source/libs/gmp/gmp-src/mpz/get_str.c

   1 /* mpz_get_str (string, base, mp_src) -- Convert the multiple precision
   2    number MP_SRC to a string STRING of base BASE.  If STRING is NULL
   3    allocate space for the result.  In any case, return a pointer to the
   4    result.  If STRING is not NULL, the caller must ensure enough space is
   5    available to store the result.
   6
   7 Copyright 1991, 1993, 1994, 1996, 2000-2002, 2005, 2012 Free Software
   8 Foundation, Inc.
   9
  10 This file is part of the GNU MP Library.
  11
  12 The GNU MP Library is free software; you can redistribute it and/or modify
  13 it under the terms of either:
  14
  15   * the GNU Lesser General Public License as published by the Free
  16     Software Foundation; either version 3 of the License, or (at your
  17     option) any later version.
  18
  19 or
  20
  21   * the GNU General Public License as published by the Free Software
  22     Foundation; either version 2 of the License, or (at your option) any
  23     later version.
  24
  25 or both in parallel, as here.
  26
  27 The GNU MP Library is distributed in the hope that it will be useful, but
  28 WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY
  29 or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
  30 for more details.
  31
  32 You should have received copies of the GNU General Public License and the
  33 GNU Lesser General Public License along with the GNU MP Library.  If not,
  34 see https://www.gnu.org/licenses/.  */
  35
  36 #include <string.h> /* for strlen */
  37 #include "gmp.h"
  38 #include "gmp-impl.h"
  39 #include "longlong.h"
  40
  41 char *
  42 mpz_get_str (char *res_str, int base, mpz_srcptr x)
  43 {
  44   mp_ptr xp;
  45   mp_size_t x_size = SIZ (x);
  46   char *return_str;
  47   size_t str_size;
  48   size_t alloc_size = 0;
  49   const char *num_to_text;
  50   int i;
  51   TMP_DECL;
  52
  53   if (base >= 0)
  54     {
  55       num_to_text = "0123456789abcdefghijklmnopqrstuvwxyz";
  56       if (base <= 1)
  57         base = 10;
  58       else if (base > 36)
  59         {
  60           num_to_text = "0123456789ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz";
  61           if (base > 62)
  62             return NULL;
  63         }
  64     }
  65   else
  66     {
  67       base = -base;
  68       if (base <= 1)
  69         base = 10;
  70       else if (base > 36)
  71         return NULL;
  72       num_to_text = "0123456789ABCDEFGHIJKLMNOPQRSTUVWXYZ";
  73     }
  74
  75   /* allocate string for the user if necessary */
  76   if (res_str == NULL)
  77     {
  78       /* digits, null terminator, possible minus sign */
  79       MPN_SIZEINBASE (alloc_size, PTR(x), ABS(x_size), base);
  80       alloc_size += 1 + (x_size<0);
  81       res_str = (char *) (*__gmp_allocate_func) (alloc_size);
  82     }
  83   return_str = res_str;
  84
  85   if (x_size < 0)
  86     {
  87       *res_str++ = '-';
  88       x_size = -x_size;
  89     }
  90
  91   /* mpn_get_str clobbers its input on non power-of-2 bases */
  92   TMP_MARK;
  93   xp = PTR (x);
  94   if (! POW2_P (base))
  95     {
  96       xp = TMP_ALLOC_LIMBS (x_size | 1);  /* |1 in case x_size==0 */
  97       MPN_COPY (xp, PTR (x), x_size);
  98     }
  99
 100   str_size = mpn_get_str ((unsigned char *) res_str, base, xp, x_size);
 101   ASSERT (alloc_size == 0 || str_size <= alloc_size - (SIZ(x) < 0));
 102
 103   /* Convert result to printable chars.  */
 104   for (i = 0; i < str_size; i++)
 105     res_str[i] = num_to_text[(int) res_str[i]];
 106   res_str[str_size] = 0;
 107
 108   TMP_FREE;
 109
 110   /* if allocated then resize down to the actual space required */
 111   if (alloc_size != 0)
 112     {
 113       size_t  actual_size = str_size + 1 + (res_str - return_str);
 114       ASSERT (actual_size == strlen (return_str) + 1);
 115       __GMP_REALLOCATE_FUNC_MAYBE_TYPE (return_str, alloc_size, actual_size,
 116                                         char);
 117     }
 118   return return_str;
 119 }