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/* SPDX-License-Identifier: GPL-3.0-or-later */
#include "config.h"
#include <stdint.h>
#include <stdlib.h>
#include <string.h>
#include <stdio.h>
#include "str_table.h"
/* R5 hash function (borrowed from reiserfs) */
static uint32_t strhash(const char *s)
{
const signed char *str = (const signed char *)s;
uint32_t a = 0;
while (*str != '\0') {
a += *str << 4;
a += *str >> 4;
a *= 11;
str++;
}
return a;
}
static int strings_grow(str_table_t *table)
{
size_t newsz;
void *new;
if (table->num_strings < table->max_strings)
return 0;
newsz = table->max_strings ? (table->max_strings * 2) : 16;
new = realloc(table->strings, sizeof(table->strings[0]) * newsz);
if (new == NULL) {
perror("growing string table");
return -1;
}
table->strings = new;
table->max_strings = newsz;
return 0;
}
int str_table_init(str_table_t *table, size_t size)
{
memset(table, 0, sizeof(*table));
table->buckets = calloc(size, sizeof(table->buckets[0]));
table->num_buckets = size;
if (table->buckets == NULL) {
perror("initializing string table");
return -1;
}
return 0;
}
void str_table_cleanup(str_table_t *table)
{
str_bucket_t *bucket;
size_t i;
for (i = 0; i < table->num_buckets; ++i) {
while (table->buckets[i] != NULL) {
bucket = table->buckets[i];
table->buckets[i] = bucket->next;
free(bucket->str);
free(bucket);
}
}
free(table->buckets);
free(table->strings);
memset(table, 0, sizeof(*table));
}
int str_table_get_index(str_table_t *table, const char *str, size_t *idx)
{
str_bucket_t *bucket;
uint32_t hash;
size_t index;
hash = strhash(str);
index = hash % table->num_buckets;
bucket = table->buckets[index];
while (bucket != NULL) {
if (strcmp(bucket->str, str) == 0) {
*idx = bucket->index;
return 0;
}
bucket = bucket->next;
}
if (strings_grow(table))
return -1;
bucket = calloc(1, sizeof(*bucket));
if (bucket == NULL)
goto fail_oom;
bucket->str = strdup(str);
if (bucket->str == NULL)
goto fail_oom;
bucket->index = table->num_strings;
table->strings[table->num_strings++] = bucket->str;
*idx = bucket->index;
bucket->next = table->buckets[index];
table->buckets[index] = bucket;
return 0;
fail_oom:
free(bucket);
perror("allocating hash table bucket");
return -1;
}
const char *str_table_get_string(str_table_t *table, size_t index)
{
if (index >= table->num_strings)
return NULL;
return table->strings[index];
}
static str_bucket_t *bucket_by_index(str_table_t *table, size_t index)
{
str_bucket_t *bucket = NULL;
uint32_t hash;
if (index < table->num_strings) {
hash = strhash(table->strings[index]);
bucket = table->buckets[hash % table->num_buckets];
while (bucket != NULL && bucket->index != index)
bucket = bucket->next;
}
return bucket;
}
void str_table_reset_ref_count(str_table_t *table)
{
str_bucket_t *bucket;
size_t i;
for (i = 0; i < table->num_buckets; ++i) {
bucket = table->buckets[i];
while (bucket != NULL) {
bucket->refcount = 0;
bucket = bucket->next;
}
}
}
void str_table_add_ref(str_table_t *table, size_t index)
{
str_bucket_t *bucket = bucket_by_index(table, index);
if (bucket != NULL && bucket->refcount < ~((size_t)0))
bucket->refcount += 1;
}
size_t str_table_get_ref_count(str_table_t *table, size_t index)
{
str_bucket_t *bucket = bucket_by_index(table, index);
return bucket != NULL ? bucket->refcount : 0;
}
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