* [FFmpeg-devel] [PATCH v4 1/2] lavu/hashtable: create generic robin hood hash table
@ 2024-02-24 20:06 Connor Worley
2024-02-24 20:06 ` [FFmpeg-devel] [PATCH v4 2/2] lavc/dxvenc: migrate DXT1 encoder to lavu hashtable Connor Worley
2024-03-03 22:44 ` [FFmpeg-devel] [PATCH v4 1/2] lavu/hashtable: create generic robin hood hash table Connor Worley
0 siblings, 2 replies; 4+ messages in thread
From: Connor Worley @ 2024-02-24 20:06 UTC (permalink / raw)
To: ffmpeg-devel; +Cc: Connor Worley
Signed-off-by: Connor Worley <connorbworley@gmail.com>
---
libavutil/Makefile | 2 +
libavutil/hashtable.c | 192 ++++++++++++++++++++++++++++++++++++
libavutil/hashtable.h | 40 ++++++++
libavutil/tests/hashtable.c | 110 +++++++++++++++++++++
4 files changed, 344 insertions(+)
create mode 100644 libavutil/hashtable.c
create mode 100644 libavutil/hashtable.h
create mode 100644 libavutil/tests/hashtable.c
diff --git a/libavutil/Makefile b/libavutil/Makefile
index e7709b97d0..be75d464fc 100644
--- a/libavutil/Makefile
+++ b/libavutil/Makefile
@@ -138,6 +138,7 @@ OBJS = adler32.o \
fixed_dsp.o \
frame.o \
hash.o \
+ hashtable.o \
hdr_dynamic_metadata.o \
hdr_dynamic_vivid_metadata.o \
hmac.o \
@@ -251,6 +252,7 @@ TESTPROGS = adler32 \
file \
fifo \
hash \
+ hashtable \
hmac \
hwdevice \
integer \
diff --git a/libavutil/hashtable.c b/libavutil/hashtable.c
new file mode 100644
index 0000000000..155a264665
--- /dev/null
+++ b/libavutil/hashtable.c
@@ -0,0 +1,192 @@
+/*
+ * Generic hashtable
+ * Copyright (C) 2024 Connor Worley <connorbworley@gmail.com>
+ *
+ * This file is part of FFmpeg.
+ *
+ * FFmpeg is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU Lesser General Public
+ * License as published by the Free Software Foundation; either
+ * version 2.1 of the License, or (at your option) any later version.
+ *
+ * FFmpeg is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
+ * Lesser General Public License for more details.
+ *
+ * You should have received a copy of the GNU Lesser General Public
+ * License along with FFmpeg; if not, write to the Free Software
+ * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
+ */
+
+#include <stdint.h>
+#include <string.h>
+
+#include "crc.h"
+#include "error.h"
+#include "mem.h"
+#include "hashtable.h"
+
+#define ALIGN _Alignof(size_t)
+
+struct AVHashtableContext {
+ 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 utilization;
+ const AVCRC *crc;
+ uint8_t *table;
+ uint8_t *swapbuf;
+};
+
+#define ENTRY_PSL(entry) (entry)
+#define ENTRY_OCC(entry) (ENTRY_PSL(entry) + FFALIGN(sizeof(size_t), ALIGN))
+#define ENTRY_KEY(entry) (ENTRY_OCC(entry) + FFALIGN(sizeof(size_t), ALIGN))
+#define ENTRY_VAL(entry) (ENTRY_KEY(entry) + ctx->key_size_aligned)
+
+#define KEYS_EQUAL(k1, k2) !memcmp(k1, k2, ctx->key_size)
+
+int av_hashtable_alloc(struct AVHashtableContext **ctx, size_t key_size, size_t val_size, size_t max_entries)
+{
+ struct AVHashtableContext *res = av_malloc(sizeof(struct AVHashtableContext));
+ 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)
+ + FFALIGN(sizeof(size_t), ALIGN)
+ + res->key_size_aligned
+ + res->val_size_aligned;
+ res->max_entries = max_entries;
+ res->utilization = 0;
+ res->crc = av_crc_get_table(AV_CRC_32_IEEE);
+ if (!res->crc) {
+ av_hashtable_freep(&res);
+ return AVERROR_BUG;
+ }
+ res->table = av_calloc(res->max_entries, res->entry_size);
+ if (!res->table) {
+ av_hashtable_freep(&res);
+ return AVERROR(ENOMEM);
+ }
+ res->swapbuf = av_calloc(2, res->key_size_aligned + res->val_size_aligned);
+ if (!res->swapbuf) {
+ av_hashtable_freep(&res);
+ return AVERROR(ENOMEM);
+ }
+ *ctx = res;
+ return 0;
+}
+
+static size_t hash_key(const struct AVHashtableContext *ctx, const void *key)
+{
+ return av_crc(ctx->crc, 0, key, ctx->key_size) % ctx->max_entries;
+}
+
+int av_hashtable_get(const struct AVHashtableContext *ctx, const void *key, void *val)
+{
