container.h

关于tor匿名通信的源代码

 */
/* Unpacks to, approximately:
 * {
 *   digestmap_iter_t *k_iter;
 *   for (k_iter = digestmap_iter_init(m); !digestmap_iter_done(k_iter);
 *        k_iter = digestmap_iter_next(m, k_iter)) {
 *     const char *k;
 *     void *r_voidp;
 *     routerinfo_t *r;
 *     digestmap_iter_get(k_iter, &k, &r_voidp);
 *     r = r_voidp;
 *     // use k and r
 *   }
 * }
 */
#define MAP_FOREACH(prefix, map, keytype, keyvar, valtype, valvar)      \
  STMT_BEGIN                                                            \
    prefix##iter_t *keyvar##_iter;                                      \
    for (keyvar##_iter = prefix##iter_init(map);                        \
         !prefix##iter_done(keyvar##_iter);                             \
         keyvar##_iter = prefix##iter_next(map, keyvar##_iter)) {       \
      keytype keyvar;                                                   \
      void *valvar##_voidp;                                             \
      valtype valvar;                                                   \
      prefix##iter_get(keyvar##_iter, &keyvar, &valvar##_voidp);        \
      valvar = valvar##_voidp;

/** As MAP_FOREACH, except allows members to be removed from the map
 * during the iteration via MAP_DEL_CURRENT.  Example use:
 *
 * Example use:
 *   MAP_FOREACH(digestmap_, m, const char *, k, routerinfo_t *, r) {
 *      if (is_very_old(r))
 *       MAP_DEL_CURRENT(k);
 *   } MAP_FOREACH_END.
 **/
/* Unpacks to, approximately:
 * {
 *   digestmap_iter_t *k_iter;
 *   int k_del=0;
 *   for (k_iter = digestmap_iter_init(m); !digestmap_iter_done(k_iter);
 *        k_iter = k_del ? digestmap_iter_next(m, k_iter)
 *                       : digestmap_iter_next_rmv(m, k_iter)) {
 *     const char *k;
 *     void *r_voidp;
 *     routerinfo_t *r;
 *     k_del=0;
 *     digestmap_iter_get(k_iter, &k, &r_voidp);
 *     r = r_voidp;
 *     if (is_very_old(r)) {
 *       k_del = 1;
 *     }
 *   }
 * }
 */
#define MAP_FOREACH_MODIFY(prefix, map, keytype, keyvar, valtype, valvar) \
  STMT_BEGIN                                                            \
    prefix##iter_t *keyvar##_iter;                                      \
    int keyvar##_del=0;                                                 \
    for (keyvar##_iter = prefix##iter_init(map);                        \
         !prefix##iter_done(keyvar##_iter);                             \
         keyvar##_iter = keyvar##_del ?                                 \
           prefix##iter_next_rmv(map, keyvar##_iter) :                  \
           prefix##iter_next(map, keyvar##_iter)) {                     \
      keytype keyvar;                                                   \
      void *valvar##_voidp;                                             \
      valtype valvar;                                                   \
      keyvar##_del=0;                                                   \
      prefix##iter_get(keyvar##_iter, &keyvar, &valvar##_voidp);        \
      valvar = valvar##_voidp;

/** Used with MAP_FOREACH_MODIFY to remove the currently-iterated-upon
 * member of the map.  */
#define MAP_DEL_CURRENT(keyvar)                   \
  STMT_BEGIN                                      \
    keyvar##_del = 1;                             \
  STMT_END

/** Used to end a MAP_FOREACH() block. */
#define MAP_FOREACH_END } STMT_END ;

/** As MAP_FOREACH, but does not require declaration of prefix or keytype.
 * Example use:
 *   DIGESTMAP_FOREACH(m, k, routerinfo_t *, r) {
 *     // use k and r
 *   } DIGESTMAP_FOREACH_END.
 */
#define DIGESTMAP_FOREACH(map, keyvar, valtype, valvar)                 \
  MAP_FOREACH(digestmap_, map, const char *, keyvar, valtype, valvar)

/** As MAP_FOREACH_MODIFY, but does not require declaration of prefix or
 * keytype.
 * Example use:
 *   DIGESTMAP_FOREACH_MODIFY(m, k, routerinfo_t *, r) {
 *      if (is_very_old(r))
 *       MAP_DEL_CURRENT(k);
 *   } DIGESTMAP_FOREACH_END.
 */
#define DIGESTMAP_FOREACH_MODIFY(map, keyvar, valtype, valvar)          \
  MAP_FOREACH_MODIFY(digestmap_, map, const char *, keyvar, valtype, valvar)
/** Used to end a DIGESTMAP_FOREACH() block. */
#define DIGESTMAP_FOREACH_END MAP_FOREACH_END

