contrib/mpc/src/get_x.c

   1 /* mpc_get_dc, mpc_get_ldc -- Transform mpc number into C complex number
   2    mpc_get_str -- Convert a complex number into a string.
   3
   4 Copyright (C) 2009, 2010, 2011 INRIA
   5
   6 This file is part of GNU MPC.
   7
   8 GNU MPC is free software; you can redistribute it and/or modify it under
   9 the terms of the GNU Lesser General Public License as published by the
  10 Free Software Foundation; either version 3 of the License, or (at your
  11 option) any later version.
  12
  13 GNU MPC is distributed in the hope that it will be useful, but WITHOUT ANY
  14 WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS
  15 FOR A PARTICULAR PURPOSE. See the GNU Lesser General Public License for
  16 more details.
  17
  18 You should have received a copy of the GNU Lesser General Public License
  19 along with this program. If not, see http://www.gnu.org/licenses/ .
  20 */
  21
  22 #include "config.h"
  23
  24 #ifdef HAVE_COMPLEX_H
  25 #include <complex.h>
  26 #endif
  27
  28 #ifdef HAVE_LOCALE_H
  29 #include <locale.h>
  30 #endif
  31
  32 #include <stdio.h> /* for sprintf, fprintf */
  33 #include <ctype.h>
  34 #include <string.h>
  35 #include "mpc-impl.h"
  36
  37 #ifdef HAVE_COMPLEX_H
  38 double _Complex
  39 mpc_get_dc (mpc_srcptr op, mpc_rnd_t rnd) {
  40    return I * mpfr_get_d (mpc_imagref (op), MPC_RND_IM (rnd))
  41           + mpfr_get_d (mpc_realref (op), MPC_RND_RE (rnd));
  42 }
  43
  44 long double _Complex
  45 mpc_get_ldc (mpc_srcptr op, mpc_rnd_t rnd) {
  46    return I * mpfr_get_ld (mpc_imagref (op), MPC_RND_IM (rnd))
  47           + mpfr_get_ld (mpc_realref (op), MPC_RND_RE (rnd));
  48 }
  49 #endif
  50
  51
  52 /* Code for mpc_get_str. The output format is "(real imag)", the decimal point
  53    of the locale is used. */
  54
  55 /* mpfr_prec_t can be either int or long int */
  56 #if (__GMP_MP_SIZE_T_INT == 1)
  57 #define MPC_EXP_FORMAT_SPEC "i"
  58 #elif (__GMP_MP_SIZE_T_INT == 0)
  59 #define MPC_EXP_FORMAT_SPEC "li"
  60 #else
  61 #error "mpfr_exp_t size not supported"
  62 #endif
  63
  64 static char *
  65 pretty_zero (mpfr_srcptr zero)
  66 {
  67   char *pretty;
  68
  69   pretty = mpc_alloc_str (3);
  70
  71   pretty[0] = mpfr_signbit (zero) ? '-' : '+';
  72   pretty[1] = '0';
  73   pretty[2] = '\0';
  74
  75   return pretty;
  76 }
  77
  78 static char *
  79 prettify (const char *str, const mp_exp_t expo, int base, int special)
  80 {
  81   size_t sz;
  82   char *pretty;
  83   char *p;
  84   const char *s;
  85   mp_exp_t x;
  86   int sign;
  87
  88   sz = strlen (str) + 1; /* + terminal '\0' */
  89
  90   if (special)
  91     {
  92       /* special number: nan or inf */
  93       pretty = mpc_alloc_str (sz);
  94       strcpy (pretty, str);
  95
  96       return pretty;
  97     }
  98
  99   /* regular number */
 100
 101   sign = (str[0] == '-' || str[0] == '+');
 102
 103   x = expo - 1; /* expo is the exponent value with decimal point BEFORE
 104                    the first digit, we wants decimal point AFTER the first
 105                    digit */
 106   if (base == 16)
