StripeMap.cpp

#include "StripeMap.h"

using namespace std;

StripeMap::StripeMap(vector<string> disks, size_t chunkSize) {
	this->diskPaths = disks;
	this->chunkSize = chunkSize;
}

int StripeMap::fetchDiskId(size_t chunkIdx) {
	if (chunkIdx >= stripeLayout.size()) {
		cerr << "Error: Chunk index is out of bounds" << endl;
		return -1;
	}

	return stripeLayout[chunkIdx];
}

string StripeMap::fetchDiskPath(int diskId) {
	if (diskId >= diskPaths.size()) {
		cerr << "Error: diskId index is out of bounds" << endl;
		return NULL;
	}

	return diskPaths[diskId];
}

/*
* Simple build map function to map disks to our stripe layout
* TODO: eventually make a 'smarter' round robin algorithm
* to check for capacity for each drive
*/
void StripeMap::buildMap(size_t totalSize) {
	stripeLayout.clear();

	// ceils the # of chunks so we can fit the file
	size_t totalChunks = (totalSize + chunkSize + 1) / chunkSize;
	int totalDisks = diskPaths.size();
	
	// reserve beforehand so vector doesn't need to recopy itself
	stripeLayout.reserve(totalChunks);

	for (size_t i = 0; i < totalChunks; i++) {
		int targetDisk = i % totalDisks;
		stripeLayout.push_back(targetDisk);
	}

	cout << "Finished building map with: " << totalChunks << " chunks for: "
		<< totalDisks << " disks" << endl;

}

void StripeMap::setDiskPaths(const vector<string>& paths) {
	diskPaths = paths;
}

size_t StripeMap::getChunkSize() {
	return chunkSize;
}