useful           1568 src/diffviewer/ydiff.c     size_t useful, offset;
useful           1609 src/diffviewer/ydiff.c     useful = base - skip;
useful           1612 src/diffviewer/ydiff.c     if (useful <= dstsize)
useful           1614 src/diffviewer/ydiff.c         if (useful != 0)
useful           1615 src/diffviewer/ydiff.c             memmove (dst, cvt + offset, useful);
useful           1619 src/diffviewer/ydiff.c             sz = f_gets (tmp, dstsize - useful + 1, f);
useful           1624 src/diffviewer/ydiff.c                 useful += cvt_ncpy (dst + useful, dstsize - useful, &ptr, sz, base, ts) - base;
useful           1629 src/diffviewer/ydiff.c         sz = useful;