+ size_t hash = hash_key(ctx, key);
+
+ if (!ctx->utilization)
+ return 0;
+
+ for (size_t psl = 0; psl < ctx->max_entries; psl++) {
+ size_t wrapped_index = (hash + psl) % ctx->max_entries;
+ uint8_t *entry = ctx->table + wrapped_index * ctx->entry_size;
+ if (!*ENTRY_OCC(entry) || *(size_t*)ENTRY_PSL(entry) < psl)
+ return 0;
+ if (KEYS_EQUAL(ENTRY_KEY(entry), key)) {
+ memcpy(val, ENTRY_VAL(entry), ctx->val_size);
+ return 1;
+ }
+ }
+ return 0;
+}
+
+int av_hashtable_set(struct AVHashtableContext *ctx, const void *key, const void *val)
+{
+ int swapping = 0;
+ size_t psl = 0;
+ size_t hash = hash_key(ctx, key);
+ uint8_t *set = ctx->swapbuf;
+ uint8_t *tmp = ctx->swapbuf + ctx->key_size_aligned + ctx->val_size_aligned;
+
+ memcpy(set, key, ctx->key_size);
+ memcpy(set + ctx->key_size_aligned, val, ctx->val_size);
+
+ for (size_t i = 0; i < ctx->max_entries; i++) {
+ size_t wrapped_index = (hash + i) % ctx->max_entries;
+ uint8_t *entry = ctx->table + wrapped_index * ctx->entry_size;
+ if (!*ENTRY_OCC(entry) || (!swapping && KEYS_EQUAL(ENTRY_KEY(entry), set))) {
+ if (!*ENTRY_OCC(entry))
+ ctx->utilization++;
+ *(size_t*)ENTRY_PSL(entry) = psl;
+ *ENTRY_OCC(entry) = 1;
+ memcpy(ENTRY_KEY(entry), set, ctx->key_size_aligned + ctx->val_size);
+ return 1;
+ }
+ if (*(size_t*)ENTRY_PSL(entry) < psl) {
+ if (ctx->utilization == ctx->max_entries)
+ return 0;
+ swapping = 1;
+ // set needs to swap with entry
+ memcpy(tmp, ENTRY_KEY(entry), ctx->key_size_aligned + ctx->val_size);
+ memcpy(ENTRY_KEY(entry), set, ctx->key_size_aligned + ctx->val_size);
+ FFSWAP(uint8_t*, set, tmp);
+ FFSWAP(size_t, psl, *(size_t*)ENTRY_PSL(entry));
+ }
+ psl++;
+ }
+ return 0;
+}
+
+int av_hashtable_delete(struct AVHashtableContext *ctx, const void *key)
+{
+ uint8_t *next_entry;
+ size_t hash = hash_key(ctx, key);
+
+ if (!ctx->utilization)
+ return 0;
+
+ for (size_t psl = 0; psl < ctx->max_entries; psl++) {
+ size_t wrapped_index = (hash + psl) % ctx->max_entries;
+ uint8_t *entry = ctx->table + wrapped_index * ctx->entry_size;
+ if (!*ENTRY_OCC(entry) || *(size_t*)ENTRY_PSL(entry) < psl)
+ return 0;
+ if (KEYS_EQUAL(ENTRY_KEY(entry), key)) {
+ *ENTRY_OCC(entry) = 0;
+ for (psl++; psl < ctx->max_entries; psl++) {
+ wrapped_index = (hash + psl) % ctx->max_entries;
+ next_entry = ctx->table + wrapped_index * ctx->entry_size;
+ if (!*ENTRY_OCC(next_entry) || !*(size_t*)ENTRY_PSL(next_entry)) {
+ ctx->utilization--;
+ return 1;
+ }
+ memcpy(entry, next_entry, ctx->entry_size);
+ (*(size_t*)ENTRY_PSL(entry))--;
+ *ENTRY_OCC(next_entry) = 0;
+ entry = next_entry;
+ }
+ }
+ };
+ return 0;
+}
+
+void av_hashtable_clear(struct AVHashtableContext *ctx)
+{
+ memset(ctx->table, 0, ctx->entry_size * ctx->max_entries);
+}
+
+void av_hashtable_freep(struct AVHashtableContext **ctx)
+{
+ if (*ctx) {
+ av_freep(&(*ctx)->table);
+ av_freep(&(*ctx)->swapbuf);
+ }
+ av_freep(ctx);
+}
diff --git a/libavutil/hashtable.h b/libavutil/hashtable.h
new file mode 100644
index 0000000000..f14086867e
--- /dev/null
+++ b/libavutil/hashtable.h
@@ -0,0 +1,40 @@
+/*
+ * Generic hashtable
+ * Copyright (C) 2024 Connor Worley <connorbworley@gmail.com>
+ *
+ * This file is part of FFmpeg.
+ *
+ * FFmpeg is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU Lesser General Public
+ * License as published by the Free Software Foundation; either
+ * version 2.1 of the License, or (at your option) any later version.
+ *
+ * FFmpeg is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
+ * Lesser General Public License for more details.
+ *
+ * You should have received a copy of the GNU Lesser General Public
+ * License along with FFmpeg; if not, write to the Free Software
+ * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
+ */
+
+#ifndef AVUTIL_HASHTABLE_H
+#define AVUTIL_HASHTABLE_H
+
+#include <stddef.h>
+
+/* Implements a hash table using Robin Hood open addressing.
