diff options
Diffstat (limited to 'lib/ngtcp2_map.c')
-rw-r--r-- | lib/ngtcp2_map.c | 336 |
1 files changed, 336 insertions, 0 deletions
diff --git a/lib/ngtcp2_map.c b/lib/ngtcp2_map.c new file mode 100644 index 0000000..12bc6e8 --- /dev/null +++ b/lib/ngtcp2_map.c @@ -0,0 +1,336 @@ +/* + * ngtcp2 + * + * Copyright (c) 2017 ngtcp2 contributors + * Copyright (c) 2012 nghttp2 contributors + * + * Permission is hereby granted, free of charge, to any person obtaining + * a copy of this software and associated documentation files (the + * "Software"), to deal in the Software without restriction, including + * without limitation the rights to use, copy, modify, merge, publish, + * distribute, sublicense, and/or sell copies of the Software, and to + * permit persons to whom the Software is furnished to do so, subject to + * the following conditions: + * + * The above copyright notice and this permission notice shall be + * included in all copies or substantial portions of the Software. + * + * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, + * EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF + * MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND + * NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE + * LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION + * OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION + * WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE. + */ +#include "ngtcp2_map.h" + +#include <string.h> +#include <assert.h> +#include <stdio.h> + +#include "ngtcp2_conv.h" + +#define NGTCP2_INITIAL_TABLE_LENBITS 4 + +void ngtcp2_map_init(ngtcp2_map *map, const ngtcp2_mem *mem) { + map->mem = mem; + map->tablelen = 0; + map->tablelenbits = 0; + map->table = NULL; + map->size = 0; +} + +void ngtcp2_map_free(ngtcp2_map *map) { + if (!map) { + return; + } + + ngtcp2_mem_free(map->mem, map->table); +} + +void ngtcp2_map_each_free(ngtcp2_map *map, int (*func)(void *data, void *ptr), + void *ptr) { + uint32_t i; + ngtcp2_map_bucket *bkt; + + for (i = 0; i < map->tablelen; ++i) { + bkt = &map->table[i]; + + if (bkt->data == NULL) { + continue; + } + + func(bkt->data, ptr); + } +} + +int ngtcp2_map_each(ngtcp2_map *map, int (*func)(void *data, void *ptr), + void *ptr) { + int rv; + uint32_t i; + ngtcp2_map_bucket *bkt; + + if (map->size == 0) { + return 0; + } + + for (i = 0; i < map->tablelen; ++i) { + bkt = &map->table[i]; + + if (bkt->data == NULL) { + continue; + } + + rv = func(bkt->data, ptr); + if (rv != 0) { + return rv; + } + } + + return 0; +} + +static uint32_t hash(ngtcp2_map_key_type key) { + return (uint32_t)((key * 11400714819323198485llu) >> 32); +} + +static size_t h2idx(uint32_t hash, uint32_t bits) { + return hash >> (32 - bits); +} + +static size_t distance(uint32_t tablelen, uint32_t tablelenbits, + ngtcp2_map_bucket *bkt, size_t idx) { + return (idx - h2idx(bkt->hash, tablelenbits)) & (tablelen - 1); +} + +static void map_bucket_swap(ngtcp2_map_bucket *bkt, uint32_t *phash, + ngtcp2_map_key_type *pkey, void **pdata) { + uint32_t h = bkt->hash; + ngtcp2_map_key_type key = bkt->key; + void *data = bkt->data; + + bkt->hash = *phash; + bkt->key = *pkey; + bkt->data = *pdata; + + *phash = h; + *pkey = key; + *pdata = data; +} + +static void map_bucket_set_data(ngtcp2_map_bucket *bkt, uint32_t hash, + ngtcp2_map_key_type key, void *data) { + bkt->hash = hash; + bkt->key = key; + bkt->data = data; +} + +void ngtcp2_map_print_distance(ngtcp2_map *map) { + uint32_t i; + size_t idx; + ngtcp2_map_bucket *bkt; + + for (i = 0; i < map->tablelen; ++i) { + bkt = &map->table[i]; + + if (bkt->data == NULL) { + fprintf(stderr, "@%u <EMPTY>\n", i); + continue; + } + + idx = h2idx(bkt->hash, map->tablelenbits); + fprintf(stderr, "@%u hash=%08x key=%" PRIu64 " base=%zu distance=%zu\n", i, + bkt->hash, bkt->key, idx, + distance(map->tablelen, map->tablelenbits, bkt, idx)); + } +} + +static