Peter McGoron
4f7847b2c0
The API is now hidden behind functions. The GC struct can have an unstable layout without affecting any compiled binaries (users of Universal Service or collectors hidden behind the API). The collectors can be called directly if desired. The API now allows for different allocation flags. These will be used in future extensions (like weak pointers). For now none are used. Tests are compiled for each collector. I can't think of a good solution that will encompass everything I want to write, but for now this will work on POSIX systems.
295 lines
8.2 KiB
C
295 lines
8.2 KiB
C
/* Copyright (c) 2024, Peter McGoron
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*
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* Redistribution and use in source and binary forms, with or without
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* modification, are permitted provided that the following conditions
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* are met:
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*
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* 1) Redistributions of source code must retain the above copyright
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* notice, this list of conditions and the following disclaimer.
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* 2) Redistributions in binary form must reproduce the above copyright
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* notice, this list of conditions and the following disclaimer in the
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* documentation and/or other materials provided with the distribution.
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*
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* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
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* "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
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* LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
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* A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
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* OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
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* SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED
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* TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR
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* PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF
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* LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING
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* NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
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* SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
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*/
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#include <stdio.h>
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#include <assert.h>
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#include <string.h>
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#include "uns.h"
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#include "uns_hashtable.h"
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enum {
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HTBL_LEN_PTR,
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HTBL_USED_PTR,
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HTBL_HDR_LEN
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};
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static size_t get_size_t(Uns_GC gc, struct uns_ctr *root, size_t i)
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{
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size_t r;
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void *p = uns_get(gc, root->p, i, NULL);
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memcpy(&r, p, sizeof(r));
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return r;
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}
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static void set_size_t(Uns_GC gc, struct uns_ctr *root, size_t i, size_t val)
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{
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void *p = uns_get(gc, root->p, i, NULL);
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memcpy(p, &val, sizeof(val));
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}
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static void *index(Uns_GC gc, struct uns_ctr *htbl, size_t i)
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{
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return uns_get(gc, htbl->p, i + HTBL_HDR_LEN, NULL);
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}
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void uns_hashtable_alloc_into(Uns_GC gc, struct uns_ctr *r, size_t size)
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{
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unsigned char *p;
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size_t i;
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r->p = uns_alloc_rec(gc, size + HTBL_HDR_LEN, 0);
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p = uns_alloc(gc, sizeof(size_t), 0);
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uns_set(gc, r->p, HTBL_LEN_PTR, UNS_POINTER, p);
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set_size_t(gc, r, HTBL_LEN_PTR, size);
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p = uns_alloc(gc, sizeof(size_t), 0);
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uns_set(gc, r->p, HTBL_USED_PTR, UNS_POINTER, p);
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set_size_t(gc, r, HTBL_USED_PTR, 0);
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/* Set entries to zero. */
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for (i = HTBL_HDR_LEN; i <= size; i++)
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uns_set(gc, r->p, i, UNS_POINTER, NULL);
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}
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size_t uns_hashtable_len(Uns_GC gc, struct uns_ctr *htbl)
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{
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return get_size_t(gc, htbl, HTBL_LEN_PTR);
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}
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size_t uns_hashtable_used(Uns_GC gc, struct uns_ctr *htbl)
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{
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return get_size_t(gc, htbl, HTBL_USED_PTR);
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}
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enum {
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LENGTH,
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STRING,
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VALUE,
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NEXT,
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HTBL_ENTRY_LEN
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};
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static void alloc_holder(Uns_GC gc, struct uns_ctr *r, struct uns_ctr *string,
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struct uns_ctr *value, size_t len)
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{
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unsigned char *alloc_ptr;
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r->p = uns_alloc_rec(gc, HTBL_ENTRY_LEN, 0);
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alloc_ptr = uns_alloc(gc, sizeof(size_t), 0);
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memcpy(alloc_ptr, &len, sizeof(size_t));
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uns_set(gc, r->p, LENGTH, UNS_POINTER, alloc_ptr);
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uns_set(gc, r->p, STRING, UNS_POINTER, string->p);
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uns_set(gc, r->p, VALUE, UNS_POINTER, value->p);
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uns_set(gc, r->p, NEXT, UNS_POINTER, NULL);
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}
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static unsigned long fnv(unsigned char *p, size_t len)
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{
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unsigned long hash = 0x811c9dc5;
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size_t i;
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for (i = 0; i < len; i++) {
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hash ^= p[i];
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hash *= 16777619;
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}
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return hash;
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}
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static int search_container(Uns_GC gc, struct uns_ctr *cur_ctr,
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unsigned char *str, size_t len)
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{
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unsigned char *ctr_str = uns_get(gc, cur_ctr->p, STRING, NULL);
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size_t ctr_str_len = get_size_t(gc, cur_ctr, LENGTH);
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void *next;
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if (ctr_str_len != len || memcmp(ctr_str, str, len) != 0) {
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/* strings do not match */
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next = uns_get(gc, cur_ctr->p, NEXT, NULL);
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if (!next)
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return 0;
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cur_ctr->p = next;
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return search_container(gc, cur_ctr, str, len);
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} else {
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return 1;
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}
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}
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static int search_for_container(Uns_GC gc, struct uns_ctr *htbl,
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struct uns_ctr *container,
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unsigned char *str, size_t len, size_t *hash_out)
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{
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size_t htbl_len = uns_hashtable_len(gc, htbl);
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size_t hash = fnv(str, len) % htbl_len;
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if (hash_out)
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*hash_out = hash;
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container->p = index(gc, htbl, hash);
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if (!container->p)
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return 0;
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return search_container(gc, container, str, len);
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}
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/* This could be made better with internal pointers, but that is not
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* portable.
