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sys: util: Add COND_CASE_1 macro #100224

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ea18d64
sys: util: Add COND_CASE_1 macro
pdgendt Nov 28, 2025
ae871c5
tests: unit: util: Add tests for COND_CASE_1
pdgendt Nov 28, 2025
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41 changes: 41 additions & 0 deletions include/zephyr/sys/util_internal.h
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Original file line number Diff line number Diff line change
Expand Up @@ -71,6 +71,47 @@
/* Used to remove brackets from around a single argument. */
#define __DEBRACKET(...) __VA_ARGS__

/* Used by COND_CASE_1(); supports up to 16 flag/value pairs */
#define Z_COND_CASE_1(...) \
Z_COND_CASE_1_CAT_N(NUM_VA_ARGS_LESS_1(__VA_ARGS__), __VA_ARGS__)

#define Z_COND_CASE_1_CAT_N(count_minus_one, ...) \
UTIL_CAT(Z_COND_CASE_1_N_, count_minus_one)(__VA_ARGS__)

#define Z_COND_CASE_1_N_0(_default) __DEBRACKET _default
#define Z_COND_CASE_1_N_2(flag0, value0, _default) \
Z_COND_CODE_1(flag0, (__DEBRACKET value0), (__DEBRACKET _default))
#define Z_COND_CASE_1_N_4(flag0, value0, ...) \
Z_COND_CODE_1(flag0, (__DEBRACKET value0), (Z_COND_CASE_1_N_2(__VA_ARGS__)))
#define Z_COND_CASE_1_N_6(flag0, value0, ...) \
Z_COND_CODE_1(flag0, (__DEBRACKET value0), (Z_COND_CASE_1_N_4(__VA_ARGS__)))
#define Z_COND_CASE_1_N_8(flag0, value0, ...) \
Z_COND_CODE_1(flag0, (__DEBRACKET value0), (Z_COND_CASE_1_N_6(__VA_ARGS__)))
#define Z_COND_CASE_1_N_10(flag0, value0, ...) \
Z_COND_CODE_1(flag0, (__DEBRACKET value0), (Z_COND_CASE_1_N_8(__VA_ARGS__)))
#define Z_COND_CASE_1_N_12(flag0, value0, ...) \
Z_COND_CODE_1(flag0, (__DEBRACKET value0), (Z_COND_CASE_1_N_10(__VA_ARGS__)))
#define Z_COND_CASE_1_N_14(flag0, value0, ...) \
Z_COND_CODE_1(flag0, (__DEBRACKET value0), (Z_COND_CASE_1_N_12(__VA_ARGS__)))
#define Z_COND_CASE_1_N_16(flag0, value0, ...) \
Z_COND_CODE_1(flag0, (__DEBRACKET value0), (Z_COND_CASE_1_N_14(__VA_ARGS__)))
#define Z_COND_CASE_1_N_18(flag0, value0, ...) \
Z_COND_CODE_1(flag0, (__DEBRACKET value0), (Z_COND_CASE_1_N_16(__VA_ARGS__)))
#define Z_COND_CASE_1_N_20(flag0, value0, ...) \
Z_COND_CODE_1(flag0, (__DEBRACKET value0), (Z_COND_CASE_1_N_18(__VA_ARGS__)))
#define Z_COND_CASE_1_N_22(flag0, value0, ...) \
Z_COND_CODE_1(flag0, (__DEBRACKET value0), (Z_COND_CASE_1_N_20(__VA_ARGS__)))
#define Z_COND_CASE_1_N_24(flag0, value0, ...) \
Z_COND_CODE_1(flag0, (__DEBRACKET value0), (Z_COND_CASE_1_N_22(__VA_ARGS__)))
#define Z_COND_CASE_1_N_26(flag0, value0, ...) \
Z_COND_CODE_1(flag0, (__DEBRACKET value0), (Z_COND_CASE_1_N_24(__VA_ARGS__)))
#define Z_COND_CASE_1_N_28(flag0, value0, ...) \
Z_COND_CODE_1(flag0, (__DEBRACKET value0), (Z_COND_CASE_1_N_26(__VA_ARGS__)))
#define Z_COND_CASE_1_N_30(flag0, value0, ...) \
Z_COND_CODE_1(flag0, (__DEBRACKET value0), (Z_COND_CASE_1_N_28(__VA_ARGS__)))
#define Z_COND_CASE_1_N_32(flag0, value0, ...) \
Z_COND_CODE_1(flag0, (__DEBRACKET value0), (Z_COND_CASE_1_N_30(__VA_ARGS__)))

/* Used by IS_EMPTY() */
/* reference: https://gustedt.wordpress.com/2010/06/08/detect-empty-macro-arguments/ */
#define Z_HAS_COMMA(...) \
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25 changes: 25 additions & 0 deletions include/zephyr/sys/util_macro.h
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Expand Up @@ -219,6 +219,31 @@ extern "C" {
#define COND_CODE_0(_flag, _if_0_code, _else_code) \
Z_COND_CODE_0(_flag, _if_0_code, _else_code)

/**
* @brief Evaluate a list of COND_CODE_1-style cases.
*
* Each case consists of a flag and a value wrapped in parentheses. The
* arguments are processed from left to right until a flag expands to the
* literal 1, in which case the corresponding value is expanded. If no flags
* expand to 1, the last argument (which must also be wrapped in parentheses)
* is used as the default value. Supplying only the default argument is also
* supported.
*
* Example:
*
* int foo = COND_CASE_1(CONFIG_SOME_BOOL, (handle_a()),
* CONFIG_SOME_OTHER_BOOL, (handle_b()),
* (handle_default()));
*
* Supports up to 16 flag/value pairs before the default.
*
* @param ... Flag/value pairs followed by the default value. Each value must
* be provided in parentheses to avoid comma handling issues.
* @see COND_CODE_1()
*/
#define COND_CASE_1(...) \
Z_COND_CASE_1(__VA_ARGS__)

/**
* @brief Insert code if @p _flag is defined and equals 1.
*
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31 changes: 31 additions & 0 deletions tests/unit/util/main.c
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Original file line number Diff line number Diff line change
Expand Up @@ -165,6 +165,37 @@ ZTEST(util, test_COND_CODE_0) {
zassert_true((y3 == 1));
}

ZTEST(util, test_COND_CASE_1) {
/* Intentionally undefined symbols used to verify that only the selected
* branch expands.
*/
int val;

#define CASE_TRUE 1
#define CASE_FALSE 0

val = COND_CASE_1(CASE_TRUE, (42),
CASE_TRUE, (COND_CASE_1_SHOULD_NOT_REACH_SECOND_TRUE_CASE),
(0));
zexpect_equal(val, 42);

val = COND_CASE_1(CASE_FALSE, (COND_CASE_1_SHOULD_NOT_USE_FIRST_CASE),
CASE_TRUE, (7),
(11));
zexpect_equal(val, 7);

val = COND_CASE_1(CASE_FALSE, (COND_CASE_1_SHOULD_NOT_USE_SECOND_CASE),
CASE_FALSE, (COND_CASE_1_SHOULD_NOT_USE_THIRD_CASE),
(5));
zexpect_equal(val, 5);

val = COND_CASE_1((9));
zexpect_equal(val, 9);

#undef CASE_TRUE
#undef CASE_FALSE
}

#undef ZERO
#undef SEVEN
#undef A_BUILD_ERROR
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