| bschoc_c |
|
Table of contents
Procedure
bschoc_c ( Binary search with order vector, character )
SpiceInt bschoc_c ( ConstSpiceChar * value,
SpiceInt ndim,
SpiceInt arrlen,
const void * array,
ConstSpiceInt * order )
AbstractDo 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_ReadingNone. KeywordsARRAY SEARCH Brief_I/OVARIABLE 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_OutputThe 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. ParametersNone. 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.
FilesNone. ParticularsA 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_ReferencesNone. Author_and_InstitutionN.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_Entriesbinary search for a string using an order vector |
Fri Dec 31 18:41:02 2021