Re: Removing Trailing Whitespace: Multiple ways.

If it is speed you are after, you can always put on your C hat:


use Benchmark;
use Inline C;

timethese (1000000, {
'regex'  => q{
  my $foo = "test    ";
  $foo =~ s/\s+$//;
},
'inline' => q{  
  my $foo = "test    ";
  rmsp($foo);
}
});
  
__END__
__C__
void rmsp(char * str) {
  int i = strlen(str) - 1; 
  while( i >= 0 && str[i] == ' ' ) {
    str[i--] = '\0';
  }
}
[download]

Results:

Benchmark: timing 1000000 iterations of inline, regex...
    inline:  4 wallclock secs ( 4.39 usr +  0.03 sys =  4.42 CPU)
     regex:  8 wallclock secs ( 6.84 usr +  0.03 sys =  6.87 CPU)
[download]

Comment on Re: Removing Trailing Whitespace: Multiple ways. Select or Download Code

Replies are listed 'Best First'.
Re: Re: Removing Trailing Whitespace: Multiple ways. by no_slogan (Deacon) on May 12, 2001 at 03:15 UTC
That would be really cool, but rmsp() leaves the string null-padded instead of removing the extra blanks.	[reply]
Re: Re: Re: Removing Trailing Whitespace: Multiple ways. by perlmonkey (Hermit) on May 12, 2001 at 04:18 UTC
Yah, so I was lazy and I cheated a bit. $foo will look good when you print it though. What can I say, there are reasons I am a perl programmer. But to be all official like and actually update the scalar value to be a proper string of length 4 you can use this code for rmsp: `void rmsp(SV * sv) { char * end; int length; if( !SvPOK(sv) ) return; end = SvEND(sv); length = SvCUR(sv); end--; /* skip \0 / while( end == ' ' && length >=0 ) { end--; length--; } if( length >= 0 ) SvCUR_set(sv, length); }` [download] And the new results I got are: `Benchmark: timing 1000000 iterations of inline, regex... inline: 6 wallclock secs ( 4.19 usr + 0.01 sys = 4.20 CPU) regex: 9 wallclock secs ( 7.71 usr + 0.02 sys = 7.73 CPU)` [download]	[reply] [d/l] [select]


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