util: add (x)bsearch_r(), the missing counterpart of qsort_r()

1 files changed, 24 insertions, 0 deletions

diff --git a/src/shared/util.c b/src/shared/util.c
index 42a2e27308..2f0aba88ae 100644
--- a/src/shared/util.c
+++ b/src/shared/util.c
@@ -6069,3 +6069,27 @@ finish:
 
         return 0;
 }
+
+/* hey glibc, APIs with callbacks without a user pointer are so useless */
+void *xbsearch_r(const void *key, const void *base, size_t nmemb, size_t size,
+                 int (*compar) (const void *, const void *, void *),
+                 void *arg) {
+        size_t l, u, idx;
+        const void *p;
+        int comparison;
+
+        l = 0;
+        u = nmemb;
+        while (l < u) {
+                idx = (l + u) / 2;
+                p = (void *)(((const char *) base) + (idx * size));
+                comparison = compar(key, p, arg);
+                if (comparison < 0)
+                        u = idx;
+                else if (comparison > 0)
+                        l = idx + 1;
+                else
+                        return (void *)p;
+        }
+        return NULL;
+}