1 /*
2  * Copyright (c) 2011-2014, Wind River Systems, Inc.
3  *
4  * SPDX-License-Identifier: Apache-2.0
5  */
6 
7 /**
8  * @file
9  * @brief Misc utilities
10  *
11  * Misc utilities usable by the kernel and application code.
12  */
13 
14 #ifndef ZEPHYR_INCLUDE_SYS_UTIL_H_
15 #define ZEPHYR_INCLUDE_SYS_UTIL_H_
16 
17 #include <zephyr/sys/util_macro.h>
18 #include <zephyr/toolchain.h>
19 
20 /* needs to be outside _ASMLANGUAGE so 'true' and 'false' can turn
21  * into '1' and '0' for asm or linker scripts
22  */
23 #include <stdbool.h>
24 
25 #ifndef _ASMLANGUAGE
26 
27 #include <zephyr/sys/__assert.h>
28 #include <zephyr/types.h>
29 #include <stddef.h>
30 #include <stdint.h>
31 
32 /** @brief Number of bits that make up a type */
33 #define NUM_BITS(t) (sizeof(t) * BITS_PER_BYTE)
34 
35 #ifdef __cplusplus
36 extern "C" {
37 #endif
38 
39 /**
40  * @defgroup sys-util Utility Functions
41  * @since 2.4
42  * @version 0.1.0
43  * @ingroup utilities
44  * @{
45  */
46 
47 /** @brief Cast @p x, a pointer, to an unsigned integer. */
48 #define POINTER_TO_UINT(x) ((uintptr_t) (x))
49 /** @brief Cast @p x, an unsigned integer, to a <tt>void*</tt>. */
50 #define UINT_TO_POINTER(x) ((void *) (uintptr_t) (x))
51 /** @brief Cast @p x, a pointer, to a signed integer. */
52 #define POINTER_TO_INT(x)  ((intptr_t) (x))
53 /** @brief Cast @p x, a signed integer, to a <tt>void*</tt>. */
54 #define INT_TO_POINTER(x)  ((void *) (intptr_t) (x))
55 
56 #if !(defined(__CHAR_BIT__) && defined(__SIZEOF_LONG__) && defined(__SIZEOF_LONG_LONG__))
57 #	error Missing required predefined macros for BITS_PER_LONG calculation
58 #endif
59 
60 /** Number of bits in a byte. */
61 #define BITS_PER_BYTE (__CHAR_BIT__)
62 
63 /** Number of bits in a nibble. */
64 #define BITS_PER_NIBBLE (__CHAR_BIT__ / 2)
65 
66 /** Number of nibbles in a byte. */
67 #define NIBBLES_PER_BYTE (BITS_PER_BYTE / BITS_PER_NIBBLE)
68 
69 /** Number of bits in a long int. */
70 #define BITS_PER_LONG	(__CHAR_BIT__ * __SIZEOF_LONG__)
71 
72 /** Number of bits in a long long int. */
73 #define BITS_PER_LONG_LONG	(__CHAR_BIT__ * __SIZEOF_LONG_LONG__)
74 
75 /**
76  * @brief Create a contiguous bitmask starting at bit position @p l
77  *        and ending at position @p h.
78  */
79 #define GENMASK(h, l) \
80 	(((~0UL) - (1UL << (l)) + 1) & (~0UL >> (BITS_PER_LONG - 1 - (h))))
81 
82 /**
83  * @brief Create a contiguous 64-bit bitmask starting at bit position @p l
84  *        and ending at position @p h.
85  */
86 #define GENMASK64(h, l) \
87 	(((~0ULL) - (1ULL << (l)) + 1) & (~0ULL >> (BITS_PER_LONG_LONG - 1 - (h))))
88 
89 /** @brief 0 if @p cond is true-ish; causes a compile error otherwise. */
90 #define ZERO_OR_COMPILE_ERROR(cond) ((int) sizeof(char[1 - 2 * !(cond)]) - 1)
91 
92 #if defined(__cplusplus)
93 
94 /* The built-in function used below for type checking in C is not
95  * supported by GNU C++.
96  */
97 #define ARRAY_SIZE(array) (sizeof(array) / sizeof((array)[0]))
98 
99 #else /* __cplusplus */
100 
101 /**
102  * @brief Zero if @p array has an array type, a compile error otherwise
103  *
104  * This macro is available only from C, not C++.
