github.com/aergoio/aergo@v1.3.1/libtool/src/gmp-6.1.2/mpz/cmpabs_d.c (about)

     1  /* mpz_cmpabs_d -- compare absolute values of mpz and double.
     2  
     3  Copyright 2001-2003, 2012 Free Software Foundation, Inc.
     4  
     5  This file is part of the GNU MP Library.
     6  
     7  The GNU MP Library is free software; you can redistribute it and/or modify
     8  it under the terms of either:
     9  
    10    * the GNU Lesser General Public License as published by the Free
    11      Software Foundation; either version 3 of the License, or (at your
    12      option) any later version.
    13  
    14  or
    15  
    16    * the GNU General Public License as published by the Free Software
    17      Foundation; either version 2 of the License, or (at your option) any
    18      later version.
    19  
    20  or both in parallel, as here.
    21  
    22  The GNU MP Library is distributed in the hope that it will be useful, but
    23  WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY
    24  or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
    25  for more details.
    26  
    27  You should have received copies of the GNU General Public License and the
    28  GNU Lesser General Public License along with the GNU MP Library.  If not,
    29  see https://www.gnu.org/licenses/.  */
    30  
    31  #include "config.h"
    32  
    33  #if HAVE_FLOAT_H
    34  #include <float.h>  /* for DBL_MAX */
    35  #endif
    36  
    37  #include "gmp.h"
    38  #include "gmp-impl.h"
    39  
    40  
    41  #define RETURN_CMP(zl, dl)              \
    42    do {                                  \
    43      zlimb = (zl);                       \
    44      dlimb = (dl);                       \
    45      if (zlimb != dlimb)                 \
    46        return (zlimb >= dlimb ? 1 : -1); \
    47    } while (0)
    48  
    49  #define RETURN_NONZERO(ptr, size, val)          \
    50    do {                                          \
    51      mp_size_t __i;                              \
    52      for (__i = (size)-1; __i >= 0; __i--)       \
    53        if ((ptr)[__i] != 0)                      \
    54          return val;                             \
    55      return 0;                                   \
    56    } while (0)
    57  
    58  
    59  int
    60  mpz_cmpabs_d (mpz_srcptr z, double d)
    61  {
    62    mp_limb_t  darray[LIMBS_PER_DOUBLE], zlimb, dlimb;
    63    mp_srcptr  zp;
    64    mp_size_t  zsize;
    65    int        dexp;
    66  
    67    /* d=NaN is an invalid operation, there's no sensible return value.
    68       d=Inf or -Inf is always bigger than z.  */
    69    DOUBLE_NAN_INF_ACTION (d, __gmp_invalid_operation (), return -1);
    70  
    71    /* 1. Check for either operand zero. */
    72    zsize = SIZ(z);
    73    if (d == 0.0)
    74      return (zsize != 0);
    75    if (zsize == 0)
    76      return -1; /* d != 0 */
    77  
    78    /* 2. Ignore signs. */
    79    zsize = ABS(zsize);
    80    d = ABS(d);
    81  
    82    /* 3. Small d, knowing abs(z) >= 1. */
    83    if (d < 1.0)
    84      return 1;
    85  
    86    dexp = __gmp_extract_double (darray, d);
    87    ASSERT (dexp >= 1);
    88  
    89    /* 4. Check for different high limb positions. */
    90    if (zsize != dexp)
    91      return (zsize >= dexp ? 1 : -1);
    92  
    93    /* 5. Limb data. */
    94    zp = PTR(z);
    95  
    96  #if LIMBS_PER_DOUBLE == 2
    97    RETURN_CMP (zp[zsize-1], darray[1]);
    98    if (zsize == 1)
    99      return (darray[0] != 0 ? -1 : 0);
   100  
   101    RETURN_CMP (zp[zsize-2], darray[0]);
   102    RETURN_NONZERO (zp, zsize-2, 1);
   103  #endif
   104  
   105  #if LIMBS_PER_DOUBLE == 3
   106    RETURN_CMP (zp[zsize-1], darray[2]);
   107    if (zsize == 1)
   108      return ((darray[0] | darray[1]) != 0 ? -1 : 0);
   109  
   110    RETURN_CMP (zp[zsize-2], darray[1]);
   111    if (zsize == 2)
   112      return (darray[0] != 0 ? -1 : 0);
   113  
   114    RETURN_CMP (zp[zsize-3], darray[0]);
   115    RETURN_NONZERO (zp, zsize-3, 1);
   116  #endif
   117  
   118  #if LIMBS_PER_DOUBLE >= 4
   119    {
   120      int i;
   121      for (i = 1; i <= LIMBS_PER_DOUBLE; i++)
   122        {
   123  	RETURN_CMP (zp[zsize-i], darray[LIMBS_PER_DOUBLE-i]);
   124  	if (i >= zsize)
   125  	  RETURN_NONZERO (darray, LIMBS_PER_DOUBLE-i, -1);
   126        }
   127      RETURN_NONZERO (zp, zsize-LIMBS_PER_DOUBLE, 1);
   128    }
   129  #endif
   130  }