branches/zip: Cleanup suggested by Osku.

ut_is_2pow(): New function for testing if a number is zero or a power of two.
Use this function instead of bitwise arithmetics or ut_2_power_up() where
possible.

fsp/fsp0fsp.c

@@ -1273,7 +1273,7 @@ fsp_fill_free_list(
 	limit = mtr_read_ulint(header + FSP_FREE_LIMIT, MLOG_4BYTES, mtr);
 
 	zip_size = mach_read_from_4(FSP_PAGE_ZIP_SIZE + header);
-	ut_a(!(zip_size & (zip_size - 1))); /* must be a power of 2 */
+	ut_a(ut_is_2pow(zip_size));
 	ut_a(zip_size <= UNIV_PAGE_SIZE);
 	ut_a(!zip_size || zip_size >= PAGE_ZIP_MIN_SIZE);
 
@@ -2842,7 +2842,7 @@ fsp_reserve_free_extents(
 
 	space_header = fsp_get_space_header(space, mtr);
 	zip_size = mach_read_from_4(FSP_PAGE_ZIP_SIZE + space_header);
-	ut_a(!(zip_size & (zip_size - 1))); /* must be a power of 2 */
+	ut_a(ut_is_2pow(zip_size));
 	ut_a(zip_size <= UNIV_PAGE_SIZE);
 	ut_a(!zip_size || zip_size >= PAGE_ZIP_MIN_SIZE);
 try_again:
@@ -3747,7 +3747,7 @@ fsp_validate(
 	header = fsp_get_space_header(space, &mtr);
 
 	zip_size = mach_read_from_4(FSP_PAGE_ZIP_SIZE + header);
-	ut_a(!(zip_size & (zip_size - 1))); /* must be a power of 2 */
+	ut_a(ut_is_2pow(zip_size));
 	ut_a(zip_size <= UNIV_PAGE_SIZE);
 	ut_a(!zip_size || zip_size >= PAGE_ZIP_MIN_SIZE);
 

ha/hash0hash.c

@@ -139,7 +139,7 @@ hash_create_mutexes(
 {
 	ulint	i;
 
-	ut_a(n_mutexes == ut_2_power_up(n_mutexes));
+	ut_a(n_mutexes > 0 && ut_is_2pow(n_mutexes));
 
 	table->mutexes = mem_alloc(n_mutexes * sizeof(mutex_t));
 

ibuf/ibuf0ibuf.c

@@ -572,7 +572,7 @@ ibuf_bitmap_page_init(
 {
 	ulint	byte_offset;
 
-	ut_ad(!(zip_size & (zip_size - 1))); /* must be a power of 2 */
+	ut_ad(ut_is_2pow(zip_size));
 
 	fil_page_set_type(page, FIL_PAGE_IBUF_BITMAP);
 
@@ -639,7 +639,7 @@ ibuf_bitmap_page_get_bits(
 #if IBUF_BITS_PER_PAGE % 2
 # error "IBUF_BITS_PER_PAGE % 2 != 0"
 #endif
-	ut_ad(!(zip_size & (zip_size - 1))); /* must be a power of 2 */
+	ut_ad(ut_is_2pow(zip_size));
 	ut_ad(mtr_memo_contains(mtr, buf_block_align(page),
 						MTR_MEMO_PAGE_X_FIX));
 
@@ -691,7 +691,7 @@ ibuf_bitmap_page_set_bits(
 #if IBUF_BITS_PER_PAGE % 2
 # error "IBUF_BITS_PER_PAGE % 2 != 0"
 #endif
-	ut_ad(!(zip_size & (zip_size - 1))); /* must be a power of 2 */
+	ut_ad(ut_is_2pow(zip_size));
 	ut_ad(mtr_memo_contains(mtr, buf_block_align(page),
 						MTR_MEMO_PAGE_X_FIX));
 #ifdef UNIV_IBUF_DEBUG
@@ -741,7 +741,7 @@ ibuf_bitmap_page_no_calc(
 				0 for uncompressed pages */
 	ulint	page_no)	/* in: tablespace page number */
 {
-	ut_ad(!(zip_size & (zip_size - 1))); /* must be a power of 2 */
+	ut_ad(ut_is_2pow(zip_size));
 
 	if (!zip_size) {
 		return(FSP_IBUF_BITMAP_OFFSET

include/fsp0fsp.ic

@@ -17,7 +17,7 @@ fsp_descr_page(
 			0 for uncompressed pages */
 	ulint	page_no)/* in: page number */
 {
-	ut_ad(!(zip_size & (zip_size - 1))); /* must be a power of 2 */
+	ut_ad(ut_is_2pow(zip_size));
 