105  */
106 #define IS_ARRAY(array) \
107 	ZERO_OR_COMPILE_ERROR( \
108 		!__builtin_types_compatible_p(__typeof__(array), \
109 					      __typeof__(&(array)[0])))
110 
111 /**
112  * @brief Number of elements in the given @p array
113  *
114  * In C++, due to language limitations, this will accept as @p array
115  * any type that implements <tt>operator[]</tt>. The results may not be
116  * particularly meaningful in this case.
117  *
118  * In C, passing a pointer as @p array causes a compile error.
119  */
120 #define ARRAY_SIZE(array) \
121 	((size_t) (IS_ARRAY(array) + (sizeof(array) / sizeof((array)[0]))))
122 
123 #endif /* __cplusplus */
124 
125 /**
126  * @brief Declare a flexible array member.
127  *
128  * This macro declares a flexible array member in a struct. The member
129  * is named @p name and has type @p type.
130  *
131  * Since C99, flexible arrays are part of the C standard, but for historical
132  * reasons many places still use an older GNU extension that is declare
133  * zero length arrays.
134  *
135  * Although zero length arrays are flexible arrays, we can't blindly
136  * replace [0] with [] because of some syntax limitations. This macro
137  * workaround these limitations.
138  *
139  * It is specially useful for cases where flexible arrays are
140  * used in unions or are not the last element in the struct.
141  */
142 #define FLEXIBLE_ARRAY_DECLARE(type, name) \
143 	struct { \
144 		struct { } __unused_##name; \
145 		type name[]; \
146 	}
147 
148 /**
149  * @brief Whether @p ptr is an element of @p array
150  *
151  * This macro can be seen as a slightly stricter version of @ref PART_OF_ARRAY
152  * in that it also ensures that @p ptr is aligned to an array-element boundary
153  * of @p array.
154  *
155  * In C, passing a pointer as @p array causes a compile error.
156  *
157  * @param array the array in question
158  * @param ptr the pointer to check
159  *
160  * @return 1 if @p ptr is part of @p array, 0 otherwise
161  */
162 #define IS_ARRAY_ELEMENT(array, ptr)                                                               \
163 	((ptr) && POINTER_TO_UINT(array) <= POINTER_TO_UINT(ptr) &&                          \
164 	 POINTER_TO_UINT(ptr) < POINTER_TO_UINT(&(array)[ARRAY_SIZE(array)]) &&                    \
165 	 (POINTER_TO_UINT(ptr) - POINTER_TO_UINT(array)) % sizeof((array)[0]) == 0)
166 
167 /**
168  * @brief Index of @p ptr within @p array
169  *
170  * With `CONFIG_ASSERT=y`, this macro will trigger a runtime assertion
171  * when @p ptr does not fall into the range of @p array or when @p ptr
172  * is not aligned to an array-element boundary of @p array.
173  *
174  * In C, passing a pointer as @p array causes a compile error.
175  *
176  * @param array the array in question
177  * @param ptr pointer to an element of @p array
178  *
179  * @return the array index of @p ptr within @p array, on success
180  */
181 #define ARRAY_INDEX(array, ptr)                                                                    \
182 	({                                                                                         \
183 		__ASSERT_NO_MSG(IS_ARRAY_ELEMENT(array, ptr));                                     \
184 		(__typeof__((array)[0]) *)(ptr) - (array);                                         \
185 	})
186 
187 /**
188  * @brief Check if a pointer @p ptr lies within @p array.
189  *
190  * In C but not C++, this causes a compile error if @p array is not an array
191  * (e.g. if @p ptr and @p array are mixed up).
192  *
193  * @param array an array
194  * @param ptr a pointer
195  * @return 1 if @p ptr is part of @p array, 0 otherwise
196  */
197 #define PART_OF_ARRAY(array, ptr)                                                                  \
198 	((ptr) && POINTER_TO_UINT(array) <= POINTER_TO_UINT(ptr) &&                                \
199 	 POINTER_TO_UINT(ptr) < POINTER_TO_UINT(&(array)[ARRAY_SIZE(array)]))
200 
201 /**
202  * @brief Array-index of @p ptr within @p array, rounded down
203  *
204  * This macro behaves much like @ref ARRAY_INDEX with the notable
205  * difference that it accepts any @p ptr in the range of @p array rather than
206  * exclusively a @p ptr aligned to an array-element boundary of @p array.
