Various code tweaks and refactorings suggested by IntelliJ

[zxing.git] / core / src / com / google / zxing / common / BitArray.java

diff --git a/core/src/com/google/zxing/common/BitArray.java b/core/src/com/google/zxing/common/BitArray.java
index 398be9e..0d2884c 100644 (file)
--- a/core/src/com/google/zxing/common/BitArray.java
+++ b/core/src/com/google/zxing/common/BitArray.java
@@ -23,17 +23,20 @@ package com.google.zxing.common;
  */\r
 public final class BitArray {\r
 \r
-  private final int[] bits;\r
+  private int[] bits;\r
+  private final int size;\r
 \r
   public BitArray(int size) {\r
-    int arraySize = size >> 5;\r
-    if ((size & 0x1F) != 0) {\r
-      arraySize++;\r
-    }\r
-    bits = new int[arraySize];\r
+    this.size = size;\r
+    this.bits = makeArray(size);\r
+  }\r
+\r
+  public int getSize() {\r
+    return size;\r
   }\r
 \r
   /**\r
+   * @param i bit to get\r
    * @return true iff bit i is set\r
    */\r
   public boolean get(int i) {\r
@@ -42,17 +45,26 @@ public final class BitArray {
 \r
   /**\r
    * Sets bit i.\r
+   *\r
+   * @param i bit to set\r
    */\r
   public void set(int i) {\r
     bits[i >> 5] |= 1 << (i & 0x1F);\r
   }\r
 \r
+  /**\r
+   * Sets a block of 32 bits, starting at bit i.\r
+   *\r
+   * @param i first bit to set\r
+   * @param newBits the new value of the next 32 bits. Note again that the least-significant bit\r
+   * corresponds to bit i, the next-least-significant to i+1, and so on.\r
+   */\r
   public void setBulk(int i, int newBits) {\r
     bits[i >> 5] = newBits;\r
   }\r
 \r
   /**\r
-   * Clears all bits.\r
+   * Clears all bits (sets to false).\r
    */\r
   public void clear() {\r
     int max = bits.length;\r
@@ -61,12 +73,82 @@ public final class BitArray {
     }\r
   }\r
 \r
+  /**\r
+   * Efficient method to check if a range of bits is set, or not set.\r
+   *\r
+   * @param start start of range, inclusive.\r
+   * @param end end of range, exclusive\r
+   * @param value if true, checks that bits in range are set, otherwise checks that they are not set\r
+   * @return true iff all bits are set or not set in range, according to value argument\r
+   * @throws IllegalArgumentException if end is less than or equal to start\r
+   */\r
+  public boolean isRange(int start, int end, boolean value) {\r
+    if (end < start) {\r
+      throw new IllegalArgumentException();\r
+    }\r
+    if (end == start) {\r
+      return true; // empty range matches\r
+    }\r
+    end--; // will be easier to treat this as the last actually set bit -- inclusive    \r
+    int firstInt = start >> 5;\r
+    int lastInt = end >> 5;\r
+    for (int i = firstInt; i <= lastInt; i++) {\r
+      int firstBit = i > firstInt ? 0 : start & 0x1F;\r
+      int lastBit = i < lastInt ? 31 : end & 0x1F;\r
+      int mask;\r
+      if (firstBit == 0 && lastBit == 31) {\r
+        mask = -1;\r
+      } else {\r
+        mask = 0;\r
+        for (int j = firstBit; j <= lastBit; j++) {\r
+          mask |= 1 << j;\r
+        }\r
+      }\r
+      if (value) {\r
+        if ((bits[i] & mask) != mask) {\r
+          return false;\r
+        }\r
+      } else {\r
+        if ((bits[i] & mask) != 0) {\r
+          return false;\r
+        }\r
+      }\r
+    }\r
+    return true;\r
+  }\r
+\r
   /**\r
    * @return underlying array of ints. The first element holds the first 32 bits, and the least\r
-   *  significant bit is bit 0.\r
+   *         significant bit is bit 0.\r
    */\r
   public int[] getBitArray() {\r
     return bits;\r
   }\r
 \r
+  /**\r
+   * Reverses all bits in the array.\r
+   */\r
+  public void reverse() {\r
+    int[] newBits = makeArray(size);\r
+    int max = newBits.length;\r
+    for (int i = 0; i < max; i++) {\r
+      newBits[i] = 0;\r
+    }\r
+    int size = this.size;\r
+    for (int i = 0; i < size; i++) {\r
+      if (get(size - i - 1)) {\r
+        newBits[i >> 5] |= 1 << (i & 0x1F);\r
+      }\r
+    }\r
+    bits = newBits;\r
+  }\r
+\r
+  private static int[] makeArray(int size) {\r
+    int arraySize = size >> 5;\r
+    if ((size & 0x1F) != 0) {\r
+      arraySize++;\r
+    }\r
+    return new int[arraySize];\r
+  }\r
+\r
 }
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