Return to get.c CVS log

Up to [CSRG BSD Unix] / 43BSD / contrib / icon / functions

Annotation of 43BSD/contrib/icon/functions/get.c, revision 1.1.1.1

1.1       root        1: #include "../h/rt.h"
                      2: 
                      3: /*
                      4:  * get(x) - get an element from end of list x.
                      5:  * Identical to  pop(x).
                      6:  */
                      7: 
                      8: Xget(nargs, arg1, arg0)
                      9: int nargs;
                     10: struct descrip arg1, arg0;
                     11:    {
                     12:    register int i;
                     13:    register struct b_list *hp;
                     14:    register struct b_lelem *bp;
                     15:    extern struct b_lelem *alclstb();
                     16: 
                     17:    /*
                     18:     * x must be a list.
                     19:     */
                     20:    DeRef(arg1)
                     21:    if (QUAL(arg1) || TYPE(arg1) != T_LIST)
                     22:       runerr(108, &arg1);
                     23: 
                     24:    /*
                     25:     * Fail if the list is empty.
                     26:     */
                     27:    hp = (struct b_list *) BLKLOC(arg1);
                     28:    if (hp->cursize <= 0)
                     29:       fail();
                     30: 
                     31:    /*
                     32:     * Point bp at the first list block.  If the first block has no
                     33:     *  elements in use, point bp at the next list block.
                     34:     */
                     35:    bp = (struct b_lelem *) BLKLOC(hp->listhead);
                     36:    if (bp->nused <= 0) {
                     37:       bp = (struct b_lelem *) BLKLOC(bp->listnext);
                     38:       BLKLOC(hp->listhead) = (union block *) bp;
                     39:       bp->listprev = nulldesc;
                     40:       }
                     41:    /*
                     42:     * Locate first element and assign it to arg0 for return.
                     43:     */
                     44:    i = bp->first;
                     45:    arg0 = bp->lslots[i];
                     46:    /*
                     47:     * Set bp->first to new first element, or 0 if the block is now
                     48:     *  empty.  Decrement the usage count for the block and the size
                     49:     *  of the list.
                     50:     */
                     51:    if (++i >= bp->nelem)
                     52:       i = 0;
                     53:    bp->first = i;
                     54:    bp->nused--;
                     55:    hp->cursize--;
                     56:    }
                     57: 
                     58: Procblock(get,1)

This archive runs on limited infrastructure. Preserving old code on modern bandwidth. Automated agents are requested to crawl responsibly.