path: root/contrib/libs/libevent/ht-internal.h

/* Copyright 2002 Christopher Clark */
/* Copyright 2005-2012 Nick Mathewson */ 
/* Copyright 2009-2012 Niels Provos and Nick Mathewson */ 
/* See license at end. */ 
 
/* Based on ideas by Christopher Clark and interfaces from Niels Provos. */ 
 
#ifndef HT_INTERNAL_H_INCLUDED_
#define HT_INTERNAL_H_INCLUDED_
 
#define HT_HEAD(name, type)                                             \ 
  struct name {                                                         \ 
    /* The hash table itself. */                                        \ 
    struct type **hth_table;                                            \ 
    /* How long is the hash table? */                                   \ 
    unsigned hth_table_length;                                          \ 
    /* How many elements does the table contain? */                     \ 
    unsigned hth_n_entries;                                             \ 
    /* How many elements will we allow in the table before resizing it? */ \ 
    unsigned hth_load_limit;                                            \ 
    /* Position of hth_table_length in the primes table. */             \ 
    int hth_prime_idx;                                                  \ 
  } 
 
#define HT_INITIALIZER()                        \ 
  { NULL, 0, 0, 0, -1 } 
 
#ifdef HT_NO_CACHE_HASH_VALUES
#define HT_ENTRY(type)                          \ 
  struct {                                      \ 
    struct type *hte_next;                      \ 
  } 
#else 
#define HT_ENTRY(type)                          \ 
  struct {                                      \ 
    struct type *hte_next;                      \ 
    unsigned hte_hash;                          \
  } 
#endif 
 
#define HT_EMPTY(head)                          \ 
  ((head)->hth_n_entries == 0) 
 
/* How many elements in 'head'? */ 
#define HT_SIZE(head)                           \ 
  ((head)->hth_n_entries) 
 
/* Return memory usage for a hashtable (not counting the entries themselves) */
#define HT_MEM_USAGE(head)                         \
  (sizeof(*head) + (head)->hth_table_length * sizeof(void*))

#define HT_FIND(name, head, elm)     name##_HT_FIND((head), (elm)) 
#define HT_INSERT(name, head, elm)   name##_HT_INSERT((head), (elm)) 
#define HT_REPLACE(name, head, elm)  name##_HT_REPLACE((head), (elm)) 
#define HT_REMOVE(name, head, elm)   name##_HT_REMOVE((head), (elm)) 
#define HT_START(name, head)         name##_HT_START(head) 
#define HT_NEXT(name, head, elm)     name##_HT_NEXT((head), (elm)) 
#define HT_NEXT_RMV(name, head, elm) name##_HT_NEXT_RMV((head), (elm)) 
#define HT_CLEAR(name, head)         name##_HT_CLEAR(head) 
#define HT_INIT(name, head)          name##_HT_INIT(head) 
/* Helper: */ 
static inline unsigned 
ht_improve_hash_(unsigned h)
{ 
  /* Aim to protect against poor hash functions by adding logic here 
   * - logic taken from java 1.4 hashtable source */ 
  h += ~(h << 9); 
  h ^=  ((h >> 14) | (h << 18)); /* >>> */ 
  h +=  (h << 4); 
  h ^=  ((h >> 10) | (h << 22)); /* >>> */ 
  return h; 
} 
 
#if 0 
/** Basic string hash function, from Java standard String.hashCode(). */ 
static inline unsigned 
ht_string_hash_(const char *s)
{ 
  unsigned h = 0; 
  int m = 1; 
  while (*s) { 
    h += ((signed char)*s++)*m; 
    m = (m<<5)-1; /* m *= 31 */ 
  } 
  return h; 
} 
#endif 
 
/** Basic string hash function, from Python's str.__hash__() */ 
static inline unsigned 
ht_string_hash_(const char *s)
{ 
  unsigned h; 
  const unsigned char *cp = (const unsigned char *)s; 
  h = *cp << 7; 
  while (*cp) { 
    h = (1000003*h) ^ *cp++; 
  } 
  /* This conversion truncates the length of the string, but that's ok. */ 
  h ^= (unsigned)(cp-(const unsigned char*)s); 
  return h; 
} 
 