207  *
208  * With `CONFIG_ASSERT=y`, this macro will trigger a runtime assertion
209  * when @p ptr does not fall into the range of @p array.
210  *
211  * In C, passing a pointer as @p array causes a compile error.
212  *
213  * @param array the array in question
214  * @param ptr pointer to an element of @p array
215  *
216  * @return the array index of @p ptr within @p array, on success
217  */
218 #define ARRAY_INDEX_FLOOR(array, ptr)                                                              \
219 	({                                                                                         \
220 		__ASSERT_NO_MSG(PART_OF_ARRAY(array, ptr));                                        \
221 		(POINTER_TO_UINT(ptr) - POINTER_TO_UINT(array)) / sizeof((array)[0]);              \
222 	})
223 
224 /**
225  * @brief Iterate over members of an array using an index variable
226  *
227  * @param array the array in question
228  * @param idx name of array index variable
229  */
230 #define ARRAY_FOR_EACH(array, idx) for (size_t idx = 0; (idx) < ARRAY_SIZE(array); ++(idx))
231 
232 /**
233  * @brief Iterate over members of an array using a pointer
234  *
235  * @param array the array in question
236  * @param ptr pointer to an element of @p array
237  */
238 #define ARRAY_FOR_EACH_PTR(array, ptr)                                                             \
239 	for (__typeof__(*(array)) *ptr = (array); (size_t)((ptr) - (array)) < ARRAY_SIZE(array);   \
240 	     ++(ptr))
241 
242 /**
243  * @brief Validate if two entities have a compatible type
244  *
245  * @param a the first entity to be compared
246  * @param b the second entity to be compared
247  * @return 1 if the two elements are compatible, 0 if they are not
248  */
249 #define SAME_TYPE(a, b) __builtin_types_compatible_p(__typeof__(a), __typeof__(b))
250 
251 /**
252  * @brief Validate CONTAINER_OF parameters, only applies to C mode.
253  */
254 #ifndef __cplusplus
255 #define CONTAINER_OF_VALIDATE(ptr, type, field)               \
256 	BUILD_ASSERT(SAME_TYPE(*(ptr), ((type *)0)->field) || \
257 		     SAME_TYPE(*(ptr), void),                 \
258 		     "pointer type mismatch in CONTAINER_OF");
259 #else
260 #define CONTAINER_OF_VALIDATE(ptr, type, field)
261 #endif
262 
263 /**
264  * @brief Get a pointer to a structure containing the element
265  *
266  * Example:
267  *
268  *	struct foo {
269  *		int bar;
270  *	};
271  *
272  *	struct foo my_foo;
273  *	int *ptr = &my_foo.bar;
274  *
275  *	struct foo *container = CONTAINER_OF(ptr, struct foo, bar);
276  *
277  * Above, @p container points at @p my_foo.
278  *
279  * @param ptr pointer to a structure element
280  * @param type name of the type that @p ptr is an element of
281  * @param field the name of the field within the struct @p ptr points to
282  * @return a pointer to the structure that contains @p ptr
283  */
284 #define CONTAINER_OF(ptr, type, field)                               \
285 	({                                                           \
286 		CONTAINER_OF_VALIDATE(ptr, type, field)              \
287 		((type *)(((char *)(ptr)) - offsetof(type, field))); \
288 	})
289 
290 /**
291  * @brief Report the size of a struct field in bytes.
292  *
293  * @param type The structure containing the field of interest.
294  * @param member The field to return the size of.
295  *
296  * @return The field size.
297  */
298 #define SIZEOF_FIELD(type, member) sizeof((((type *)0)->member))
299 
300 /**
301  * @brief Concatenate input arguments
302  *
303  * Concatenate provided tokens into a combined token during the preprocessor pass.
304  * This can be used to, for ex., build an identifier out of multiple parts,
305  * where one of those parts may be, for ex, a number, another macro, or a macro argument.
306  *
307  * @param ... Tokens to concatencate
308  *
309  * @return Concatenated token.
