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;
+/**
+ * Convenience macro to create a memory area for the BitArray.
+ * \param name Name of the variable.
+ * \param size Number of bits requested. It will be rounded to the nearest
+ * byte
+ */
#define BITARRAY_ALLOC(name, size) uint8_t name[DIV_ROUNDUP((size), 8)]
-#define BITARRAY_SIZE(name) (sizeof((name)) * 8)
+/**
+ * Set one bit into the bit array.
+ * \param bitx BitArray context
+ * \param idx The bit to set
+ */
INLINE void bitarray_set(BitArray *bitx, int idx)
{
ASSERT((size_t)idx <= bitx->bitarray_len);
bitx->array[page] |= BV(bit);
}
+/**
+ * Clear one bit in the bit array.
+ * \param bitx BitArray context
+ * \param idx The bit to clear
+ */
INLINE void bitarray_clear(BitArray *bitx, int idx)
{
ASSERT((size_t)idx <= bitx->bitarray_len);
bitx->array[page] &= ~BV(bit);
}
+/**
+ * Set a range of bits.
+ *
+ * The range starts from \a idx (inclusive) and spans \a offset bits.
+ *
+ * \param bitx BitArray context
+ * \param idx Starting bit
+ * \param offset Number of bit to set
+ */
INLINE void bitarray_setRange(BitArray *bitx, int idx, int offset)
{
ASSERT((size_t)idx <= bitx->bitarray_len);
bitarray_set(bitx, i);
}
-
+/**
+ * Clear a range of bits.
+ *
+ * The range starts from \a idx (inclusive) and spans \a offset bits.
+ *
+ * \param bitx BitArray context
+ * \param idx Starting bit
+ * \param offset Number of bits to clear
+ */
INLINE void bitarray_clearRange(BitArray *bitx, int idx, int offset)
{
ASSERT((size_t)idx <= bitx->bitarray_len);
bitarray_clear(bitx, i);
}
+/**
+ * Test a bit.
+ *
+ * \param bitx BitArray context
+ * \param idx Bit to test
+ * \return True if bit is set, false otherwise.
+ */
INLINE bool bitarray_test(BitArray *bitx, int idx)
{
ASSERT((size_t)idx <= bitx->bitarray_len);
return (bitx->array[page] & BV(bit));
}
-/*
- * Ugly!.. reformat it.
+/**
+ * Check if the bitarray is full
+ *
+ * Only \a bitarray_len bits are tested.
+ *
+ * \param bitx BitArray to test
+ * \return True if \a bitx is full, false otherwise
*/
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;
}
/*
* Ugly!.. reformat it.
*/
+/**
+ * Test if a range of bit is full.
+ *
+ * \param bitx BitArray context
+ * \param idx Starting bit
+ * \param offset Number of bits to test
+ * \return True if range is full, false otherwise
+ */
INLINE bool bitarray_isRangeFull(BitArray *bitx, int idx, int offset)
{
ASSERT((size_t)(idx + offset) <= bitx->bitarray_len);
/*
* Ugly!.. reformat it.
*/
+/**
+ * Test if a range of bit is empty.
+ *
+ * \param bitx BitArray context
+ * \param idx Starting bit
+ * \param offset Number of bits to test
+ * \return True if range is empty, false otherwise
+ */
INLINE bool bitarray_isRangeEmpty(BitArray *bitx, int idx, int offset)
{
ASSERT((size_t)(idx + offset) <= bitx->bitarray_len);
return 1;
}
-
+/**
+ * Print on debug serial a BitArray.
+ * \note This module does not use the logging module, so you
+ * can't decide the logging level.
+ * \param bitx BitArray to be printed.
+ */
INLINE void bitarray_dump(BitArray *bitx)
{
kprintf("bitarray size[%zu]bits on [%zu]bytes\n", bitx->bitarray_len, bitx->size);
kprintf("..%02x [%d]\n", bitx->array[i / 8], i);
}
-INLINE void init_bitarray(BitArray *bitx, size_t bitarray_len, uint8_t *array, size_t size)
+int bitarray_firstSetBit(BitArray *bitx);
+
+/**
+ * Init a BitArray.
+ *
+ * The BitArray uses an external array for storage. You can use the macro
+ * BITARRAY_ALLOC to declare an appropriate memory size. Example usage:
+ * \code
+ * BITARRAY_ALLOC(bits_mem, 17);
+ * BitArray bits;
+ * bitarray_init(&bits, 17, bits_mem, sizeof(bits_mem))
+ * \endcode
+ *
+ * \param bitx BitArray context
+ * \param bitarray_len Number of bits in the BitArray
+ * \param array Memory area for the BitArray
+ * \param size Size (in bytes) of the memory area \a array
+ */
+INLINE void bitarray_init(BitArray *bitx, size_t bitarray_len, uint8_t *array, size_t size)
{
bitx->size = size;
bitx->array = array;