#ifndef HT_NO_CACHE_HASH_VALUES
#define HT_SET_HASH_(elm, field, hashfn)        \
	do { (elm)->field.hte_hash = hashfn(elm); } while (0) 
#define HT_SET_HASHVAL_(elm, field, val)	\
	do { (elm)->field.hte_hash = (val); } while (0) 
#define HT_ELT_HASH_(elm, field, hashfn)	\
	((elm)->field.hte_hash) 
#else 
#define HT_SET_HASH_(elm, field, hashfn)	\
	((void)0) 
#define HT_ELT_HASH_(elm, field, hashfn)	\
	(hashfn(elm)) 
#define HT_SET_HASHVAL_(elm, field, val)	\
        ((void)0) 
#endif 
 
/* Helper: alias for the bucket containing 'elm'. */ 
#define HT_BUCKET_(head, field, elm, hashfn)				\
	((head)->hth_table[HT_ELT_HASH_(elm,field,hashfn) % head->hth_table_length])
 
#define HT_FOREACH(x, name, head)                 \ 
  for ((x) = HT_START(name, head);                \ 
       (x) != NULL;                               \ 
       (x) = HT_NEXT(name, head, x)) 
 
#define HT_PROTOTYPE(name, type, field, hashfn, eqfn)                   \ 
  int name##_HT_GROW(struct name *ht, unsigned min_capacity);           \ 
  void name##_HT_CLEAR(struct name *ht);                                \ 
  int name##_HT_REP_IS_BAD_(const struct name *ht);			\
  static inline void                                                    \ 
  name##_HT_INIT(struct name *head) {                                   \ 
    head->hth_table_length = 0;                                         \ 
    head->hth_table = NULL;                                             \ 
    head->hth_n_entries = 0;                                            \ 
    head->hth_load_limit = 0;                                           \ 
    head->hth_prime_idx = -1;                                           \ 
  }                                                                     \ 
  /* Helper: returns a pointer to the right location in the table       \ 
   * 'head' to find or insert the element 'elm'. */                     \ 
  static inline struct type **                                          \ 
  name##_HT_FIND_P_(struct name *head, struct type *elm)		\
  {                                                                     \ 
    struct type **p;                                                    \ 
    if (!head->hth_table)                                               \ 
      return NULL;                                                      \ 
    p = &HT_BUCKET_(head, field, elm, hashfn);				\
    while (*p) {                                                        \ 
      if (eqfn(*p, elm))                                                \ 
        return p;                                                       \ 
      p = &(*p)->field.hte_next;                                        \ 
    }                                                                   \ 
    return p;                                                           \ 
  }                                                                     \ 
  /* Return a pointer to the element in the table 'head' matching 'elm', \ 
   * or NULL if no such element exists */                               \ 
  static inline struct type *                                           \ 
  name##_HT_FIND(const struct name *head, struct type *elm)             \ 
  {                                                                     \ 
    struct type **p;                                                    \ 
    struct name *h = (struct name *) head;                              \ 
    HT_SET_HASH_(elm, field, hashfn);                                   \
    p = name##_HT_FIND_P_(h, elm);					\
    return p ? *p : NULL;                                               \ 
  }                                                                     \ 
  /* Insert the element 'elm' into the table 'head'.  Do not call this  \ 
   * function if the table might already contain a matching element. */ \ 
  static inline void                                                    \ 
  name##_HT_INSERT(struct name *head, struct type *elm)                 \ 
  {                                                                     \ 
    struct type **p;                                                    \ 
    if (!head->hth_table || head->hth_n_entries >= head->hth_load_limit) \ 
      name##_HT_GROW(head, head->hth_n_entries+1);                      \ 
    ++head->hth_n_entries;                                              \ 
    HT_SET_HASH_(elm, field, hashfn);                                   \
    p = &HT_BUCKET_(head, field, elm, hashfn);				\
    elm->field.hte_next = *p;                                           \ 
    *p = elm;                                                           \ 
  }                                                                     \ 
  /* Insert the element 'elm' into the table 'head'. If there already   \ 
   * a matching element in the table, replace that element and return   \ 
   * it. */                                                             \ 
  static inline struct type *                                           \ 
  name##_HT_REPLACE(struct name *head, struct type *elm)                \ 
  {                                                                     \ 
    struct type **p, *r;                                                \ 
    if (!head->hth_table || head->hth_n_entries >= head->hth_load_limit) \ 
      name##_HT_GROW(head, head->hth_n_entries+1);                      \ 
    HT_SET_HASH_(elm, field, hashfn);                                   \
    p = name##_HT_FIND_P_(head, elm);					\
    r = *p;                                                             \ 
    *p = elm;                                                           \ 
    if (r && (r!=elm)) {                                                \ 
      elm->field.hte_next = r->field.hte_next;                          \ 
      r->field.hte_next = NULL;                                         \ 
      return r;                                                         \ 
    } else {                                                            \ 
      ++head->hth_n_entries;                                            \ 
      return NULL;                                                      \ 
    }                                                                   \ 
  }                                                                     \ 
  /* Remove any element matching 'elm' from the table 'head'.  If such  \ 
   * an element is found, return it; otherwise return NULL. */          \ 
  static inline struct type *                                           \ 
  name##_HT_REMOVE(struct name *head, struct type *elm)                 \ 
