From be43be1f8cdb18f54690da2bfbc050ab9af1614c Mon Sep 17 00:00:00 2001 From: Andreas Rheinhardt Date: Tue, 3 Jun 2025 22:08:46 +0200 Subject: [PATCH 4/9] avcodec/hashtable: Only align complete entries It is unnecessary to align both key and val, as they are only accessed via memcpy()/memcmp(), which has no alignment requirements. We only need to ensure that that the entries as a whole are suitable aligned for the probe sequence length. Signed-off-by: Andreas Rheinhardt --- libavcodec/hashtable.c | 24 +++++++++--------------- 1 file changed, 9 insertions(+), 15 deletions(-) diff --git a/libavcodec/hashtable.c b/libavcodec/hashtable.c index 4c7d3e18ba..fa79330603 100644 --- a/libavcodec/hashtable.c +++ b/libavcodec/hashtable.c @@ -31,9 +31,7 @@ struct FFHashtableContext { size_t key_size; - size_t key_size_aligned; size_t val_size; - size_t val_size_aligned; size_t entry_size; size_t max_entries; size_t nb_entries; @@ -51,8 +49,8 @@ struct FFHashtableContext { */ #define ENTRY_PSL_VAL(entry) (*(size_t*)(entry)) -#define ENTRY_KEY_PTR(entry) ((entry) + FFALIGN(sizeof(size_t), ALIGN)) -#define ENTRY_VAL_PTR(entry) (ENTRY_KEY_PTR(entry) + ctx->key_size_aligned) +#define ENTRY_KEY_PTR(entry) ((entry) + sizeof(size_t)) +#define ENTRY_VAL_PTR(entry) (ENTRY_KEY_PTR(entry) + ctx->key_size) #define KEYS_EQUAL(k1, k2) (!memcmp((k1), (k2), ctx->key_size)) @@ -62,12 +60,8 @@ int ff_hashtable_alloc(struct FFHashtableContext **ctx, size_t key_size, size_t if (!res) return AVERROR(ENOMEM); res->key_size = key_size; - res->key_size_aligned = FFALIGN(key_size, ALIGN); res->val_size = val_size; - res->val_size_aligned = FFALIGN(val_size, ALIGN); - res->entry_size = FFALIGN(sizeof(size_t), ALIGN) - + res->key_size_aligned - + res->val_size_aligned; + res->entry_size = FFALIGN(sizeof(size_t) + key_size + val_size, ALIGN); res->max_entries = max_entries; res->nb_entries = 0; res->crc = av_crc_get_table(AV_CRC_32_IEEE); @@ -81,7 +75,7 @@ int ff_hashtable_alloc(struct FFHashtableContext **ctx, size_t key_size, size_t return AVERROR(ENOMEM); } - res->swapbuf = av_calloc(2, res->key_size_aligned + res->val_size_aligned); + res->swapbuf = av_calloc(2, res->key_size + res->val_size); if (!res->swapbuf) { ff_hashtable_freep(&res); return AVERROR(ENOMEM); @@ -124,10 +118,10 @@ int ff_hashtable_set(struct FFHashtableContext *ctx, const void *key, const void size_t hash = hash_key(ctx, key); size_t wrapped_index = hash % ctx->max_entries; uint8_t *set = ctx->swapbuf; - uint8_t *tmp = ctx->swapbuf + ctx->key_size_aligned + ctx->val_size_aligned; + uint8_t *tmp = ctx->swapbuf + ctx->key_size + ctx->val_size; memcpy(set, key, ctx->key_size); - memcpy(set + ctx->key_size_aligned, val, ctx->val_size); + memcpy(set + ctx->key_size, val, ctx->val_size); for (size_t i = 0; i < ctx->max_entries; i++) { if (++wrapped_index == ctx->max_entries) @@ -137,7 +131,7 @@ int ff_hashtable_set(struct FFHashtableContext *ctx, const void *key, const void if (!ENTRY_PSL_VAL(entry)) ctx->nb_entries++; ENTRY_PSL_VAL(entry) = psl; - memcpy(ENTRY_KEY_PTR(entry), set, ctx->key_size_aligned + ctx->val_size); + memcpy(ENTRY_KEY_PTR(entry), set, ctx->key_size + ctx->val_size); return 1; } if (ENTRY_PSL_VAL(entry) < psl) { @@ -151,8 +145,8 @@ int ff_hashtable_set(struct FFHashtableContext *ctx, const void *key, const void // PSL of the inserted entry. swapping = 1; // set needs to swap with entry - memcpy(tmp, ENTRY_KEY_PTR(entry), ctx->key_size_aligned + ctx->val_size_aligned); - memcpy(ENTRY_KEY_PTR(entry), set, ctx->key_size_aligned + ctx->val_size_aligned); + memcpy(tmp, ENTRY_KEY_PTR(entry), ctx->key_size + ctx->val_size); + memcpy(ENTRY_KEY_PTR(entry), set, ctx->key_size + ctx->val_size); FFSWAP(uint8_t*, set, tmp); FFSWAP(size_t, psl, ENTRY_PSL_VAL(entry)); } -- 2.45.2