///////    File: SortKey.C    ///////
#include <iostream.h>
#include <string.h>
#include "SortKey.h"

const char *SortKey::key(const char *s)
{   int i = position;           // key position
    while ( --i > 0 )           // skipping positions
    {   s += strspn(s,delim);
        s += strcspn(s,delim);
    }
    s += strspn(s,delim);
    return(s);                  // first char of key
}

int SortKey::cmp(const char *a, const char *b)
{   if (position == 0)
       return( strcmp(a,b));
    int ans = keycmp(key(a), key(b));
    return(ans);
}

inline int SortKey::is_del(const char* c)
{  return(strspn(c,delim) || *c == '\0');  }

int SortKey::keycmp(const char *a, const char *b)
{   for(; *a == *b; a++, b++)
    {   if ( is_del(a) ) return(0);     // a equal to b
    }
    if ( is_del(a) && is_del(b) )
        return(0);
    if ( is_del(a) ) return(-1);        // a less than b
    else if ( is_del(b) ) return(1);    // a greater than b
    else return(*a - *b);               // a not equal to b
}