C++ strvec::insert方法代码示例

//Returns true if it processes something
//Returns false if it never finds a parallel for
bool processParallelFor()
{
	bool foundPragma = false;

	for (int i = 0; i < input.size(); i++)
	{
		std::string curStr = input.at(i);
		if (curStr.substr(0, 24).compare("#pragma omp parallel for") == 0 ||
			curStr.substr(0, 15).compare("#pragma omp for") == 0)
		{
			foundPragma = true;
			int j = i + 2; //move up to pragma and pass the for loop
			if (input.at(j).substr(0,1).compare("{") == 0) //if the for is contained in brackets. weird case also where trim did not remove tab after bracket
			{
				int brackets = 1;
				//find the end of the parallel region
				while (j < input.size())
				{
					j++;

					std::string tempStr = input.at(j);
					if (tempStr.length() <= 0)
					{
						continue;
					}

					if (tempStr.at(0) == '{')
					{
						brackets++;
					}
					if (tempStr.at(0) == '}')
					{
						brackets--;
					}
					if (brackets == 0)
					{
						break;
					}
				}
			}
			else //if there are no brackets, then j is pointing to the contents of the for loop
			{
				i += 2;
				j += 2;
				input.insert(input.begin() + i, "{");
				input.insert(input.begin() + j, "}");
				i -= 2; //move i back to the pragma
			}
			//at this point, j points to the ending bracket, and i points to the pragma
			parallelForHelper(i, j);
		}
		//otherwise, move on--handle it elsewhere
	}

	return foundPragma;

}

//Declares the varlist in the main function
void declarePrivatesInMain(strvec& varList)
{
	int mainLine = 0;
	for (mainLine; mainLine < input.size(); mainLine++)
	{
		std::string curStr = input.at(mainLine);
		if (curStr.compare("int main()") == 0)
		{
			break;
		}
	}

	mainLine += 2; //move past brackets
	for (int i = 0; i < varList.size(); i++)
	{
		input.insert(input.begin() + mainLine++, varList.at(i));
	}
}

//Pushes the vecRef into input after the include statements (at the top)
void insertAfterIncludes(strvec& vecRef)
{
	//move past any includes
	int i;
	for (i = 0; i < input.size(); i++)
	{
		if (input.at(i).length() > 0 && input.at(i).at(0) != '#')
		{
			break;
		}
	}

	//once we're here, we're past the includes and we can copy the new function
	//we need to insert this in reverse order
	for (int j = vecRef.size()-1; j >= 0; j--)
	{
		input.insert(input.begin() + i, vecRef.at(j));
	}
}

//Worker function. Start and end represent the #pragma line and the closing brace
//Drives all the work for a critical
void criticalHelper(int start, int end)
{
	//simply lock at the beginning and the end
	input.at(start) = "pthread_mutex_lock( &theMutex );";
	input.insert(input.begin() + end + 1, "pthread_mutex_unlock (&theMutex );");
}

//Worker function. Start and end represent the #pragma line and the closing brace
//Drives all the work for a parallel for
void parallelForHelper(int start, int end)
{
	//grab the necessary values from the #pragma line
	std::string pragmaString = input.at(start);
	strvec privVars = getConstructVars(pragmaString, "private");
	strvec sharedVars = getConstructVars(pragmaString, "shared");
	int numThreads = getNumThreads(pragmaString);

	//create a vector for the new pthreads void* function
	std::vector<std::string> newFunction;

	std::string newFuncName;
	std::string smallNewFuncName = std::string("func").append(std::to_string(currentFunction));
	newFuncName.append("void* func").append(std::to_string(currentFunction)).append("(void* paramStruct)");
	newFunction.push_back(newFuncName);
	currentFunction++;
	newFunction.push_back("{");

	//now handle the case when a parallel for is inside a parallel. in that case, the parfor will not have priv/shared declared
	//it will instead use the priv/shared declared above
	//those are backed up in global vars.
	if (privVars.size() == 0 && sharedVars.size() == 0) //if we determine nothing is private, copy the global backup to the local strvecs
	{
		for (int i = 0; i < privVarBackup.size(); i++)
		{
			privVars.push_back(privVarBackup.at(i));
		}
		for (int i = 0; i < sharedVarBackup.size(); i++)
		{
			sharedVars.push_back(sharedVarBackup.at(i));
		}
	}

	//redeclare privates in the new function
	redeclareVars(privVars, newFunction);
	strvec privVarDeclarations;
	redeclareVars(privVars, privVarDeclarations);
	add(privVarDeclarations, totalPrivBackup);

	//globals will appear later
	redeclareVars(sharedVars, globalVars);

	//move the code to the new function
	//first modify the for loop to use the start and end from the new struct
	int numIterations = getNumIterations(input.at(start + 1));
	input.at(start + 1) = fixForLine(input.at(start + 1));

	//then copy the rest of the stuff
	for (int i = start + 1; i < end; i++)
	{
		newFunction.push_back(input.at(i));
	}
	newFunction.push_back("}");
	newFunction.push_back("}");

	//delete the #pragma section
	input.erase(input.begin() + start, input.begin() + end + 1);

	//record the offset as start since we're going to be changing the size of the vector
	int newOffset = start;

	//set up the pthreads code
	//first we need an array of pthread_t threadids with size = numthreads
	std::string tempString = std::string("pthread_t threads[").append(std::to_string(numThreads)).append("];");
	input.insert(input.begin() + newOffset++, tempString);

