#This script is designed to run with Understand - CodeCheck
use base ("Understand::Codecheck");
use strict;


use constant ERR1 => 'More than %1 characers are significant';

sub register_tr_text() {
  my $check = shift;
  $check->add_tr_text(ERR1);
}

sub name { return "5.1 Identifiers shall not rely on the significance of more than 31 characters";}

sub description { return "5.1 (Required)  Identifiers (internal and external) shall not rely on the significance of more than 31 characters.";}

sub detailed_description { return <<"END_DESC"
<p>The ISO standard requires internal identifiers to be distinct in the first 31 characters to guarantee 
code portability. This limitation shall not be exceeded, even if the compiler supports it. This rule 
shall  apply  across  all  name  spaces.  Macro  names  are  also  included  and  the  31  character limit 
applies before and after substitution.</p>
<p>The ISO standard requires external identifiers to be distinct in the first 6 characters, regardless 
of  case,  to  guarantee  optimal  portability.  However  this  limitation  is  particularly  severe  and  is 
considered unnecessary. The intent of this rule is to sanction a relaxation of the ISO requirement 
to a degree commensurate with modern environments and it shall be confirmed that 31 character/
case significance is supported by the implementation.</p>
<p>Note  that  there  is  a  related  issue  with  using  identifier  names  that  differ  by  only  one  or  a  few 
characters, especially if the identifier names are long. The problem is heightened if the differences 
are in easily mis-read characters like 1 (one) and l (lower case L), 0 and O, 2 and Z, 5 and S, or n 
and h. It is recommended to ensure that identifier names are always easily visually distinguishable. 
Specific guidelines on this issue could be placed in the style guidelines (see section 4.2.2).</p>
END_DESC
}

sub test_language {
  my $language = shift;
  return $language =~ /C\+\+/; #Handles C and C++
}

sub test_entity { return 0;}

sub test_global { return 1;}

sub define_options{
  my $check = shift;
  $check->option->integer("significantChars","Signficant Characters",31);
}


sub check {
  my $check = shift; 
  my $significantChars = $check->option->lookup("significantChars");
  my @ents = $check->db->ents("~file");
  my @longEnts;
  
  foreach (@ents){
    push @longEnts,$_ if length($_->name) > $significantChars;
  }
  
  my $prev;
  my $prevReported;
  foreach my $ent (sort {$a->name cmp $b->name;} @longEnts){
    my $beginning = substr($ent->name,0,$significantChars);
    my $prevBegin = substr($prev->name,0,$significantChars) if $prev;
    if ($prevBegin eq $beginning && $prev->name ne $ent->name){
      reportEnt($ent,$check);
      reportEnt($prev,$check) unless $prevReported;
      $prevReported = 1;
    }else{
      $prev = $ent;
      $prevReported = 0;
    }
  }
}

sub reportEnt{
  my ($ent, $check) = @_;
  my $ref = $ent->ref("define, declare");
  $ref = $ent->ref unless $ref;
  $check->violation($ent,$ref->file,$ref->line,$ref->column,ERR1,$check->option->lookup("significantChars"));
}