lib/: Use NITEMS() instead of SIZEOF_ARRAY() where number of elements is meant

[alejandro-colomar]

For arrays of char, both NITEMS() and SIZEOF_ARRAY() return the same value. However, NITEMS() is more appropriate. Think of wide-character equivalents of the same code; with NITEMS(), they would continue to be valid, while with SIZEOF_ARRAY(), they would be wrong.

[alejandro-colomar]

v2 changes:

• Revert a change in the implementation of ZUSTR2STP().

$ git range-diff shadow/master gh/nitems nitems 
1:  ca51a134 ! 1:  38d1b779 lib/: Use NITEMS() instead of SIZEOF_ARRAY() where number of elements is meant
    @@ Commit message
         equivalents of the same code; with NITEMS(), they would continue to be
         valid, while with SIZEOF_ARRAY(), they would be wrong.
     
    +    In the implementation of ZUSTR2STP(), we want SIZEOF_ARRAY() within the
    +    static assert, because we're just comparing the sizes of the source and
    +    destination buffers, and we don't care if we compare sizes of numbers of
    +    elements, and using sizes is just simpler.  But we want NITEMS() in the
    +    zustr2stp() call, where we want to copy a specific number of characters.
    +
         Signed-off-by: Alejandro Colomar <[email protected]>
     
      ## lib/strtcpy.h ##
    @@ lib/utmp.c: static
     
      ## lib/zustr2stp.h ##
     @@
    - 
    - #define ZUSTR2STP(dst, src)                                                   \
      ({                                                                            \
    --  static_assert(!is_array(dst) || sizeof(dst) > SIZEOF_ARRAY(src), ""); \
    -+  static_assert(!is_array(dst) || sizeof(dst) > NITEMS(src), "");       \
    +   static_assert(!is_array(dst) || sizeof(dst) > SIZEOF_ARRAY(src), ""); \
                                                                                    \
     -  zustr2stp(dst, src, SIZEOF_ARRAY(src));                               \
     +  zustr2stp(dst, src, NITEMS(src));                                     \

[alejandro-colomar]

v2b changes:

• tfix

$ git range-diff shadow/master gh/nitems nitems 
1:  38d1b779 ! 1:  6c72182d lib/: Use NITEMS() instead of SIZEOF_ARRAY() where number of elements is meant
    @@ Commit message
     
         In the implementation of ZUSTR2STP(), we want SIZEOF_ARRAY() within the
         static assert, because we're just comparing the sizes of the source and
    -    destination buffers, and we don't care if we compare sizes of numbers of
    +    destination buffers, and we don't care if we compare sizes or numbers of
         elements, and using sizes is just simpler.  But we want NITEMS() in the
         zustr2stp() call, where we want to copy a specific number of characters.
     

[alejandro-colomar]

v2c changes:

• Rebase to master

$ git range-diff master..gh/nitems shadow/master..nitems 
1:  6c72182d = 1:  f760d404 lib/: Use NITEMS() instead of SIZEOF_ARRAY() where number of elements is meant

[alejandro-colomar]

v2d changes:

• Rebase to master

$ git range-diff master..gh/nitems shadow/master..nitems 
1:  f760d404 = 1:  fd051a19 lib/: Use NITEMS() instead of SIZEOF_ARRAY() where number of elements is meant