  {                                                                     \ 
    struct type **p, *r;                                                \ 
    HT_SET_HASH_(elm, field, hashfn);                                   \
    p = name##_HT_FIND_P_(head,elm);					\
    if (!p || !*p)                                                      \ 
      return NULL;                                                      \ 
    r = *p;                                                             \ 
    *p = r->field.hte_next;                                             \ 
    r->field.hte_next = NULL;                                           \ 
    --head->hth_n_entries;                                              \ 
    return r;                                                           \ 
  }                                                                     \ 
  /* Invoke the function 'fn' on every element of the table 'head',     \ 
   * using 'data' as its second argument.  If the function returns      \ 
   * nonzero, remove the most recently examined element before invoking \ 
   * the function again. */                                             \ 
  static inline void                                                    \ 
  name##_HT_FOREACH_FN(struct name *head,                               \ 
                       int (*fn)(struct type *, void *),                \ 
                       void *data)                                      \ 
  {                                                                     \ 
    unsigned idx;                                                       \ 
    struct type **p, **nextp, *next;                                    \ 
    if (!head->hth_table)                                               \ 
      return;                                                           \ 
    for (idx=0; idx < head->hth_table_length; ++idx) {                  \ 
      p = &head->hth_table[idx];                                        \ 
      while (*p) {                                                      \ 
        nextp = &(*p)->field.hte_next;                                  \ 
        next = *nextp;                                                  \ 
        if (fn(*p, data)) {                                             \ 
          --head->hth_n_entries;                                        \ 
          *p = next;                                                    \ 
        } else {                                                        \ 
          p = nextp;                                                    \ 
        }                                                               \ 
      }                                                                 \ 
    }                                                                   \ 
  }                                                                     \ 
  /* Return a pointer to the first element in the table 'head', under   \ 
   * an arbitrary order.  This order is stable under remove operations, \ 
   * but not under others. If the table is empty, return NULL. */       \ 
  static inline struct type **                                          \ 
  name##_HT_START(struct name *head)                                    \ 
  {                                                                     \ 
    unsigned b = 0;                                                     \ 
    while (b < head->hth_table_length) {                                \ 
      if (head->hth_table[b])                                           \ 
        return &head->hth_table[b];                                     \ 
      ++b;                                                              \ 
    }                                                                   \ 
    return NULL;                                                        \ 
  }                                                                     \ 
  /* Return the next element in 'head' after 'elm', under the arbitrary \ 
   * order used by HT_START.  If there are no more elements, return     \ 
   * NULL.  If 'elm' is to be removed from the table, you must call     \ 
   * this function for the next value before you remove it.             \ 
   */                                                                   \ 
  static inline struct type **                                          \ 
  name##_HT_NEXT(struct name *head, struct type **elm)                  \ 
  {                                                                     \ 
    if ((*elm)->field.hte_next) {                                       \ 
      return &(*elm)->field.hte_next;                                   \ 
    } else {                                                            \ 
      unsigned b = (HT_ELT_HASH_(*elm, field, hashfn) % head->hth_table_length)+1; \
      while (b < head->hth_table_length) {                              \ 
        if (head->hth_table[b])                                         \ 
          return &head->hth_table[b];                                   \ 
        ++b;                                                            \ 
      }                                                                 \ 
      return NULL;                                                      \ 
    }                                                                   \ 
  }                                                                     \ 
  static inline struct type **                                          \ 
  name##_HT_NEXT_RMV(struct name *head, struct type **elm)              \ 
  {                                                                     \ 
    unsigned h = HT_ELT_HASH_(*elm, field, hashfn);		        \
    *elm = (*elm)->field.hte_next;                                      \ 
    --head->hth_n_entries;                                              \ 
    if (*elm) {                                                         \ 
      return elm;                                                       \ 
    } else {                                                            \ 
      unsigned b = (h % head->hth_table_length)+1;                      \ 
      while (b < head->hth_table_length) {                              \ 
        if (head->hth_table[b])                                         \ 
          return &head->hth_table[b];                                   \ 
        ++b;                                                            \ 
      }                                                                 \ 
      return NULL;                                                      \ 
    }                                                                   \ 
  } 
 