+ * See: https://cs.uwaterloo.ca/research/tr/1986/CS-86-14.pdf
+ */
+
+struct AVHashtableContext;
+
+int av_hashtable_alloc(struct AVHashtableContext **ctx, size_t key_size, size_t val_size, size_t max_entries);
+int av_hashtable_get(const struct AVHashtableContext *ctx, const void *key, void *val);
+int av_hashtable_set(struct AVHashtableContext *ctx, const void *key, const void *val);
+int av_hashtable_delete(struct AVHashtableContext *ctx, const void *key);
+void av_hashtable_clear(struct AVHashtableContext *ctx);
+void av_hashtable_freep(struct AVHashtableContext **ctx);
+
+#endif
diff --git a/libavutil/tests/hashtable.c b/libavutil/tests/hashtable.c
new file mode 100644
index 0000000000..1e37d7663b
--- /dev/null
+++ b/libavutil/tests/hashtable.c
@@ -0,0 +1,110 @@
+/*
+ * Generic hashtable tests
+ * Copyright (C) 2024 Connor Worley <connorbworley@gmail.com>
+ *
+ * This file is part of FFmpeg.
+ *
+ * FFmpeg is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU Lesser General Public
+ * License as published by the Free Software Foundation; either
+ * version 2.1 of the License, or (at your option) any later version.
+ *
+ * FFmpeg is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
+ * Lesser General Public License for more details.
+ *
+ * You should have received a copy of the GNU Lesser General Public
+ * License along with FFmpeg; if not, write to the Free Software
+ * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
+ */
+
+#include <stdint.h>
+
+#include "libavutil/avassert.h"
+#include "libavutil/hashtable.h"
+
+int main(void)
+{
+ struct AVHashtableContext *ctx;
+ uint8_t k;
+ uint64_t v;
+
+ // impossibly large allocation should fail gracefully
+ av_assert0(av_hashtable_alloc(&ctx, -1, -1, -1) < 0);
+
+ // hashtable can store up to 3 uint8_t->uint64_t entries
+ av_assert0(!av_hashtable_alloc(&ctx, sizeof(k), sizeof(v), 3));
+
+ // unsuccessful deletes return 0
+ k = 1;
+ av_assert0(!av_hashtable_delete(ctx, &k));
+
+ // unsuccessful gets return 0
+ k = 1;
+ av_assert0(!av_hashtable_get(ctx, &k, &v));
+
+ // successful sets returns 1
+ k = 1;
+ v = 1;
+ av_assert0(av_hashtable_set(ctx, &k, &v));
+
+ // get should now contain 1
+ k = 1;
+ v = 0;
+ av_assert0(av_hashtable_get(ctx, &k, &v));
+ av_assert0(v == 1);
+
+ // updating sets should return 1
+ k = 1;
+ v = 2;
+ av_assert0(av_hashtable_set(ctx, &k, &v));
+
+ // get should now contain 2
+ k = 1;
+ v = 0;
+ av_assert0(av_hashtable_get(ctx, &k, &v));
+ av_assert0(v == 2);
+
+ // fill the table
+ k = 2;
+ v = 2;
+ av_assert0(av_hashtable_set(ctx, &k, &v));
+ k = 3;
+ v = 3;
+ av_assert0(av_hashtable_set(ctx, &k, &v));
+
+ // inserting sets on a full table should return 0
+ k = 4;
+ v = 4;
+ av_assert0(!av_hashtable_set(ctx, &k, &v));
+
+ // updating sets on a full table should return 1
+ k = 1;
+ v = 4;
+ av_assert0(av_hashtable_set(ctx, &k, &v));
+ v = 0;
+ av_assert0(av_hashtable_get(ctx, &k, &v));
+ av_assert0(v == 4);
+
+ // successful deletes should return 1
+ k = 1;
+ av_assert0(av_hashtable_delete(ctx, &k));
+
+ // get should now return 0
+ av_assert0(!av_hashtable_get(ctx, &k, &v));
+
+ // sanity check remaining keys
+ k = 2;
+ v = 0;
+ av_assert0(av_hashtable_get(ctx, &k, &v));
+ av_assert0(v == 2);
+ k = 3;
+ v = 0;
+ av_assert0(av_hashtable_get(ctx, &k, &v));
+ av_assert0(v == 3);
+
+ av_hashtable_freep(&ctx);
+
+ return 0;
+}
--
2.43.1
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^ permalink raw reply [flat|nested] 4+ messages in thread
* [FFmpeg-devel] [PATCH v4 2/2] lavc/dxvenc: migrate DXT1 encoder to lavu hashtable
2024-02-24 20:06 [FFmpeg-devel] [PATCH v4 1/2] lavu/hashtable: create generic robin hood hash table Connor Worley
@ 2024-02-24 20:06 ` Connor Worley
2024-03-03 22:44 ` [FFmpeg-devel] [PATCH v4 1/2] lavu/hashtable: create generic robin hood hash table Connor Worley
1 sibling, 0 replies; 4+ messages in thread
From: Connor Worley @ 2024-02-24 20:06 UTC (permalink / raw)
To: ffmpeg-devel; +Cc: Connor Worley
Offers a modest performance gain due to the switch from naive linear
probling to robin hood.
