Re: Your favorite hex conversion routine - ILE

[boldt@xxxxxxxxxx]

booth wrote:
>HTML color values are red:blue:green.  0 to 255, or 00 to ff.   How would
>i make color Value  255:255:255 appear in a string as  ff:ff:ff?

Barbara told me someone already posted this solution.  But since
I couldn't find it anywhere in the archives, I'll post it anyways.

One way to convert *several* numeric values to a string containing
hex values is to use the C runtime library function "sprintf".

Coding the prototype is a bit tricky.  The trick to calling C
functions with varying length argument list is to code
OPTIONS(*NOPASS) for at least one of the arguments.  (It has
something to do with making sure the arguments are not passed in
registers.)  Check the following RPG program for an example of how
to call "sprintf":

H dftactgrp(*no) bnddir('QC2LE')
D sprintfxxx      pr            10i 0 extproc(*cwiden:'sprintf')
D   recvr                         *   value
D   format                        *   value options(*string)
D   red                          3u 0 value
D   blue                         3u 0 value
D   green                        3u 0 value options(*nopass)
D FMTXXX          c                   '"#%2.2lx%2.2lx%2.2lx"'
D recv            s             50a
D len             s             10i 0
 /free
    len = sprintfxxx(%addr(recv):FMTXXX:12:34:45);
    dsply ('|' + %subst(recv:1:len) + '|');
    *inlr = *on;
 /end-free

This working program displays the html color argument value:

DSPLY  |"#0c222d"|

Note that it's important to save the length returned by "sprintf"
and use it to substring the receiver variable since C likes to
deal with null terminated strings.  (Or, you could access the
result value by coding "result=%str(%addr(recv));".)

BTW, it should be noted that specifying colors within html is
deprecated.  You should be using style sheets instead.  One of
the methods for specifying color is "rgb(x,x,x)", where each x
can be a decimal number from 0 to 255.  That would simplify the
problem significantly I would say.

Cheers!  Hans

Hans Boldt, ILE RPG Development, IBM Toronto Lab, boldt@ca.ibm.com