#define HT_GENERATE(name, type, field, hashfn, eqfn, load, mallocfn,    \ 
                    reallocfn, freefn)                                  \ 
  static unsigned name##_PRIMES[] = {                                   \ 
    53, 97, 193, 389,                                                   \ 
    769, 1543, 3079, 6151,                                              \ 
    12289, 24593, 49157, 98317,                                         \ 
    196613, 393241, 786433, 1572869,                                    \ 
    3145739, 6291469, 12582917, 25165843,                               \ 
    50331653, 100663319, 201326611, 402653189,                          \ 
    805306457, 1610612741                                               \ 
  };                                                                    \ 
  static unsigned name##_N_PRIMES =                                     \ 
    (unsigned)(sizeof(name##_PRIMES)/sizeof(name##_PRIMES[0]));         \ 
  /* Expand the internal table of 'head' until it is large enough to    \ 
   * hold 'size' elements.  Return 0 on success, -1 on allocation       \ 
   * failure. */                                                        \ 
  int                                                                   \ 
  name##_HT_GROW(struct name *head, unsigned size)                      \ 
  {                                                                     \ 
    unsigned new_len, new_load_limit;                                   \ 
    int prime_idx;                                                      \ 
    struct type **new_table;                                            \ 
    if (head->hth_prime_idx == (int)name##_N_PRIMES - 1)                \ 
      return 0;                                                         \ 
    if (head->hth_load_limit > size)                                    \ 
      return 0;                                                         \ 
    prime_idx = head->hth_prime_idx;                                    \ 
    do {                                                                \ 
      new_len = name##_PRIMES[++prime_idx];                             \ 
      new_load_limit = (unsigned)(load*new_len);                        \ 
    } while (new_load_limit <= size &&                                  \ 
             prime_idx < (int)name##_N_PRIMES);                         \ 
    if ((new_table = mallocfn(new_len*sizeof(struct type*)))) {         \ 
      unsigned b;                                                       \ 
      memset(new_table, 0, new_len*sizeof(struct type*));               \ 
      for (b = 0; b < head->hth_table_length; ++b) {                    \ 
        struct type *elm, *next;                                        \ 
        unsigned b2;                                                    \ 
        elm = head->hth_table[b];                                       \ 
        while (elm) {                                                   \ 
          next = elm->field.hte_next;                                   \ 
          b2 = HT_ELT_HASH_(elm, field, hashfn) % new_len;              \
          elm->field.hte_next = new_table[b2];                          \ 
          new_table[b2] = elm;                                          \ 
          elm = next;                                                   \ 
        }                                                               \ 
      }                                                                 \ 
      if (head->hth_table)                                              \ 
        freefn(head->hth_table);                                        \ 
      head->hth_table = new_table;                                      \ 
    } else {                                                            \ 
      unsigned b, b2;                                                   \ 
      new_table = reallocfn(head->hth_table, new_len*sizeof(struct type*)); \ 
      if (!new_table) return -1;                                        \ 
      memset(new_table + head->hth_table_length, 0,                     \ 
             (new_len - head->hth_table_length)*sizeof(struct type*));  \ 
      for (b=0; b < head->hth_table_length; ++b) {                      \ 
        struct type *e, **pE;                                           \ 
        for (pE = &new_table[b], e = *pE; e != NULL; e = *pE) {         \ 
          b2 = HT_ELT_HASH_(e, field, hashfn) % new_len;                \
          if (b2 == b) {                                                \ 
            pE = &e->field.hte_next;                                    \ 
          } else {                                                      \ 
            *pE = e->field.hte_next;                                    \ 
            e->field.hte_next = new_table[b2];                          \ 
            new_table[b2] = e;                                          \ 
          }                                                             \ 
        }                                                               \ 
      }                                                                 \ 
      head->hth_table = new_table;                                      \ 
    }                                                                   \ 
    head->hth_table_length = new_len;                                   \ 
    head->hth_prime_idx = prime_idx;                                    \ 
    head->hth_load_limit = new_load_limit;                              \ 
    return 0;                                                           \ 
  }                                                                     \ 
  /* Free all storage held by 'head'.  Does not free 'head' itself, or  \ 
   * individual elements. */                                            \ 
  void                                                                  \ 
  name##_HT_CLEAR(struct name *head)                                    \ 
  {                                                                     \ 
    if (head->hth_table)                                                \ 
      freefn(head->hth_table);                                          \ 
    name##_HT_INIT(head);                                               \ 
  }                                                                     \ 
  /* Debugging helper: return false iff the representation of 'head' is \ 
   * internally consistent. */                                          \ 
  int                                                                   \ 
  name##_HT_REP_IS_BAD_(const struct name *head)			\
  {                                                                     \ 
    unsigned n, i;                                                      \ 
    struct type *elm;                                                   \ 
    if (!head->hth_table_length) {                                      \ 
      if (!head->hth_table && !head->hth_n_entries &&                   \ 
          !head->hth_load_limit && head->hth_prime_idx == -1)           \ 
        return 0;                                                       \ 
      else                                                              \ 
        return 1;                                                       \ 
    }                                                                   \ 
    if (!head->hth_table || head->hth_prime_idx < 0 ||                  \ 
        !head->hth_load_limit)                                          \ 
      return 2;                                                         \ 
    if (head->hth_n_entries > head->hth_load_limit)                     \ 
      return 3;                                                         \ 
    if (head->hth_table_length != name##_PRIMES[head->hth_prime_idx])   \ 
      return 4;                                                         \ 
    if (head->hth_load_limit != (unsigned)(load*head->hth_table_length)) \ 
      return 5;                                                         \ 
    for (n = i = 0; i < head->hth_table_length; ++i) {                  \ 
      for (elm = head->hth_table[i]; elm; elm = elm->field.hte_next) {  \ 
        if (HT_ELT_HASH_(elm, field, hashfn) != hashfn(elm))	        \
          return 1000 + i;                                              \ 
        if ((HT_ELT_HASH_(elm, field, hashfn) % head->hth_table_length) != i) \
          return 10000 + i;                                             \ 
        ++n;                                                            \ 
      }                                                                 \ 
    }                                                                   \ 
    if (n != head->hth_n_entries)                                       \ 
      return 6;                                                         \ 
    return 0;                                                           \ 
  } 
 
