The MIN, MAX, CLAMP, MINIMUM, and MAXIMUM macros appear
throughout the codebase with many re-definitions. Make
a single copy of each in a common header file, and use
the BSD variants of MINIMUM/MAXIMUM due to conflicts in
the system <sys/param.h> headers.
Reasoning:
- implementation was unsound -- broke down when I added a fairly
basic macro definition expanding to a struct initializer in a *.c
file.
- made it way too easy (e.g. via otherwise totally innocuous git
commands) to end up with timestamps such that it always ran
MakeHeader.py but never used its output, leading to overbuild noise
when running what should be a null 'make'.
- but mostly: it's just an awkward way of dealing with C code.
Rationale (copied from htop issue #471):
The function name "setValues" is misleading. For most OOP (object-
oriented programming) contexts, setXXX functions mean they will change
some member variables of an object into something specified in
function arguments. But in the *Meter_setValues() case, the new values
are not from the arguments, but from a hard-coded source. The caller
is not supposed to change the values[] to anything it likes, but
rather to "update" the values from the source. Hence, updateValues is
a better name for this family of functions.
(Cherry-picked from e93028d7fa0c5f00b5dc3336fd28abaf905cd572, the
experimental graph coloring branch)
Currently GRAPH_HEIGHT=4 . This prevents hard-coding the height of the graph
meters, and allows user to change it at compile-time.
With the CLAMP macro replacing the combination of MIN and MAX, we will
have at least two advantages:
1. It's more obvious semantically.
2. There are no more mixes of confusing uses like MIN(MAX(a,b),c) and
MAX(MIN(a,b),c) and MIN(a,MAX(b,c)) appearing everywhere. We unify
the 'clamping' with a single macro.
Note that the behavior of this CLAMP macro is different from
the combination `MAX(low,MIN(x,high))`.
* This CLAMP macro expands to two comparisons instead of three from
MAX and MIN combination. In theory, this makes the code slightly
smaller, in case that (low) or (high) or both are computed at
runtime, so that compilers cannot optimize them. (The third
comparison will matter if (low)>(high); see below.)
* CLAMP has a side effect, that if (low)>(high) it will produce weird
results. Unlike MIN & MAX which will force either (low) or (high) to
win. No assertion of ((low)<=(high)) is done in this macro, for now.
This CLAMP macro is implemented like described in glib
<http://developer.gnome.org/glib/stable/glib-Standard-Macros.html>
and does not handle weird uses like CLAMP(a++, low++, high--) .
With more dimensional arrays we have to define the array size. Use
one dimensional arrays to be more flexible.
Additionally this allows to shrink array size for ASCII.
disable useless code in release builds such as runtime type-checking on
dynamic data structures and process fields that are not being computed,
faster(?) method for verifying the process owner (still need to ensure
correctness), don't destroy and create process objects for hidden kernel
threads over and over. Phew. I shouldn't be doing all this today, but I
could not resist.
Nathan Scott