Fix Base32 decode

Mw3y · May 8, 2024 · a0e170d · a0e170d
1 parent 9a3e9ac
commit a0e170d
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Showing 3 changed files with 12 additions and 15 deletions.
diff --git a/src/ch/epfl/chacun/ActionEncoder.java b/src/ch/epfl/chacun/ActionEncoder.java
@@ -160,10 +160,6 @@ public static StateAction decodeAndApply(GameState gameState, String action) {
      * @throws IllegalActionException if the action is illegal
      */
     private static StateAction unsafeDecodeAndApply(GameState gameState, String action) throws IllegalActionException {
-        // Check if the received action is valid
-        if (!Base32.isValid(action) || action.isEmpty())
-            throw new IllegalActionException();
-
         int decodedAction = Base32.decode(action);
         // Execute the provided action based on the next action context
         return switch (gameState.nextAction()) {

diff --git a/src/ch/epfl/chacun/Base32.java b/src/ch/epfl/chacun/Base32.java
@@ -14,9 +14,9 @@ public class Base32 {
     public static final String ALPHABET = "ABCDEFGHIJKLMNOPQRSTUVWXYZ234567";
 
     /**
-     * The size of the base 32 alphabet.
+     * The number of bits to represent a symbol in base 32.
      */
-    public static final int ALPHABET_SIZE = ALPHABET.length();
+    private static final int BASE_32_SYMBOL_BITS = 5;
 
     /**
      * Checks if the given string is valid in base 32.
@@ -36,7 +36,7 @@ public static boolean isValid(String string) {
      */
     public static String encodeBits5(int value) {
         // Keep only the 5 less significand bits
-        int fiveLSB = value & ((1 << 5) - 1);
+        int fiveLSB = value & ((1 << BASE_32_SYMBOL_BITS) - 1);
         return String.valueOf(ALPHABET.charAt(fiveLSB));
     }
 
@@ -48,7 +48,7 @@ public static String encodeBits5(int value) {
      */
     public static String encodeBits10(int value) {
         // Encoded independently two 5-bit parts and merge them
-        return encodeBits5(value) + encodeBits5(value >> 5);
+        return encodeBits5(value  >> BASE_32_SYMBOL_BITS) + encodeBits5(value);
     }
 
     /**
@@ -60,11 +60,12 @@ public static String encodeBits10(int value) {
      * @return the integer corresponding to the decoded value
      */
     public static int decode(String value) {
+        Preconditions.checkArgument(value.length() == 1 || value.length() == 2);
+        Preconditions.checkArgument(isValid(value));
         int decodedValue = 0;
-        // For each value, add its index in the base 32 alphabet times the corresponding power of 32
-        // to the decoded integer value
+        // For each value, add its index in the base 32 alphabet times
         for (int i = 0; i < value.length(); ++i) {
-            decodedValue += (int) (ALPHABET.indexOf(value.charAt(i)) * Math.pow(ALPHABET_SIZE, i));
+            decodedValue = decodedValue << BASE_32_SYMBOL_BITS | ALPHABET.indexOf(value.charAt(i));
         }
         return decodedValue;
     }

diff --git a/src/ch/epfl/chacun/gui/Main.java b/src/ch/epfl/chacun/gui/Main.java
@@ -188,10 +188,10 @@ private TileDecks createTileDecksWithSeed(String rawSeed) {
         }
 
         List<Tile> tiles = new ArrayList<>(Tiles.TILES);
-        for (int i = 79; i <= 94; ++i) {
-            if (i != 88)
-                tiles.remove(Tiles.TILES.get(i));
-        }
+        // for (int i = 79; i <= 94; ++i) {
+        //     if (i != 88)
+        //         tiles.remove(Tiles.TILES.get(i));
+        /// }
         Collections.shuffle(tiles, shuffler);
         // Group tiles by kind to create the decks
         return new TileDecks(tiles.stream().collect(Collectors.groupingBy(Tile::kind)));