stdlib_str2num Module

The stdlib_str2num module provides procedures and interfaces for conversion of characters to numerical types. Currently supported: integer and real. (Specification)

This code was modified from https://github.com/jalvesz/Fortran-String-to-Num by Alves Jose And was possible thanks to all the discussions in this thread https://fortran-lang.discourse.group/t/faster-string-to-double/

Known precisions limits of current proposal : Conversion to double precision is exact up to epsilon(0.0_dp) example:

input : 123456.78901234567890123456789012345678901234567890+2

formatted read : 12345678.90123457

to_num : 12345678.90123457

difference abs : 0.1862645149230957E-08

difference rel : 0.1508742584455759E-13%

Conversion to quadruple precision can deviate at about 200*epsilon(0.0_qp) example:

input : 0.140129846432481707092372958328991613128026194187651577175706828388979108268586060148663818836212158203125E-443

formatted read : 0.140129846432481707092372958328991608E-443

to_num : 0.140129846432481707092372958328996233E-443

difference abs : 0.4625E-475

difference rel : 0.3300E-029%

Interfaces

public interface to_num

Conversion of strings to numbers (Specification)

• private elemental function to_int8(s, mold) result(v)

  Arguments

  Type	Intent	Optional	Attributes		Name
  character(len=*),	intent(in)			::	s	input string
  integer(kind=int8),	intent(in)			::	mold	dummy argument to disambiguate at compile time the generic interface

  Return Value integer(kind=int8)

  Output integer(int8) value

• private elemental function to_int16(s, mold) result(v)

  Arguments

  Type	Intent	Optional	Attributes		Name
  character(len=*),	intent(in)			::	s	input string
  integer(kind=int16),	intent(in)			::	mold	dummy argument to disambiguate at compile time the generic interface

  Return Value integer(kind=int16)

  Output integer(int16) value

• private elemental function to_int32(s, mold) result(v)

  Arguments

  Type	Intent	Optional	Attributes		Name
  character(len=*),	intent(in)			::	s	input string
  integer(kind=int32),	intent(in)			::	mold	dummy argument to disambiguate at compile time the generic interface

  Return Value integer(kind=int32)

  Output integer(int32) value

• private elemental function to_int64(s, mold) result(v)

  Arguments

  Type	Intent	Optional	Attributes		Name
  character(len=*),	intent(in)			::	s	input string
  integer(kind=int64),	intent(in)			::	mold	dummy argument to disambiguate at compile time the generic interface

  Return Value integer(kind=int64)

  Output integer(int64) value

• private elemental function to_sp(s, mold) result(v)

  Arguments

  Type	Intent	Optional	Attributes		Name
  character(len=*),	intent(in)			::	s	input string
  real(kind=sp),	intent(in)			::	mold	dummy argument to disambiguate at compile time the generic interface

  Return Value real(kind=sp)

  Output real(sp) value

• private elemental function to_dp(s, mold) result(v)

  Arguments

  Type	Intent	Optional	Attributes		Name
  character(len=*),	intent(in)			::	s	input string
  real(kind=dp),	intent(in)			::	mold	dummy argument to disambiguate at compile time the generic interface

  Return Value real(kind=dp)

  Output real(dp) value

public interface to_num_from_stream

Conversion of a stream of values in a string to numbers (Specification)

• private function to_int8_from_stream(s, mold, stat) result(v)

  Arguments

  Type	Intent	Optional	Attributes		Name
  character(len=:),			pointer	::	s	input string
  integer(kind=int8),	intent(in)			::	mold	dummy argument to disambiguate at compile time the generic interface
  integer(kind=int8),	intent(inout),	optional		::	stat

  Return Value integer(kind=int8)

  Output integer(int8) value

• private function to_int16_from_stream(s, mold, stat) result(v)

  Arguments

  Type	Intent	Optional	Attributes		Name
  character(len=:),			pointer	::	s	input string
  integer(kind=int16),	intent(in)			::	mold	dummy argument to disambiguate at compile time the generic interface
  integer(kind=int8),	intent(inout),	optional		::	stat

  Return Value integer(kind=int16)

  Output integer(int16) value

• private function to_int32_from_stream(s, mold, stat) result(v)

  Arguments

  Type	Intent	Optional	Attributes		Name
  character(len=:),			pointer	::	s	input string
  integer(kind=int32),	intent(in)			::	mold	dummy argument to disambiguate at compile time the generic interface
  integer(kind=int8),	intent(inout),	optional		::	stat

  Return Value integer(kind=int32)

  Output integer(int32) value

• private function to_int64_from_stream(s, mold, stat) result(v)

  Arguments

  Type	Intent	Optional	Attributes		Name
  character(len=:),			pointer	::	s	input string
  integer(kind=int64),	intent(in)			::	mold	dummy argument to disambiguate at compile time the generic interface
  integer(kind=int8),	intent(inout),	optional		::	stat

  Return Value integer(kind=int64)

  Output integer(int64) value

• private function to_sp_from_stream(s, mold, stat) result(v)

  Arguments

  Type	Intent	Optional	Attributes		Name
  character(len=:),			pointer	::	s	input string
  real(kind=sp),	intent(in)			::	mold	dummy argument to disambiguate at compile time the generic interface
  integer(kind=int8),	intent(inout),	optional		::	stat

  Return Value real(kind=sp)

  Output real(sp) value

• private function to_dp_from_stream(s, mold, stat) result(v)

  Arguments

  Type	Intent	Optional	Attributes		Name
  character(len=:),			pointer	::	s	input string
  real(kind=dp),	intent(in)			::	mold	dummy argument to disambiguate at compile time the generic interface
  integer(kind=int8),	intent(inout),	optional		::	stat

  Return Value real(kind=dp)

  Output real(dp) value