voron

experimental ARM OS
git clone git://git.2f30.org/voron.git
Log | Files | Refs | LICENSE

commit 9a9e3101e592116cf8b3d758cdefe4da583f9624
parent f75befe40ebae02606b7fce1e74adc9d1b8c5fda
Author: sin <sin@2f30.org>
Date:   Sun Jul 21 14:01:52 +0100

Add simple hash table implementation using open-addressing

Diffstat:
include/hash.h | 15+++++++++++++++
kernel/hash.c | 150+++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
2 files changed, 165 insertions(+), 0 deletions(-)
diff --git a/include/hash.h b/include/hash.h @@ -0,0 +1,15 @@ +#ifndef __HASH_H +#define __HASH_H + +struct hent_ops { + unsigned long (*hash)(void *data, size_t siz); + int (*cmp)(void *src, void *dst, size_t siz); +}; + +struct htable *init_htable(struct hent_ops *hent_ops, size_t n); +void free_htable(struct htable *htable); +int search_htable(struct htable *htable, void *data, size_t siz); +int insert_htable(struct htable *htable, void *data, size_t siz); +int remove_htable(struct htable *htable, void *data, size_t siz); + +#endif diff --git a/kernel/hash.c b/kernel/hash.c @@ -0,0 +1,150 @@ +/* Simple hash table implementation using open-addressing */ +#include <kernel.h> +#include <mmu.h> +#include <alloc.h> +#include <spinlock.h> +#include "hash.h" + +enum hent_state { + UNUSED, + USED, + REMOVED, +}; + +struct hent { + void *data; + size_t siz; + enum hent_state state; +}; + +struct htable { + struct hent *hent; + struct hent_ops *hent_ops; + size_t siz; +}; + +static spinlock_t htable_lock = SPINLOCK_INIT; + +struct htable * +init_htable(struct hent_ops *hent_ops, size_t n) +{ + struct htable *htable; + size_t i; + + htable = kmalloc(sizeof(*htable)); + if (!htable) + return NULL; + htable->hent = kcalloc(n, sizeof(struct hent)); + if (!htable->hent) { + kfree(htable); + return NULL; + } + for (i = 0; i < n; i++) + htable->hent[i].state = UNUSED; + htable->siz = n; + htable->hent_ops = hent_ops; + return htable; +} + +void +free_htable(struct htable *htable) +{ + spinlock_lock(&htable_lock); + kfree(htable->hent); + kfree(htable); + spinlock_unlock(&htable_lock); +} + +/* Search the hash table for the given entry. Returns -1 + * on failure and the index of the entry on success. */ +int +search_htable(struct htable *htable, void *data, size_t siz) +{ + struct hent *hent; + struct hent_ops *ops; + size_t idx, i, j; + + spinlock_lock(&htable_lock); + ops = htable->hent_ops; + idx = ops->hash(data, siz) % htable->siz; + j = idx; + for (i = 0; i < htable->siz; i++) { + hent = &htable->hent[j]; + if (hent->state == UNUSED) { + spinlock_unlock(&htable_lock); + return -1; + } + if (hent->state == USED && !ops->cmp(hent->data, data, siz)) { + spinlock_unlock(&htable_lock); + return j; + } + j++; + j %= htable->siz; + } + spinlock_unlock(&htable_lock); + return -1; +} + +/* Insert the given entry in the hash table. Ignore duplicates. + * Return the index on a successful insertion, -1 if the table is full. */ +int +insert_htable(struct htable *htable, void *data, size_t siz) +{ + struct hent *hent; + struct hent_ops *ops; + size_t idx, i, j; + + spinlock_lock(&htable_lock); + ops = htable->hent_ops; + idx = ops->hash(data, siz) % htable->siz; + j = idx; + for (i = 0; i < htable->siz; i++) { + hent = &htable->hent[j]; + if (hent->state == USED && !ops->cmp(hent->data, data, siz)) { + spinlock_unlock(&htable_lock); + return j; + } + if (hent->state == UNUSED || hent->state == REMOVED) { + hent->data = data; + hent->siz = siz; + hent->state = USED; + spinlock_unlock(&htable_lock); + return j; + } + j++; + j %= htable->siz; + } + spinlock_unlock(&htable_lock); + return -1; +} + +/* Remove an entry from the hash table. Return -1 on failure, + * and the index of the entry on success. */ +int +remove_htable(struct htable *htable, void *data, size_t siz) +{ + struct hent *hent; + struct hent_ops *ops; + size_t idx, i, j; + + spinlock_lock(&htable_lock); + ops = htable->hent_ops; + idx = ops->hash(data, siz) % htable->siz; + j = idx; + for (i = 0; i < htable->siz; i++) { + hent = &htable->hent[j]; + if (hent->state == UNUSED) { + spinlock_unlock(&htable_lock); + return -1; + } + if (hent->state == USED && !ops->cmp(hent->data, data, siz)) { + hent->state = REMOVED; + spinlock_unlock(&htable_lock); + return j; + } + j++; + j %= htable->siz; + } + spinlock_unlock(&htable_lock); + return -1; +}