May I ask for your quick opinion on code formatting. MIDAS had a coding style 
which pretty much followed the ROOT coding style described at

https://root.cern/contribute/coding_conventions/

so we followed the "3 spaces indent" convention, braces according to Kernigham & 
Ritchie and a few other things. I see however that code written by different 
people still is formatted differently, like spaces before and after comparators 
etc. I wonder if it would make sense to keep a consistent code formatting through 
the whole midas repository.

Looking again at what the ROOT guys doe (see link above), they have a ClangFormat 
file, which I attached to this post. Putting this file into the root of midas 
ensures that all files are formatted in exactly the same way, which would increase 
readability largely.

The nice thing with ClangFormat is that can be integrated into my editor (Clion) as 
well as in emacs and vim:

https://clang.llvm.org/docs/ClangFormat.html

This would also make the emacs settings in our files obsolete:

/* emacs
 * Local Variables:
 * tab-width: 8
 * c-basic-offset: 3
 * indent-tabs-mode: nil
 * End:
 */

I don't like these because they are only for people using emacs. If everybody would 
put statements into the files with their favourite editor, all our source files 
would be cluttered quite a bit.

So the question is now how style to use? I attached different trials with a simple 
file from the distribution, so you can see the differences. They use the style from

- LLVM
- ROOT
- GNU
- Google

I consciously skipped the "Microsoft" style ;-)

Which one should we settle on? Any opinion? If I don't hear anything, I will pick a 
style at the end of this year 2020. I have a slight favour of the ROOT style, although 
I don't like that the "case" is not indented there under the opening brace of the 
switch statement which seems inconsistent to me. The only one doing that right is the 
Google format, but that one has an indentation of 2 chars instead our usual 3 chars. 
At the end of the day I think it's not so important on which style we agree, as long 
as we DO have a common style for all midas files.

Best,
Stefan

---
Language:        Cpp
# BasedOnStyle:  LLVM
AccessModifierOffset: -3
AlignAfterOpenBracket: Align
AlignConsecutiveAssignments: true
# This would be nice to have but seems to also (mis)align function parameters
AlignConsecutiveDeclarations: true
AlignEscapedNewlinesLeft: true
AlignOperands:   true
AlignTrailingComments: true
AllowAllParametersOfDeclarationOnNextLine: true
AllowShortBlocksOnASingleLine: false
AllowShortCaseLabelsOnASingleLine: true
AllowShortFunctionsOnASingleLine: Inline
AllowShortIfStatementsOnASingleLine: true
AllowShortLoopsOnASingleLine: true
# This option is "deprecated and is retained for backwards compatibility."
# AlwaysBreakAfterDefinitionReturnType: None
AlwaysBreakAfterReturnType: None
AlwaysBreakBeforeMultilineStrings: false
AlwaysBreakTemplateDeclarations: true
BinPackArguments: true
BinPackParameters: true
BraceWrapping:
  AfterClass:      false
  AfterControlStatement: false
  AfterEnum:       false
  AfterFunction:   true
  AfterNamespace:  false
  AfterObjCDeclaration: false
  AfterStruct:     false
  AfterUnion:      false
  BeforeCatch:     false
  BeforeElse:      false
  IndentBraces:    false
BreakBeforeBinaryOperators: None
BreakBeforeBraces: Custom
BreakBeforeTernaryOperators: true
BreakConstructorInitializersBeforeComma: false
ColumnLimit:     120
CommentPragmas:  '^ IWYU pragma:'
ConstructorInitializerAllOnOneLineOrOnePerLine: false
ConstructorInitializerIndentWidth: 3
ContinuationIndentWidth: 3
Cpp11BracedListStyle: true
DerivePointerAlignment: false
DisableFormat:   false
ExperimentalAutoDetectBinPacking: false
ForEachMacros:   [ foreach, Q_FOREACH, BOOST_FOREACH ]
IncludeCategories:
  - Regex:           '^("|<)T'
    Priority:        4
  - Regex:           '^("|<)ROOT/'
    Priority:        5
  - Regex:           '^<.*\.h>'
    Priority:        1
  - Regex:           '^"(llvm|llvm-c|clang|clang-c)/'
    Priority:        2
  - Regex:           '^(<|"(gtest|isl|json)/)'
    Priority:        3
  - Regex:           '.*'
    Priority:        6
IndentCaseLabels: false
IndentWidth:     3
IndentWrappedFunctionNames: false
KeepEmptyLinesAtTheStartOfBlocks: true
MacroBlockBegin: ''
MacroBlockEnd:   ''
MaxEmptyLinesToKeep: 1
NamespaceIndentation: None
ObjCBlockIndentWidth: 3
ObjCSpaceAfterProperty: false
ObjCSpaceBeforeProtocolList: true
PenaltyBreakBeforeFirstCallParameter: 19
PenaltyBreakComment: 300
PenaltyBreakFirstLessLess: 120
PenaltyBreakString: 1000
PenaltyExcessCharacter: 1000000
PenaltyReturnTypeOnItsOwnLine: 60000
PointerAlignment: Right
ReflowComments:  true
SortIncludes: false
SpaceAfterCStyleCast: false
SpaceBeforeAssignmentOperators: true
SpaceBeforeParens: ControlStatements
SpaceInEmptyParentheses: false
SpacesBeforeTrailingComments: 1
SpacesInAngles:  false
SpacesInContainerLiterals: true
SpacesInCStyleCastParentheses: false
SpacesInParentheses: false
SpacesInSquareBrackets: false
Standard:        Cpp11
TabWidth:        3
UseTab:          Never
...