 	if (!zip_size) {
 		return(UNIV_UNLIKELY((page_no & (UNIV_PAGE_SIZE - 1))

include/ibuf0ibuf.ic

@@ -116,7 +116,7 @@ ibuf_bitmap_page(
 			0 for uncompressed pages */
 	ulint	page_no)/* in: page number */
 {
-	ut_ad(!(zip_size & (zip_size - 1))); /* must be a power of 2 */
+	ut_ad(ut_is_2pow(zip_size));
 
 	if (!zip_size) {
 		return(UNIV_UNLIKELY((page_no & (UNIV_PAGE_SIZE - 1))

include/page0zip.ic

@@ -132,7 +132,7 @@ page_zip_simple_validate(
 {
 	ut_ad(page_zip);
 	ut_ad(page_zip->data);
-	ut_ad(!(page_zip->size & (page_zip->size - 1))); /* power of 2 */
+	ut_ad(ut_is_2pow(zip_size));
 	ut_ad(page_zip->size <= UNIV_PAGE_SIZE);
 	ut_ad(page_zip->size > PAGE_DATA + PAGE_ZIP_DIR_SLOT_SIZE);
 	ut_ad(page_zip->m_start <= page_zip->m_end);

include/ut0byte.ic

@@ -273,7 +273,7 @@ ut_calc_align(
 	ulint	 align_no)	/* in: align by this number */
 {
 	ut_ad(align_no > 0);
-	ut_ad(((align_no - 1) & align_no) == 0);
+	ut_ad(ut_is_2pow(align_no));
 
 	return((n + align_no - 1) & ~(align_no - 1));
 }
@@ -310,7 +310,7 @@ ut_calc_align_down(
 	ulint	 align_no)	 /* in: align by this number */
 {
 	ut_ad(align_no > 0);
-	ut_ad(((align_no - 1) & align_no) == 0);
+	ut_ad(ut_is_2pow(align_no));
 
 	return(n & ~(align_no - 1));
 }

include/ut0ut.h

@@ -79,6 +79,14 @@ ut_pair_cmp(
 	ulint	b1,	/* in: more significant part of second pair */
 	ulint	b2);	/* in: less significant part of second pair */
 /*****************************************************************
+Determines if a number is zero or a power of two.
+This function is used in assertions or assertion-like tests. */
+UNIV_INLINE
+ibool
+ut_is_2pow(
+/*=======*/		/* out: TRUE if zero or a power of 2 */
+	ulint	n);	/* in: number to be tested */
+/*****************************************************************
 Calculates fast the remainder when divided by a power of two. */
 UNIV_INLINE
 ulint

include/ut0ut.ic

@@ -101,6 +101,18 @@ ut_pair_cmp(
 	}
 }
 
+/*****************************************************************
+Determines if a number is zero or a power of two.
+This function is used in assertions or assertion-like tests. */
+UNIV_INLINE
+ibool
+ut_is_2pow(
+/*=======*/		/* out: TRUE if zero or a power of 2 */
+	ulint	n)	/* in: number to be tested */
+{
+	return(UNIV_LIKELY(!(n & (n - 1))));
+}
+
 /*****************************************************************
 Calculates fast the remainder when divided by a power of two. */
 UNIV_INLINE
@@ -110,7 +122,7 @@ ut_2pow_remainder(
 	ulint	n,	/* in: number to be divided */
 	ulint	m)	/* in: divisor; power of 2 */
 {
-	ut_ad(0x80000000UL % m == 0);
+	ut_ad(ut_is_2pow(m));
 
 	return(n & (m - 1));
 }
@@ -125,7 +137,7 @@ ut_2pow_round(
 	ulint	n,	/* in: number to be rounded */
 	ulint	m)	/* in: divisor; power of 2 */
 {
-	ut_ad(0x80000000UL % m == 0);
+	ut_ad(ut_is_2pow(m));
 
 	return(n & ~(m - 1));
 }

mem/mem0pool.c

@@ -496,7 +496,7 @@ mem_area_free(
 
 		next_size = mem_area_get_size(
 					(mem_area_t*)(((byte*)area) + size));
-		if (ut_2_power_up(next_size) != next_size) {
+		if (UNIV_UNLIKELY(!next_size || !ut_is_2pow(next_size))) {
 			fprintf(stderr,
 "InnoDB: Error: Memory area size %lu, next area size %lu not a power of 2!\n"
 "InnoDB: Possibly a memory overrun of the buffer being freed here.\n",