310  */
311 #define CONCAT(...) \
312 	UTIL_CAT(_CONCAT_, NUM_VA_ARGS_LESS_1(__VA_ARGS__))(__VA_ARGS__)
313 
314 /**
315  * @brief Check if @p ptr is aligned to @p align alignment
316  */
317 #define IS_ALIGNED(ptr, align) (((uintptr_t)(ptr)) % (align) == 0)
318 
319 /**
320  * @brief Value of @p x rounded up to the next multiple of @p align.
321  */
322 #define ROUND_UP(x, align)                                   \
323 	((((unsigned long)(x) + ((unsigned long)(align) - 1)) / \
324 	  (unsigned long)(align)) * (unsigned long)(align))
325 
326 /**
327  * @brief Value of @p x rounded down to the previous multiple of @p align.
328  */
329 #define ROUND_DOWN(x, align)                                 \
330 	(((unsigned long)(x) / (unsigned long)(align)) * (unsigned long)(align))
331 
332 /** @brief Value of @p x rounded up to the next word boundary. */
333 #define WB_UP(x) ROUND_UP(x, sizeof(void *))
334 
335 /** @brief Value of @p x rounded down to the previous word boundary. */
336 #define WB_DN(x) ROUND_DOWN(x, sizeof(void *))
337 
338 /**
339  * @brief Divide and round up.
340  *
341  * Example:
342  * @code{.c}
343  * DIV_ROUND_UP(1, 2); // 1
344  * DIV_ROUND_UP(3, 2); // 2
345  * @endcode
346  *
347  * @param n Numerator.
348  * @param d Denominator.
349  *
350  * @return The result of @p n / @p d, rounded up.
351  */
352 #define DIV_ROUND_UP(n, d) (((n) + (d) - 1) / (d))
353 
354 /**
355  * @brief Divide and round to the nearest integer.
356  *
357  * Example:
358  * @code{.c}
359  * DIV_ROUND_CLOSEST(5, 2); // 3
360  * DIV_ROUND_CLOSEST(5, -2); // -3
361  * DIV_ROUND_CLOSEST(5, 3); // 2
362  * @endcode
363  *
364  * @param n Numerator.
365  * @param d Denominator.
366  *
367  * @return The result of @p n / @p d, rounded to the nearest integer.
368  */
369 #define DIV_ROUND_CLOSEST(n, d)                                                                    \
370 	(((((__typeof__(n))-1) < 0) && (((__typeof__(d))-1) < 0) && ((n) < 0) ^ ((d) < 0))         \
371 		 ? ((n) - ((d) / 2)) / (d)                                                         \
372 		 : ((n) + ((d) / 2)) / (d))
373 
374 #ifndef MAX
375 /**
376  * @brief Obtain the maximum of two values.
377  *
378  * @note Arguments are evaluated twice. Use Z_MAX for a GCC-only, single
379  * evaluation version
380  *
381  * @param a First value.
382  * @param b Second value.
383  *
384  * @returns Maximum value of @p a and @p b.
385  */
386 #define MAX(a, b) (((a) > (b)) ? (a) : (b))
387 #endif
388 
389 #ifndef MIN
390 /**
391  * @brief Obtain the minimum of two values.
392  *
393  * @note Arguments are evaluated twice. Use Z_MIN for a GCC-only, single
394  * evaluation version
395  *
396  * @param a First value.
397  * @param b Second value.
398  *
399  * @returns Minimum value of @p a and @p b.
400  */
401 #define MIN(a, b) (((a) < (b)) ? (a) : (b))
402 #endif
403 
404 #ifndef CLAMP
405 /**
406  * @brief Clamp a value to a given range.
407  *
408  * @note Arguments are evaluated multiple times. Use Z_CLAMP for a GCC-only,
409  * single evaluation version.
410  *
411  * @param val Value to be clamped.
412  * @param low Lowest allowed value (inclusive).
413  * @param high Highest allowed value (inclusive).
414  *
415  * @returns Clamped value.
416  */
417 #define CLAMP(val, low, high) (((val) <= (low)) ? (low) : MIN(val, high))
418 #endif
419 
420 /**
421  * @brief Checks if a value is within range.
422  *
423  * @note @p val is evaluated twice.
424  *
425  * @param val Value to be checked.
426  * @param min Lower bound (inclusive).
427  * @param max Upper bound (inclusive).
