Return to move.c CVS log

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

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

1.1     ! root        1: #include "../h/rt.h"
        !             2: 
        !             3: /*
        !             4:  * move(i) - move &pos by i, return substring of &subject spanned.
        !             5:  *  Reverses effects if resumed.
        !             6:  */
        !             7: Xmove(nargs, oldsubj, arg1, arg0)
        !             8: int nargs;
        !             9: struct descrip oldsubj, arg1, arg0;
        !            10:    {
        !            11:    register int i, j;
        !            12:    long l;
        !            13:    int oldpos;
        !            14: 
        !            15:    /*
        !            16:     * i must be a (non-long) integer.
        !            17:     */
        !            18:    switch (cvint(&arg1, &l)) {
        !            19:       case T_INTEGER:  j = (int)l; break;
        !            20: #ifdef LONGS
        !            21:       case T_LONGINT:  fail();
        !            22: #endif LONGS
        !            23:       default:         runerr(101, &arg1);
        !            24:       }
        !            25: 
        !            26:    /*
        !            27:     * Save old &subject and &pos.  Local variable i holds &pos
        !            28:     *  before the move.
        !            29:     */
        !            30:    oldsubj = k_subject;
        !            31:    oldpos = i = k_pos;
        !            32: 
        !            33:    /*
        !            34:     * If attempted move is past either end of the string, fail.
        !            35:     */
        !            36:    if (i + j <= 0 || i + j > STRLEN(k_subject) + 1)
        !            37:       fail();
        !            38: 
        !            39:    /*
        !            40:     * Set new &pos.
        !            41:     */
        !            42:    k_pos += j;
        !            43: 
        !            44:    /*
        !            45:     * Make sure j >= 0.
        !            46:     */
        !            47:    if (j < 0) {
        !            48:       i += j;
        !            49:       j = -j;
        !            50:       }
        !            51: 
        !            52:    /*
        !            53:     * Suspend substring of &subject that was moved over.
        !            54:     */
        !            55:    STRLEN(arg0) = j;
        !            56:    STRLOC(arg0) = STRLOC(k_subject) + i - 1;
        !            57:    suspend();
        !            58: 
        !            59:    /*
        !            60:     * If move is resumed, restore the old subject and position
        !            61:     *  and fail.
        !            62:     */
        !            63:    k_subject = oldsubj;
        !            64:    k_pos = oldpos;
        !            65:    fail();
        !            66:    }
        !            67: 
        !            68: Procblock(move,2)

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