/********************************************************************\

  Name:         cnaf_callback.c
  Created by:   Stefan Ritt
  Created by:   moved here from mfe.c by Konstantin Olchanski

  Contents:     The system part of the MIDAS frontend. Has to be
                linked with user code to form a complete frontend

  $Id$

\********************************************************************/

#include <stdio.h>
#include <assert.h>
#include "midas.h"
#include "msystem.h"
#include "mcstd.h"

/*------------------------------------------------------------------*/

static int cnaf_debug = 0;

INT cnaf_callback(INT index, void *prpc_param[]) {
  DWORD cmd, b, c, n, a, f, *pdword, *size, *x, *q, dtemp;
  WORD *pword, *pdata, temp;
  INT i, count;

  /* Decode parameters */
  cmd = CDWORD(0);
  b = CDWORD(1);
  c = CDWORD(2);
  n = CDWORD(3);
  a = CDWORD(4);
  f = CDWORD(5);
  pdword = CPDWORD(6);
  pword = CPWORD(6);
  pdata = CPWORD(6);
  size = CPDWORD(7);
  x = CPDWORD(8);
  q = CPDWORD(9);

  /* determine repeat count */
  if (index == RPC_CNAF16)
    count = *size / sizeof(WORD); /* 16 bit */
  else
    count = *size / sizeof(DWORD); /* 24 bit */

  switch (cmd) {
    /*---- special commands ----*/

  case CNAF_INHIBIT_SET: cam_inhibit_set(c);
    break;
  case CNAF_INHIBIT_CLEAR: cam_inhibit_clear(c);
    break;
  case CNAF_CRATE_CLEAR: cam_crate_clear(c);
    break;
  case CNAF_CRATE_ZINIT: cam_crate_zinit(c);
    break;

  case CNAF_TEST: break;

  case CNAF:
    if (index == RPC_CNAF16) {
      for (i = 0; i < count; i++)
        if (f < 16)
          cam16i_q(c, n, a, f, pword++, (int *) x, (int *) q);
        else if (f < 24)
          cam16o_q(c, n, a, f, pword[i], (int *) x, (int *) q);
        else
          cam16i_q(c, n, a, f, &temp, (int *) x, (int *) q);
    } else {
      for (i = 0; i < count; i++)
        if (f < 16)
          cam24i_q(c, n, a, f, pdword++, (int *) x, (int *) q);
        else if (f < 24)
          cam24o_q(c, n, a, f, pdword[i], (int *) x, (int *) q);
        else
          cam24i_q(c, n, a, f, &dtemp, (int *) x, (int *) q);
    }

    break;

  case CNAF_nQ:
    if (index == RPC_CNAF16) {
      if (f < 16) {
        cam16i_rq(c, n, a, f, &pword, count);
        *size = (POINTER_T) pword - (POINTER_T) pdata;
      }
    } else {
      if (f < 16) {
        cam24i_rq(c, n, a, f, &pdword, count);
        *size = (POINTER_T) pdword - (POINTER_T) pdata;
      }
    }

    /* return reduced return size */
    break;

  default: printf("cnaf: Unknown command 0x%X\n", (unsigned int) cmd);
  }

  if (cnaf_debug) {
    if (index == RPC_CNAF16)
      printf("cmd=%d r=%d c=%d n=%d a=%d f=%d d=%X x=%d q=%d\n", (int) cmd, (int) count, (int) c, (int) n, (int) a,
             (int) f, (int) pword[0], (int) *x, (int) *q);
    else if (index == RPC_CNAF24)
      printf("cmd=%d r=%d c=%d n=%d a=%d f=%d d=%X x=%d q=%d\n", (int) cmd, (int) count, (int) c, (int) n, (int) a,
             (int) f, (int) pdword[0], (int) *x, (int) *q);
  }

  return RPC_SUCCESS;
}

void register_cnaf_callback(int debug) {
  cnaf_debug = debug;
  /* register CNAF callback */
  cm_register_function(RPC_CNAF16, cnaf_callback);
  cm_register_function(RPC_CNAF24, cnaf_callback);
}