428  *
429  * @retval true If value is within range
430  * @retval false If the value is not within range
431  */
432 #define IN_RANGE(val, min, max) ((val) >= (min) && (val) <= (max))
433 
434 /**
435  * @brief Is @p x a power of two?
436  * @param x value to check
437  * @return true if @p x is a power of two, false otherwise
438  */
is_power_of_two(unsigned int x)439 static inline bool is_power_of_two(unsigned int x)
440 {
441 	return IS_POWER_OF_TWO(x);
442 }
443 
444 /**
445  * @brief Is @p p equal to ``NULL``?
446  *
447  * Some macros may need to check their arguments against NULL to support
448  * multiple use-cases, but NULL checks can generate warnings if such a macro
449  * is used in contexts where that particular argument can never be NULL.
450  *
451  * The warnings can be triggered if:
452  * a) all macros are expanded (e.g. when using CONFIG_COMPILER_SAVE_TEMPS=y)
453  * or
454  * b) tracking of macro expansions are turned off (-ftrack-macro-expansion=0)
455  *
456  * The warnings can be circumvented by using this inline function for doing
457  * the NULL check within the macro. The compiler is still able to optimize the
458  * NULL check out at a later stage.
459  *
460  * @param p Pointer to check
461  * @return true if @p p is equal to ``NULL``, false otherwise
462  */
is_null_no_warn(void * p)463 static ALWAYS_INLINE bool is_null_no_warn(void *p)
464 {
465 	return p == NULL;
466 }
467 
468 /**
469  * @brief Arithmetic shift right
470  * @param value value to shift
471  * @param shift number of bits to shift
472  * @return @p value shifted right by @p shift; opened bit positions are
473  *         filled with the sign bit
474  */
arithmetic_shift_right(int64_t value,uint8_t shift)475 static inline int64_t arithmetic_shift_right(int64_t value, uint8_t shift)
476 {
477 	int64_t sign_ext;
478 
479 	if (shift == 0U) {
480 		return value;
481 	}
482 
483 	/* extract sign bit */
484 	sign_ext = (value >> 63) & 1;
485 
486 	/* make all bits of sign_ext be the same as the value's sign bit */
487 	sign_ext = -sign_ext;
488 
489 	/* shift value and fill opened bit positions with sign bit */
490 	return (value >> shift) | (sign_ext << (64 - shift));
491 }
492 
493 /**
494  * @brief byte by byte memcpy.
495  *
496  * Copy `size` bytes of `src` into `dest`. This is guaranteed to be done byte by byte.
497  *
498  * @param dst Pointer to the destination memory.
499  * @param src Pointer to the source of the data.
500  * @param size The number of bytes to copy.
501  */
bytecpy(void * dst,const void * src,size_t size)502 static inline void bytecpy(void *dst, const void *src, size_t size)
503 {
504 	size_t i;
505 
506 	for (i = 0; i < size; ++i) {
507 		((volatile uint8_t *)dst)[i] = ((volatile const uint8_t *)src)[i];
508 	}
509 }
510 
511 /**
512  * @brief byte by byte swap.
513  *
514  * Swap @a size bytes between memory regions @a a and @a b. This is
515  * guaranteed to be done byte by byte.
516  *
517  * @param a Pointer to the first memory region.
518  * @param b Pointer to the second memory region.
519  * @param size The number of bytes to swap.
520  */
byteswp(void * a,void * b,size_t size)521 static inline void byteswp(void *a, void *b, size_t size)
522 {
523 	uint8_t t;
524 	uint8_t *aa = (uint8_t *)a;
525 	uint8_t *bb = (uint8_t *)b;
526 
527 	for (; size > 0; --size) {
528 		t = *aa;
529 		*aa++ = *bb;
530 		*bb++ = t;
531 	}
532 }
533 
534 /**
535  * @brief      Convert a single character into a hexadecimal nibble.
536  *
537  * @param c     The character to convert
538  * @param x     The address of storage for the converted number.
539  *
540  *  @return Zero on success or (negative) error code otherwise.
541  */
542 int char2hex(char c, uint8_t *x);
543 
544 /**
545  * @brief      Convert a single hexadecimal nibble into a character.
546  *
547  * @param c     The number to convert
548  * @param x     The address of storage for the converted character.
549  *
550  *  @return Zero on success or (negative) error code otherwise.