	//populate the threads[] array
	std::string loopVar = std::string("uniqueVar").append(std::to_string(uniqueVarNum));
	uniqueVarNum++;
	tempString = std::string("for (int ").append(loopVar).append(" = 0; ").append(loopVar).append(" < ").append(std::to_string(numThreads)).append("; ").append(loopVar).append("++)");
	input.insert(input.begin() + newOffset++, tempString);
	input.insert(input.begin() + newOffset++, "{");
	tempString = std::string("threads[").append(loopVar).append("] = ").append(loopVar).append(";");
	input.insert(input.begin() + newOffset++, tempString);
	input.insert(input.begin() + newOffset++, "}");

	//create the pthreads code
	int uneven = numIterations - ((numIterations / numThreads) * numThreads); //figure out how many don't go in evenly
	int basicNum = numIterations / numThreads;
	//now distribute the iterations among the pthreads
	//example: 18 iterations among 4 threads
	//break it down as follows:
	//0-3 thread 1
	//4-7 thread 2
	//8-11 thread 3
	//12-17 thread 4
	//or 12-14 thread 4

	int startIteration = 0;
	int endIteration = basicNum - 1;
	for (int i = 0; i < numThreads; i++)
	{
		tempString = std::string("StartEnd paramStruct").append(std::to_string(i)).append(";");
		input.insert(input.begin() + newOffset++, tempString);

		tempString = std::string("paramStruct").append(std::to_string(i)).append(".start = ").append(std::to_string(startIteration)).append(";");
		input.insert(input.begin() + newOffset++, tempString);
		startIteration += basicNum;
//.........这里部分代码省略.........

//Worker function. Start and end represent the #pragma line and the closing brace
//Drives all the work for a parallel
void parallelHelper(int start, int end)
{
	//grab the necessary values from the #pragma line
	std::string pragmaString = input.at(start);
	strvec privVars = getConstructVars(pragmaString, "private");
	strvec sharedVars = getConstructVars(pragmaString, "shared");
	int numThreads = getNumThreads(pragmaString);

	//save the values in a backup for redeclaration in an inner function
	privVarBackup.clear();
	for (int i = 0; i < privVars.size(); i++)
	{
		privVarBackup.push_back(privVars.at(i));
	}
	sharedVarBackup.clear();
	for (int i = 0; i < sharedVars.size(); i++)
	{
		sharedVarBackup.push_back(sharedVars.at(i));
	}

	//create a vector for the new pthreads void* function
	std::vector<std::string> newFunction;

	//add to the new function
	std::string newFuncName;
	std::string smallNewFuncName = std::string("func").append(std::to_string(currentFunction));
	newFuncName.append("void* func").append(std::to_string(currentFunction)).append("(void* paramStruct)");
	newFunction.push_back(newFuncName);
	currentFunction++;
	newFunction.push_back("{");

	//redeclare variables in the new function
	redeclareVars(privVars, newFunction);
	strvec privVarDeclarations;
	redeclareVars(privVars, privVarDeclarations);
	add(privVarDeclarations, totalPrivBackup);

	//stick shared vars in the global vector for declaration later
	redeclareVars(sharedVars, globalVars);

	//copy the function code as-is
	for (int i = start + 2; i < end; i++) //move start up to pass first bracket, < end to not include last bracket.
	{
		newFunction.push_back(input.at(i));
	}
	newFunction.push_back("}");

	//delete the #pragma section
	input.erase(input.begin() + start, input.begin() + end + 1);

	//record the offset as start since we're going to be changing the size of the vector
	int newOffset = start;

	//set up the pthreads code
	//first we need an array of pthread_t threadids with size = numthreads
	std::string tempString = std::string("pthread_t threads[").append(std::to_string(numThreads)).append("];"); //TODO do we need to populate this?
	input.insert(input.begin() + newOffset++, tempString);

	//populate the threads[] array
	std::string loopVar = std::string("uniqueVar").append(std::to_string(uniqueVarNum));
	uniqueVarNum++;
	tempString = std::string("for (int ").append(loopVar).append(" = 0; ").append(loopVar).append(" < ").append(std::to_string(numThreads)).append("; ").append(loopVar).append("++)");
	input.insert(input.begin() + newOffset++, tempString);
	input.insert(input.begin() + newOffset++, "{");
	tempString = std::string("threads[").append(loopVar).append("] = ").append(loopVar).append(";");
	input.insert(input.begin() + newOffset++, tempString);
	input.insert(input.begin() + newOffset++, "}");

	//now create the pthreads
	for (int i = 0; i < numThreads; i++)
	{
		tempString = std::string("StartEnd paramStruct").append(std::to_string(i)).append(";");
		input.insert(input.begin() + newOffset++, tempString);

		tempString = std::string("paramStruct").append(std::to_string(i)).append(".threadNum = ").append(std::to_string(i)).append(";");
		input.insert(input.begin() + newOffset++, tempString);

		tempString = std::string("pthread_create(&threads[").append(std::to_string(i)).append("], NULL, ").append(smallNewFuncName).append(", (void*) &paramStruct").append(std::to_string(i)).append(");");
		input.insert(input.begin() + newOffset++, tempString);
	}

	//now set up a for loop to join the pthreads
	loopVar = std::string("uniqueVar").append(std::to_string(uniqueVarNum));
	uniqueVarNum++;
	tempString = std::string("for (int ").append(loopVar).append(" = 0; ").append(loopVar).append(" < ").append(std::to_string(numThreads)).append("; ").append(loopVar).append("++)");
	input.insert(input.begin() + newOffset++, tempString);
	input.insert(input.begin() + newOffset++, "{");
	tempString = std::string("pthread_join(threads[").append(loopVar).append("], NULL);");
	input.insert(input.begin() + newOffset++, tempString);
	input.insert(input.begin() + newOffset++, "}");

	//insert the new stuff, in reverse order!!
	insertAfterIncludes(newFunction); //first, new function
}