Xpetra_BlockReorderManager.cpp

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#include <Xpetra_BlockReorderManager.hpp>

namespace Xpetra {

void BlockReorderManager::SetBlock(int blockIndex, int reorder) {
  TEUCHOS_ASSERT(blockIndex < (int) children_.size());
  Teuchos::RCP<BlockReorderManager> child = Teuchos::rcp(new BlockReorderLeaf(reorder));
  children_[blockIndex] = child;
}

void BlockReorderManager::SetBlock(int blockIndex, const Teuchos::RCP<BlockReorderManager> & reorder) {
  TEUCHOS_ASSERT(blockIndex < (int) children_.size());
  children_[blockIndex] = reorder;
}

// this function tokenizes a string, breaking out whitespace but saving the
// brackets [,] as special tokens.
void tokenize(std::string srcInput,std::string whitespace,std::string prefer, std::vector<std::string> & tokens) {
   std::string input = srcInput;
   std::vector<std::string> wsTokens;
   std::size_t endPos   = input.length()-1;
   while(endPos<input.length()) {
      std::size_t next = input.find_first_of(whitespace);

      // get the sub string
      std::string s;
      if(next!=std::string::npos) {
         s = input.substr(0,next);

         // break out the old substring
         input = input.substr(next+1,endPos);
      }
      else {
         s = input;
         input = "";
      }

      endPos   = input.length()-1;

      // add it to the WS tokens list
      if(s=="") continue;
      wsTokens.push_back(s);
   }

   for(unsigned int i=0;i<wsTokens.size();i++) {
      // get string to break up
      input = wsTokens[i];

      endPos   = input.length()-1;
      while(endPos<input.length()) {
         std::size_t next = input.find_first_of(prefer);

         std::string s = input;
         if(next>0 && next<input.length()) {

            // get the sub string
            s = input.substr(0,next);

            input = input.substr(next,endPos);
         }
         else if(next==0) {
            // get the sub string
            s = input.substr(0,next+1);

            input = input.substr(next+1,endPos);
         }
         else input = "";

         // break out the old substring
         endPos   = input.length()-1;

         // add it to the tokens list
         tokens.push_back(s);
      }
   }
}

// this function takes a set of tokens and returns the first "block", i.e. those
// values (including) brackets that correspond to the first block
std::vector<std::string>::const_iterator buildSubBlock(
    std::vector<std::string>::const_iterator begin,
    std::vector<std::string>::const_iterator end,
    std::vector<std::string> & subBlock) {
   std::stack<std::string> matched;
   std::vector<std::string>::const_iterator itr;
   for(itr=begin;itr!=end;++itr) {

      subBlock.push_back(*itr);

      // push/pop brackets as they are discovered
      if(*itr=="[") matched.push("[");
      else if(*itr=="]") matched.pop();

      // found all matching brackets
      if(matched.empty())
         return itr;
   }

   TEUCHOS_ASSERT(matched.empty());

   return itr-1;
}

// This function takes a tokenized vector and converts it to a block reorder manager
Teuchos::RCP<Xpetra::BlockReorderManager> blockedReorderFromTokens(const std::vector<std::string> & tokens)
{
   // base case
   if(tokens.size()==1)
      return Teuchos::rcp(new Xpetra::BlockReorderLeaf(Teuchos::StrUtils::atoi(tokens[0])));

   // check first and last character
   TEUCHOS_ASSERT(*(tokens.begin())=="[")
   TEUCHOS_ASSERT(*(tokens.end()-1)=="]");

   std::vector<Teuchos::RCP<Xpetra::BlockReorderManager> > vecRMgr;
   std::vector<std::string>::const_iterator itr = tokens.begin()+1;
   while(itr!=tokens.end()-1) {
      // figure out which tokens are relevant for this block
      std::vector<std::string> subBlock;
      itr = buildSubBlock(itr,tokens.end()-1,subBlock);

      // build the child block reorder manager
      vecRMgr.push_back(blockedReorderFromTokens(subBlock));

      // move the iterator one more
      itr++;
   }

   // build the parent reorder manager
   Teuchos::RCP<Xpetra::BlockReorderManager> rMgr = Teuchos::rcp(new Xpetra::BlockReorderManager());
   rMgr->SetNumBlocks(vecRMgr.size());
   for(unsigned int i=0;i<vecRMgr.size();i++)
      rMgr->SetBlock(i,vecRMgr[i]);

   return rMgr;
}

Teuchos::RCP<const Xpetra::BlockReorderManager> blockedReorderFromString(std::string reorder)
{
   // vector of tokens to use
   std::vector<std::string> tokens;

   // manager to be returned

   // build tokens vector
   tokenize(reorder," \t\n","[]",tokens);

   // parse recursively and build reorder manager
   Teuchos::RCP<Xpetra::BlockReorderManager> mgr = blockedReorderFromTokens(tokens);

   return mgr;
}

} // end namespace