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Annotation of 43BSD/contrib/icon/operators/inter.c, revision 1.1

1.1     ! root        1: #include "../h/rt.h"
        !             2: 
        !             3: /*
        !             4:  * x ** y - intersection of csets x and y or of sets x and y.
        !             5:  */
        !             6: 
        !             7: inter(nargs, arg2, arg1, arg0)
        !             8: int nargs;
        !             9: struct descrip arg2, arg1, arg0;
        !            10:    {
        !            11:    DclSave
        !            12:    register int i;
        !            13:    union block *bp;
        !            14:    int *cs1, csbuf1[CSETSIZE], *cs2, csbuf2[CSETSIZE];
        !            15:    extern struct b_cset *alccset();
        !            16: #ifdef SETS
        !            17:    struct descrip *dp;
        !            18:    struct b_set *srcp, *tstp, *dstp;
        !            19:    struct b_selem *sep;
        !            20:    extern struct b_set *alcset();
        !            21:    extern struct b_selem *alcselem();
        !            22: #endif SETS
        !            23: 
        !            24:    SetBound;
        !            25: #ifdef SETS
        !            26:    DeRef(arg1)
        !            27:    DeRef(arg2)
        !            28:    if (QUAL(arg1) || QUAL(arg2))
        !            29:       goto skipsets;
        !            30:    if (TYPE(arg1) == T_SET && TYPE(arg2) != T_SET)
        !            31:       runerr(119,&arg2);
        !            32:    if (TYPE(arg2) == T_SET && TYPE(arg1) != T_SET)
        !            33:       runerr(119,&arg1);
        !            34:    if (TYPE(arg1) == T_SET && TYPE(arg2) == T_SET) {
        !            35:       /*
        !            36:        * Both x and y are sets - do set intersection
        !            37:        *  get enough space for a new set the size of the smaller
        !            38:        *  of the two sets.
        !            39:        */
        !            40:       hneed(sizeof(struct b_set) + MIN(BLKLOC(arg1)->set.setsize,
        !            41:          BLKLOC(arg2)->set.setsize) * sizeof(struct b_selem));
        !            42:       /*
        !            43:        * Using the smaller of the two sets as the source
        !            44:        *  copy directly into the result each of its elements
        !            45:        *  that are also members of the other set.
        !            46:        */
        !            47:       if (BLKLOC(arg1)->set.setsize <= BLKLOC(arg2)->set.setsize) {
        !            48:          srcp = (struct b_set *) BLKLOC(arg1);
        !            49:          tstp = (struct b_set *) BLKLOC(arg2);
        !            50:          }
        !            51:       else {
        !            52:          srcp = (struct b_set *) BLKLOC(arg2);
        !            53:          tstp = (struct b_set *) BLKLOC(arg1);
        !            54:          }
        !            55:       arg0.type = D_SET;
        !            56:       dstp = alcset();
        !            57:       BLKLOC(arg0) = (union block *) dstp;
        !            58:       for (i = 0; i < NBUCKETS; i++) {
        !            59:          sep = (struct b_selem *) BLKLOC(srcp->sbucks[i]);
        !            60:          dp = &dstp->sbucks[i];
        !            61:          while (sep != NULL) {
        !            62:             if (locate(BLKLOC(tstp->sbucks[i]), sep)) {
        !            63:                dp->type = D_SELEM;
        !            64:                BLKLOC(*dp) = (union block *) alcselem(&sep->setmem, sep->hnum);
        !            65:                dp = &BLKLOC(*dp)->selem.sblink;
        !            66:                dstp->setsize++;
        !            67:                }
        !            68:             sep = (struct b_selem *) BLKLOC(sep->sblink);
        !            69:             }
        !            70:          }
        !            71:       }
        !            72:       else {
        !            73:          skipsets:
        !            74: #endif SETS
        !            75:    hneed(sizeof(struct b_cset));
        !            76: 
        !            77:    /*
        !            78:     * x and y must be csets.
        !            79:     */
        !            80:    if (cvcset(&arg1, &cs1, csbuf1) == NULL)
        !            81:       runerr(104, &arg1);
        !            82:    if (cvcset(&arg2, &cs2, csbuf2) == NULL)
        !            83:       runerr(104, &arg2);
        !            84: 
        !            85:    /*
        !            86:     * Allocate a new cset and in each word of it, compute the value
        !            87:     *  of the bitwise intersection of the corresponding words in the
        !            88:     *  x and y csets.
        !            89:     */
        !            90:    bp = (union block *) alccset();
        !            91:    for (i = 0; i < CSETSIZE; i++)
        !            92:       bp->cset.bits[i] = cs1[i] & cs2[i];
        !            93: 
        !            94:    arg0.type = D_CSET;
        !            95:    BLKLOC(arg0) = bp;
        !            96: #ifdef SETS
        !            97:    }
        !            98: #endif SETS
        !            99:    ClearBound;
        !           100:    }
        !           101: 
        !           102: Opblock(inter,2,"**")

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