Add hex dump support for trace output

[bobbingwide]

Sometimes, when you want to see the exact contents of data a print_r() is not good enough. We need to be able to see a hex dump of each character.

Proposed solution

Provide a helper function to return data in hex dump format.

[bobbingwide]

In the first version I'll just include the helper functon bw_trace_hexdump which will load and call oik_hexdump from the hexdump shared library. oik-bwtrace will deliver the hexdump library in the libs folder. This file will need to be added to the oik-libs repository. The hexdump logic is currently tested in oik-batch.

[bobbingwide]

The hexdump function was written to support single byte characters. To hexdump the first line of Hello Dolly add the following code in hello_dolly_get_lyric()

$lyr = bw_trace_hexdump( $lyrics[0]);
bw_trace2( $lyr, "lyric");

The hexdump output for the first line of "Hello Dolly" is

13
Hello, Dolly........ 48 65 6c 6c 6f 2c 20 44 6f 6c 6c 79 0d 

Notes:

• When hexdumping characters such as £ and € the number of characters dislplayed in the first half of the hexdump output may be fewer than 20.
• e.g. For the input string ABCDEFG\n12345678910\t£" the output is

  22\r\n
  ABCDEFG.12345678910. 41 42 43 44 45 46 47 0a 31 32 33 34 35 36 37 38 39 31 30 09 \r\n
  £.................. c2 a3 \r\n

• The '.''s represent unprintable ( ctype_cntrl() ) characters or are just padding.
• In the above example I'm showing the CRLFs that are part of the output