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diff --git a/math/slalib/doc/flotin.hlp b/math/slalib/doc/flotin.hlp new file mode 100644 index 00000000..5e3d8bd6 --- /dev/null +++ b/math/slalib/doc/flotin.hlp @@ -0,0 +1,118 @@ +.help flotin Jun99 "Slalib Package" +.nf + + SUBROUTINE slRFLI (STRING, NSTRT, RESLT, JFLAG) + + - - - - - - - + R F L I + - - - - - - - + + 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: slDFLI + + 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 + Copyright (C) 1995 Association of Universities for Research in Astronomy Inc. + +.fi +.endhelp |