166 char *
 167 _itoa_word (_ITOA_WORD_TYPE value, char *buflim,
 168             unsigned int base, int upper_case)
 169 {
 170   const char *digits = (upper_case
 171                         ? _itoa_upper_digits
 172                         : _itoa_lower_digits);
 173
 174   switch (base)
 175     {
 176 #define SPECIAL(Base)                                                         \
 177     case Base:                                                                \
 178       do                                                                      \
 179         *--buflim = digits[value % Base];                                     \
 180       while ((value /= Base) != 0);                                           \
 181       break
 182
 183       SPECIAL (10);
 184       SPECIAL (16);
 185       SPECIAL (8);
 186     default:
 187       do
 188         *--buflim = digits[value % base];
 189       while ((value /= base) != 0);
 190     }
 191   return buflim;
 192 }
 193 #undef SPECIAL
 194 #endif /* IS_IN (libc) */
 195
 196
 197 #if _ITOA_NEEDED
 198 char *
 199 _itoa (unsigned long long int value, char *buflim, unsigned int base,
 200        int upper_case)
 201 {
 202   const char *digits = (upper_case
 203                         ? _itoa_upper_digits
 204                         : _itoa_lower_digits);
 205   const struct base_table_t *brec = &_itoa_base_table[base - 2];
 206
 207   switch (base)
 208     {
 209 # define RUN_2N(BITS) \
 210       do                                                                      \
 211         {                                                                     \
 212           /* `unsigned long long int' always has 64 bits.  */                 \
 213           mp_limb_t work_hi = value >> (64 - BITS_PER_MP_LIMB);               \
 214                                                                               \
 215           if (BITS_PER_MP_LIMB == 32)                                         \
 216             {                                                                 \
 217               if (work_hi != 0)                                               \
 218                 {                                                             \
 219                   mp_limb_t work_lo;                                          \
 220                   int cnt;                                                    \
 221                                                                               \
 222                   work_lo = value & 0xfffffffful;                             \
 223                   for (cnt = BITS_PER_MP_LIMB / BITS; cnt > 0; --cnt)         \
 224                     {                                                         \
 225                       *--buflim = digits[work_lo & ((1ul << BITS) - 1)];      \
 226                       work_lo >>= BITS;                                       \
 227                     }                                                         \
 228                   if (BITS_PER_MP_LIMB % BITS != 0)                           \
 229                     {                                                         \
 230                       work_lo                                                 \
 231                         |= ((work_hi                                          \
 232                              & ((1 << (BITS - BITS_PER_MP_LIMB%BITS))         \
 233                                 - 1))                                         \
 234                             << BITS_PER_MP_LIMB % BITS);                      \
 235                       work_hi >>= BITS - BITS_PER_MP_LIMB % BITS;             \
 236                       if (work_hi == 0)                                       \
 237                         work_hi = work_lo;                                    \
 238                       else                                                    \
 239                         *--buflim = digits[work_lo];                          \
 240                     }                                                         \
 241                 }                                                             \
 242               else                                                            \
 243                 work_hi = value & 0xfffffffful;                               \
 244             }                                                                 \
 245           do                                                                  \
 246             {                                                                 \
 247               *--buflim = digits[work_hi & ((1 << BITS) - 1)];                \
 248               work_hi >>= BITS;                                               \
 249             }                                                                 \
 250           while (work_hi != 0);                                               \
 251         }                                                                     \
 252       while (0)
 253     case 8:
 254       RUN_2N (3);
 255       break;
 256
 257     case 16:
 258       RUN_2N (4);
 259       break;
 260
 261     default:
 262       {
 263         char *bufend = buflim;
 264 # if BITS_PER_MP_LIMB == 64
 265         mp_limb_t base_multiplier = brec->base_multiplier;
 266         if (brec->flag)
 267           while (value != 0)
 268             {
 269               mp_limb_t quo, rem, x;
 270               mp_limb_t dummy __attribute__ ((unused));
 271
 272               umul_ppmm (x, dummy, value, base_multiplier);
 273               quo = (x + ((value - x) >> 1)) >> (brec->post_shift - 1);
 274               rem = value - quo * base;
 275               *--buflim = digits[rem];
 276               value = quo;
 277             }
 278         else
 279           while (value != 0)
 280             {
 281               mp_limb_t quo, rem, x;
 282               mp_limb_t dummy __attribute__ ((unused));
 283
 284               umul_ppmm (x, dummy, value, base_multiplier);
 285               quo = x >> brec->post_shift;
 286               rem = value - quo * base;
 287               *--buflim = digits[rem];
 288               value = quo;
 289             }
 290 # endif
 291 # if BITS_PER_MP_LIMB == 32
 292         mp_limb_t t[3];
 293         int n;
 294
 295         /* First convert x0 to 1-3 words in base s->big.base.
