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macros: add CMP(a, b) macro. 

Macro returns -1, 0, 1 depending on whether a < b, a == b or a > b.

It's safe to use on unsigned types.

Add tests to confirm corner cases are properly covered.
This commit is contained in:
Filipe Brandenburger 2018-08-02 14:37:42 -07:00
parent 117efe065a
commit 84fb2131d0
2 changed files with 44 additions and 0 deletions
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9
src/basic/macro.h
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@ -222,6 +222,15 @@ static inline unsigned long ALIGN_POWER2(unsigned long u) {
UNIQ_T(A, aq) > UNIQ_T(B, bq) ? UNIQ_T(A, aq) - UNIQ_T(B, bq) : 0; \
})
#define CMP(a, b) __CMP(UNIQ, (a), UNIQ, (b))
#define __CMP(aq, a, bq, b) \
({ \
const typeof(a) UNIQ_T(A, aq) = (a); \
const typeof(b) UNIQ_T(B, bq) = (b); \
UNIQ_T(A, aq) < UNIQ_T(B, bq) ? -1 : \
UNIQ_T(A, aq) > UNIQ_T(B, bq) ? 1 : 0; \
})
#undef CLAMP
#define CLAMP(x, low, high) __CLAMP(UNIQ, (x), UNIQ, (low), UNIQ, (high))
#define __CLAMP(xq, x, lowq, low, highq, high) \

35
src/test/test-util.c
View File

@ -53,6 +53,12 @@ static void test_max(void) {
.a = CONST_MAX(10, 100),
};
int d = 0;
unsigned long x = 12345;
unsigned long y = 54321;
const char str[] = "a_string_constant";
const unsigned long long arr[] = {9999ULL, 10ULL, 0ULL, 3000ULL, 2000ULL, 1000ULL, 100ULL, 9999999ULL};
void *p = (void *)str;
void *q = (void *)&str[16];
assert_cc(sizeof(val1.b) == sizeof(int) * 100);
@ -80,6 +86,35 @@ static void test_max(void) {
assert_se(LESS_BY(4, 8) == 0);
assert_se(LESS_BY(16, LESS_BY(8, 4)) == 12);
assert_se(LESS_BY(4, LESS_BY(8, 4)) == 0);
assert_se(CMP(-5, 5) == -1);
assert_se(CMP(5, -5) == 1);
assert_se(CMP(5, 5) == 0);
assert_se(CMP(x, y) == -1);
assert_se(CMP(y, x) == 1);
assert_se(CMP(x, x) == 0);
assert_se(CMP(y, y) == 0);
assert_se(CMP(UINT64_MAX, 0L) == 1);
assert_se(CMP(0L, UINT64_MAX) == -1);
assert_se(CMP(UINT64_MAX, UINT64_MAX) == 0);
assert_se(CMP(INT64_MIN, INT64_MAX) == -1);
assert_se(CMP(INT64_MAX, INT64_MIN) == 1);
assert_se(CMP(INT64_MAX, INT64_MAX) == 0);
assert_se(CMP(INT64_MIN, INT64_MIN) == 0);
assert_se(CMP(INT64_MAX, 0L) == 1);
assert_se(CMP(0L, INT64_MIN) == 1);
assert_se(CMP(INT64_MIN, 0L) == -1);
assert_se(CMP(0L, INT64_MAX) == -1);
assert_se(CMP(&str[2], &str[7]) == -1);
assert_se(CMP(&str[2], &str[2]) == 0);
assert_se(CMP(&str[7], (const char *)str) == 1);
assert_se(CMP(str[2], str[7]) == 1);
assert_se(CMP(str[7], *str) == 1);
assert_se(CMP((const unsigned long long *)arr, &arr[3]) == -1);
assert_se(CMP(*arr, arr[3]) == 1);
assert_se(CMP(p, q) == -1);
assert_se(CMP(q, p) == 1);
assert_se(CMP(p, p) == 0);
assert_se(CMP(q, q) == 0);
assert_se(CLAMP(-5, 0, 1) == 0);
assert_se(CLAMP(5, 0, 1) == 1);
assert_se(CLAMP(5, -10, 1) == 1);