Signed-off-by: Connor Worley <connorbworley@gmail.com>
---
libavcodec/dxvenc.c | 121 ++++++++++++--------------------------------
1 file changed, 33 insertions(+), 88 deletions(-)
diff --git a/libavcodec/dxvenc.c b/libavcodec/dxvenc.c
index 1ce2b1d014..980269657d 100644
--- a/libavcodec/dxvenc.c
+++ b/libavcodec/dxvenc.c
@@ -21,7 +21,7 @@
#include <stdint.h>
-#include "libavutil/crc.h"
+#include "libavutil/hashtable.h"
#include "libavutil/imgutils.h"
#include "libavutil/opt.h"
@@ -38,72 +38,9 @@
* appeared in the decompressed stream. Using a simple hash table (HT)
* significantly speeds up the lookback process while encoding.
*/
-#define LOOKBACK_HT_ELEMS 0x40000
+#define LOOKBACK_HT_ELEMS 0x20202
#define LOOKBACK_WORDS 0x20202
-typedef struct HTEntry {
- uint32_t key;
- uint32_t pos;
-} HTEntry;
-
-static void ht_init(HTEntry *ht)
-{
- for (size_t i = 0; i < LOOKBACK_HT_ELEMS; i++) {
- ht[i].pos = -1;
- }
-}
-
-static uint32_t ht_lookup_and_upsert(HTEntry *ht, const AVCRC *hash_ctx,
- uint32_t key, uint32_t pos)
-{
- uint32_t ret = -1;
- size_t hash = av_crc(hash_ctx, 0, (uint8_t*)&key, 4) % LOOKBACK_HT_ELEMS;
- for (size_t i = hash; i < hash + LOOKBACK_HT_ELEMS; i++) {
- size_t wrapped_index = i % LOOKBACK_HT_ELEMS;
- HTEntry *entry = &ht[wrapped_index];
- if (entry->key == key || entry->pos == -1) {
- ret = entry->pos;
- entry->key = key;
- entry->pos = pos;
- break;
- }
- }
- return ret;
-}
-
-static void ht_delete(HTEntry *ht, const AVCRC *hash_ctx,
- uint32_t key, uint32_t pos)
-{
- HTEntry *removed_entry = NULL;
- size_t removed_hash;
- size_t hash = av_crc(hash_ctx, 0, (uint8_t*)&key, 4) % LOOKBACK_HT_ELEMS;
-
- for (size_t i = hash; i < hash + LOOKBACK_HT_ELEMS; i++) {
- size_t wrapped_index = i % LOOKBACK_HT_ELEMS;
- HTEntry *entry = &ht[wrapped_index];
- if (entry->pos == -1)
- return;
- if (removed_entry) {
- size_t candidate_hash = av_crc(hash_ctx, 0, (uint8_t*)&entry->key, 4) % LOOKBACK_HT_ELEMS;
- if ((wrapped_index > removed_hash && (candidate_hash <= removed_hash || candidate_hash > wrapped_index)) ||
- (wrapped_index < removed_hash && (candidate_hash <= removed_hash && candidate_hash > wrapped_index))) {
- *removed_entry = *entry;
- entry->pos = -1;
- removed_entry = entry;
- removed_hash = wrapped_index;
- }
- } else if (entry->key == key) {
- if (entry->pos <= pos) {
- entry->pos = -1;
- removed_entry = entry;
- removed_hash = wrapped_index;
- } else {
- return;
- }
- }
- }
-}
-
typedef struct DXVEncContext {
AVClass *class;
@@ -120,10 +57,8 @@ typedef struct DXVEncContext {
DXVTextureFormat tex_fmt;
int (*compress_tex)(AVCodecContext *avctx);
- const AVCRC *crc_ctx;
-
- HTEntry color_lookback_ht[LOOKBACK_HT_ELEMS];
- HTEntry lut_lookback_ht[LOOKBACK_HT_ELEMS];
+ struct AVHashtableContext *color_ht;
+ struct AVHashtableContext *lut_ht;
} DXVEncContext;
/* Converts an index offset value to a 2-bit opcode and pushes it to a stream.
