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Index Page bschoc_c

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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

       bschoc_c ( Binary search with order vector, character )

       SpiceInt bschoc_c ( ConstSpiceChar  * value,
                           SpiceInt          ndim,
                           SpiceInt          arrlen,
                           const void      * array,
                           ConstSpiceInt   * order    )

#### Abstract

       Do a binary search for a given value within an array of character
       strings, accompanied by an order vector. Return the index of the
       matching array entry, or -1 if the key value is not found.

#### Required_Reading

       None.

#### Keywords

       ARRAY
       SEARCH

#### Brief_I/O

       VARIABLE  I/O  DESCRIPTION
       --------  ---  --------------------------------------------------
       value      I   Key value to be found in `array'.
       ndim       I   Dimension of `array'.
       arrlen     I   Declared length of the strings in `array'.
       array      I   Character string array to search.
       order      I   Order vector.

       The function returns the index of the first matching array element
       or -1 if the value is not found.

#### Detailed_Input

       value       is the key value to be found in the array. Trailing
                   blanks in this key are not significant: string matches
                   found by this routine do not require trailing blanks in
                   value to match those in the corresponding element of
                   array.

       ndim        is the number of elements in the input array.

       arrlen      is the declared length of the strings in the input
                   string array, including null terminators. The input
                   array should be declared with dimension

                      [ndim][arrlen]

       array       is the array of character strings to be searched. Trailing
                   blanks in the strings in this array are not significant.

       order       is an order array that can be used to access the elements
                   of `array' in order (according to the ASCII collating
                   sequence). The contents of `order' are a permutation of
                   the sequence of integers ranging from 0 to ndim-1.

#### Detailed_Output

       The function returns the index of the specified value in the input
       array. Indices range from 0 to ndim-1.

       If the input array does not contain the specified value, the
       function returns -1.

       If the input array contains more than one occurrence of the
       specified value, the returned index may point to any of the
       occurrences.

#### Parameters

       None.

#### Exceptions

       1)  If ndim < 1, the value of the function is -1. This is not
           considered an error.

       2)  If the `value' input string pointer is null, the error
           SPICE(NULLPOINTER) is signaled. The function returns the
           value -1.

       3)  If the `array' input array pointer is null, the error
           SPICE(NULLPOINTER) is signaled. The function returns the
           value -1.

       4)  If the `array' input array strings have length less than two
           characters, the error SPICE(EMPTYSTRING) is signaled. The
           function returns the value -1.

#### Files

       None.

#### Particulars

       A binary search is performed on the input array, whose order is
       given by an associated order vector. If an element of the array is
       found to match the input value, the index of that element is
       returned. If no matching element is found, -1 is returned.

#### Examples

       The numerical results shown for this example may differ across
       platforms. The results depend on the SPICE kernels used as
       input, the compiler and supporting libraries, and the machine
       specific arithmetic implementation.

       1) Search for different character strings in an array that
          is sorted following a given criteria, not necessarily
          alphabetically.

          Example code begins here.

          /.
             Program bschoc_ex1
          ./
          #include <stdio.h>
          #include "SpiceUsr.h"

          int main( )
          {

             /.
             Local constants.
             ./
             #define NDIM         5
             #define STRLEN       9

             /.
             Local variables.
             ./

             SpiceInt             i;
             SpiceInt             idx;

             /.
             Let `array' and `order' contain the following elements:
             ./
             SpiceChar            array  [NDIM][STRLEN] = {
                            "FEYNMAN", "BOHR", "EINSTEIN", "NEWTON",  "GALILEO" };

             SpiceInt             order  [NDIM] = { 1, 2, 0, 4, 3 };

             /.
             Set the list of `names' to be searched.
             ./
             SpiceChar            names  [NDIM][STRLEN] = {
                           "NEWTON", "EINSTEIN", "GALILEO", "Galileo",  "BETHE" };

             /.
             Search for the `names'.
             ./
             for ( i = 0; i < NDIM; i++ )
             {

                idx = bschoc_c( names[i], NDIM, STRLEN, array, order );

                if ( idx == -1 )
                {
                   printf( "Name %-8s not found in `array'.\n", names[i] );
                }
                else
                {
                   printf( "Name %-8s found in position %d\n", names[i], idx );
                }

             }

             return ( 0 );
          }

          When this program was executed on a Mac/Intel/cc/64-bit
          platform, the output was:

          Name NEWTON   found in position 3
          Name EINSTEIN found in position 2
          Name GALILEO  found in position 4
          Name Galileo  not found in `array'.
          Name BETHE    not found in `array'.

          Note that these results indicate that:

              array[3] = "NEWTON"
              array[2] = "EINSTEIN"
              array[4] = "GALILEO"

#### Restrictions

       1)  `order' is assumed to give the order of the elements of `array' in
           increasing order according to the ASCII collating sequence. If
           this condition is not met, the results of bschoc_c are
           unpredictable.

       2)  String comparisons performed by this routine are Fortran-style:
           trailing blanks in the input array or key value are ignored.
           This gives consistent behavior with CSPICE code generated by
           the f2c translator, as well as with the Fortran SPICE Toolkit.

           Note that this behavior is not identical to that of the ANSI
           C library functions strcmp and strncmp.

#### Literature_References

       None.

#### Author_and_Institution

       N.J. Bachman        (JPL)
       J. Diaz del Rio     (ODC Space)
       W.L. Taber          (JPL)
       I.M. Underwood      (JPL)

#### Version

       -CSPICE Version 1.2.0, 08-JUL-2021 (JDR)

           Changed the input argument name "lenvals" to "arrlen" for consistency
           with other routines.

           Edited the header to comply with NAIF standard. Added complete code
           example.

           Updated -Index_Entries and -Restrictions to better explain the objective
           of this function and its limitations.

       -CSPICE Version 1.1.0, 07-MAR-2009 (NJB)

           This file now includes the header file f2cMang.h.
           This header supports name mangling of f2c library
           functions.

           Header sections were re-ordered.

       -CSPICE Version 1.0.0, 26-AUG-2002 (NJB) (WLT) (IMU)

#### Index_Entries

       binary search for a string using an order vector

#### Link to routine bschoc_c source file bschoc_c.c

    Fri Dec 31 18:41:02 2021