 107     x <<= 2; /* the output exponent is a binary exponent */
 108
 109   ++sz; /* + decimal point */
 110
 111   if (x != 0)
 112     {
 113       /* augment sz with the size needed for an exponent written in base
 114          ten */
 115       mp_exp_t xx;
 116
 117       sz += 3; /* + exponent char + sign + 1 digit */
 118
 119       if (x < 0)
 120         {
 121           /* avoid overflow when changing sign (assuming that, for the
 122              mp_exp_t type, (max value) is greater than (- min value / 10)) */
 123           if (x < -10)
 124             {
 125               xx = - (x / 10);
 126               sz++;
 127             }
 128           else
 129             xx = -x;
 130         }
 131       else
 132         xx = x;
 133
 134       /* compute sz += floor(log(expo)/log(10)) without using libm
 135          functions */
 136       while (xx > 9)
 137         {
 138           sz++;
 139           xx /= 10;
 140         }
 141     }
 142
 143   pretty = mpc_alloc_str (sz);
 144   p = pretty;
 145
 146   /* 1. optional sign plus first digit */
 147   s = str;
 148   *p++ = *s++;
 149   if (sign)
 150     *p++ = *s++;
 151
 152   /* 2. decimal point */
 153 #ifdef HAVE_LOCALECONV
 154   *p++ = *localeconv ()->decimal_point;
 155 #else
 156   *p++ = '.';
 157 #endif
 158   *p = '\0';
 159
 160   /* 3. other significant digits */
 161   strcat (pretty, s);
 162
 163   /* 4. exponent (in base ten) */
 164   if (x == 0)
 165     return pretty;
 166
 167   p = pretty + strlen (str) + 1;
 168
 169   switch (base)
 170     {
 171     case 10:
 172       *p++ = 'e';
 173       break;
 174     case 2:
 175     case 16:
 176       *p++ = 'p';
 177       break;
 178     default:
 179       *p++ = '@';
 180     }
 181
 182   *p = '\0';
 183
 184   sprintf (p, "%+"MPC_EXP_FORMAT_SPEC, x);
 185
 186   return pretty;
 187 }
 188
 189 static char *
 190 get_pretty_str (const int base, const size_t n, mpfr_srcptr x, mpfr_rnd_t rnd)
 191 {
 192   mp_exp_t expo;
 193   char *ugly;
 194   char *pretty;
 195
 196   if (mpfr_zero_p (x))
 197     return pretty_zero (x);
 198
 199   ugly = mpfr_get_str (NULL, &expo, base, n, x, rnd);
 200   MPC_ASSERT (ugly != NULL);
 201   pretty = prettify (ugly, expo, base, !mpfr_number_p (x));
 202   mpfr_free_str (ugly);
 203
 204   return pretty;
 205 }
 206
 207 char *
 208 mpc_get_str (int base, size_t n, mpc_srcptr op, mpc_rnd_t rnd)
 209 {
 210   size_t needed_size;
 211   char *real_str;
 212   char *imag_str;
 213   char *complex_str = NULL;
 214
 215   if (base < 2 || base > 36)
 216     return NULL;
 217
 218   real_str = get_pretty_str (base, n, mpc_realref (op), MPC_RND_RE (rnd));
 219   imag_str = get_pretty_str (base, n, mpc_imagref (op), MPC_RND_IM (rnd));
 220
 221   needed_size = strlen (real_str) + strlen (imag_str) + 4;
 222
 223   complex_str = mpc_alloc_str (needed_size);
 224 MPC_ASSERT (complex_str != NULL);
 225
 226   strcpy (complex_str, "(");
 227   strcat (complex_str, real_str);
 228   strcat (complex_str, " ");
 229   strcat (complex_str, imag_str);
 230   strcat (complex_str, ")");
 231
 232   mpc_free_str (real_str);
 233   mpc_free_str (imag_str);
 234
 235   return complex_str;
 236 }