@@ -158,27 +93,32 @@ static int dxv_compress_dxt1(AVCodecContext *avctx)
DXVEncContext *ctx = avctx->priv_data;
PutByteContext *pbc = &ctx->pbc;
uint32_t *value;
- uint32_t color, lut, idx, color_idx, lut_idx, prev_pos, state = 16, pos = 2, op = 0;
+ uint32_t color, lut, idx, color_idx, lut_idx, prev_pos, state = 16, pos = 0, op = 0;
- ht_init(ctx->color_lookback_ht);
- ht_init(ctx->lut_lookback_ht);
+ av_hashtable_clear(ctx->color_ht);
+ av_hashtable_clear(ctx->lut_ht);
bytestream2_put_le32(pbc, AV_RL32(ctx->tex_data));
+ av_hashtable_set(ctx->color_ht, ctx->tex_data, &pos);
+ pos++;
bytestream2_put_le32(pbc, AV_RL32(ctx->tex_data + 4));
-
- ht_lookup_and_upsert(ctx->color_lookback_ht, ctx->crc_ctx, AV_RL32(ctx->tex_data), 0);
- ht_lookup_and_upsert(ctx->lut_lookback_ht, ctx->crc_ctx, AV_RL32(ctx->tex_data + 4), 1);
+ av_hashtable_set(ctx->lut_ht, ctx->tex_data + 4, &pos);
+ pos++;
while (pos + 2 <= ctx->tex_size / 4) {
idx = 0;
+ color_idx = 0;
+ lut_idx = 0;
color = AV_RL32(ctx->tex_data + pos * 4);
- prev_pos = ht_lookup_and_upsert(ctx->color_lookback_ht, ctx->crc_ctx, color, pos);
- color_idx = prev_pos != -1 ? pos - prev_pos : 0;
+ if (av_hashtable_get(ctx->color_ht, &color, &prev_pos))
+ color_idx = pos - prev_pos;
+ av_hashtable_set(ctx->color_ht, &color, &pos);
+
if (pos >= LOOKBACK_WORDS) {
uint32_t old_pos = pos - LOOKBACK_WORDS;
- uint32_t old_color = AV_RL32(ctx->tex_data + old_pos * 4);
- ht_delete(ctx->color_lookback_ht, ctx->crc_ctx, old_color, old_pos);
+ if (av_hashtable_get(ctx->color_ht, ctx->tex_data + old_pos * 4, &prev_pos) && prev_pos <= old_pos)
+ av_hashtable_delete(ctx->color_ht, ctx->tex_data + old_pos * 4);
}
pos++;
@@ -187,13 +127,14 @@ static int dxv_compress_dxt1(AVCodecContext *avctx)
idx = color_idx;
} else {
idx = 0;
- prev_pos = ht_lookup_and_upsert(ctx->lut_lookback_ht, ctx->crc_ctx, lut, pos);
- lut_idx = prev_pos != -1 ? pos - prev_pos : 0;
+ if (av_hashtable_get(ctx->lut_ht, &lut, &prev_pos))
+ lut_idx = pos - prev_pos;
+ av_hashtable_set(ctx->lut_ht, &lut, &pos);
}
if (pos >= LOOKBACK_WORDS) {
uint32_t old_pos = pos - LOOKBACK_WORDS;
- uint32_t old_lut = AV_RL32(ctx->tex_data + old_pos * 4);
- ht_delete(ctx->lut_lookback_ht, ctx->crc_ctx, old_lut, old_pos);
+ if (av_hashtable_get(ctx->lut_ht, ctx->tex_data + old_pos * 4, &prev_pos) && prev_pos <= old_pos)
+ av_hashtable_delete(ctx->lut_ht, ctx->tex_data + old_pos * 4);
}
pos++;
@@ -305,11 +246,12 @@ static av_cold int dxv_init(AVCodecContext *avctx)
return AVERROR(ENOMEM);
}
- ctx->crc_ctx = av_crc_get_table(AV_CRC_32_IEEE);
- if (!ctx->crc_ctx) {
- av_log(avctx, AV_LOG_ERROR, "Could not initialize CRC table.\n");
- return AVERROR_BUG;
- }
+ ret = av_hashtable_alloc(&ctx->color_ht, sizeof(uint32_t), sizeof(uint32_t), LOOKBACK_HT_ELEMS);
+ if (ret < 0)
+ return ret;
+ ret = av_hashtable_alloc(&ctx->lut_ht, sizeof(uint32_t), sizeof(uint32_t), LOOKBACK_HT_ELEMS);
+ if (ret < 0)
+ return ret;
return 0;
}
@@ -320,6 +262,9 @@ static av_cold int dxv_close(AVCodecContext *avctx)
av_freep(&ctx->tex_data);
+ av_hashtable_freep(&ctx->color_ht);
+ av_hashtable_freep(&ctx->lut_ht);
+
return 0;
}
--
2.43.1
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* Re: [FFmpeg-devel] [PATCH v4 1/2] lavu/hashtable: create generic robin hood hash table
2024-02-24 20:06 [FFmpeg-devel] [PATCH v4 1/2] lavu/hashtable: create generic robin hood hash table Connor Worley
2024-02-24 20:06 ` [FFmpeg-devel] [PATCH v4 2/2] lavc/dxvenc: migrate DXT1 encoder to lavu hashtable Connor Worley
@ 2024-03-03 22:44 ` Connor Worley
2024-03-04 8:15 ` Anton Khirnov
1 sibling, 1 reply; 4+ messages in thread
From: Connor Worley @ 2024-03-03 22:44 UTC (permalink / raw)
To: ffmpeg-devel
Any objections to this patchset?
On Sat, Feb 24, 2024 at 12:06 PM Connor Worley <connorbworley@gmail.com>
wrote:
> Signed-off-by: Connor Worley <connorbworley@gmail.com>
> ---
> libavutil/Makefile | 2 +
> libavutil/hashtable.c | 192 ++++++++++++++++++++++++++++++++++++
> libavutil/hashtable.h | 40 ++++++++
> libavutil/tests/hashtable.c | 110 +++++++++++++++++++++
> 4 files changed, 344 insertions(+)
> create mode 100644 libavutil/hashtable.c
> create mode 100644 libavutil/hashtable.h
> create mode 100644 libavutil/tests/hashtable.c
>
> diff --git a/libavutil/Makefile b/libavutil/Makefile
> index e7709b97d0..be75d464fc 100644
> --- a/libavutil/Makefile
> +++ b/libavutil/Makefile
> @@ -138,6 +138,7 @@ OBJS = adler32.o
> \
> fixed_dsp.o \
> frame.o \
> hash.o \
> + hashtable.o \
> hdr_dynamic_metadata.o \
> hdr_dynamic_vivid_metadata.o \
> hmac.o \
> @@ -251,6 +252,7 @@ TESTPROGS = adler32
> \
> file \
> fifo \
> hash \
> + hashtable \
> hmac \
> hwdevice \
> integer \
> diff --git a/libavutil/hashtable.c b/libavutil/hashtable.c
> new file mode 100644
> index 0000000000..155a264665
> --- /dev/null
> +++ b/libavutil/hashtable.c
> @@ -0,0 +1,192 @@
> +/*
> + * Generic hashtable
> + * Copyright (C) 2024 Connor Worley <connorbworley@gmail.com>
> + *
> + * This file is part of FFmpeg.
