useful           1508 src/diffviewer/ydiff.c     size_t useful, offset;
useful           1547 src/diffviewer/ydiff.c     useful = base - skip;
useful           1550 src/diffviewer/ydiff.c     if (useful <= dstsize)
useful           1552 src/diffviewer/ydiff.c         if (useful != 0)
useful           1553 src/diffviewer/ydiff.c             memmove (dst, cvt + offset, useful);
useful           1557 src/diffviewer/ydiff.c             sz = dview_fgets (tmp, dstsize - useful + 1, f);
useful           1562 src/diffviewer/ydiff.c                 useful += cvt_ncpy (dst + useful, dstsize - useful, &ptr, sz, base, ts) - base;
useful           1567 src/diffviewer/ydiff.c         sz = useful;