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Annotation of 43BSD/contrib/icon/functions/put.c, revision 1.1

1.1     ! root        1: #include "../h/rt.h"
        !             2: 
        !             3: /*
        !             4:  * put(x,val) - put val onto end of list x.
        !             5:  */
        !             6: Xput(nargs, arg2, arg1, arg0)
        !             7: int nargs;
        !             8: struct descrip arg2, arg1, arg0;
        !             9:    {
        !            10:    register int i;
        !            11:    register struct b_list *hp;
        !            12:    register struct b_lelem *bp;
        !            13:    extern struct b_lelem *alclstb();
        !            14: 
        !            15:    /*
        !            16:     * x must be a list.
        !            17:     */
        !            18:    DeRef(arg1)
        !            19:    DeRef(arg2)
        !            20:    if (QUAL(arg1) || TYPE(arg1) != T_LIST)
        !            21:       runerr(108, &arg1);
        !            22: 
        !            23:    /*
        !            24:     * A new list element block might be needed, so ensure space for it.
        !            25:     */
        !            26:    hneed(sizeof(struct b_lelem)+LISTBLKSIZE*sizeof(struct descrip));
        !            27: 
        !            28:    /*
        !            29:     * Point hp at the list header block and bp at the last list element block.
        !            30:     */
        !            31:    hp = (struct b_list *) BLKLOC(arg1);
        !            32:    bp = (struct b_lelem *) BLKLOC(hp->listtail);
        !            33: 
        !            34:    /*
        !            35:     * If the last list element block is full,
        !            36:     *  allocate a new list element block, make it the first list
        !            37:     *  element block and it make it the next block of the
        !            38:     *  former last list element block.
        !            39:     */
        !            40:    if (bp->nused >= bp->nelem) {
        !            41:       bp = alclstb(LISTBLKSIZE, 0, 0);
        !            42:       BLKLOC(hp->listtail)->lelem.listnext.type = D_LELEM;
        !            43:       BLKLOC(BLKLOC(hp->listtail)->lelem.listnext) = (union block *) bp;
        !            44:       bp->listprev = hp->listtail;
        !            45:       BLKLOC(hp->listtail) = (union block *) bp;
        !            46:       }
        !            47:    /*
        !            48:     * Set i to position of new last element and assign val (arg2) to
        !            49:     *  that element.
        !            50:     */
        !            51:    i = bp->first + bp->nused;
        !            52:    if (i >= bp->nelem)
        !            53:       i -= bp->nelem;
        !            54:    bp->lslots[i] = arg2;
        !            55:    /*
        !            56:     * Adjust block usage count and current list size.
        !            57:     */
        !            58:    bp->nused++;
        !            59:    hp->cursize++;
        !            60:    /*
        !            61:     * Return the list.
        !            62:     */
        !            63:    arg0 = arg1;
        !            64:    }
        !            65: 
        !            66: Procblock(put,2)

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