lx4sgn_c

Index Page lx4sgn_c
A B C D E F G H I J K L M N O P Q R S T U V W X
Procedure Abstract Required_Reading Keywords Brief_I/O Detailed_Input | Detailed_Output Parameters Exceptions Files Particulars Examples | Restrictions Literature_References Author_and_Institution Version Index_Entries
#### Procedure
       void lx4sgn_c ( ConstSpiceChar   * string,
                       SpiceInt           first,
                       SpiceInt         * last,
                       SpiceInt         * nchar  )
#### Abstract
       Scan a string from a specified starting position for the
       end of a signed integer.
#### Required_Reading
       None.
#### Keywords
       PARSING
#### Brief_I/O
       VARIABLE  I/O  DESCRIPTION
       --------  ---  --------------------------------------------------
       string     I   Any character string.
       first      I   First character to scan from in string.
       last       O   Last character that is part of a signed integer.
       nchar      O   Number of characters in the signed integer.
#### Detailed_Input
       string      is any character string.

       first       is the location in the string to beginning scanning
                   for a signed integer.  It is assumed that the
                   signed integer begins at first.

                   The normal range of first is 0 : strlen(string)-1.
#### Detailed_Output
       last        is the last character at or after first such that the
                   substring ranging from string[first] through
                   string[last] is a signed integer.  If there is no such
                   substring, last will be returned with the value first-1.

                   If a signed integer is found, last will be in the
                   range is 0 : strlen(string)-1.

       nchar       is the number of characters in the signed integer that
                   begins at index first and ends at last.  If there is no
                   such string nchar will be given the value 0.
#### Parameters
       None.
#### Exceptions
       1) If first is beyond either end of the string, then
          last will be returned with the value first-1 and nchar
          will be returned with the value 0.

       2) If string[first] is not part of a signed integer then last
          will be returned with the value first-1 and nchar will be
          returned with the value 0.

       3) If the input string pointer is null, the error SPICE(NULLPOINTER)
          will be signaled.

       4) If the input string has length zero, last will be set to first-1
          and nchar will be set to zero.  This case is not considered an
          error.
#### Files
       None.
#### Particulars
       This routine allows you to scan forward in a string to locate a
       signed integer that begins on the input character at index first.
       Note that all unsigned integers are included in the list of signed
       integers.  The signed integers may in addition have a leading plus
       ('+') or minus ('-') sign.
#### Examples
       1) Suppose you believe that a string has the form

             X%Y%Z

          where X, Y, and Z are signed integers of some unknown length and
          % stands for any character that cannot occur in a signed integer.
          You could use this routine to locate the signed integers in the
          string as shown below.  We'll keep track of the beginning and
          ending of the signed integers in the integer arrays b and e.

             #include <string.h>
             #include "SpiceUsr.h"

                   .
                   .
                   .

             first = 0;
             i     = 0;
             len   = strlen(string);

             while ( first < len-1 )
             {
                lx4sgn_c ( string, first, &last, &nchar );

                if ( nchar > 0 )
                {
                   i++;

                   b[i]  = first;
                   e[i]  = last;
                   first = last  +  2;
                }
                else
                {
                   first++;
                }
             }
#### Restrictions
       None.
#### Literature_References
       None.
#### Author_and_Institution
       N.J. Bachman    (JPL)
       W.L. Taber      (JPL)
#### Version
       -CSPICE Version 1.0.0, 18-AUG-2002 (NJB) (WLT)
#### Index_Entries
       Scan a string for a signed integer.
#### Link to routine lx4sgn_c source file lx4sgn_c.c

    Thu Apr 16 08:58:33 2009