 296            Optimize for frequent cases of 32 bit numbers.  */
 297         if ((mp_limb_t) (value >> 32) >= 1)
 298           {
 299 #  if UDIV_TIME > 2 * UMUL_TIME || UDIV_NEEDS_NORMALIZATION
 300             int big_normalization_steps = brec->big.normalization_steps;
 301             mp_limb_t big_base_norm
 302               = brec->big.base << big_normalization_steps;
 303 #  endif
 304             if ((mp_limb_t) (value >> 32) >= brec->big.base)
 305               {
 306                 mp_limb_t x1hi, x1lo, r;
 307                 /* If you want to optimize this, take advantage of
 308                    that the quotient in the first udiv_qrnnd will
 309                    always be very small.  It might be faster just to
 310                    subtract in a tight loop.  */
 311
 312 #  if UDIV_TIME > 2 * UMUL_TIME
 313                 mp_limb_t x, xh, xl;
 314
 315                 if (big_normalization_steps == 0)
 316                   xh = 0;
 317                 else
 318                   xh = (mp_limb_t) (value >> (64 - big_normalization_steps));
 319                 xl = (mp_limb_t) (value >> (32 - big_normalization_steps));
 320                 udiv_qrnnd_preinv (x1hi, r, xh, xl, big_base_norm,
 321                                    brec->big.base_ninv);
 322
 323                 xl = ((mp_limb_t) value) << big_normalization_steps;
 324                 udiv_qrnnd_preinv (x1lo, x, r, xl, big_base_norm,
 325                                    brec->big.base_ninv);
 326                 t[2] = x >> big_normalization_steps;
 327
 328                 if (big_normalization_steps == 0)
 329                   xh = x1hi;
 330                 else
 331                   xh = ((x1hi << big_normalization_steps)
 332                         | (x1lo >> (32 - big_normalization_steps)));
 333                 xl = x1lo << big_normalization_steps;
 334                 udiv_qrnnd_preinv (t[0], x, xh, xl, big_base_norm,
 335                                    brec->big.base_ninv);
 336                 t[1] = x >> big_normalization_steps;
 337 #  elif UDIV_NEEDS_NORMALIZATION
 338                 mp_limb_t x, xh, xl;
 339
 340                 if (big_normalization_steps == 0)
 341                   xh = 0;
 342                 else
 343                   xh = (mp_limb_t) (value >> 64 - big_normalization_steps);
 344                 xl = (mp_limb_t) (value >> 32 - big_normalization_steps);
 345                 udiv_qrnnd (x1hi, r, xh, xl, big_base_norm);
 346
 347                 xl = ((mp_limb_t) value) << big_normalization_steps;
 348                 udiv_qrnnd (x1lo, x, r, xl, big_base_norm);
 349                 t[2] = x >> big_normalization_steps;
 350
 351                 if (big_normalization_steps == 0)
 352                   xh = x1hi;
 353                 else
 354                   xh = ((x1hi << big_normalization_steps)
 355                         | (x1lo >> 32 - big_normalization_steps));
 356                 xl = x1lo << big_normalization_steps;
 357                 udiv_qrnnd (t[0], x, xh, xl, big_base_norm);
 358                 t[1] = x >> big_normalization_steps;
 359 #  else
 360                 udiv_qrnnd (x1hi, r, 0, (mp_limb_t) (value >> 32),
 361                             brec->big.base);
 362                 udiv_qrnnd (x1lo, t[2], r, (mp_limb_t) value, brec->big.base);
 363                 udiv_qrnnd (t[0], t[1], x1hi, x1lo, brec->big.base);
 364 #  endif
 365                 n = 3;
 366               }
 367             else
 368               {
 369 #  if UDIV_TIME > 2 * UMUL_TIME
 370                 mp_limb_t x;
 371
 372                 value <<= brec->big.normalization_steps;
 373                 udiv_qrnnd_preinv (t[0], x, (mp_limb_t) (value >> 32),
 374                                    (mp_limb_t) value, big_base_norm,
