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%% options
copyright owner = Dirk Krause
copyright year = 2013-xxxx
SPDX-License-Identifier: BSD-3-Clause
%% header
#ifndef DK4CONF_H_INCLUDED
#if DK4_BUILDING_DKTOOLS4
#include "dk4conf.h"
#else
#include <dktools-4/dk4conf.h>
#endif
#endif
#if DK4_HAVE_STDLIB_H
#include <stdlib.h>
#endif
#if DK4_HAVE_UNISTD_H
#include <unistd.h>
#endif
/** Namespace to protect Container and Iterator from name collisions.
*/
namespace DkTools4 {
/** Comparable is a general base class for objects we want to compare,
for example for sorted storage.
Derived classes must implement the compareAgainst() method.
*/
class Comparable
{
public:
/** Compare object against another object or some data.
Derived classes must implement this method.
The comparison is used by sorted containers.
Example: When storing persons (name and age) we can use
crit=0 as comparison criteria in the container to compare
person object against person object.
When searching the container for an object with a specific name
we can use crit=1 for comparisons of the object against a
string.
@param pt Address of other object or data.
@param crit Comparison criteria, see documentation of
derived classes for class-specific numbers.
@return Positive number if larger than ptr, 0 if
evaluates equal to ptr, negative number if
smaller than ptr.
*/
virtual
int
compareAgainst(void const *ptr, int crit) const = 0;
/** Compare two pointers
@param l Left pointer.
@param r Right pointer.
@param cr Comparison criteria.
@return 1 for left object is large, 0 for right object
is large, 0 for objects evaluating equally.
*/
static
int
compareTwoPointers(void const *l, void const *r, int cr);
/** Virtual destructor required by compiler.
*/
virtual
~Comparable();
}; /* End of class Comparable. */
} /* End of namespace DkTools4 */
%% module
#include "Dk4Comparable.h"
int
DkTools4::Comparable::compareTwoPointers(void const *l, void const *r, int cr)
{
int back = 0;
if(NULL != l) {
if(NULL != r) {
DkTools4::Comparable const *pl = (DkTools4::Comparable const *)l;
back = pl->compareAgainst(r, cr);
}
else {
back = 1;
}
} else {
if(r) back = -1;
}
return back;
}
DkTools4::Comparable::~Comparable()
{
}
/* vim: set ai sw=4 ts=4 : */
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