C:/Users/Dennis/src/lang/russell.orig/src/pass2/retrieve.c

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/*
 *      retrieve(key)
 *
 *      Return a pointer to the Identry with i_sttindx key.
 */

# include "parm.h"
# include "stree/ststructs.mh"
# include "pass1/stt/sttdefs.h"
# include "Idtable.h"
# define DEBUG yes

/* int nprobes = 0; */
int nkeys = 0;

Identry * retrieve(key)
sttrelptr key;
{
        nkeys++;
        return ( &Idtable[retr1(key, 0, sttnstrings-1)] );
}

/*
 *      retr1(key, f, l)
 *
 *      Hidden routine to search Idtable between the bounds f and l for the entry
 *      with i_sttindx equal to indx. An interpolation search is used.
 */
retr1(key, f, l)
register sttrelptr key;
register int f, l;                                      /* first, last indices                          */
{       register int c;                                 /* "current" probe index                        */

        for(;;) {

                /* nprobes++; */

        if ( f > l || Idtable[f].i_sttindx > key || Idtable[l].i_sttindx < key) {
                dbgmsg("retr1: Can't find name!\n");
                /* abort(); */ return;
        }
    
        c = f;
                if( l != f ) {
                  long r;
                  int t;

                  /*c +=
                                ( ((long)(l-f)) * ((long)(key-Idtable[f].i_sttindx)) ) /
                                        ( (int) (Idtable[l].i_sttindx - Idtable[f].i_sttindx) ); */

                        r= ( ((long)(l-f)) * ((long)(key-Idtable[f].i_sttindx)) ); 
                        t=              ( (int) (Idtable[l].i_sttindx - Idtable[f].i_sttindx) );
                        r += t >> 1;
                        c += r / t;
                }
/*              printf("f=%d, l=%d, c=%d\n", f, l, c); */
                if ( Idtable[c].i_sttindx == key )
                        return(c);
        else if ( key < Idtable[c].i_sttindx ) {
                f += 1; l = c-1;
        } else {
                f = c+1; l -= 1;
                }
        }
}

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