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slalib/flotin.f

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+      SUBROUTINE sla_FLOTIN (STRING, NSTRT, RESLT, JFLAG)
+*+
+*     - - - - - - -
+*      F L O T I N
+*     - - - - - - -
+*
+*  Convert free-format input into single precision floating point
+*
+*  Given:
+*     STRING     c     string containing number to be decoded
+*     NSTRT      i     pointer to where decoding is to start
+*     RESLT      r     current value of result
+*
+*  Returned:
+*     NSTRT      i      advanced to next number
+*     RESLT      r      result
+*     JFLAG      i      status: -1 = -OK, 0 = +OK, 1 = null, 2 = error
+*
+*  Called:  sla_DFLTIN
+*
+*  Notes:
+*
+*     1     The reason FLOTIN has separate OK status values for +
+*           and - is to enable minus zero to be detected.   This is
+*           of crucial importance when decoding mixed-radix numbers.
+*           For example, an angle expressed as deg, arcmin, arcsec
+*           may have a leading minus sign but a zero degrees field.
+*
+*     2     A TAB is interpreted as a space, and lowercase characters
+*           are interpreted as uppercase.
+*
+*     3     The basic format is the sequence of fields #^.^@#^, where
+*           # is a sign character + or -, ^ means a string of decimal
+*           digits, and @, which indicates an exponent, means D or E.
+*           Various combinations of these fields can be omitted, and
+*           embedded blanks are permissible in certain places.
+*
+*     4     Spaces:
+*
+*             .  Leading spaces are ignored.
+*
+*             .  Embedded spaces are allowed only after +, -, D or E,
+*                and after the decomal point if the first sequence of
+*                digits is absent.
+*
+*             .  Trailing spaces are ignored;  the first signifies
+*                end of decoding and subsequent ones are skipped.
+*
+*     5     Delimiters:
+*
+*             .  Any character other than +,-,0-9,.,D,E or space may be
+*                used to signal the end of the number and terminate
+*                decoding.
+*
+*             .  Comma is recognized by FLOTIN as a special case;  it
+*                is skipped, leaving the pointer on the next character.
+*                See 13, below.
+*
+*     6     Both signs are optional.  The default is +.
+*
+*     7     The mantissa ^.^ defaults to 1.
+*
+*     8     The exponent @#^ defaults to E0.
+*
+*     9     The strings of decimal digits may be of any length.
+*
+*     10    The decimal point is optional for whole numbers.
+*
+*     11    A "null result" occurs when the string of characters being
+*           decoded does not begin with +,-,0-9,.,D or E, or consists
+*           entirely of spaces.  When this condition is detected, JFLAG
+*           is set to 1 and RESLT is left untouched.
+*
+*     12    NSTRT = 1 for the first character in the string.
+*
+*     13    On return from FLOTIN, NSTRT is set ready for the next
+*           decode - following trailing blanks and any comma.  If a
+*           delimiter other than comma is being used, NSTRT must be
+*           incremented before the next call to FLOTIN, otherwise
+*           all subsequent calls will return a null result.
+*
+*     14    Errors (JFLAG=2) occur when:
+*
+*             .  a +, -, D or E is left unsatisfied;  or
+*
+*             .  the decimal point is present without at least
+*                one decimal digit before or after it;  or
+*
+*             .  an exponent more than 100 has been presented.
+*
+*     15    When an error has been detected, NSTRT is left
+*           pointing to the character following the last
+*           one used before the error came to light.  This
+*           may be after the point at which a more sophisticated
+*           program could have detected the error.  For example,
+*           FLOTIN does not detect that '1E999' is unacceptable
+*           (on a computer where this is so) until the entire number
+*           has been decoded.
+*
+*     16    Certain highly unlikely combinations of mantissa &
+*           exponent can cause arithmetic faults during the
+*           decode, in some cases despite the fact that they
+*           together could be construed as a valid number.
+*
+*     17    Decoding is left to right, one pass.
+*
+*     18    See also DFLTIN and INTIN
+*
+*  P.T.Wallace   Starlink   23 November 1995
+*
+*  Copyright (C) 1995 Rutherford Appleton Laboratory
+*
+*  License:
+*    This program is free software; you can redistribute it and/or modify
+*    it under the terms of the GNU General Public License as published by
+*    the Free Software Foundation; either version 2 of the License, or
+*    (at your option) any later version.
+*
+*    This program is distributed in the hope that it will be useful,
+*    but WITHOUT ANY WARRANTY; without even the implied warranty of
+*    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+*    GNU General Public License for more details.
+*
+*    You should have received a copy of the GNU General Public License
+*    along with this program (see SLA_CONDITIONS); if not, write to the 
+*    Free Software Foundation, Inc., 59 Temple Place, Suite 330, 
+*    Boston, MA  02111-1307  USA
+*
+*-
+
+      IMPLICIT NONE
+
+      CHARACTER*(*) STRING
+      INTEGER NSTRT
+      REAL RESLT
+      INTEGER JFLAG
+
+      DOUBLE PRECISION DRESLT
+
+
+*  Call the double precision version
+      CALL sla_DFLTIN(STRING,NSTRT,DRESLT,JFLAG)
+      IF (JFLAG.LE.0) RESLT=REAL(DRESLT)
+
+      END