Your esteemed worshipnesses...

I have a 40-char hex string, and 20 40-char hex mask strings, and I need to generate 20 32-bit integer vectors.

e.g. given input 

"DA39A3EE5E6B4B0D3255BFEF95601890AFD80709"
and masks 
"FFFF804020100804020100804020100804000102"
"0102FFFF80402010080402010080402010080400"
"04000102FFFF8040201008040201008040201008"
...

I need to & the input and mask_1, like so

DA39A3EE5E6B4B0D3255BFEF95601890AFD80709
FFFF804020100804020100804020100804000102
========================================
DA39804000000804020100800020100004000100

then use only the 32 bits from mask_1 that remain set in the &'ed result to generate a scalar 0<x<2**32. In this case, "DA398040..." = 3661221814.

I can do it, with a boatload of hex, substr, pack, unpack, and & use, but there's got to be a better (faster) way. I do 100 million of these at a time. I've looked at vec, but I can't figure a good way to use it.

Can anyone help me improve on this? 

my $in="DA39A3EE5E6B4B0D3255BFEF95601890AFD80709"; 
my $mask="FFFF804020100804020100804020100804000102"; 
my $comb="";
for($i=0;$i<20;$i++) { 
  $comb .= sprintf("%02X", ( hex(substr($in,$i*2,2)) & hex(substr($mas
+k,$i*2,2))) ); 
} 
print "$in\n"; 
print "$mask\n========================================\n"; 
print "$comb\n"; 

my $bits = unpack("B*", pack("H40",$mask));
my $vecbits = unpack("B*", pack("H40",$comb));
my $vecs = "";
for ($i=0;$i<160;$i++) {
      if (substr($bits,$i,1) eq "1") {
        $vecs .= substr($vecbits,$i,1);
      }
}
my $vextor = hex(unpack("H*", pack("B32",$vecs)));
print "$vextor\n";

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In reply to bitmask to vector problem by dwhite20899

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