tor/src/lib/container/map.c

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/* Copyright (c) 2003-2004, Roger Dingledine
* Copyright (c) 2004-2006, Roger Dingledine, Nick Mathewson.
* Copyright (c) 2007-2018, The Tor Project, Inc. */
/* See LICENSE for licensing information */
/**
* \file container.c
* \brief Implements a smartlist (a resizable array) along
* with helper functions to use smartlists. Also includes
* hash table implementations of a string-to-void* map, and of
* a digest-to-void* map.
**/
#include "lib/container/map.h"
#include "lib/ctime/di_ops.h"
#include "lib/defs/digest_sizes.h"
#include "common/util_bug.h"
#include "common/util.h" // For strlower
#include <stdlib.h>
#include <string.h>
#include "ht.h"
/** Helper: Declare an entry type and a map type to implement a mapping using
* ht.h. The map type will be called <b>maptype</b>. The key part of each
* entry is declared using the C declaration <b>keydecl</b>. All functions
* and types associated with the map get prefixed with <b>prefix</b> */
#define DEFINE_MAP_STRUCTS(maptype, keydecl, prefix) \
typedef struct prefix ## entry_t { \
HT_ENTRY(prefix ## entry_t) node; \
void *val; \
keydecl; \
} prefix ## entry_t; \
struct maptype { \
HT_HEAD(prefix ## impl, prefix ## entry_t) head; \
}
DEFINE_MAP_STRUCTS(strmap_t, char *key, strmap_);
DEFINE_MAP_STRUCTS(digestmap_t, char key[DIGEST_LEN], digestmap_);
DEFINE_MAP_STRUCTS(digest256map_t, uint8_t key[DIGEST256_LEN], digest256map_);
/** Helper: compare strmap_entry_t objects by key value. */
static inline int
strmap_entries_eq(const strmap_entry_t *a, const strmap_entry_t *b)
{
return !strcmp(a->key, b->key);
}
/** Helper: return a hash value for a strmap_entry_t. */
static inline unsigned int
strmap_entry_hash(const strmap_entry_t *a)
{
return (unsigned) siphash24g(a->key, strlen(a->key));
}
/** Helper: compare digestmap_entry_t objects by key value. */
static inline int
digestmap_entries_eq(const digestmap_entry_t *a, const digestmap_entry_t *b)
{
return tor_memeq(a->key, b->key, DIGEST_LEN);
}
/** Helper: return a hash value for a digest_map_t. */
static inline unsigned int
digestmap_entry_hash(const digestmap_entry_t *a)
{
return (unsigned) siphash24g(a->key, DIGEST_LEN);
}
/** Helper: compare digestmap_entry_t objects by key value. */
static inline int
digest256map_entries_eq(const digest256map_entry_t *a,
const digest256map_entry_t *b)
{
return tor_memeq(a->key, b->key, DIGEST256_LEN);
}
/** Helper: return a hash value for a digest_map_t. */
static inline unsigned int
digest256map_entry_hash(const digest256map_entry_t *a)
{
return (unsigned) siphash24g(a->key, DIGEST256_LEN);
}
HT_PROTOTYPE(strmap_impl, strmap_entry_t, node, strmap_entry_hash,
strmap_entries_eq)
HT_GENERATE2(strmap_impl, strmap_entry_t, node, strmap_entry_hash,
strmap_entries_eq, 0.6, tor_reallocarray_, tor_free_)
HT_PROTOTYPE(digestmap_impl, digestmap_entry_t, node, digestmap_entry_hash,
digestmap_entries_eq)
HT_GENERATE2(digestmap_impl, digestmap_entry_t, node, digestmap_entry_hash,
digestmap_entries_eq, 0.6, tor_reallocarray_, tor_free_)
HT_PROTOTYPE(digest256map_impl, digest256map_entry_t, node,
digest256map_entry_hash,
digest256map_entries_eq)
HT_GENERATE2(digest256map_impl, digest256map_entry_t, node,
digest256map_entry_hash,
digest256map_entries_eq, 0.6, tor_reallocarray_, tor_free_)
#define strmap_entry_free(ent) \
FREE_AND_NULL(strmap_entry_t, strmap_entry_free_, (ent))
#define digestmap_entry_free(ent) \
FREE_AND_NULL(digestmap_entry_t, digestmap_entry_free_, (ent))
#define digest256map_entry_free(ent) \
FREE_AND_NULL(digest256map_entry_t, digest256map_entry_free_, (ent))
static inline void
strmap_entry_free_(strmap_entry_t *ent)
{
tor_free(ent->key);
tor_free(ent);
}
static inline void
digestmap_entry_free_(digestmap_entry_t *ent)
{
tor_free(ent);
}
static inline void
digest256map_entry_free_(digest256map_entry_t *ent)
{
tor_free(ent);
}
static inline void
strmap_assign_tmp_key(strmap_entry_t *ent, const char *key)
{
ent->key = (char*)key;
}
static inline void
digestmap_assign_tmp_key(digestmap_entry_t *ent, const char *key)
{
memcpy(ent->key, key, DIGEST_LEN);
}
static inline void
digest256map_assign_tmp_key(digest256map_entry_t *ent, const uint8_t *key)
{
memcpy(ent->key, key, DIGEST256_LEN);
}
static inline void
strmap_assign_key(strmap_entry_t *ent, const char *key)
{
ent->key = tor_strdup(key);
}
static inline void
digestmap_assign_key(digestmap_entry_t *ent, const char *key)
{
memcpy(ent->key, key, DIGEST_LEN);
}
static inline void
digest256map_assign_key(digest256map_entry_t *ent, const uint8_t *key)
{
memcpy(ent->key, key, DIGEST256_LEN);
}
/**
* Macro: implement all the functions for a map that are declared in
* container.h by the DECLARE_MAP_FNS() macro. You must additionally define a
* prefix_entry_free_() function to free entries (and their keys), a
* prefix_assign_tmp_key() function to temporarily set a stack-allocated
* entry to hold a key, and a prefix_assign_key() function to set a
* heap-allocated entry to hold a key.
