Function: deserialize_v2

CALL:

S = deserialize_v2(str)

DESCRIPTION:

Deserialize Matlab variable, without writing to disk.

INPUT:

serialized form of S. Encode with serialize_v2.

OUTPUT:

A Matlab variable.

APPROACH:

 
  serialize_v2:
     CONVERSION:          getByteStreamFromArray     zipdata          encodebase64
     DATATYPE:   Any Matlab datatype ====> uint8 array ====>  int8 array  ====> char array
  
  deserialize_v2:
     CONVERSION:            getByteStreamFromArray   unzipdata          decodebase64
     DATATYPE:   Any Matlab datatype <==== uint8 array <====  int8 array  <==== char array
  
  NOTES:
      serialize_v2 and deserialize_v2 are improved versions of serialize
      and deserialize. The following improvements where implemented:
      - no reading or writing of tempfiles required
      - lower CPU tim erequired
      - usage of Base64 encoding instead of hex encoding results in smaller
      transfer size 
  
  BENCHARK:
     Setup: a randon vector of N doubles was serializedan deserialized. CPU
     time and serialized size were compared between new an dold method.
  
      Benchmark result table (NEW=serialize_v2, OLD=serialize):
                  CPUNEW CPUOLD SIZENEW  SIZEOLD
          SIZE    [sec]  [sec]  [bytes]  [bytes]
               10 0.0012 0.0173      184      516
              100 0.0007 0.0116     1160     1984
             1000 0.0016 0.0153    10160    15486
            10000 0.0124 0.0598   100688   151706
           100000 0.0903 0.4767  1006020  1513756
          1000000 1.1486 4.6368 10058932 15132634
 
       Further notes: 
       - in the new method, about 50% of the CPU time is used by a
       "lowtech" module BASE64.encode/decode.   
       - in the old method about 90% of the CPU time is used by an aeven
       more lowtech module dec2hex. This indicates much room for
       improvement. 
       - This also indicates that the Matlab save method (including
       compression) is faster than in memory compression, which is
       supprising.  
  
  BENCHMARK SCRIPT:
  if nargin==0
      N=6;
      for k=1:N
          n(k)=10^k;
          input=rand(1,n(k));
          tic; 
          byteData=serialize_v2(input);
          copy=deserialize_v2(byteData);
          t1(k)=toc;
          l1(k)=length(byteData);
          assert(all(input==copy),'desrialize(serialize(data))~=data')
          
          tic; 
          byteData=serialize(input,false);
          copy=deserialize(byteData,false);
          t2(k)=toc;
          l2(k)=length(byteData);
          assert(all(input==copy),'desrialize(serialize(data))~=data')
  
      end
      figure('name','cpu');
      plot(t1);
      line(1:N,t2,'col','r')
      legend('stateless','disk method');
      
      figure('name','bytes transferred');
      plot(l1);
      line(1:N,l2,'col','r')
      legend('stateless','disk method');
      
      disp([n(:),t1(:),t2(:),l1(:),l2(:)]);  
      return
  end
      
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