/* end file */

/********************************************************************\

  Name:         cnaf_callback.c
  Created by:   Stefan Ritt
  Created by:   moved here from mfe.c by Konstantin Olchanski

  Contents:     The system part of the MIDAS frontend. Has to be
                linked with user code to form a complete frontend

  $Id$

\********************************************************************/

#include <stdio.h>
#include <assert.h>
#include "midas.h"
#include "msystem.h"
#include "mcstd.h"

/*------------------------------------------------------------------*/

static int cnaf_debug = 0;

INT cnaf_callback(INT index, void *prpc_param[])
{
   DWORD cmd, b, c, n, a, f, *pdword, *size, *x, *q, dtemp;
   WORD *pword, *pdata, temp;
   INT   i, count;

   /* Decode parameters */
   cmd    = CDWORD(0);
   b      = CDWORD(1);
   c      = CDWORD(2);
   n      = CDWORD(3);
   a      = CDWORD(4);
   f      = CDWORD(5);
   pdword = CPDWORD(6);
   pword  = CPWORD(6);
   pdata  = CPWORD(6);
   size   = CPDWORD(7);
   x      = CPDWORD(8);
   q      = CPDWORD(9);

   /* determine repeat count */
   if (index == RPC_CNAF16)
      count = *size / sizeof(WORD); /* 16 bit */
   else
      count = *size / sizeof(DWORD); /* 24 bit */

   switch (cmd) {
      /*---- special commands ----*/

   case CNAF_INHIBIT_SET: cam_inhibit_set(c); break;
   case CNAF_INHIBIT_CLEAR: cam_inhibit_clear(c); break;
   case CNAF_CRATE_CLEAR: cam_crate_clear(c); break;
   case CNAF_CRATE_ZINIT: cam_crate_zinit(c); break;

   case CNAF_TEST: break;

   case CNAF:
      if (index == RPC_CNAF16) {
         for (i = 0; i < count; i++)
            if (f < 16)
               cam16i_q(c, n, a, f, pword++, (int *)x, (int *)q);
            else if (f < 24)
               cam16o_q(c, n, a, f, pword[i], (int *)x, (int *)q);
            else
               cam16i_q(c, n, a, f, &temp, (int *)x, (int *)q);
      } else {
         for (i = 0; i < count; i++)
            if (f < 16)
               cam24i_q(c, n, a, f, pdword++, (int *)x, (int *)q);
            else if (f < 24)
               cam24o_q(c, n, a, f, pdword[i], (int *)x, (int *)q);
            else
               cam24i_q(c, n, a, f, &dtemp, (int *)x, (int *)q);
      }

      break;

   case CNAF_nQ:
      if (index == RPC_CNAF16) {
         if (f < 16) {
            cam16i_rq(c, n, a, f, &pword, count);
            *size = (POINTER_T)pword - (POINTER_T)pdata;
         }
      } else {
         if (f < 16) {
            cam24i_rq(c, n, a, f, &pdword, count);
            *size = (POINTER_T)pdword - (POINTER_T)pdata;
         }
      }

      /* return reduced return size */
      break;

   default: printf("cnaf: Unknown command 0x%X\n", (unsigned int)cmd);
   }

   if (cnaf_debug) {
      if (index == RPC_CNAF16)
         printf("cmd=%d r=%d c=%d n=%d a=%d f=%d d=%X x=%d q=%d\n", (int)cmd, (int)count, (int)c, (int)n, (int)a,
                (int)f, (int)pword[0], (int)*x, (int)*q);
      else if (index == RPC_CNAF24)
         printf("cmd=%d r=%d c=%d n=%d a=%d f=%d d=%X x=%d q=%d\n", (int)cmd, (int)count, (int)c, (int)n, (int)a,
                (int)f, (int)pdword[0], (int)*x, (int)*q);
   }

   return RPC_SUCCESS;
}

void register_cnaf_callback(int debug)
{
   cnaf_debug = debug;
   /* register CNAF callback */
   cm_register_function(RPC_CNAF16, cnaf_callback);
   cm_register_function(RPC_CNAF24, cnaf_callback);
}

/* end file */