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Annotation of 43BSD/contrib/notes/src/pagemove.c, revision 1.1.1.1

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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