khash.h

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/* The MIT License

   Copyright (c) 2008, 2009, 2011 by Attractive Chaos <attractor@live.co.uk>

   Permission is hereby granted, free of charge, to any person obtaining
   a copy of this software and associated documentation files (the
   "Software"), to deal in the Software without restriction, including
   without limitation the rights to use, copy, modify, merge, publish,
   distribute, sublicense, and/or sell copies of the Software, and to
   permit persons to whom the Software is furnished to do so, subject to
   the following conditions:

   The above copyright notice and this permission notice shall be
   included in all copies or substantial portions of the Software.

   THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
   EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
   MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
   NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS
   BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN
   ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN
   CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
   SOFTWARE.
*/

/*
  An example:

#include "khash.h"
KHASH_MAP_INIT_INT(32, char)
int main() {
  int ret, is_missing;
  khiter_t k;
  khash_t(32) *h = kh_init(32);
  k = kh_put(32, h, 5, &ret);
  kh_value(h, k) = 10;
  k = kh_get(32, h, 10);
  is_missing = (k == kh_end(h));
  k = kh_get(32, h, 5);
  kh_del(32, h, k);
  for (k = kh_begin(h); k != kh_end(h); ++k)
    if (kh_exist(h, k)) kh_value(h, k) = 1;
  kh_destroy(32, h);
  return 0;
}
*/

/*
  2013-05-02 (0.2.8):

  * Use quadratic probing. When the capacity is power of 2, stepping function
    i*(i+1)/2 guarantees to traverse each bucket. It is better than double
    hashing on cache performance and is more robust than linear probing.

    In theory, double hashing should be more robust than quadratic probing.
    However, my implementation is probably not for large hash tables, because
    the second hash function is closely tied to the first hash function,
    which reduce the effectiveness of double hashing.

  Reference: http://research.cs.vt.edu/AVresearch/hashing/quadratic.php

  2011-12-29 (0.2.7):

    * Minor code clean up; no actual effect.

  2011-09-16 (0.2.6):

  * The capacity is a power of 2. This seems to dramatically improve the
    speed for simple keys. Thank Zilong Tan for the suggestion. Reference:

     - http://code.google.com/p/ulib/
     - http://nothings.org/computer/judy/

  * Allow to optionally use linear probing which usually has better
    performance for random input. Double hashing is still the default as it
    is more robust to certain non-random input.

  * Added Wang's integer hash function (not used by default). This hash
    function is more robust to certain non-random input.

  2011-02-14 (0.2.5):

    * Allow to declare global functions.

  2009-09-26 (0.2.4):

    * Improve portability

  2008-09-19 (0.2.3):

  * Corrected the example
  * Improved interfaces

  2008-09-11 (0.2.2):

  * Improved speed a little in kh_put()

  2008-09-10 (0.2.1):

  * Added kh_clear()
  * Fixed a compiling error

  2008-09-02 (0.2.0):

  * Changed to token concatenation which increases flexibility.

  2008-08-31 (0.1.2):

  * Fixed a bug in kh_get(), which has not been tested previously.

  2008-08-31 (0.1.1):

  * Added destructor
*/


#ifndef __AC_KHASH_H
#define __AC_KHASH_H

#define AC_VERSION_KHASH_H "0.2.8"

#include <stdlib.h>
#include <string.h>
#include <limits.h>

/* compiler specific configuration */

#if UINT_MAX == 0xffffffffu
typedef unsigned int khint32_t;
#elif ULONG_MAX == 0xffffffffu
typedef unsigned long khint32_t;
#endif

#if ULONG_MAX == ULLONG_MAX
typedef unsigned long khint64_t;
#else
typedef unsigned long long khint64_t;
#endif

#ifdef _MSC_VER
#define kh_inline __inline
#else
#define kh_inline inline
#endif

typedef khint32_t khint_t;
typedef khint_t khiter_t;

#define __ac_isempty(flag, i) ((flag[i>>4]>>((i&0xfU)<<1))&2)
#define __ac_isdel(flag, i) ((flag[i>>4]>>((i&0xfU)<<1))&1)
#define __ac_iseither(flag, i) ((flag[i>>4]>>((i&0xfU)<<1))&3)
#define __ac_set_isdel_false(flag, i) (flag[i>>4]&=~(1ul<<((i&0xfU)<<1)))
#define __ac_set_isempty_false(flag, i) (flag[i>>4]&=~(2ul<<((i&0xfU)<<1)))
#define __ac_set_isboth_false(flag, i) (flag[i>>4]&=~(3ul<<((i&0xfU)<<1)))
#define __ac_set_isdel_true(flag, i) (flag[i>>4]|=1ul<<((i&0xfU)<<1))

#define __ac_fsize(m) ((m) < 16? 1 : (m)>>4)

