Re: [PATCH v3 01/10] pkt-line: extract set_packet_header()

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W dniu 01.08.2016 o 13:33, Lars Schneider pisze: 

quoted

On 30 Jul 2016, at 12:30, Jakub Narębski [off-list ref] wrote:

quoted

quoted

#define hex(a) (hexchar[(a) & 15])

I guess that this is inherited from the original, but this preprocessor
macro is local to the format_header() / set_packet_header() function,
and would not work outside it.  Therefore I think we should #undef it
after set_packet_header(), just in case somebody mistakes it for
a generic hex() function.  Perhaps even put it inside set_packet_header(),
together with #undef.

But I might be mistaken... let's check... no, it isn't used outside it.

Agreed. Would that be OK?

static void set_packet_header(char *buf, const int size)
{
	static char hexchar[] = "0123456789abcdef";
	#define hex(a) (hexchar[(a) & 15])
	buf[0] = hex(size >> 12);
	buf[1] = hex(size >> 8);
	buf[2] = hex(size >> 4);
	buf[3] = hex(size);
	#undef hex
}

That's better, though I wonder if we need to start #defines at begining
of line.  But I think current proposal is O.K.


Either this (which has unnecessary larger scope)

  #define hex(a) (hexchar[(a) & 15])
  static void set_packet_header(char *buf, const int size)
  {
  	static char hexchar[] = "0123456789abcdef";

  	buf[0] = hex(size >> 12);
  	buf[1] = hex(size >> 8);
  	buf[2] = hex(size >> 4);
  	buf[3] = hex(size);
  }
  #undef hex

or this (which looks worse)

  static void set_packet_header(char *buf, const int size)
  {
  	static char hexchar[] = "0123456789abcdef";
  #define hex(a) (hexchar[(a) & 15])
  	buf[0] = hex(size >> 12);
  	buf[1] = hex(size >> 8);
  	buf[2] = hex(size >> 4);
  	buf[3] = hex(size);
  #undef hex
  }