Line data    Source code

       1             : #ifndef HEADER_fd_src_flamenco_types_fd_cast_h
       2             : #define HEADER_fd_src_flamenco_types_fd_cast_h
       3             : 
       4             : #include "../../util/bits/fd_float.h"
       5             : 
       6             : /* From https://doc.rust-lang.org/rust-by-example/types/cast.html
       7             : 
       8             :    Since Rust 1.45, the `as` keyword performs a *saturating cast*
       9             :    when casting from float to int. If the floating point value exceeds
      10             :    the upper bound or is less than the lower bound, the returned value
      11             :    will be equal to the bound crossed. */
      12             : 
      13             : FD_PROTOTYPES_BEGIN
      14             : 
      15             : #if FD_HAS_DOUBLE
      16             : 
      17             : /* Cast a double to unsigned long the same way as rust by suturating.
      18             :    Saturate to 0 if the value is negative or NaN.
      19             :    Saturate to ULONG_MAX if the value is greater than ULONG_MAX. */
      20             : FD_FN_CONST static inline ulong
      21      936186 : fd_rust_cast_double_to_ulong( double f ) {
      22      936186 :   ulong u = fd_dblbits( f );
      23             :   /* Check if the exponent is all 1s (infinity or NaN )*/
      24      936186 :   if( fd_dblbits_bexp( u )==0x7FFUL ) {
      25             :     /* Check if the mantissa is 0 (infinity) */
      26           9 :     if( fd_dblbits_mant( u )==0 ) {
      27           6 :       return ULONG_MAX;
      28           6 :     } else {
      29             :       /* NaN case */
      30           3 :       return 0;
      31           3 :     }
      32           9 :   }
      33             : 
      34             :   /* If the value is negative saturate to 0 */
      35      936177 :   if( fd_dblbits_sign( u )==1 ) {
      36           3 :     return 0;
      37           3 :   }
      38             : 
      39             :   /* Saturate to max unsigned long value */
      40      936174 :   if( f>=(double)ULONG_MAX ) {
      41          12 :     return ULONG_MAX;
      42          12 :   }
      43             : 
      44             :   /* Normal value, cast to unsigned long */
      45      936162 :   return (ulong)f;
      46      936174 : }
      47             : 
      48             : #endif /* FD_HAS_DOUBLE */
      49             : 
      50             : FD_PROTOTYPES_END
      51             : 
      52             : #endif /* HEADER_fd_src_flamenco_types_fd_cast_h */