Procedure

     INT2HX  ( Integer to signed hexadecimal string )

     SUBROUTINE INT2HX ( NUMBER, STRING, LENGTH )

Abstract

     Convert an integer to an equivalent signed hexadecimal string.

Required_Reading

     None.

Keywords

     ALPHANUMERIC
     CONVERSION

Declarations

     IMPLICIT NONE

     INTEGER               NUMBER
     CHARACTER*(*)         STRING
     INTEGER               LENGTH

Brief_I/O

     VARIABLE  I/O  DESCRIPTION
     --------  ---  --------------------------------------------------
     NUMBER     I   Integer to be converted.
     STRING     O   Equivalent hexadecimal string, left justified.
     LENGTH     O   The length of the hexadecimal string produced.

Detailed_Input

     NUMBER   is the integer to be converted.

Detailed_Output

     STRING   is the signed hexadecimal string representing the integer
              NUMBER.

              The following table describes the character set used
              to represent the hexadecimal digits and their
              corresponding values.

              Character    Value           Character    Value
              ---------    -----           ---------    -----
                '0'          0                '8'          8
                '1'          1                '9'          9
                '2'          2                'A'         10
                '3'          3                'B'         11
                '4'          4                'C'         12
                '5'          5                'D'         13
                '6'          6                'E'         14
                '7'          7                'F'         15

              In order to obtain the entire signed hexadecimal number,
              the output character string should be at least N
              characters long, where

                              # of bits per integer + 3
                    N = 1 + ---------------------------- .
                                         4

              There should be 1 character position for the sign, and
              one character position for each hexadecimal digit that
              could be produced from any integer which can be
              represented by a particular computer system.

              The following table contains minimum output string
              lengths necessary to obtain the complete hexadecimal
              string for various integer sizes.

                 Integer size in bits      Minimum output length
                 --------------------      ---------------------
                 8                         3
                 16                        5
                 32                        9
                 36 (really,it exists)     10
                 64                        17
                 etc.

              The hexadecimal character string produced by this
              routine will be left justified and consist of a
              contiguous sequence of hexadecimal digits, or in the
              case of a negative number, a contiguous sequence of
              hexadecimal digits immediately preceded by a minus
              sign, '-', e.g.:

                 (1)   h h ... h
                        1 2     n

                 (2)   -h h ... h
                         1 2     n

              where h  represents an hexadecimal digit.
                     i

              The character string produced will be blank padded on
              the right if LENGTH < LEN( STRING ).

     LENGTH   is the length of the hexadecimal character string
              produced by the conversion.

Parameters

     None.

Exceptions

     Error free.

     1)  If the output character string is not long enough to
         contain the entire hexadecimal string that was produced,
         the hexadecimal string will be truncated on the right.

     2)  If LEN( STRING ) > LENGTH, the output character string will
         be blank padded on the right.

Files

     None.

Particulars

     This routine will convert a signed integer into an equivalent
     signed hexadecimal character string. This provides a machine
     independent mechanism for storing or porting integer values.
     This routine is used by the routine DP2HX which converts a
     double precision value into an equivalent character string.

     This routine is one of a pair of routines which are used to
     perform conversions between integers and equivalent signed
     hexadecimal character strings:

           INT2HX -- Convert an integer into a signed hexadecimal
                     character string.

           HX2INT -- Convert a signed hexadecimal character string
                     into an integer.

Examples

     All of the values shown are for a two's complement representation
     for signed integers.

     The following input and output argument values illustrate the
     action of INT2HX for various input values of NUMBER.

         NUMBER       STRING           LENGTH
         -----------  ---------------  ------
          1           '1'              1
         -1           '-1'             2
          223         'DF'             2
         -32          '-20'            3
          0           '0'              1

          2147483647  '7FFFFFFF'       8
          (Maximum 32 bit integer)

         -2147483647  '-7FFFFFFF'      9
          (Minimum 32 bit integer + 1)

         -2147483648  '-80000000'      9
          (Minimum 32 bit integer)

Restrictions

     1)  The maximum number of characters permitted in the output
         string is specified by the local parameter STRLEN.

Literature_References

     None.

Author_and_Institution

     J. Diaz del Rio    (ODC Space)
     K.R. Gehringer     (JPL)

Version

    SPICELIB Version 1.1.0, 12-AUG-2021 (JDR)

        Added IMPLICIT NONE statement.

        Edited the header to comply with NAIF standard.

    SPICELIB Version 1.0.0, 22-OCT-1992 (KRG)