*/
#define IMPLEMENT_MAP_FNS(maptype, keytype, prefix) \
/** Create and return a new empty map. */ \
MOCK_IMPL(maptype *, \
prefix##_new,(void)) \
{ \
maptype *result; \
result = tor_malloc(sizeof(maptype)); \
HT_INIT(prefix##_impl, &result->head); \
return result; \
} \
\
/** Return the item from <b>map</b> whose key matches <b>key</b>, or \
* NULL if no such value exists. */ \
void * \
prefix##_get(const maptype *map, const keytype key) \
{ \
prefix ##_entry_t *resolve; \
prefix ##_entry_t search; \
tor_assert(map); \
tor_assert(key); \
prefix ##_assign_tmp_key(&search, key); \
resolve = HT_FIND(prefix ##_impl, &map->head, &search); \
if (resolve) { \
return resolve->val; \
} else { \
return NULL; \
} \
} \
\
/** Add an entry to <b>map</b> mapping <b>key</b> to <b>val</b>; \
* return the previous value, or NULL if no such value existed. */ \
void * \
prefix##_set(maptype *map, const keytype key, void *val) \
{ \
prefix##_entry_t search; \
void *oldval; \
tor_assert(map); \
tor_assert(key); \
tor_assert(val); \
prefix##_assign_tmp_key(&search, key); \
/* We a lot of our time in this function, so the code below is */ \
/* meant to optimize the check/alloc/set cycle by avoiding the two */\
/* trips to the hash table that we would do in the unoptimized */ \
/* version of this code. (Each of HT_INSERT and HT_FIND calls */ \
/* HT_SET_HASH and HT_FIND_P.) */ \
HT_FIND_OR_INSERT_(prefix##_impl, node, prefix##_entry_hash, \
&(map->head), \
prefix##_entry_t, &search, ptr, \
{ \
/* we found an entry. */ \
oldval = (*ptr)->val; \
(*ptr)->val = val; \
return oldval; \
}, \
{ \
/* We didn't find the entry. */ \
prefix##_entry_t *newent = \
tor_malloc_zero(sizeof(prefix##_entry_t)); \
prefix##_assign_key(newent, key); \
newent->val = val; \
HT_FOI_INSERT_(node, &(map->head), \
&search, newent, ptr); \
return NULL; \
}); \
} \
\
/** Remove the value currently associated with <b>key</b> from the map. \
* Return the value if one was set, or NULL if there was no entry for \
* <b>key</b>. \
* \
* Note: you must free any storage associated with the returned value. \
*/ \
void * \
prefix##_remove(maptype *map, const keytype key) \
{ \
prefix##_entry_t *resolve; \
prefix##_entry_t search; \
void *oldval; \
tor_assert(map); \
tor_assert(key); \
prefix##_assign_tmp_key(&search, key); \
resolve = HT_REMOVE(prefix##_impl, &map->head, &search); \
if (resolve) { \
oldval = resolve->val; \
prefix##_entry_free(resolve); \
return oldval; \
} else { \
return NULL; \
} \
} \
\
/** Return the number of elements in <b>map</b>. */ \
int \
prefix##_size(const maptype *map) \
{ \
return HT_SIZE(&map->head); \
} \
\
/** Return true iff <b>map</b> has no entries. */ \
int \
prefix##_isempty(const maptype *map) \
{ \
return HT_EMPTY(&map->head); \
} \
\
/** Assert that <b>map</b> is not corrupt. */ \
void \
prefix##_assert_ok(const maptype *map) \
{ \
tor_assert(!prefix##_impl_HT_REP_IS_BAD_(&map->head)); \
} \
\
/** Remove all entries from <b>map</b>, and deallocate storage for \
* those entries. If free_val is provided, invoked it every value in \
* <b>map</b>. */ \
MOCK_IMPL(void, \
prefix##_free_, (maptype *map, void (*free_val)(void*))) \
{ \
prefix##_entry_t **ent, **next, *this; \