#define STRMAP_FOREACH(map, keyvar, valtype, valvar)                 \
  MAP_FOREACH(strmap_, map, const char *, keyvar, valtype, valvar)
#define STRMAP_FOREACH_MODIFY(map, keyvar, valtype, valvar)          \
  MAP_FOREACH_MODIFY(strmap_, map, const char *, keyvar, valtype, valvar)
#define STRMAP_FOREACH_END MAP_FOREACH_END

void* strmap_set_lc(strmap_t *map, const char *key, void *val);
void* strmap_get_lc(const strmap_t *map, const char *key);
void* strmap_remove_lc(strmap_t *map, const char *key);

#define DECLARE_TYPED_DIGESTMAP_FNS(prefix, maptype, valtype)           \
  typedef struct maptype maptype;                                       \
  typedef struct prefix##iter_t prefix##iter_t;                         \
  static INLINE maptype* prefix##new(void)                              \
  {                                                                     \
    return (maptype*)digestmap_new();                                   \
  }                                                                     \
  static INLINE digestmap_t* prefix##to_digestmap(maptype *map)         \
  {                                                                     \
    return (digestmap_t*)map;                                           \
  }                                                                     \
  static INLINE valtype* prefix##get(maptype *map, const char *key)     \
  {                                                                     \
    return (valtype*)digestmap_get((digestmap_t*)map, key);             \
  }                                                                     \
  static INLINE valtype* prefix##set(maptype *map, const char *key,     \
                                     valtype *val)                      \
  {                                                                     \
    return (valtype*)digestmap_set((digestmap_t*)map, key, val);        \
  }                                                                     \
  static INLINE valtype* prefix##remove(maptype *map, const char *key)  \
  {                                                                     \
    return (valtype*)digestmap_remove((digestmap_t*)map, key);          \
  }                                                                     \
  static INLINE void prefix##free(maptype *map, void (*free_val)(void*)) \
  {                                                                     \
    digestmap_free((digestmap_t*)map, free_val);                        \
  }                                                                     \
  static INLINE int prefix##isempty(maptype *map)                       \
  {                                                                     \
    return digestmap_isempty((digestmap_t*)map);                        \
  }                                                                     \
  static INLINE int prefix##size(maptype *map)                          \
  {                                                                     \
    return digestmap_size((digestmap_t*)map);                           \
  }                                                                     \
  static INLINE prefix##iter_t *prefix##iter_init(maptype *map)         \
  {                                                                     \
    return (prefix##iter_t*) digestmap_iter_init((digestmap_t*)map);    \
  }                                                                     \
  static INLINE prefix##iter_t *prefix##iter_next(maptype *map,         \
                                                  prefix##iter_t *iter) \
  {                                                                     \
    return (prefix##iter_t*) digestmap_iter_next(                       \
                       (digestmap_t*)map, (digestmap_iter_t*)iter);     \
  }                                                                     \
  static INLINE prefix##iter_t *prefix##iter_next_rmv(maptype *map,     \
                                                  prefix##iter_t *iter) \
  {                                                                     \
    return (prefix##iter_t*) digestmap_iter_next_rmv(                   \
                       (digestmap_t*)map, (digestmap_iter_t*)iter);     \
  }                                                                     \
  static INLINE void prefix##iter_get(prefix##iter_t *iter,             \
                                      const char **keyp,                \
                                      valtype **valp)                   \
  {                                                                     \
    void *v;                                                            \
    digestmap_iter_get((digestmap_iter_t*) iter, keyp, &v);             \
    *valp = v;                                                          \
  }                                                                     \
  static INLINE int prefix##iter_done(prefix##iter_t *iter)             \
  {                                                                     \
    return digestmap_iter_done((digestmap_iter_t*)iter);                \
  }

#if SIZEOF_INT == 4
#define BITARRAY_SHIFT 5
#elif SIZEOF_INT == 8
#define BITARRAY_SHIFT 6
#else
#error "int is neither 4 nor 8 bytes. I can't deal with that."
#endif
#define BITARRAY_MASK ((1u<<BITARRAY_SHIFT)-1)