551  */
552 int hex2char(uint8_t x, char *c);
553 
554 /**
555  * @brief      Convert a binary array into string representation.
556  *
557  * @param buf     The binary array to convert
558  * @param buflen  The length of the binary array to convert
559  * @param hex     Address of where to store the string representation.
560  * @param hexlen  Size of the storage area for string representation.
561  *
562  * @return     The length of the converted string, or 0 if an error occurred.
563  */
564 size_t bin2hex(const uint8_t *buf, size_t buflen, char *hex, size_t hexlen);
565 
566 /**
567  * @brief      Convert a hexadecimal string into a binary array.
568  *
569  * @param hex     The hexadecimal string to convert
570  * @param hexlen  The length of the hexadecimal string to convert.
571  * @param buf     Address of where to store the binary data
572  * @param buflen  Size of the storage area for binary data
573  *
574  * @return     The length of the binary array, or 0 if an error occurred.
575  */
576 size_t hex2bin(const char *hex, size_t hexlen, uint8_t *buf, size_t buflen);
577 
578 /**
579  * @brief Convert a binary coded decimal (BCD 8421) value to binary.
580  *
581  * @param bcd BCD 8421 value to convert.
582  *
583  * @return Binary representation of input value.
584  */
bcd2bin(uint8_t bcd)585 static inline uint8_t bcd2bin(uint8_t bcd)
586 {
587 	return ((10 * (bcd >> 4)) + (bcd & 0x0F));
588 }
589 
590 /**
591  * @brief Convert a binary value to binary coded decimal (BCD 8421).
592  *
593  * @param bin Binary value to convert.
594  *
595  * @return BCD 8421 representation of input value.
596  */
bin2bcd(uint8_t bin)597 static inline uint8_t bin2bcd(uint8_t bin)
598 {
599 	return (((bin / 10) << 4) | (bin % 10));
600 }
601 
602 /**
603  * @brief      Convert a uint8_t into a decimal string representation.
604  *
605  * Convert a uint8_t value into its ASCII decimal string representation.
606  * The string is terminated if there is enough space in buf.
607  *
608  * @param buf     Address of where to store the string representation.
609  * @param buflen  Size of the storage area for string representation.
610  * @param value   The value to convert to decimal string
611  *
612  * @return     The length of the converted string (excluding terminator if
613  *             any), or 0 if an error occurred.
614  */
615 uint8_t u8_to_dec(char *buf, uint8_t buflen, uint8_t value);
616 
617 /**
618  * @brief Sign extend an 8, 16 or 32 bit value using the index bit as sign bit.
619  *
620  * @param value The value to sign expand.
621  * @param index 0 based bit index to sign bit (0 to 31)
622  */
sign_extend(uint32_t value,uint8_t index)623 static inline int32_t sign_extend(uint32_t value, uint8_t index)
624 {
625 	__ASSERT_NO_MSG(index <= 31);
626 
627 	uint8_t shift = 31 - index;
628 
629 	return (int32_t)(value << shift) >> shift;
630 }
631 
632 /**
633  * @brief Sign extend a 64 bit value using the index bit as sign bit.
634  *
635  * @param value The value to sign expand.
636  * @param index 0 based bit index to sign bit (0 to 63)
637  */
sign_extend_64(uint64_t value,uint8_t index)638 static inline int64_t sign_extend_64(uint64_t value, uint8_t index)
639 {
640 	__ASSERT_NO_MSG(index <= 63);
641 
642 	uint8_t shift = 63 - index;
643 
644 	return (int64_t)(value << shift) >> shift;
645 }
646 
647 /**
648  * @brief Properly truncate a NULL-terminated UTF-8 string
649  *
650  * Take a NULL-terminated UTF-8 string and ensure that if the string has been
651  * truncated (by setting the NULL terminator) earlier by other means, that
652  * the string ends with a properly formatted UTF-8 character (1-4 bytes).
