Calculating a hash of zero-terminated string is a common need when using
hashmap, so extract it for reuse.
Signed-off-by: Andrii Nakryiko <andriin@xxxxxx>
---
tools/lib/bpf/btf_dump.c | 9 +--------
tools/lib/bpf/hashmap.h | 12 ++++++++++++
2 files changed, 13 insertions(+), 8 deletions(-)
diff --git a/tools/lib/bpf/btf_dump.c b/tools/lib/bpf/btf_dump.c
index 6c079b3c8679..91310e528a3a 100644
--- a/tools/lib/bpf/btf_dump.c
+++ b/tools/lib/bpf/btf_dump.c
@@ -90,14 +90,7 @@ struct btf_dump {
static size_t str_hash_fn(const void *key, void *ctx)
{
- const char *s = key;
- size_t h = 0;
-
- while (*s) {
- h = h * 31 + *s;
- s++;
- }
- return h;
+ return str_hash(key);
}
static bool str_equal_fn(const void *a, const void *b, void *ctx)
diff --git a/tools/lib/bpf/hashmap.h b/tools/lib/bpf/hashmap.h
index e0af36b0e5d8..d9b385fe808c 100644
--- a/tools/lib/bpf/hashmap.h
+++ b/tools/lib/bpf/hashmap.h
@@ -25,6 +25,18 @@ static inline size_t hash_bits(size_t h, int bits)
#endif
}
+/* generic C-string hashing function */
+static inline size_t str_hash(const char *s)
+{
+ size_t h = 0;
+
+ while (*s) {
+ h = h * 31 + *s;
+ s++;
+ }
+ return h;
+}
+
typedef size_t (*hashmap_hash_fn)(const void *key, void *ctx);
typedef bool (*hashmap_equal_fn)(const void *key1, const void *key2, void *ctx);
--
2.24.1