/** Implements an over-optimized "find and insert if absent" block; 
 * not meant for direct usage by typical code, or usage outside the critical 
 * path.*/ 
#define HT_FIND_OR_INSERT_(name, field, hashfn, head, eltype, elm, var, y, n) \
  {                                                                     \ 
    struct name *var##_head_ = head;                                    \
    struct eltype **var;                                                \
    if (!var##_head_->hth_table ||                                      \
        var##_head_->hth_n_entries >= var##_head_->hth_load_limit)      \
      name##_HT_GROW(var##_head_, var##_head_->hth_n_entries+1);        \
    HT_SET_HASH_((elm), field, hashfn);                                 \
    var = name##_HT_FIND_P_(var##_head_, (elm));                        \
    if (*var) {                                                         \ 
      y;                                                                \ 
    } else {                                                            \ 
      n;                                                                \ 
    }                                                                   \ 
  } 
#define HT_FOI_INSERT_(field, head, elm, newent, var)       \
  {                                                         \ 
    HT_SET_HASHVAL_(newent, field, (elm)->field.hte_hash);  \
    newent->field.hte_next = NULL;                          \ 
    *var = newent;                                          \ 
    ++((head)->hth_n_entries);                              \ 
  } 
 
/* 
 * Copyright 2005, Nick Mathewson.  Implementation logic is adapted from code 
 * by Christopher Clark, retrofit to allow drop-in memory management, and to
 * use the same interface as Niels Provos's tree.h.  This is probably still 
 * a derived work, so the original license below still applies. 
 * 
 * Copyright (c) 2002, Christopher Clark 
 * All rights reserved. 
 * 
 * Redistribution and use in source and binary forms, with or without 
 * modification, are permitted provided that the following conditions 
 * are met: 
 * 
 * * Redistributions of source code must retain the above copyright 
 * notice, this list of conditions and the following disclaimer. 
 * 
 * * Redistributions in binary form must reproduce the above copyright 
 * notice, this list of conditions and the following disclaimer in the 
 * documentation and/or other materials provided with the distribution. 
 * 
 * * Neither the name of the original author; nor the names of any contributors 
 * may be used to endorse or promote products derived from this software 
 * without specific prior written permission. 
 * 
 * 
 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS 
 * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT 
 * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR 
 * A PARTICULAR PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL THE COPYRIGHT OWNER 
 * OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, 
 * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, 
 * PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR 
 * PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF 
 * LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING 
 * NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS 
 * SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. 
*/ 
 
#endif