int insert(ngtcp2_map_bucket *table, uint32_t tablelen, + uint32_t tablelenbits, uint32_t hash, ngtcp2_map_key_type key, + void *data) { + size_t idx = h2idx(hash, tablelenbits); + size_t d = 0, dd; + ngtcp2_map_bucket *bkt; + + for (;;) { + bkt = &table[idx]; + + if (bkt->data == NULL) { + map_bucket_set_data(bkt, hash, key, data); + return 0; + } + + dd = distance(tablelen, tablelenbits, bkt, idx); + if (d > dd) { + map_bucket_swap(bkt, &hash, &key, &data); + d = dd; + } else if (bkt->key == key) { + /* TODO This check is just a waste after first swap or if this + function is called from map_resize. That said, there is no + difference with or without this conditional in performance + wise. */ + return NGTCP2_ERR_INVALID_ARGUMENT; + } + + ++d; + idx = (idx + 1) & (tablelen - 1); + } +} + +/* new_tablelen must be power of 2 and new_tablelen == (1 << + new_tablelenbits) must hold. */ +static int map_resize(ngtcp2_map *map, uint32_t new_tablelen, + uint32_t new_tablelenbits) { + uint32_t i; + ngtcp2_map_bucket *new_table; + ngtcp2_map_bucket *bkt; + int rv; + (void)rv; + + new_table = + ngtcp2_mem_calloc(map->mem, new_tablelen, sizeof(ngtcp2_map_bucket)); + if (new_table == NULL) { + return NGTCP2_ERR_NOMEM; + } + + for (i = 0; i < map->tablelen; ++i) { + bkt = &map->table[i]; + if (bkt->data == NULL) { + continue; + } + rv = insert(new_table, new_tablelen, new_tablelenbits, bkt->hash, bkt->key, + bkt->data); + + assert(0 == rv); + } + + ngtcp2_mem_free(map->mem, map->table); + map->tablelen = new_tablelen; + map->tablelenbits = new_tablelenbits; + map->table = new_table; + + return 0; +} + +int ngtcp2_map_insert(ngtcp2_map *map, ngtcp2_map_key_type key, void *data) { + int rv; + + assert(data); + + /* Load factor is 0.75 */ + if ((map->size + 1) * 4 > map->tablelen * 3) { + if (map->tablelen) { + rv = map_resize(map, map->tablelen * 2, map->tablelenbits + 1); + if (rv != 0) { + return rv; + } + } else { + rv = map_resize(map, 1 << NGTCP2_INITIAL_TABLE_LENBITS, + NGTCP2_INITIAL_TABLE_LENBITS); + if (rv != 0) { + return rv; + } + } + } + + rv = insert(map->table, map->tablelen, map->tablelenbits, hash(key), key, + data); + if (rv != 0) { + return rv; + } + ++map->size; + return 0; +} + +void *ngtcp2_map_find(ngtcp2_map *map, ngtcp2_map_key_type key) { + uint32_t h; + size_t idx; + ngtcp2_map_bucket *bkt; + size_t d = 0; + + if (map->size == 0) { + return NULL; + } + + h = hash(key); + idx = h2idx(h, map->tablelenbits); + + for (;;) { + bkt = &map->table[idx]; + + if (bkt->data == NULL || + d > distance(map->tablelen, map->tablelenbits, bkt, idx)) { + return NULL; + } + + if (bkt->key == key) { + return bkt->data; + } + + ++d; + idx = (idx + 1) & (map->tablelen - 1); + } +} + +int ngtcp2_map_remove(ngtcp2_map *map, ngtcp2_map_key_type key) { + uint32_t h; + size_t idx, didx; + ngtcp2_map_bucket *bkt; + size_t d = 0; + + if (map->size == 0) { + return NGTCP2_ERR_INVALID_ARGUMENT; + } + + h = hash(key); + idx = h2idx(h, map->tablelenbits); + + for (;;) { + bkt = &map->table[idx]; + + if (bkt->data == NULL || + d > distance(map->tablelen, map->tablelenbits, bkt, idx)) { + return NGTCP2_ERR_INVALID_ARGUMENT; + } + + if (bkt->key == key) { + map_bucket_set_data(bkt, 0, 0, NULL); + + didx = idx; + idx = (idx + 1) & (map->tablelen - 1); + + for (;;) { + bkt = &map->table[idx]; + if (bkt->data == NULL || + distance(map->tablelen, map->tablelenbits, bkt, idx) == 0) { + break; + } + + map->table[didx] = *bkt; + map_bucket_set_data(bkt, 0, 0, NULL); + didx = idx; + + idx = (idx + 1) & (map->tablelen - 1); + } + + --map->size; + + return 0; + } + + ++d; + idx = (idx + 1) & (map->tablelen - 1); + } +} + +void ngtcp2_map_clear(ngtcp2_map *map) { + if (map->tablelen == 0) { + return; + } + + memset(map->table, 0, sizeof(*map->table) * map->tablelen); + map->size = 0; +} + +size_t ngtcp2_map_size(ngtcp2_map *map) { return map->size; } |