Improve performance of bitarray_isFull(). Add documentation.

git-svn-id: https://src.develer.com/svnoss/bertos/trunk@4225 38d2e660-2303-0410-9eaa-f027e97ec537

diff --git a/bertos/struct/bitarray.h b/bertos/struct/bitarray.h
index 36d1aa2abef552c051f695abd7c2ebe32cb1ec38..3e96b7c5f92e2c9d86a8cc588863b7e4247e9f29 100644 (file)
--- a/bertos/struct/bitarray.h
+++ b/bertos/struct/bitarray.h
@@ -47,9 +47,9 @@
 
 typedef struct BitArray
 {
-       size_t size;
-       size_t bitarray_len;
-       uint8_t *array;
+       size_t size;          /// Size in bytes of the bitarray
+       size_t bitarray_len;  /// Number of bits used
+       uint8_t *array;       /// Pointer to memory occupied by the bitarray
 } BitArray;
 
 #define BITARRAY_ALLOC(name, size)   uint8_t name[DIV_ROUNDUP((size), 8)]
@@ -101,28 +101,23 @@ INLINE bool bitarray_test(BitArray *bitx, int idx)
        return (bitx->array[page] & BV(bit));
 }
 
-/*
- * Ugly!.. reformat it.
+/**
+ * Check if the bitarray is full
+ *
+ * Only \a bitarray_len bits are tested.
  */
 INLINE bool bitarray_isFull(BitArray *bitx)
 {
-       int count = bitx->size;
-       for (size_t page = 0; page <= bitx->size / 8; page++)
+       // test full bytes except the last one
+       for (size_t page = 0; page <= bitx->size - 2; page++)
        {
-               if (count < 8)
-               {
-                       for (size_t i = page * 8; i <= bitx->bitarray_len; i++)
-                               if (!bitarray_test(bitx, i))
-                                       return 0;
-                               count--;
-               }
-               else
-               {
-                       if (!(bitx->array[page] == 0xff))
-                               return 0;
-               }
-               count -= 8;
+               if (!(bitx->array[page] == 0xff))
+                       return 0;
        }
+       // test the last byte using the correct bitmask
+       uint8_t mask = BV(bitx->bitarray_len >> 3) - 1;
+       if (!(bitx->array[bitx->size - 1] & mask))
+               return 0;
 
        return 1;
 }