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// SPDX-License-Identifier: (LGPL-2.1 OR BSD-2-Clause)
/* Copyright (c) 2021 Facebook */
#include <stdint.h>
#include <stdlib.h>
#include <stdio.h>
#include <errno.h>
#include <linux/err.h>
#include "hashmap.h"
#include "libbpf_internal.h"
#include "strset.h"
struct strset {
void *strs_data;
size_t strs_data_len;
size_t strs_data_cap;
size_t strs_data_max_len;
/* lookup index for each unique string in strings set */
struct hashmap *strs_hash;
};
static size_t strset_hash_fn(long key, void *ctx)
{
const struct strset *s = ctx;
const char *str = s->strs_data + key;
return str_hash(str);
}
static bool strset_equal_fn(long key1, long key2, void *ctx)
{
const struct strset *s = ctx;
const char *str1 = s->strs_data + key1;
const char *str2 = s->strs_data + key2;
return strcmp(str1, str2) == 0;
}
struct strset *strset__new(size_t max_data_sz, const char *init_data, size_t init_data_sz)
{
struct strset *set = calloc(1, sizeof(*set));
struct hashmap *hash;
int err = -ENOMEM;
if (!set)
return ERR_PTR(-ENOMEM);
hash = hashmap__new(strset_hash_fn, strset_equal_fn, set);
if (IS_ERR(hash))
goto err_out;
set->strs_data_max_len = max_data_sz;
set->strs_hash = hash;
if (init_data) {
long off;
set->strs_data = malloc(init_data_sz);
if (!set->strs_data)
goto err_out;
memcpy(set->strs_data, init_data, init_data_sz);
set->strs_data_len = init_data_sz;
set->strs_data_cap = init_data_sz;
for (off = 0; off < set->strs_data_len; off += strlen(set->strs_data + off) + 1) {
/* hashmap__add() returns EEXIST if string with the same
* content already is in the hash map
*/
err = hashmap__add(hash, off, off);
if (err == -EEXIST)
continue; /* duplicate */
if (err)
goto err_out;
}
}
return set;
err_out:
strset__free(set);
return ERR_PTR(err);
}
void strset__free(struct strset *set)
{
if (IS_ERR_OR_NULL(set))
return;
hashmap__free(set->strs_hash);
free(set->strs_data);
free(set);
}
size_t strset__data_size(const struct strset *set)
{
return set->strs_data_len;
}
const char *strset__data(const struct strset *set)
{
return set->strs_data;
}
static void *strset_add_str_mem(struct strset *set, size_t add_sz)
{
return libbpf_add_mem(&set->strs_data, &set->strs_data_cap, 1,
set->strs_data_len, set->strs_data_max_len, add_sz);
}
/* Find string offset that corresponds to a given string *s*.
* Returns:
* - >0 offset into string data, if string is found;
* - -ENOENT, if string is not in the string data;
* - <0, on any other error.
*/
int strset__find_str(struct strset *set, const char *s)
{
long old_off, new_off, len;
void *p;
/* see strset__add_str() for why we do this */
len = strlen(s) + 1;
p = strset_add_str_mem(set, len);
if (!p)
return -ENOMEM;
new_off = set->strs_data_len;
memcpy(p, s, len);
if (hashmap__find(set->strs_hash, new_off, &old_off))
return old_off;
return -ENOENT;
}
/* Add a string s to the string data. If the string already exists, return its
* offset within string data.
* Returns:
* - > 0 offset into string data, on success;
* - < 0, on error.
*/
int strset__add_str(struct strset *set, const char *s)
{
long old_off, new_off, len;
void *p;
int err;
/* Hashmap keys are always offsets within set->strs_data, so to even
* look up some string from the "outside", we need to first append it
* at the end, so that it can be addressed with an offset. Luckily,
* until set->strs_data_len is incremented, that string is just a piece
* of garbage for the rest of the code, so no harm, no foul. On the
* other hand, if the string is unique, it's already appended and
* ready to be used, only a simple set->strs_data_len increment away.
*/
len = strlen(s) + 1;
p = strset_add_str_mem(set, len);
if (!p)
return -ENOMEM;
new_off = set->strs_data_len;
memcpy(p, s, len);
/* Now attempt to add the string, but only if the string with the same
* contents doesn't exist already (HASHMAP_ADD strategy). If such
* string exists, we'll get its offset in old_off (that's old_key).
*/
err = hashmap__insert(set->strs_hash, new_off, new_off,
HASHMAP_ADD, &old_off, NULL);
if (err == -EEXIST)
return old_off; /* duplicated string, return existing offset */
if (err)
return err;
set->strs_data_len += len; /* new unique string, adjust data length */
return new_off;
}
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