 375                                    brec->big.base_ninv);
 376                 t[1] = x >> brec->big.normalization_steps;
 377 #  elif UDIV_NEEDS_NORMALIZATION
 378                 mp_limb_t x;
 379
 380                 value <<= big_normalization_steps;
 381                 udiv_qrnnd (t[0], x, (mp_limb_t) (value >> 32),
 382                             (mp_limb_t) value, big_base_norm);
 383                 t[1] = x >> big_normalization_steps;
 384 #  else
 385                 udiv_qrnnd (t[0], t[1], (mp_limb_t) (value >> 32),
 386                             (mp_limb_t) value, brec->big.base);
 387 #  endif
 388                 n = 2;
 389               }
 390           }
 391         else
 392           {
 393             t[0] = value;
 394             n = 1;
 395           }
 396
 397         /* Convert the 1-3 words in t[], word by word, to ASCII.  */
 398         do
 399           {
 400             mp_limb_t ti = t[--n];
 401             int ndig_for_this_limb = 0;
 402
 403 #  if UDIV_TIME > 2 * UMUL_TIME
 404             mp_limb_t base_multiplier = brec->base_multiplier;
 405             if (brec->flag)
 406               while (ti != 0)
 407                 {
 408                   mp_limb_t quo, rem, x;
 409                   mp_limb_t dummy __attribute__ ((unused));
 410
 411                   umul_ppmm (x, dummy, ti, base_multiplier);
 412                   quo = (x + ((ti - x) >> 1)) >> (brec->post_shift - 1);
 413                   rem = ti - quo * base;
 414                   *--buflim = digits[rem];
 415                   ti = quo;
 416                   ++ndig_for_this_limb;
 417                 }
 418             else
 419               while (ti != 0)
 420                 {
 421                   mp_limb_t quo, rem, x;
 422                   mp_limb_t dummy __attribute__ ((unused));
 423
 424                   umul_ppmm (x, dummy, ti, base_multiplier);
 425                   quo = x >> brec->post_shift;
 426                   rem = ti - quo * base;
 427                   *--buflim = digits[rem];
 428                   ti = quo;
 429                   ++ndig_for_this_limb;
 430                 }
 431 #  else
 432             while (ti != 0)
 433               {
 434                 mp_limb_t quo, rem;
 435
 436                 quo = ti / base;
 437                 rem = ti % base;
 438                 *--buflim = digits[rem];
 439                 ti = quo;
 440                 ++ndig_for_this_limb;
 441               }
 442 #  endif
 443             /* If this wasn't the most significant word, pad with zeros.  */
 444             if (n != 0)
 445               while (ndig_for_this_limb < brec->big.ndigits)
 446                 {
 447                   *--buflim = '0';
 448                   ++ndig_for_this_limb;
 449                 }
 450           }
 451         while (n != 0);
 452 # endif
 453         if (buflim == bufend)
 454           *--buflim = '0';
 455       }
 456       break;
 457     }
 458
 459   return buflim;
 460 }
 461 #endif
 462
 463 char *
 464 _fitoa_word (_ITOA_WORD_TYPE value, char *buf, unsigned int base,
 465              int upper_case)
 466 {
 467   char tmpbuf[sizeof (value) * 4];            /* Worst case length: base 2.  */
 468   char *cp = _itoa_word (value, tmpbuf + sizeof (value) * 4, base, upper_case);
 469   while (cp < tmpbuf + sizeof (value) * 4)
 470     *buf++ = *cp++;
 471   return buf;
 472 }
 473
 474 #if _ITOA_NEEDED
 475 char *
 476 _fitoa (unsigned long long value, char *buf, unsigned int base, int upper_case)
 477 {
 478   char tmpbuf[sizeof (value) * 4];            /* Worst case length: base 2.  */
 479   char *cp = _itoa (value, tmpbuf + sizeof (value) * 4, base, upper_case);
 480   while (cp < tmpbuf + sizeof (value) * 4)
 481     *buf++ = *cp++;
 482   return buf;
 483 }
 484 #endif