hashmap: refactor hash_func

All our hash functions are based on siphash24(), factor out
siphash_init() and siphash24_finalize() and pass the siphash
state to the hash functions rather than the hash key.

This simplifies the hash functions, and in particular makes
composition simpler as calling siphash24_compress() repeatedly
on separate chunks of input has the same effect as first
concatenating the input and then calling siphash23_compress()
on the result.

1 files changed, 8 insertions, 2 deletions

diff --git a/src/journal/journald-rate-limit.c b/src/journal/journald-rate-limit.c
index 6f83035a4e..7e06117b31 100644
--- a/src/journal/journald-rate-limit.c
+++ b/src/journal/journald-rate-limit.c
@@ -145,6 +145,7 @@ static void journal_rate_limit_vacuum(JournalRateLimit *r, usec_t ts) {
 
 static JournalRateLimitGroup* journal_rate_limit_group_new(JournalRateLimit *r, const char *id, usec_t ts) {
         JournalRateLimitGroup *g;
+        struct siphash state;
 
         assert(r);
         assert(id);
@@ -157,7 +158,9 @@ static JournalRateLimitGroup* journal_rate_limit_group_new(JournalRateLimit *r,
         if (!g->id)
                 goto fail;
 
-        g->hash = string_hash_func(g->id, r->hash_key);
+        siphash_init(&state, r->hash_key);
+        string_hash_func(g->id, &state);
+        g->hash = siphash24_finalize(&state);
 
         journal_rate_limit_vacuum(r, ts);
 
@@ -207,6 +210,7 @@ int journal_rate_limit_test(JournalRateLimit *r, const char *id, int priority, u
         unsigned long h;
         JournalRateLimitGroup *g;
         JournalRateLimitPool *p;
+        struct siphash state;
         unsigned burst;
         usec_t ts;
 
@@ -222,7 +226,9 @@ int journal_rate_limit_test(JournalRateLimit *r, const char *id, int priority, u
 
         ts = now(CLOCK_MONOTONIC);
 
-        h = string_hash_func(id, r->hash_key);
+        siphash_init(&state, r->hash_key);
+        string_hash_func(id, &state);
+        h = siphash24_finalize(&state);
         g = r->buckets[h % BUCKETS_MAX];
 
         LIST_FOREACH(bucket, g, g)