> + *
> + * FFmpeg is free software; you can redistribute it and/or
> + * modify it under the terms of the GNU Lesser General Public
> + * License as published by the Free Software Foundation; either
> + * version 2.1 of the License, or (at your option) any later version.
> + *
> + * FFmpeg is distributed in the hope that it will be useful,
> + * but WITHOUT ANY WARRANTY; without even the implied warranty of
> + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
> + * Lesser General Public License for more details.
> + *
> + * You should have received a copy of the GNU Lesser General Public
> + * License along with FFmpeg; if not, write to the Free Software
> + * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA
> 02110-1301 USA
> + */
> +
> +#include <stdint.h>
> +#include <string.h>
> +
> +#include "crc.h"
> +#include "error.h"
> +#include "mem.h"
> +#include "hashtable.h"
> +
> +#define ALIGN _Alignof(size_t)
> +
> +struct AVHashtableContext {
> + 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 utilization;
> + const AVCRC *crc;
> + uint8_t *table;
> + uint8_t *swapbuf;
> +};
> +
> +#define ENTRY_PSL(entry) (entry)
> +#define ENTRY_OCC(entry) (ENTRY_PSL(entry) + FFALIGN(sizeof(size_t),
> ALIGN))
> +#define ENTRY_KEY(entry) (ENTRY_OCC(entry) + FFALIGN(sizeof(size_t),
> ALIGN))
> +#define ENTRY_VAL(entry) (ENTRY_KEY(entry) + ctx->key_size_aligned)
> +
> +#define KEYS_EQUAL(k1, k2) !memcmp(k1, k2, ctx->key_size)
> +
> +int av_hashtable_alloc(struct AVHashtableContext **ctx, size_t key_size,
> size_t val_size, size_t max_entries)
> +{
> + struct AVHashtableContext *res = av_malloc(sizeof(struct
> AVHashtableContext));
> + 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)
> + + FFALIGN(sizeof(size_t), ALIGN)
> + + res->key_size_aligned
> + + res->val_size_aligned;
> + res->max_entries = max_entries;
> + res->utilization = 0;
> + res->crc = av_crc_get_table(AV_CRC_32_IEEE);
> + if (!res->crc) {
> + av_hashtable_freep(&res);
> + return AVERROR_BUG;
> + }
> + res->table = av_calloc(res->max_entries, res->entry_size);
> + if (!res->table) {
> + av_hashtable_freep(&res);
> + return AVERROR(ENOMEM);
> + }
> + res->swapbuf = av_calloc(2, res->key_size_aligned +
> res->val_size_aligned);
> + if (!res->swapbuf) {
> + av_hashtable_freep(&res);
> + return AVERROR(ENOMEM);
> + }
> + *ctx = res;
> + return 0;
> +}
> +
> +static size_t hash_key(const struct AVHashtableContext *ctx, const void
> *key)
> +{
> + return av_crc(ctx->crc, 0, key, ctx->key_size) % ctx->max_entries;
> +}
> +
> +int av_hashtable_get(const struct AVHashtableContext *ctx, const void
> *key, void *val)
> +{
> + size_t hash = hash_key(ctx, key);
> +
> + if (!ctx->utilization)
> + return 0;
> +
> + for (size_t psl = 0; psl < ctx->max_entries; psl++) {
> + size_t wrapped_index = (hash + psl) % ctx->max_entries;
> + uint8_t *entry = ctx->table + wrapped_index * ctx->entry_size;
> + if (!*ENTRY_OCC(entry) || *(size_t*)ENTRY_PSL(entry) < psl)
> + return 0;
> + if (KEYS_EQUAL(ENTRY_KEY(entry), key)) {
> + memcpy(val, ENTRY_VAL(entry), ctx->val_size);
> + return 1;
> + }
> + }
> + return 0;
> +}
> +
> +int av_hashtable_set(struct AVHashtableContext *ctx, const void *key,
> const void *val)
> +{
> + int swapping = 0;
> + size_t psl = 0;
> + size_t hash = hash_key(ctx, key);
> + uint8_t *set = ctx->swapbuf;
> + uint8_t *tmp = ctx->swapbuf + ctx->key_size_aligned +
> ctx->val_size_aligned;
> +
> + memcpy(set, key, ctx->key_size);
> + memcpy(set + ctx->key_size_aligned, val, ctx->val_size);
> +
> + for (size_t i = 0; i < ctx->max_entries; i++) {
> + size_t wrapped_index = (hash + i) % ctx->max_entries;
> + uint8_t *entry = ctx->table + wrapped_index * ctx->entry_size;
> + if (!*ENTRY_OCC(entry) || (!swapping &&
> KEYS_EQUAL(ENTRY_KEY(entry), set))) {
> + if (!*ENTRY_OCC(entry))
> + ctx->utilization++;
> + *(size_t*)ENTRY_PSL(entry) = psl;
> + *ENTRY_OCC(entry) = 1;
> + memcpy(ENTRY_KEY(entry), set, ctx->key_size_aligned +
