Add MarkovMatrix class

Makefile

@@ -7,7 +7,7 @@ RM = rm -f
 SRCDIR = src
 TMPDIR = build
 TARGET = trumpotron
-FILES = main Markov
+FILES = main Markov MarkovMatrix
 
 #SOURCES = $(patsubst %,$(SRCDIR)/%.cpp,$(FILES))
 OBJECTS = $(patsubst %,$(TMPDIR)/%.o,$(FILES))

src/MarkovMatrix.cpp

@@ -0,0 +1,47 @@
+#include "MarkovMatrix.hpp"
+
+#include <algorithm> // for std::max
+
+
+MarkovMatrix::MarkovMatrix(int length)
+{
+	this->length = length;
+}
+
+
+MarkovMatrix::~MarkovMatrix()
+{
+	// do nothing
+}
+
+
+void MarkovMatrix::feed(std::string line)
+{
+	for (int i=0; i<=int(line.size()); ++i) {
+		int pos = std::max(i-this->length, 0);
+		int len = i - pos;
+		std::string before = line.substr(pos, len);
+		std::string current = line.substr(i, 1);
+		this->matrix[before][current] += 1;
+	}
+}
+
+
+void MarkovMatrix::reset(int length)
+{
+	this->matrix.clear();
+	
+	if (length>0) {
+		this->length = length;
+	}
+}
+
+
+std::map<std::string, int> MarkovMatrix::hiccup(std::string& previous)
+{
+	int size = previous.size();
+	int pos = std::max(size-this->length, 0);
+	int len = size - pos;
+	std::string before = previous.substr(pos, len);
+	return this->matrix[before];
+}

src/MarkovMatrix.hpp

@@ -0,0 +1,23 @@
+#ifndef MARKOVMATRIX_HPP
+#define MARKOVMATRIX_HPP
+
+#include <map>
+#include <string>
+
+
+class MarkovMatrix
+{
+public:
+	MarkovMatrix(int length);
+	~MarkovMatrix();
+	
+	void feed(std::string line);
+	void reset(int length=0); // reset the matrix, length>0 -> set a new length
+	std::map<std::string, int> hiccup(std::string& previous);
+	
+private:
+	int length;
+	std::map<std::string, std::map<std::string, int> > matrix;
+};
+
+#endif