#ifndef kroundup32
#define kroundup32(x) (--(x), (x)|=(x)>>1, (x)|=(x)>>2, (x)|=(x)>>4, (x)|=(x)>>8, (x)|=(x)>>16, ++(x))
#endif

#ifndef kcalloc
#define kcalloc(N,Z) calloc(N,Z)
#endif
#ifndef kmalloc
#define kmalloc(Z) malloc(Z)
#endif
#ifndef krealloc
#define krealloc(P,Z) realloc(P,Z)
#endif
#ifndef kfree
#define kfree(P) free(P)
#endif

static const double __ac_HASH_UPPER = 0.77;

#define __KHASH_TYPE(name, khkey_t, khval_t) \
  typedef struct { \
    khint_t n_buckets, size, n_occupied, upper_bound; \
    khint32_t *flags; \
    khkey_t *keys; \
    khval_t *vals; \
  } kh_##name##_t;

#define __KHASH_PROTOTYPES(name, khkey_t, khval_t)            \
  extern kh_##name##_t *kh_init_##name(void);             \
  extern void kh_destroy_##name(kh_##name##_t *h);          \
  extern void kh_clear_##name(kh_##name##_t *h);            \
  extern khint_t kh_get_##name(const kh_##name##_t *h, khkey_t key);  \
  extern int kh_resize_##name(kh_##name##_t *h, khint_t new_n_buckets); \
  extern khint_t kh_put_##name(kh_##name##_t *h, khkey_t key, int *ret); \
  extern void kh_del_##name(kh_##name##_t *h, khint_t x);