> ctx->val_size);
> + return 1;
> + }
> + if (*(size_t*)ENTRY_PSL(entry) < psl) {
> + if (ctx->utilization == ctx->max_entries)
> + return 0;
> + swapping = 1;
> + // set needs to swap with entry
> + memcpy(tmp, ENTRY_KEY(entry), ctx->key_size_aligned +
> ctx->val_size);
> + memcpy(ENTRY_KEY(entry), set, ctx->key_size_aligned +
> ctx->val_size);
> + FFSWAP(uint8_t*, set, tmp);
> + FFSWAP(size_t, psl, *(size_t*)ENTRY_PSL(entry));
> + }
> + psl++;
> + }
> + return 0;
> +}
> +
> +int av_hashtable_delete(struct AVHashtableContext *ctx, const void *key)
> +{
> + uint8_t *next_entry;
> + size_t hash = hash_key(ctx, key);
> +
> + if (!ctx->utilization)
> + return 0;
> +
> + for (size_t psl = 0; psl < ctx->max_entries; psl++) {
> + size_t wrapped_index = (hash + psl) % ctx->max_entries;
> + uint8_t *entry = ctx->table + wrapped_index * ctx->entry_size;
> + if (!*ENTRY_OCC(entry) || *(size_t*)ENTRY_PSL(entry) < psl)
> + return 0;
> + if (KEYS_EQUAL(ENTRY_KEY(entry), key)) {
> + *ENTRY_OCC(entry) = 0;
> + for (psl++; psl < ctx->max_entries; psl++) {
> + wrapped_index = (hash + psl) % ctx->max_entries;
> + next_entry = ctx->table + wrapped_index * ctx->entry_size;
> + if (!*ENTRY_OCC(next_entry) ||
> !*(size_t*)ENTRY_PSL(next_entry)) {
> + ctx->utilization--;
> + return 1;
> + }
> + memcpy(entry, next_entry, ctx->entry_size);
> + (*(size_t*)ENTRY_PSL(entry))--;
> + *ENTRY_OCC(next_entry) = 0;
> + entry = next_entry;
> + }
> + }
> + };
> + return 0;
> +}
> +
> +void av_hashtable_clear(struct AVHashtableContext *ctx)
> +{
> + memset(ctx->table, 0, ctx->entry_size * ctx->max_entries);
> +}
> +
> +void av_hashtable_freep(struct AVHashtableContext **ctx)
> +{
> + if (*ctx) {
> + av_freep(&(*ctx)->table);
> + av_freep(&(*ctx)->swapbuf);
> + }
> + av_freep(ctx);
> +}
> diff --git a/libavutil/hashtable.h b/libavutil/hashtable.h
> new file mode 100644
> index 0000000000..f14086867e
> --- /dev/null
> +++ b/libavutil/hashtable.h
> @@ -0,0 +1,40 @@
> +/*
> + * Generic hashtable
> + * Copyright (C) 2024 Connor Worley <connorbworley@gmail.com>
> + *
> + * This file is part of FFmpeg.
> + *
> + * FFmpeg is free software; you can redistribute it and/or
> + * modify it under the terms of the GNU Lesser General Public
> + * License as published by the Free Software Foundation; either
> + * version 2.1 of the License, or (at your option) any later version.
> + *
> + * FFmpeg is distributed in the hope that it will be useful,
> + * but WITHOUT ANY WARRANTY; without even the implied warranty of
> + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
> + * Lesser General Public License for more details.
> + *
> + * You should have received a copy of the GNU Lesser General Public
> + * License along with FFmpeg; if not, write to the Free Software
> + * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA
> 02110-1301 USA
> + */
> +
> +#ifndef AVUTIL_HASHTABLE_H
> +#define AVUTIL_HASHTABLE_H
> +
> +#include <stddef.h>
> +
> +/* Implements a hash table using Robin Hood open addressing.
> + * See: https://cs.uwaterloo.ca/research/tr/1986/CS-86-14.pdf
> + */
> +
> +struct AVHashtableContext;
> +
> +int av_hashtable_alloc(struct AVHashtableContext **ctx, size_t key_size,
> size_t val_size, size_t max_entries);
> +int av_hashtable_get(const struct AVHashtableContext *ctx, const void
> *key, void *val);
> +int av_hashtable_set(struct AVHashtableContext *ctx, const void *key,
> const void *val);
> +int av_hashtable_delete(struct AVHashtableContext *ctx, const void *key);
> +void av_hashtable_clear(struct AVHashtableContext *ctx);
> +void av_hashtable_freep(struct AVHashtableContext **ctx);
> +
> +#endif
> diff --git a/libavutil/tests/hashtable.c b/libavutil/tests/hashtable.c
> new file mode 100644
> index 0000000000..1e37d7663b
> --- /dev/null
> +++ b/libavutil/tests/hashtable.c
> @@ -0,0 +1,110 @@
> +/*
> + * Generic hashtable tests
> + * Copyright (C) 2024 Connor Worley <connorbworley@gmail.com>
> + *
> + * This file is part of FFmpeg.
