add support for loading and printing out matrices from files

labs/2/Main.java

@@ -59,8 +59,13 @@ public class Main {
             if (allow_networking) {
                 System.err.println("[WARN] File is missing, downloading random matrix from the server");
                 fetchResource("http://lab2.kpi.dev:16554/matrix.py", matrix_file_name);
+            } else {
+                System.err.println("[WARN] File is missing; networking is disabled, not recovering");
+                System.exit(1);
             }
         }
+        
+        int[][] matrix = loadMatrixFromFile(matrix_file);
 
     }
 
@@ -106,4 +111,45 @@ public class Main {
             System.exit(1);
         }
     }
+
+    private static int[][] loadMatrixFromFile(File matrix_file) {
+        try {
+            Scanner matrix_file_reader = new Scanner(matrix_file);
+
+            ArrayList<String> raw_matrix_lines = new ArrayList<String>();
+            while (matrix_file_reader.hasNextLine()) {
+                raw_matrix_lines.add(matrix_file_reader.nextLine());
+            }
+    
+            ArrayList<String[]> baked_matrix_lines = new ArrayList<String[]>();
+    
+            for (String s : raw_matrix_lines) {
+                baked_matrix_lines.add(s.split(" "));
+            }
+            
+            int ref_length = baked_matrix_lines.get(0).length;
+            int[][] baked_matrix = new int[baked_matrix_lines.size()][ref_length];
+            
+            for (int i = 0; i < baked_matrix_lines.size(); i++) {
+            //for (String[] sa : baked_matrix_lines) {
+                if (baked_matrix_lines.get(i).length != ref_length) {
+                    System.err.println("[ERROR] Matrix lines have different length! Assuming the matrix was corrupted");
+                    System.exit(2);
+                }
+
+                for (int j = 0; j < baked_matrix_lines.get(i).length; j++) {
+                    System.out.print(baked_matrix_lines.get(i)[j] + " ");
+                    baked_matrix[i][j] = Integer.parseInt(baked_matrix_lines.get(i)[j]);
+                }
+
+                System.out.print("\n");
+            }
+
+            return baked_matrix;
+        } catch (Exception e) {
+            System.err.println("[ERROR] Failed to read matrix from file " + matrix_file.getName());
+            System.exit(1);
+            return new int[1][1];
+        }
+    }
 }