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*/
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void uns_hashtable_del(Uns_GC gc, struct uns_ctr *htbl,
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unsigned char *str, size_t len,
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struct uns_ctr *old_value)
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{
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size_t hash = fnv(str, len) % uns_hashtable_len(gc, htbl);
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struct uns_ctr rec = {0};
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struct uns_ctr prevptr = {0};
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old_value->p = NULL;
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rec.p = index(gc, htbl, hash);
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if (!rec.p) {
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return;
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}
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/* Special case: first pointer */
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if (len == get_size_t(gc, &rec, LENGTH) &&
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memcmp(str, uns_get(gc, rec.p, STRING, NULL), len) == 0) {
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old_value->p = uns_get(gc, rec.p, VALUE, NULL);
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uns_set(gc, htbl->p, HTBL_HDR_LEN + hash, UNS_POINTER,
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uns_get(gc, rec.p, NEXT, NULL));
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}
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prevptr = rec;
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for (rec.p = uns_get(gc, rec.p, NEXT, NULL); rec.p;
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rec.p = uns_get(gc, rec.p, NEXT, NULL)) {
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if (len == get_size_t(gc, &rec, LENGTH)
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&& memcmp(str, uns_get(gc, rec.p, VALUE, NULL), len) == 0) {
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old_value->p = uns_get(gc, rec.p, VALUE, NULL);
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uns_set(gc, prevptr.p, UNS_POINTER, NEXT,
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uns_get(gc, rec.p, NEXT, NULL));
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return;
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}
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}
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}
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void uns_hashtable_search(Uns_GC gc, struct uns_ctr *htbl,
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unsigned char *str, size_t string_len,
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struct uns_ctr *found)
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{
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int r;
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r = search_for_container(gc, htbl, found, str, string_len, NULL);
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if (r)
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found->p = uns_get(gc, found->p, VALUE, NULL);
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else
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found->p = NULL;
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}
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void uns_hashtable_add(Uns_GC gc, struct uns_ctr *htbl,
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struct uns_ctr *string, size_t string_len,
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struct uns_ctr *value, struct uns_ctr *old_value)
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{
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struct uns_ctr container = {0};
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struct uns_ctr next_container = {0};
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size_t hash;
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if (uns_hashtable_used(gc, htbl) >= uns_hashtable_len(gc, htbl)*7/10)
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uns_hashtable_resize(gc, htbl, uns_hashtable_len(gc, htbl)*2);
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if (search_for_container(gc, htbl, &container, (unsigned char *)string->p, string_len, &hash)) {
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old_value->p = uns_get(gc, container.p, VALUE, NULL);
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uns_set(gc, container.p, VALUE, UNS_POINTER, value->p);
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return;
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}
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set_size_t(gc, htbl, HTBL_USED_PTR,
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uns_hashtable_used(gc, htbl) + 1);
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old_value->p = NULL;
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uns_root_add(gc, &container);
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uns_root_add(gc, &next_container);
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alloc_holder(gc, &next_container, string, value, string_len);
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if (container.p) {
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uns_set(gc, container.p, NEXT, UNS_POINTER, next_container.p);
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} else {
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uns_set(gc, htbl->p, hash + HTBL_HDR_LEN, UNS_POINTER, next_container.p);
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}
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uns_root_remove(gc, &next_container);
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uns_root_remove(gc, &container);
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}
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static void add_for_ent(Uns_GC gc, struct uns_ctr *htbl, void *ctrp)
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{
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struct uns_ctr ctr = {0};
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struct uns_ctr str = {0};
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size_t str_len;
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struct uns_ctr value = {0};
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struct uns_ctr old_value_should_never_happen = {0};
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if (!ctrp)
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return;
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ctr.p = ctrp;
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uns_root_add(gc, &ctr);
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uns_root_add(gc, &str);
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uns_root_add(gc, &value);
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uns_root_add(gc, &old_value_should_never_happen);
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str.p = uns_get(gc, ctr.p, STRING, NULL);
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value.p = uns_get(gc, ctr.p, VALUE, NULL);
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str_len = get_size_t(gc, &ctr, LENGTH);
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uns_hashtable_add(gc, htbl, &str, str_len, &value,
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&old_value_should_never_happen);
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assert(!old_value_should_never_happen.p);
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uns_root_remove(gc, &old_value_should_never_happen);
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uns_root_remove(gc, &value);
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uns_root_remove(gc, &str);
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uns_root_remove(gc, &ctr);
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ctrp = uns_get(gc, ctr.p, NEXT, NULL);
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add_for_ent(gc, htbl, ctrp);
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}
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void uns_hashtable_resize(Uns_GC gc, struct uns_ctr *htbl, size_t newsize)
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{
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struct uns_ctr newtbl = {0};
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size_t i;
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size_t oldlen = uns_hashtable_len(gc, htbl);
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uns_root_add(gc, &newtbl);
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uns_hashtable_alloc_into(gc, &newtbl, newsize);
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set_size_t(gc, &newtbl, HTBL_USED_PTR,
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uns_hashtable_used(gc, &newtbl));
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for (i = 0; i < oldlen; i++)
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add_for_ent(gc, &newtbl, index(gc, htbl, i));
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htbl->p = newtbl.p;
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uns_root_remove(gc, &newtbl);
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}
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