> + *
> + * FFmpeg is free software; you can redistribute it and/or
> + * modify it under the terms of the GNU Lesser General Public
> + * License as published by the Free Software Foundation; either
> + * version 2.1 of the License, or (at your option) any later version.
> + *
> + * FFmpeg is distributed in the hope that it will be useful,
> + * but WITHOUT ANY WARRANTY; without even the implied warranty of
> + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
> + * Lesser General Public License for more details.
> + *
> + * You should have received a copy of the GNU Lesser General Public
> + * License along with FFmpeg; if not, write to the Free Software
> + * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA
> 02110-1301 USA
> + */
> +
> +#include <stdint.h>
> +
> +#include "libavutil/avassert.h"
> +#include "libavutil/hashtable.h"
> +
> +int main(void)
> +{
> + struct AVHashtableContext *ctx;
> + uint8_t k;
> + uint64_t v;
> +
> + // impossibly large allocation should fail gracefully
> + av_assert0(av_hashtable_alloc(&ctx, -1, -1, -1) < 0);
> +
> + // hashtable can store up to 3 uint8_t->uint64_t entries
> + av_assert0(!av_hashtable_alloc(&ctx, sizeof(k), sizeof(v), 3));
> +
> + // unsuccessful deletes return 0
> + k = 1;
> + av_assert0(!av_hashtable_delete(ctx, &k));
> +
> + // unsuccessful gets return 0
> + k = 1;
> + av_assert0(!av_hashtable_get(ctx, &k, &v));
> +
> + // successful sets returns 1
> + k = 1;
> + v = 1;
> + av_assert0(av_hashtable_set(ctx, &k, &v));
> +
> + // get should now contain 1
> + k = 1;
> + v = 0;
> + av_assert0(av_hashtable_get(ctx, &k, &v));
> + av_assert0(v == 1);
> +
> + // updating sets should return 1
> + k = 1;
> + v = 2;
> + av_assert0(av_hashtable_set(ctx, &k, &v));
> +
> + // get should now contain 2
> + k = 1;
> + v = 0;
> + av_assert0(av_hashtable_get(ctx, &k, &v));
> + av_assert0(v == 2);
> +
> + // fill the table
> + k = 2;
> + v = 2;
> + av_assert0(av_hashtable_set(ctx, &k, &v));
> + k = 3;
> + v = 3;
> + av_assert0(av_hashtable_set(ctx, &k, &v));
> +
> + // inserting sets on a full table should return 0
> + k = 4;
> + v = 4;
> + av_assert0(!av_hashtable_set(ctx, &k, &v));
> +
> + // updating sets on a full table should return 1
> + k = 1;
> + v = 4;
> + av_assert0(av_hashtable_set(ctx, &k, &v));
> + v = 0;
> + av_assert0(av_hashtable_get(ctx, &k, &v));
> + av_assert0(v == 4);
> +
> + // successful deletes should return 1
> + k = 1;
> + av_assert0(av_hashtable_delete(ctx, &k));
> +
> + // get should now return 0
> + av_assert0(!av_hashtable_get(ctx, &k, &v));
> +
> + // sanity check remaining keys
> + k = 2;
> + v = 0;
> + av_assert0(av_hashtable_get(ctx, &k, &v));
> + av_assert0(v == 2);
> + k = 3;
> + v = 0;
> + av_assert0(av_hashtable_get(ctx, &k, &v));
> + av_assert0(v == 3);
> +
> + av_hashtable_freep(&ctx);
> +
> + return 0;
> +}
> --
> 2.43.1
>
>
--
Connor Worley
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^ permalink raw reply [flat|nested] 4+ messages in thread
* Re: [FFmpeg-devel] [PATCH v4 1/2] lavu/hashtable: create generic robin hood hash table
2024-03-03 22:44 ` [FFmpeg-devel] [PATCH v4 1/2] lavu/hashtable: create generic robin hood hash table Connor Worley
@ 2024-03-04 8:15 ` Anton Khirnov
0 siblings, 0 replies; 4+ messages in thread
From: Anton Khirnov @ 2024-03-04 8:15 UTC (permalink / raw)
To: FFmpeg development discussions and patches
Quoting Connor Worley (2024-03-03 23:44:55)
> Any objections to this patchset?
Lack of documentation, for one thing.
--
Anton Khirnov
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^ permalink raw reply [flat|nested] 4+ messages in thread
end of thread, other threads:[~2024-03-04 8:16 UTC | newest]
Thread overview: 4+ messages (download: mbox.gz / follow: Atom feed)
-- links below jump to the message on this page --
2024-02-24 20:06 [FFmpeg-devel] [PATCH v4 1/2] lavu/hashtable: create generic robin hood hash table Connor Worley
2024-02-24 20:06 ` [FFmpeg-devel] [PATCH v4 2/2] lavc/dxvenc: migrate DXT1 encoder to lavu hashtable Connor Worley
2024-03-03 22:44 ` [FFmpeg-devel] [PATCH v4 1/2] lavu/hashtable: create generic robin hood hash table Connor Worley
2024-03-04 8:15 ` Anton Khirnov
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