/** A random-access array of one-bit-wide elements. */
typedef unsigned int bitarray_t;
/** Create a new bit array that can hold <b>n_bits</b> bits. */
static INLINE bitarray_t *
bitarray_init_zero(unsigned int n_bits)
{
  /* round up to the next int. */
  size_t sz = (n_bits+BITARRAY_MASK) >> BITARRAY_SHIFT;
  return tor_malloc_zero(sz*sizeof(unsigned int));
}
/** Expand <b>ba</b> from holding <b>n_bits_old</b> to <b>n_bits_new</b>,
 * clearing all new bits.  Returns a possibly changed pointer to the
 * bitarray. */
static INLINE bitarray_t *
bitarray_expand(bitarray_t *ba,
                unsigned int n_bits_old, unsigned int n_bits_new)
{
  size_t sz_old = (n_bits_old+BITARRAY_MASK) >> BITARRAY_SHIFT;
  size_t sz_new = (n_bits_new+BITARRAY_MASK) >> BITARRAY_SHIFT;
  char *ptr;
  if (sz_new <= sz_old)
    return ba;
  ptr = tor_realloc(ba, sz_new*sizeof(unsigned int));
  /* This memset does nothing to the older excess bytes.  But they were
   * already set to 0 by bitarry_init_zero. */
  memset(ptr+sz_old*sizeof(unsigned int), 0,
         (sz_new-sz_old)*sizeof(unsigned int));
  return (bitarray_t*) ptr;
}
/** Free the bit array <b>ba</b>. */
static INLINE void
bitarray_free(bitarray_t *ba)
{
  tor_free(ba);
}
/** Set the <b>bit</b>th bit in <b>b</b> to 1. */
static INLINE void
bitarray_set(bitarray_t *b, int bit)
{
  b[bit >> BITARRAY_SHIFT] |= (1u << (bit & BITARRAY_MASK));
}
/** Set the <b>bit</b>th bit in <b>b</b> to 0. */
static INLINE void
bitarray_clear(bitarray_t *b, int bit)
{
  b[bit >> BITARRAY_SHIFT] &= ~ (1u << (bit & BITARRAY_MASK));
}
/** Return true iff <b>bit</b>th bit in <b>b</b> is nonzero.  NOTE: does
 * not necessarily return 1 on true. */
static INLINE unsigned int
bitarray_is_set(bitarray_t *b, int bit)
{
  return b[bit >> BITARRAY_SHIFT] & (1u << (bit & BITARRAY_MASK));
}

/** A set of digests, implemented as a Bloom filter. */
typedef struct {
  int mask; /* One less than the number of bits in <b>ba</b>; always one less
             * than a power of two. */
  bitarray_t *ba; /* A bit array to implement the Bloom filter. */
} digestset_t;

#define BIT(n) ((n) & set->mask)
/** Add the digest <b>digest</b> to <b>set</b>. */
static INLINE void
digestset_add(digestset_t *set, const char *digest)
{
  const uint32_t *p = (const uint32_t *)digest;
  const uint32_t d1 = p[0] + (p[1]>>16);
  const uint32_t d2 = p[1] + (p[2]>>16);
  const uint32_t d3 = p[2] + (p[3]>>16);
  const uint32_t d4 = p[3] + (p[0]>>16);
  bitarray_set(set->ba, BIT(d1));
  bitarray_set(set->ba, BIT(d2));
  bitarray_set(set->ba, BIT(d3));
  bitarray_set(set->ba, BIT(d4));
}

/** If <b>digest</b> is in <b>set</b>, return nonzero.  Otherwise,
 * <em>probably</em> return zero. */
static INLINE int
digestset_isin(const digestset_t *set, const char *digest)
{
  const uint32_t *p = (const uint32_t *)digest;
  const uint32_t d1 = p[0] + (p[1]>>16);
  const uint32_t d2 = p[1] + (p[2]>>16);
  const uint32_t d3 = p[2] + (p[3]>>16);
  const uint32_t d4 = p[3] + (p[0]>>16);
  return bitarray_is_set(set->ba, BIT(d1)) &&
         bitarray_is_set(set->ba, BIT(d2)) &&
         bitarray_is_set(set->ba, BIT(d3)) &&
         bitarray_is_set(set->ba, BIT(d4));
}
#undef BIT

digestset_t *digestset_new(int max_elements);
void digestset_free(digestset_t* set);

/* These functions, given an <b>array</b> of <b>n_elements</b>, return the
 * <b>nth</b> lowest element. <b>nth</b>=0 gives the lowest element;
 * <b>n_elements</b>-1 gives the highest; and (<b>n_elements</b>-1) / 2 gives
 * the median.  As a side effect, the elements of <b>array</b> are sorted. */
int find_nth_int(int *array, int n_elements, int nth);
time_t find_nth_time(time_t *array, int n_elements, int nth);
double find_nth_double(double *array, int n_elements, int nth);
uint32_t find_nth_uint32(uint32_t *array, int n_elements, int nth);
long find_nth_long(long *array, int n_elements, int nth);
static INLINE int
median_int(int *array, int n_elements)
{
  return find_nth_int(array, n_elements, (n_elements-1)/2);
}
static INLINE time_t
median_time(time_t *array, int n_elements)
{
  return find_nth_time(array, n_elements, (n_elements-1)/2);
}
static INLINE double
median_double(double *array, int n_elements)
{
  return find_nth_double(array, n_elements, (n_elements-1)/2);
}
static INLINE uint32_t
median_uint32(uint32_t *array, int n_elements)
{
  return find_nth_uint32(array, n_elements, (n_elements-1)/2);
}
static INLINE long
median_long(long *array, int n_elements)
{
  return find_nth_long(array, n_elements, (n_elements-1)/2);
}

#endif