653  *
654  * @htmlonly
655  * Example:
656  *      char test_str[] = "€€€";
657  *      char trunc_utf8[8];
658  *
659  *      printf("Original : %s\n", test_str); // €€€
660  *      strncpy(trunc_utf8, test_str, sizeof(trunc_utf8));
661  *      trunc_utf8[sizeof(trunc_utf8) - 1] = '\0';
662  *      printf("Bad      : %s\n", trunc_utf8); // €€�
663  *      utf8_trunc(trunc_utf8);
664  *      printf("Truncated: %s\n", trunc_utf8); // €€
665  * @endhtmlonly
666  *
667  * @param utf8_str NULL-terminated string
668  *
669  * @return Pointer to the @p utf8_str
670  */
671 char *utf8_trunc(char *utf8_str);
672 
673 /**
674  * @brief Copies a UTF-8 encoded string from @p src to @p dst
675  *
676  * The resulting @p dst will always be NULL terminated if @p n is larger than 0,
677  * and the @p dst string will always be properly UTF-8 truncated.
678  *
679  * @param dst The destination of the UTF-8 string.
680  * @param src The source string
681  * @param n   The size of the @p dst buffer. Maximum number of characters copied
682  *            is @p n - 1. If 0 nothing will be done, and the @p dst will not be
683  *            NULL terminated.
684  *
685  * @return Pointer to the @p dst
686  */
687 char *utf8_lcpy(char *dst, const char *src, size_t n);
688 
689 #define __z_log2d(x) (32 - __builtin_clz(x) - 1)
690 #define __z_log2q(x) (64 - __builtin_clzll(x) - 1)
691 #define __z_log2(x) (sizeof(__typeof__(x)) > 4 ? __z_log2q(x) : __z_log2d(x))
692 
693 /**
694  * @brief Compute log2(x)
695  *
696  * @note This macro expands its argument multiple times (to permit use
697  *       in constant expressions), which must not have side effects.
698  *
699  * @param x An unsigned integral value to compute logarithm of (positive only)
700  *
701  * @return log2(x) when 1 <= x <= max(x), -1 when x < 1
702  */
703 #define LOG2(x) ((x) < 1 ? -1 : __z_log2(x))
704 
705 /**
706  * @brief Compute ceil(log2(x))
707  *
708  * @note This macro expands its argument multiple times (to permit use
709  *       in constant expressions), which must not have side effects.
710  *
711  * @param x An unsigned integral value
712  *
713  * @return ceil(log2(x)) when 1 <= x <= max(type(x)), 0 when x < 1
714  */
715 #define LOG2CEIL(x) ((x) <= 1 ?  0 : __z_log2((x)-1) + 1)
716 
717 /**
718  * @brief Compute next highest power of two
719  *
720  * Equivalent to 2^ceil(log2(x))
721  *
722  * @note This macro expands its argument multiple times (to permit use
723  *       in constant expressions), which must not have side effects.
724  *
725  * @param x An unsigned integral value
726  *
727  * @return 2^ceil(log2(x)) or 0 if 2^ceil(log2(x)) would saturate 64-bits
728  */
729 #define NHPOT(x) ((x) < 1 ? 1 : ((x) > (1ULL<<63) ? 0 : 1ULL << LOG2CEIL(x)))
730 
731 /**
732  * @brief Determine if a buffer exceeds highest address
733  *
734  * This macro determines if a buffer identified by a starting address @a addr
735  * and length @a buflen spans a region of memory that goes beyond the highest
736  * possible address (thereby resulting in a pointer overflow).
737  *
738  * @param addr Buffer starting address
739  * @param buflen Length of the buffer
740  *
741  * @return true if pointer overflow detected, false otherwise
742  */
743 #define Z_DETECT_POINTER_OVERFLOW(addr, buflen)  \
744 	(((buflen) != 0) &&                        \
745 	((UINTPTR_MAX - (uintptr_t)(addr)) <= ((uintptr_t)((buflen) - 1))))
746 
747 /**
748  * @brief XOR n bytes
749  *
750  * @param dst  Destination of where to store result. Shall be @p len bytes.
751  * @param src1 First source. Shall be @p len bytes.
752  * @param src2 Second source. Shall be @p len bytes.
753  * @param len  Number of bytes to XOR.
754  */
mem_xor_n(uint8_t * dst,const uint8_t * src1,const uint8_t * src2,size_t len)755 static inline void mem_xor_n(uint8_t *dst, const uint8_t *src1, const uint8_t *src2, size_t len)
756 {
757 	while (len--) {
758 		*dst++ = *src1++ ^ *src2++;
759 	}
760 }
761 
762 /**
763  * @brief XOR 32 bits
764  *
765  * @param dst  Destination of where to store result. Shall be 32 bits.
