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Add rz_vector_find_sorted() for O(log n) search in vectors. (#6190)

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Rot127 2026-04-11 10:30:25 +00:00 committed by GitHub
parent 1a57d18cc4
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3 changed files with 111 additions and 0 deletions
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1
librz/include/rz_vector.h
View file

@ -144,6 +144,7 @@ RZ_API void *rz_vector_insert(RzVector *vec, size_t index, void *x);
RZ_API void *rz_vector_insert_range(RzVector *vec, size_t index, RZ_NULLABLE void *first, size_t count);
RZ_API void *rz_vector_insert_sorted(RZ_NONNULL RzVector *vec, RZ_NONNULL void *elem, RzVectorComparator cmp, void *user);
RZ_API size_t rz_vector_find_sorted(RZ_NONNULL RzVector *vec, RZ_NONNULL void *elem, RzVectorComparator cmp, void *user);
// like rz_vector_remove_at for the last element
RZ_API void rz_vector_pop(RzVector *vec, void *into);

53
librz/util/vector.c
View file

@ -291,6 +291,59 @@ RZ_API void *rz_vector_insert_sorted(RZ_NONNULL RzVector *vec, RZ_NONNULL void *
return vec->reverse_sorted ? rz_vector_push_front(vec, elem) : rz_vector_push(vec, elem);
}
static bool bin_search_range(RZ_NONNULL RzVector *vec, RZ_NONNULL void *elem, RzVectorComparator cmp, void *user, RZ_OUT size_t *i) {
size_t vlen = rz_vector_len(vec);
if (vlen == 0) {
return false;
}
int inc = vec->reverse_sorted ? -1 : 1;
ssize_t low = vec->reverse_sorted ? vlen - 1 : 0;
ssize_t hi = vec->reverse_sorted ? 0 : vlen - 1;
do {
size_t mid = (low + hi) >> 1;
if (cmp(elem, rz_vector_index_ptr(vec, mid), user) == 0) {
*i = mid;
return true;
}
if (low == hi) {
break;
}
if (cmp(elem, rz_vector_index_ptr(vec, mid), user) > 0) {
low = mid + inc;
}
if (cmp(elem, rz_vector_index_ptr(vec, mid), user) < 0) {
hi = mid - inc;
}
} while (vec->reverse_sorted ? hi <= low : low <= hi);
return false;
}
/**
* \brief Finds an element in the sorted vector via binary search.
* NOTE: This function assumes the vector is already sorted!
* If it isn't the result is undefined!
*
* \param vec A sorted vector to find the element in.
* \param elem Pointer to the element to find in the vector.
* \param cmp The comparator for the elements.
* \param user The user data passed to the comparator.
*
* \return Index into the vector where the element is located.
* Or SZT_MAX in case of failure or if no element was found.
*/
RZ_API size_t rz_vector_find_sorted(RZ_NONNULL RzVector *vec, RZ_NONNULL void *elem, RzVectorComparator cmp, void *user) {
rz_return_val_if_fail(vec && elem, SZT_MAX);
size_t i;
if (!bin_search_range(vec, elem, cmp, user, &i)) {
return SZT_MAX;
}
return i;
}
RZ_API void rz_vector_pop(RzVector *vec, void *into) {
if (rz_vector_empty(vec)) {
return;

57
test/unit/test_vector.c
View file

@ -305,6 +305,62 @@ static bool test_vector_insert_sorted(void) {
mu_end;
}
static bool test_vector_find_sorted(void) {
RzVector *v = rz_vector_new(sizeof(ut64), NULL, NULL);
for (size_t i = 1; i < 13; i++) {
rz_vector_push(v, &i);
}
ut64 i = UT64_MAX;
rz_vector_push(v, &i);
rz_vector_sort(v, (RzVectorComparator)uint_cmp, false, NULL);
i = 5;
mu_assert_eq(rz_vector_find_sorted(v, &i, (RzVectorComparator)uint_cmp, NULL), 4, "Not found");
i = 6;
mu_assert_eq(rz_vector_find_sorted(v, &i, (RzVectorComparator)uint_cmp, NULL), 5, "Not found");
i = 7;
mu_assert_eq(rz_vector_find_sorted(v, &i, (RzVectorComparator)uint_cmp, NULL), 6, "Not found");
i = 8;
mu_assert_eq(rz_vector_find_sorted(v, &i, (RzVectorComparator)uint_cmp, NULL), 7, "Not found");
i = 12;
mu_assert_eq(rz_vector_find_sorted(v, &i, (RzVectorComparator)uint_cmp, NULL), 11, "Not found");
i = UT64_MAX;
mu_assert_eq(rz_vector_find_sorted(v, &i, (RzVectorComparator)uint_cmp, NULL), 12, "Not found");
i = 0;
mu_assert_eq(rz_vector_find_sorted(v, &i, (RzVectorComparator)uint_cmp, NULL), SZT_MAX, "Not failed");
i = 13;
mu_assert_eq(rz_vector_find_sorted(v, &i, (RzVectorComparator)uint_cmp, NULL), SZT_MAX, "Not failed");
i = UT64_MAX - 1;
mu_assert_eq(rz_vector_find_sorted(v, &i, (RzVectorComparator)uint_cmp, NULL), SZT_MAX, "Not failed");
rz_vector_sort(v, (RzVectorComparator)uint_cmp, true, NULL);
i = 5;
mu_assert_eq(rz_vector_find_sorted(v, &i, (RzVectorComparator)uint_cmp, NULL), 8, "Not found");
i = 6;
mu_assert_eq(rz_vector_find_sorted(v, &i, (RzVectorComparator)uint_cmp, NULL), 7, "Not found");
i = 7;
mu_assert_eq(rz_vector_find_sorted(v, &i, (RzVectorComparator)uint_cmp, NULL), 6, "Not found");
i = 8;
mu_assert_eq(rz_vector_find_sorted(v, &i, (RzVectorComparator)uint_cmp, NULL), 5, "Not found");
i = 12;
mu_assert_eq(rz_vector_find_sorted(v, &i, (RzVectorComparator)uint_cmp, NULL), 1, "Not found");
i = UT64_MAX;
mu_assert_eq(rz_vector_find_sorted(v, &i, (RzVectorComparator)uint_cmp, NULL), 0, "Not found");
i = 0;
mu_assert_eq(rz_vector_find_sorted(v, &i, (RzVectorComparator)uint_cmp, NULL), SZT_MAX, "Not failed");
i = 13;
mu_assert_eq(rz_vector_find_sorted(v, &i, (RzVectorComparator)uint_cmp, NULL), SZT_MAX, "Not failed");
i = UT64_MAX - 1;
mu_assert_eq(rz_vector_find_sorted(v, &i, (RzVectorComparator)uint_cmp, NULL), SZT_MAX, "Not failed");
rz_vector_free(v);
mu_end;
}
static bool test_vector_empty(void) {
RzVector v;
rz_vector_init(&v, 1, NULL, NULL);
@ -1562,6 +1618,7 @@ static int all_tests(void) {
mu_run_test(test_vector_insert);
mu_run_test(test_vector_insert_range);
mu_run_test(test_vector_insert_sorted);
mu_run_test(test_vector_find_sorted);
mu_run_test(test_vector_pop);
mu_run_test(test_vector_pop_front);
mu_run_test(test_vector_push);