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Annotation of 43BSD/contrib/notes/src/pagemove.c, revision 1.1

1.1     ! root        1: #include "parms.h"
        !             2: #include "structs.h"
        !             3: 
        !             4: #ifdef RCSIDENT
        !             5: static char rcsid[] = "$Header: pagemove.c,v 1.7.0.2 85/05/20 09:55:01 notes Rel $";
        !             6: #endif RCSIDENT
        !             7: 
        !             8: /*
        !             9:  *     pagemove(io,where,io2,where2,lockflag)
        !            10:  *
        !            11:  *     Take the text pointed to by the (io,where) pair and stuff
        !            12:  *     it into the (io2) notesfile. Return the address in
        !            13:  *     (where2).
        !            14:  *
        !            15:  *     Lock the io2 notesfile for the transfer if the lockflag
        !            16:  *     parameter is non-zero.
        !            17:  *
        !            18:  *     Ray Essick, March 1985
        !            19:  */
        !            20: 
        !            21: pagemove (io, where, io2, where2, lockflag)
        !            22: struct io_f *io;
        !            23: struct daddr_f *where;
        !            24: struct io_f *io2;
        !            25: struct daddr_f *where2;
        !            26: int     lockflag;
        !            27: {
        !            28:     char    buf[BUFSIZ];                               /* for moving chunks */
        !            29:     register int    bufchars;                          /* in buffer */
        !            30:     register long   moved;                             /* actually moved */
        !            31:     register long   total;
        !            32:     register long   need;
        !            33:     struct daddr_f  nwhere;
        !            34: 
        !            35:     if (where -> addr == 0 || where -> textlen == 0)
        !            36:     {                                                  /* no text or empty */
        !            37:        where2 -> addr = 0;
        !            38:        where2 -> textlen = 0;
        !            39:        return;                                         /* cheap move */
        !            40:     }
        !            41: 
        !            42:     if (lockflag)                                      /* lock if wanted */
        !            43:        locknf (io2, TXTLOCK);
        !            44: 
        !            45:     /* 
        !            46:      * position the input and output files.
        !            47:      * we have to grab the free pointer for the output file.
        !            48:      */
        !            49:     x (lseek (io -> fidtxt, where -> addr, 0) != where -> addr, "pagemove: old seek");
        !            50:     x (lseek (io2 -> fidtxt, 0L, 0) != 0, "pagemove: io2 seek 0");
        !            51:     x (read (io2 -> fidtxt, where2, sizeof *where) != sizeof *where, "pagemove: read free");
        !            52:     x (lseek (io2 -> fidtxt, where2 -> addr, 0) != where2 -> addr, "pagemove: new seek");
        !            53:     moved = 0;
        !            54:     total = where -> textlen;                          /* total to move */
        !            55:     bufchars = 0;
        !            56:     where2 -> textlen = 0;                             /* start empty */
        !            57: 
        !            58:     while (moved != total)                             /* more text */
        !            59:     {
        !            60:        need = total - moved;                           /* how much wanted? */
        !            61:        if (need >= BUFSIZ)
        !            62:            need = BUFSIZ;                              /* only so many at once */
        !            63:        bufchars = read (io -> fidtxt, buf, ((int) need));/* read them */
        !            64:        x (bufchars != need, "pagemove: bad read from old");/* check */
        !            65:        x (write (io2 -> fidtxt, buf, bufchars) != bufchars, "pagemove: bad write to new");
        !            66:        moved += bufchars;                              /* bump counts */
        !            67:        where2 -> textlen += bufchars;
        !            68:     }
        !            69:     x (where -> textlen != where2 -> textlen, "pagemove: moved wrong count");
        !            70:     /* 
        !            71:      * we now have shoved the text into the second notesfile.
        !            72:      * We need to go back and update the free pointer.
        !            73:      * and then we can return...
        !            74:      */
        !            75:     nwhere.textlen = 0;
        !            76:     nwhere.addr = where2 -> addr + where2 -> textlen;
        !            77:     if (nwhere.addr & 1)                               /* odd? */
        !            78:        nwhere.addr++;                                  /* round up */
        !            79:     x (lseek (io2 -> fidtxt, 0L, 0) != 0, "pagemove: bad reseek");
        !            80:     x (write (io2 -> fidtxt, &nwhere, sizeof nwhere) != sizeof nwhere, "pagemove: bad write free pointer");
        !            81: 
        !            82:     if (lockflag)                                      /* cleanup */
        !            83:        unlocknf (io2, TXTLOCK);
        !            84: }

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