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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
*-
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
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