proj/portage-utils:master commit in: libq/

commit:     30478cabeba02f808b6399c75577e4d23017c18c
Author:     Fabian Groffen <grobian <AT> gentoo <DOT> org>
AuthorDate: Sun Jun 21 15:28:00 2026 +0000
Commit:     Fabian Groffen <grobian <AT> gentoo <DOT> org>
CommitDate: Sun Jun 21 15:28:00 2026 +0000
URL:        https://gitweb.gentoo.org/proj/portage-utils.git/commit/?id=30478cab

libq/set: add set_has_intersection

The set_intersect function doesn't exist (yet) but this function is
cheaper in that it returns immediately from the first match between the
two input sets.

Signed-off-by: Fabian Groffen <grobian <AT> gentoo.org>

 libq/set.c | 39 +++++++++++++++++++++++++++++++++++++++
 libq/set.h |  2 ++
 2 files changed, 41 insertions(+)

diff --git a/libq/set.c b/libq/set.c
index 96b1d597..b77095a5 100644
--- a/libq/set.c
+++ b/libq/set.c
@@ -12,6 +12,7 @@
 #include <stdio.h>
 #include <unistd.h>
 #include <stdlib.h>
+#include <stdbool.h>
 #include <string.h>
 #include <ctype.h>
 #include <xalloc.h>
@@ -320,6 +321,44 @@ void *set_delete
   return ret;
 }
 
+/* this is a cheap version of intersect that just returns whether there
+ * is at least one element common in both sets */
+bool set_has_intersection
+(
+  set_t *l,
+  set_t *r
+)
+{
+  set_t      *s;
+  set_elem_t *w1;
+  set_elem_t *w2;
+  size_t      i;
+
+  /* find smallest set, assign to s, let l be largest */
+  if (l->len < r->len)
+  {
+    s = l;
+    l = r;
+  }
+  else
+  {
+    s = r;
+  }
+
+  for (i = 0; i < _SET_HASH_SIZE; i++)
+  {
+    for (w1 = s->buckets[i]; w1 != NULL; w1 = w1->next)
+    {
+      for (w2 = l->buckets[i]; w2 != NULL; w2 = w1->next)
+        if (w1->hash == w2->hash &&
+            strcmp(w1->name, w2->name) == 0)
+          return true;
+    }
+  }
+
+  return false;
+}
+
 size_t set_size
 (
   set_t *q

diff --git a/libq/set.h b/libq/set.h
index 5df23b72..4fde8ec7 100644
--- a/libq/set.h
+++ b/libq/set.h
@@ -7,6 +7,7 @@
 #define _SET_H 1
 
 #include <stdlib.h>
+#include <stdbool.h>
 #include <unistd.h>
 
 #include "array.h"
@@ -22,6 +23,7 @@ set_t      *set_clone(set_t *s);
 const char *set_get(set_t *s, const char *key);
 void       *set_delete(set_t *s, const char *key, bool *removed);
 #define     set_keys(S)        hash_keys((hash_t *)S)
+bool        set_has_intersection(set_t *l, set_t *r);
 size_t      set_size(set_t *s);
 void        set_clear(set_t *s);
 void        set_free(set_t *s);