#! /usr/sepp/bin/perl -w

############################################################
## Copyright: 2011 Integrated Sytems Laboratory, ETH Zurich
##            http://www.iis.ee.ethz.ch/~sha3
############################################################
use strict;

# v0.1 - kgf@ee.ethz.ch - Fri Aug 12 14:11:07 CEST 2011
# - adapted from keccak v0.3 
# V0.2 - chrikell@ethz.ch - Adapted for FirstBlk Signal


# make sure the lengths are ok later on

## CONSTANTS
my $HASH_BLOCK_SIZE=512;   # SHA-256 version
my $MIN_PADDING_SIZE= 72;  # this is not completely correct. Min size is 
                           # 65 but it is so much easier to generate this

## let us extract the information first 
my @L;  # length array
my @M;  # message array
my @D;  # digest array

# steal all the information
# Note: if one of the entries MD, Len, Msg is missing trouble will arise

open (S, "< expresp.txt");
while (S){
   push (@L,$1) if (/^\s*Len\s*=\s*([0-9]+)/i);
   push (@M,$1) if (/^\s*Msg\s*=\s*([0-9A-F]+)/i);
   push (@D,$1) if (/^\s*MD\s*=\s*([0-9A-F]+)/i);
}
close(S);


  my $date= `date`;
  chomp ($date);

print <<"BUGU";
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
%% Test vectors for ETHZ SHA2
%%   generated by ethz_sha2_stimuli.pl
%%   on $date
%% 
BUGU


## loop over all read messages 
for my $i (0..$#L){
 ## how many blocks will we need
 my $num_blocks=int (($L[$i] + $MIN_PADDING_SIZE - 1) / $HASH_BLOCK_SIZE) +1; 

 ## now let us determine the padding
 ## Because of the brain dead scheme that these guys interpret 
 ## MSBs 100..0001 actually becomes 01 00 00 80 
 ## It is very easy to calculate this provided the pad size is at least 16
 ## it is a restriction at the moment but it works easily.. 
 ## for other lengths we need a more elaborate code.. 
 my $zero_cnt = (($HASH_BLOCK_SIZE * $num_blocks) - $L[$i] -72) / 8;
 my $bit_len=sprintf("%016X",$L[$i]);   # get the length 
 my $pad = "80". "00" x $zero_cnt .$bit_len;

## these two are so that the reports look cute
my $pretty_i   = $i + 1;
my $pretty_len = $#L + 1;

# comment character is '%' n the testbench

print <<"BUGU";
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
%% vector $pretty_i of $pretty_len
%% Length  = $L[$i], Number of $HASH_BLOCK_SIZE bit blocks = $num_blocks, Padding = $pad
%% Message = $M[$i]
%% Digest  = $D[$i]
BUGU

 ## add the pad to the message
 $M[$i]=$M[$i].$pad;

 ## now loop over number of blocks
 for my $j (1..$num_blocks){
   ## this is the part of the message that goes out
   my $sub=substr($M[$i],($j-1)*($HASH_BLOCK_SIZE/4),($HASH_BLOCK_SIZE/4));
   
   ## generate the output
   print unpack("B*",pack("H*",$sub))." ";            # this is the block input
#   ## generate first block signal
#   if ($j eq 1){
#     print "1 ";  
#   }
#   else{
#       print "0 ";  
#   }
   ## are we in the last block 
   if ($j eq $num_blocks){
     print "1 ".unpack("B*",pack("H*",$D[$i]))."\n";  # set last and compare
   }
   else{
     print "0 ". '-' x 256 . "\n";                    # don't set last and don't care
   }
 }
}