if (!map) \
return; \
for (ent = HT_START(prefix##_impl, &map->head); ent != NULL; \
ent = next) { \
this = *ent; \
next = HT_NEXT_RMV(prefix##_impl, &map->head, ent); \
if (free_val) \
free_val(this->val); \
prefix##_entry_free(this); \
} \
tor_assert(HT_EMPTY(&map->head)); \
HT_CLEAR(prefix##_impl, &map->head); \
tor_free(map); \
} \
\
/** return an <b>iterator</b> pointer to the front of a map. \
* \
* Iterator example: \
* \
* \code \
* // uppercase values in "map", removing empty values. \
* \
* strmap_iter_t *iter; \
* const char *key; \
* void *val; \
* char *cp; \
* \
* for (iter = strmap_iter_init(map); !strmap_iter_done(iter); ) { \
* strmap_iter_get(iter, &key, &val); \
* cp = (char*)val; \
* if (!*cp) { \
* iter = strmap_iter_next_rmv(map,iter); \
* free(val); \
* } else { \
* for (;*cp;cp++) *cp = TOR_TOUPPER(*cp); \
*/ \
prefix##_iter_t * \
prefix##_iter_init(maptype *map) \
{ \
tor_assert(map); \
return HT_START(prefix##_impl, &map->head); \
} \
\
/** Advance <b>iter</b> a single step to the next entry, and return \
* its new value. */ \
prefix##_iter_t * \
prefix##_iter_next(maptype *map, prefix##_iter_t *iter) \
{ \
tor_assert(map); \
tor_assert(iter); \
return HT_NEXT(prefix##_impl, &map->head, iter); \
} \
/** Advance <b>iter</b> a single step to the next entry, removing the \
* current entry, and return its new value. */ \
prefix##_iter_t * \
prefix##_iter_next_rmv(maptype *map, prefix##_iter_t *iter) \
{ \
prefix##_entry_t *rmv; \
tor_assert(map); \
tor_assert(iter); \
tor_assert(*iter); \
rmv = *iter; \
iter = HT_NEXT_RMV(prefix##_impl, &map->head, iter); \
prefix##_entry_free(rmv); \
return iter; \
} \
/** Set *<b>keyp</b> and *<b>valp</b> to the current entry pointed \
* to by iter. */ \
void \
prefix##_iter_get(prefix##_iter_t *iter, const keytype *keyp, \
void **valp) \
{ \
tor_assert(iter); \
tor_assert(*iter); \
tor_assert(keyp); \
tor_assert(valp); \
*keyp = (*iter)->key; \
*valp = (*iter)->val; \
} \
/** Return true iff <b>iter</b> has advanced past the last entry of \
* <b>map</b>. */ \
int \
prefix##_iter_done(prefix##_iter_t *iter) \
{ \
return iter == NULL; \
}
IMPLEMENT_MAP_FNS(strmap_t, char *, strmap)
IMPLEMENT_MAP_FNS(digestmap_t, char *, digestmap)
IMPLEMENT_MAP_FNS(digest256map_t, uint8_t *, digest256map)
/** Same as strmap_set, but first converts <b>key</b> to lowercase. */
void *
strmap_set_lc(strmap_t *map, const char *key, void *val)
{
/* We could be a little faster by using strcasecmp instead, and a separate
* type, but I don't think it matters. */
void *v;
char *lc_key = tor_strdup(key);
tor_strlower(lc_key);
v = strmap_set(map,lc_key,val);
tor_free(lc_key);
return v;
}
/** Same as strmap_get, but first converts <b>key</b> to lowercase. */
void *
strmap_get_lc(const strmap_t *map, const char *key)
{
void *v;
char *lc_key = tor_strdup(key);
tor_strlower(lc_key);
v = strmap_get(map,lc_key);
tor_free(lc_key);
return v;
}
/** Same as strmap_remove, but first converts <b>key</b> to lowercase */
void *
strmap_remove_lc(strmap_t *map, const char *key)
{
void *v;
char *lc_key = tor_strdup(key);
tor_strlower(lc_key);
v = strmap_remove(map,lc_key);
tor_free(lc_key);
return v;
}