766  * @param src1 First source. Shall be 32 bits.
767  * @param src2 Second source. Shall be 32 bits.
768  */
mem_xor_32(uint8_t dst[4],const uint8_t src1[4],const uint8_t src2[4])769 static inline void mem_xor_32(uint8_t dst[4], const uint8_t src1[4], const uint8_t src2[4])
770 {
771 	mem_xor_n(dst, src1, src2, 4U);
772 }
773 
774 /**
775  * @brief XOR 128 bits
776  *
777  * @param dst  Destination of where to store result. Shall be 128 bits.
778  * @param src1 First source. Shall be 128 bits.
779  * @param src2 Second source. Shall be 128 bits.
780  */
mem_xor_128(uint8_t dst[16],const uint8_t src1[16],const uint8_t src2[16])781 static inline void mem_xor_128(uint8_t dst[16], const uint8_t src1[16], const uint8_t src2[16])
782 {
783 	mem_xor_n(dst, src1, src2, 16);
784 }
785 
786 #ifdef __cplusplus
787 }
788 #endif
789 
790 /* This file must be included at the end of the !_ASMLANGUAGE guard.
791  * It depends on macros defined in this file above which cannot be forward declared.
792  */
793 #include <zephyr/sys/time_units.h>
794 
795 #endif /* !_ASMLANGUAGE */
796 
797 /** @brief Number of bytes in @p x kibibytes */
798 #ifdef _LINKER
799 /* This is used in linker scripts so need to avoid type casting there */
800 #define KB(x) ((x) << 10)
801 #else
802 #define KB(x) (((size_t)(x)) << 10)
803 #endif
804 /** @brief Number of bytes in @p x mebibytes */
805 #define MB(x) (KB(x) << 10)
806 /** @brief Number of bytes in @p x gibibytes */
807 #define GB(x) (MB(x) << 10)
808 
809 /** @brief Number of Hz in @p x kHz */
810 #define KHZ(x) ((x) * 1000)
811 /** @brief Number of Hz in @p x MHz */
812 #define MHZ(x) (KHZ(x) * 1000)
813 
814 /**
815  * @brief For the POSIX architecture add a minimal delay in a busy wait loop.
816  * For other architectures this is a no-op.
817  *
818  * In the POSIX ARCH, code takes zero simulated time to execute,
819  * so busy wait loops become infinite loops, unless we
820  * force the loop to take a bit of time.
821  * Include this macro in all busy wait/spin loops
822  * so they will also work when building for the POSIX architecture.
823  *
824  * @param t Time in microseconds we will busy wait
825  */
826 #if defined(CONFIG_ARCH_POSIX)
827 #define Z_SPIN_DELAY(t) k_busy_wait(t)
828 #else
829 #define Z_SPIN_DELAY(t)
830 #endif
831 
832 /**
833  * @brief Wait for an expression to return true with a timeout
834  *
835  * Spin on an expression with a timeout and optional delay between iterations
836  *
837  * Commonly needed when waiting on hardware to complete an asynchronous
838  * request to read/write/initialize/reset, but useful for any expression.
839  *
840  * @param expr Truth expression upon which to poll, e.g.: XYZREG & XYZREG_EN
841  * @param timeout Timeout to wait for in microseconds, e.g.: 1000 (1ms)
842  * @param delay_stmt Delay statement to perform each poll iteration
843  *                   e.g.: NULL, k_yield(), k_msleep(1) or k_busy_wait(1)
844  *
845  * @retval expr As a boolean return, if false then it has timed out.
846  */
847 #define WAIT_FOR(expr, timeout, delay_stmt)                                                        \
848 	({                                                                                         \
849 		uint32_t _wf_cycle_count = k_us_to_cyc_ceil32(timeout);                            \
850 		uint32_t _wf_start = k_cycle_get_32();                                             \
851 		while (!(expr) && (_wf_cycle_count > (k_cycle_get_32() - _wf_start))) {            \
852 			delay_stmt;                                                                \
853 			Z_SPIN_DELAY(10);                                                          \
854 		}                                                                                  \
855 		(expr);                                                                            \
856 	})
857 
858 /**
859  * @}
860  */
861 
862 #endif /* ZEPHYR_INCLUDE_SYS_UTIL_H_ */
863