#define __KHASH_IMPL(name, SCOPE, khkey_t, khval_t, kh_is_map, __hash_func, __hash_equal) \
  SCOPE kh_##name##_t *kh_init_##name(void) {             \
    return (kh_##name##_t*)kcalloc(1, sizeof(kh_##name##_t));   \
  }                                 \
  SCOPE void kh_destroy_##name(kh_##name##_t *h)            \
  {                                 \
    if (h) {                            \
      kfree((void *)h->keys); kfree(h->flags);          \
      kfree((void *)h->vals);                   \
      kfree(h);                         \
    }                               \
  }                                 \
  SCOPE void kh_clear_##name(kh_##name##_t *h)            \
  {                                 \
    if (h && h->flags) {                      \
      memset(h->flags, 0xaa, __ac_fsize(h->n_buckets) * sizeof(khint32_t)); \
      h->size = h->n_occupied = 0;                \
    }                               \
  }                                 \
  SCOPE khint_t kh_get_##name(const kh_##name##_t *h, khkey_t key)  \
  {                                 \
    if (h->n_buckets) {                       \
      khint_t k, i, last, mask, step = 0; \
      mask = h->n_buckets - 1;                  \
      k = __hash_func(key); i = k & mask;             \
      last = i; \
      while (!__ac_isempty(h->flags, i) && (__ac_isdel(h->flags, i) || !__hash_equal(h->keys[i], key))) { \
        i = (i + (++step)) & mask; \
        if (i == last) return h->n_buckets;           \
      }                             \
      return __ac_iseither(h->flags, i)? h->n_buckets : i;    \
    } else return 0;                        \
  }                                 \
  SCOPE int kh_resize_##name(kh_##name##_t *h, khint_t new_n_buckets) \
  { /* This function uses 0.25*n_buckets bytes of working space instead of [sizeof(key_t+val_t)+.25]*n_buckets. */ \
    khint32_t *new_flags = 0;                   \
    khint_t j = 1;                          \
    {                               \
      kroundup32(new_n_buckets);                  \
      if (new_n_buckets < 4) new_n_buckets = 4;         \
      if (h->size >= (khint_t)(new_n_buckets * __ac_HASH_UPPER + 0.5)) j = 0; /* requested size is too small */ \
      else { /* hash table size to be changed (shrink or expand); rehash */ \
        new_flags = (khint32_t*)kmalloc(__ac_fsize(new_n_buckets) * sizeof(khint32_t)); \
        if (!new_flags) return -1;                \
        memset(new_flags, 0xaa, __ac_fsize(new_n_buckets) * sizeof(khint32_t)); \
        if (h->n_buckets < new_n_buckets) { /* expand */    \
          khkey_t *new_keys = (khkey_t*)krealloc((void *)h->keys, new_n_buckets * sizeof(khkey_t)); \
          if (!new_keys) return -1;             \
          h->keys = new_keys;                 \
          if (kh_is_map) {                  \
            khval_t *new_vals = (khval_t*)krealloc((void *)h->vals, new_n_buckets * sizeof(khval_t)); \
            if (!new_vals) return -1;           \
            h->vals = new_vals;               \
          }                         \
        } /* otherwise shrink */                \
      }                             \
    }                               \
    if (j) { /* rehashing is needed */                \
      for (j = 0; j != h->n_buckets; ++j) {           \
        if (__ac_iseither(h->flags, j) == 0) {          \
          khkey_t key = h->keys[j];             \
          khval_t val;                    \
          khint_t new_mask;                 \
          new_mask = new_n_buckets - 1;             \
          if (kh_is_map) val = h->vals[j];          \
          __ac_set_isdel_true(h->flags, j);         \
          while (1) { /* kick-out process; sort of like in Cuckoo hashing */ \
            khint_t k, i, step = 0; \
            k = __hash_func(key);             \
            i = k & new_mask;               \
            while (!__ac_isempty(new_flags, i)) i = (i + (++step)) & new_mask; \
            __ac_set_isempty_false(new_flags, i);     \
            if (i < h->n_buckets && __ac_iseither(h->flags, i) == 0) { /* kick out the existing element */ \
              { khkey_t tmp = h->keys[i]; h->keys[i] = key; key = tmp; } \
              if (kh_is_map) { khval_t tmp = h->vals[i]; h->vals[i] = val; val = tmp; } \
              __ac_set_isdel_true(h->flags, i); /* mark it as deleted in the old hash table */ \
            } else { /* write the element and jump out of the loop */ \
              h->keys[i] = key;             \
              if (kh_is_map) h->vals[i] = val;      \
              break;                    \
            }                       \
          }                         \
        }                           \
      }                             \
      if (h->n_buckets > new_n_buckets) { /* shrink the hash table */ \
        h->keys = (khkey_t*)krealloc((void *)h->keys, new_n_buckets * sizeof(khkey_t)); \
        if (kh_is_map) h->vals = (khval_t*)krealloc((void *)h->vals, new_n_buckets * sizeof(khval_t)); \
      }                             \
      kfree(h->flags); /* free the working space */       \
      h->flags = new_flags;                   \
      h->n_buckets = new_n_buckets;               \
      h->n_occupied = h->size;                  \
      h->upper_bound = (khint_t)(h->n_buckets * __ac_HASH_UPPER + 0.5); \
    }                               \
    return 0;                           \
  }                                 \
  SCOPE khint_t kh_put_##name(kh_##name##_t *h, khkey_t key, int *ret) \
  {                                 \
    khint_t x;                            \
    if (h->n_occupied >= h->upper_bound) { /* update the hash table */ \
      if (h->n_buckets > (h->size<<1)) {              \
        if (kh_resize_##name(h, h->n_buckets - 1) < 0) { /* clear "deleted" elements */ \
          *ret = -1; return h->n_buckets;           \
        }                           \
      } else if (kh_resize_##name(h, h->n_buckets + 1) < 0) { /* expand the hash table */ \
        *ret = -1; return h->n_buckets;             \
      }                             \
    } /* TODO: to implement automatically shrinking; resize() already support shrinking */ \
    {                               \
      khint_t k, i, site, last, mask = h->n_buckets - 1, step = 0; \
      x = site = h->n_buckets; k = __hash_func(key); i = k & mask; \
      if (__ac_isempty(h->flags, i)) x = i; /* for speed up */  \
      else {                            \
        last = i; \
        while (!__ac_isempty(h->flags, i) && (__ac_isdel(h->flags, i) || !__hash_equal(h->keys[i], key))) { \
          if (__ac_isdel(h->flags, i)) site = i;        \
          i = (i + (++step)) & mask; \
          if (i == last) { x = site; break; }         \
        }                           \
        if (x == h->n_buckets) {                \
          if (__ac_isempty(h->flags, i) && site != h->n_buckets) x = site; \
          else x = i;                     \
        }                           \
      }                             \
    }                               \
    if (__ac_isempty(h->flags, x)) { /* not present at all */   \
      h->keys[x] = key;                     \
      __ac_set_isboth_false(h->flags, x);             \
      ++h->size; ++h->n_occupied;                 \
      *ret = 1;                         \
    } else if (__ac_isdel(h->flags, x)) { /* deleted */       \
      h->keys[x] = key;                     \
      __ac_set_isboth_false(h->flags, x);             \
      ++h->size;                          \
      *ret = 2;                         \
    } else *ret = 0; /* Don't touch h->keys[x] if present and not deleted */ \
    return x;                           \
  }                                 \
  SCOPE void kh_del_##name(kh_##name##_t *h, khint_t x)       \
  {                                 \
    if (x != h->n_buckets && !__ac_iseither(h->flags, x)) {     \
      __ac_set_isdel_true(h->flags, x);             \
      --h->size;                          \
    }                               \
  }

