Moved Life implementations into 'life' directory.

[cellular-automata.git] / life / 004 / life.awk

diff --git a/life/004/life.awk b/life/004/life.awk
new file mode 100755 (executable)
index 0000000..73cad1d
--- /dev/null
+++ b/life/004/life.awk
@@ -0,0 +1,128 @@
+#! /usr/bin/awk -f
+
+
+function CHAR_BORDER() {return "-"}
+function CHAR_ALIVE()  {return "o"}
+function CHAR_DEAD()   {return " "}
+
+
+function get_random_state() {
+    return int(2 * rand())
+}
+
+
+function get_init_board(n) {
+    board = "";
+
+    for (i=1; i <= n; i++) {
+        board = sprintf("%s%d", board, get_random_state())
+    };
+
+    return board
+}
+
+
+function get_char_of_state(state) {
+    if (state == 1) {
+        return CHAR_ALIVE()
+    } else if (state == 0) {
+        return CHAR_DEAD()
+    }
+}
+
+
+function do_print_border(x) {
+    for (i=1; i <= x; i++) {
+        printf CHAR_BORDER()
+    };
+    print
+}
+
+
+function do_print_board(x, n, board) {
+    do_print_border(x);
+
+    for (i=1; i <= n; i++) {
+        printf "%s", get_char_of_state(substr(board, i, 1));
+
+        if (i % x == 0) {
+            printf "\n"
+        }
+    };
+
+    do_print_border(x)
+}
+
+
+function get_new_state(state, live_neighbors) {
+    if (state == 1 && live_neighbors < 2) {
+        return 0
+    } else if (state == 1 && live_neighbors < 4) {
+        return 1
+    } else if (state == 1 && live_neighbors > 3) {
+        return 0
+    } else if (state == 0 && live_neighbors == 3) {
+        return 1
+    } else {
+        return state
+    }
+}
+
+
+function get_new_generation(x, n, board) {
+    offsets["N" ] =  - x     ;
+    offsets["NE"] =  -(x - 1);
+    offsets["E" ] =        1 ;
+    offsets["SE"] =    x + 1 ;
+    offsets["S" ] =    x     ;
+    offsets["SW"] =    x - 1 ;
+    offsets["W" ] =      - 1 ;
+    offsets["NW"] =  -(x + 1);
+
+    new_board = "";
+
+    for (cell_id=1; cell_id <= n; cell_id++) {
+        cell_state = substr(board, cell_id, 1);
+        live_neighbors = 0;
+
+        for (direction in offsets) {
+            neighbor_id = offsets[direction] + cell_id;
+
+            # -----------------------------------------------------------------
+            # Real neighbors within boundaries, ghosts beyond that!
+            # -----------------------------------------------------------------
+            if ((neighbor_id >= 1) && (neighbor_id <= n)) {
+                neighbor_state = substr(board, neighbor_id, 1)
+            } else {
+                neighbor_state = get_random_state()
+            };
+
+            live_neighbors += neighbor_state
+        }
+
+        new_cell_state = get_new_state(cell_state, live_neighbors);
+        new_board = sprintf("%s%d", new_board, new_cell_state)
+    };
+
+    return new_board
+}
+
+
+function life() {
+    "stty size" | getline stty_size_out;
+    split(stty_size_out, stty_size);
+
+    x = stty_size[2];
+    y = stty_size[1] - 3;  # Minus 1 char for each: border, border, cursor
+    n = x * y;
+
+    board = get_init_board(n);
+
+    while (1) {
+        do_print_board(x, n, board);
+        board = get_new_generation(x, n, board)
+    }
+}
+
+
+BEGIN {life()}