src/integer/conv/cl_I_to_L.cc

   1 // cl_I_to_L().
   2
   3 // General includes.
   4 #include "cl_sysdep.h"
   5
   6 // Specification.
   7 #include "cln/integer.h"
   8
   9
  10 // Implementation.
  11
  12 #include "cln/number.h"
  13 #include "cl_I.h"
  14 #include "cl_DS.h"
  15 #include "cln/io.h"
  16 #include "cln/integer_io.h"
  17 #include "cln/abort.h"
  18
  19 namespace cln {
  20
  21 sint32 cl_I_to_L (const cl_I& obj)
  22 {
  23         if (fixnump(obj))
  24                 // Fixnum
  25                 return FN_to_L(obj);
  26     {   // Bignum
  27         var cl_heap_bignum* bn = TheBignum(obj);
  28         var uintC len = bn->length;
  29         if ((sintD)mspref(arrayMSDptr(bn->data,len),0) >= 0) {
  30                 // Bignum > 0
  31                 #define IF_LENGTH(i)  \
  32                   if (bn_minlength <= i) /* genau i Digits überhaupt möglich? */\
  33                     if (len == i) /* genau i Digits? */                         \
  34                       /* 2^((i-1)*intDsize-1) <= obj < 2^(i*intDsize-1) */      \
  35                       if ( (i*intDsize > 32)                                    \
  36                            && ( ((i-1)*intDsize >= 32)                          \
  37                                 || (mspref(arrayMSDptr(bn->data,len),0) >= (uintD)bitc(31-(i-1)*intDsize)) \
  38                          )    )                                                 \
  39                         goto bad;                                               \
  40                         else
  41                 IF_LENGTH(1)
  42                         return get_uint1D_Dptr(arrayLSDptr(bn->data,1));
  43                 IF_LENGTH(2)
  44                         return get_uint2D_Dptr(arrayLSDptr(bn->data,2));
  45                 IF_LENGTH(3)
  46                         return get_uint3D_Dptr(arrayLSDptr(bn->data,3));
  47                 IF_LENGTH(4)
  48                         return get_uint4D_Dptr(arrayLSDptr(bn->data,4));
  49                 #undef IF_LENGTH
  50         } else {
  51                 // Bignum < 0
  52                 #define IF_LENGTH(i)  \
  53                   if (bn_minlength <= i) /* genau i Digits überhaupt möglich? */\
  54                     if (len == i) /* genau i Digits? */                         \
  55                       /* - 2^(i*intDsize-1) <= obj < - 2^((i-1)*intDsize-1) */  \
  56                       if ( (i*intDsize > 32)                                    \
  57                            && ( ((i-1)*intDsize >= 32)                          \
  58                                 || (mspref(arrayMSDptr(bn->data,len),0) < (uintD)(-bitc(31-(i-1)*intDsize))) \
  59                          )    )                                                 \
  60                         goto bad;                                               \
  61                         else
  62                 IF_LENGTH(1)
  63                         return get_sint1D_Dptr(arrayLSDptr(bn->data,1));
  64                 IF_LENGTH(2)
  65                         return get_sint2D_Dptr(arrayLSDptr(bn->data,2));
  66                 IF_LENGTH(3)
  67                         return get_sint3D_Dptr(arrayLSDptr(bn->data,3));
  68                 IF_LENGTH(4)
  69                         return get_sint4D_Dptr(arrayLSDptr(bn->data,4));
  70                 #undef IF_LENGTH
  71         }
  72         bad: // unpassendes Objekt
  73         fprint(std::cerr, "Not a 32-bit integer: ");
  74         fprint(std::cerr, obj);
  75         fprint(std::cerr, "\n");
  76         cl_abort();
  77     }
  78 }
  79
  80 }  // namespace cln