#define KHASH_DECLARE(name, khkey_t, khval_t)             \
  __KHASH_TYPE(name, khkey_t, khval_t)                \
  __KHASH_PROTOTYPES(name, khkey_t, khval_t)

#define KHASH_INIT2(name, SCOPE, khkey_t, khval_t, kh_is_map, __hash_func, __hash_equal) \
  __KHASH_TYPE(name, khkey_t, khval_t)                \
  __KHASH_IMPL(name, SCOPE, khkey_t, khval_t, kh_is_map, __hash_func, __hash_equal)

#define KHASH_INIT(name, khkey_t, khval_t, kh_is_map, __hash_func, __hash_equal) \
  KHASH_INIT2(name, static kh_inline, khkey_t, khval_t, kh_is_map, __hash_func, __hash_equal)

/* --- BEGIN OF HASH FUNCTIONS --- */

#define kh_int_hash_func(key) (khint32_t)(key)

#define kh_int_hash_equal(a, b) ((a) == (b))

#define kh_int64_hash_func(key) (khint32_t)((key)>>33^(key)^(key)<<11)

#define kh_int64_hash_equal(a, b) ((a) == (b))

static kh_inline khint_t __ac_X31_hash_string(const char *s)
{
  khint_t h = (khint_t)*s;
  if (h) for (++s ; *s; ++s) h = (h << 5) - h + (khint_t)*s;
  return h;
}
#define kh_str_hash_func(key) __ac_X31_hash_string(key)

#define kh_str_hash_equal(a, b) (strcmp(a, b) == 0)

static kh_inline khint_t __ac_Wang_hash(khint_t key)
{
    key += ~(key << 15);
    key ^=  (key >> 10);
    key +=  (key << 3);
    key ^=  (key >> 6);
    key += ~(key << 11);
    key ^=  (key >> 16);
    return key;
}
#define kh_int_hash_func2(k) __ac_Wang_hash((khint_t)key)

/* --- END OF HASH FUNCTIONS --- */

/* Other convenient macros... */

#define khash_t(name) kh_##name##_t

#define kh_init(name) kh_init_##name()

#define kh_destroy(name, h) kh_destroy_##name(h)

#define kh_clear(name, h) kh_clear_##name(h)

#define kh_resize(name, h, s) kh_resize_##name(h, s)

#define kh_put(name, h, k, r) kh_put_##name(h, k, r)

#define kh_get(name, h, k) kh_get_##name(h, k)

#define kh_del(name, h, k) kh_del_##name(h, k)

#define kh_exist(h, x) (!__ac_iseither((h)->flags, (x)))

#define kh_key(h, x) ((h)->keys[x])

#define kh_val(h, x) ((h)->vals[x])

#define kh_value(h, x) ((h)->vals[x])

#define kh_begin(h) (khint_t)(0)

#define kh_end(h) ((h)->n_buckets)

#define kh_size(h) ((h)->size)

#define kh_n_buckets(h) ((h)->n_buckets)

#define kh_foreach(h, kvar, vvar, code) { khint_t __i;    \
  for (__i = kh_begin(h); __i != kh_end(h); ++__i) {    \
    if (!kh_exist(h,__i)) continue;           \
    (kvar) = kh_key(h,__i);               \
    (vvar) = kh_val(h,__i);               \
    code;                       \
  } }

#define kh_foreach_value(h, vvar, code) { khint_t __i;    \
  for (__i = kh_begin(h); __i != kh_end(h); ++__i) {    \
    if (!kh_exist(h,__i)) continue;           \
    (vvar) = kh_val(h,__i);               \
    code;                       \
  } }

/* More conenient interfaces */

#define KHASH_SET_INIT_INT(name)                    \
  KHASH_INIT(name, khint32_t, char, 0, kh_int_hash_func, kh_int_hash_equal)

#define KHASH_MAP_INIT_INT(name, khval_t)               \
  KHASH_INIT(name, khint32_t, khval_t, 1, kh_int_hash_func, kh_int_hash_equal)

#define KHASH_SET_INIT_INT64(name)                    \
  KHASH_INIT(name, khint64_t, char, 0, kh_int64_hash_func, kh_int64_hash_equal)

#define KHASH_MAP_INIT_INT64(name, khval_t)               \
  KHASH_INIT(name, khint64_t, khval_t, 1, kh_int64_hash_func, kh_int64_hash_equal)

typedef const char *kh_cstr_t;
#define KHASH_SET_INIT_STR(name)                    \
  KHASH_INIT(name, kh_cstr_t, char, 0, kh_str_hash_func, kh_str_hash_equal)

#define KHASH_MAP_INIT_STR(name, khval_t)               \
  KHASH_INIT(name, kh_cstr_t, khval_t, 1, kh_str_hash_func, kh_str_hash_equal)

#endif /* __AC_KHASH_H */