refactor(map): enhanced implementation, Clean Code™, etc etc

This involves two redesigns of the map.c implementations:

1. Change of macro style and code organization

The old khash.h and map.c implementation used huge #define blocks with a
lot of backslash line continuations.

This instead uses the "implementation file" .c.h pattern. Such a file is
meant to be included multiple times, with different macros set prior to
inclusion as parameters. we already use this pattern e.g. for
eval/typval_encode.c.h to implement different typval encoders reusing a
similar structure.

We can structure this code into two parts. one that only depends on key
type and is enough to implement sets, and one which depends on both key
and value to implement maps (as a wrapper around sets, with an added
value[] array)

2. Separate the main hash buckets from the key / value arrays

Change the hack buckets to only contain an index into separate key /
value arrays
This is a common pattern in modern, state of the art hashmap
implementations. Even though this leads to one more allocated array, it
is this often is a net reduction of memory consumption. Consider
key+value consuming at least 12 bytes per pair. On average, we will have
twice as many buckets per item.
Thus old implementation:

  2*12 = 24 bytes per item

New implementation

  1*12 + 2*4 = 20 bytes per item

And the difference gets bigger with larger items.
One might think we have pulled a fast one here, as wouldn't the average size of
the new key/value arrays be 1.5 slots per items due to amortized grows?
But remember, these arrays are fully dense, and thus the accessed memory,
measured in _cache lines_, the unit which actually matters, will be the
fully used memory but just rounded up to the nearest cache line
boundary.

This has some other interesting properties, such as an insert-only
set/map will be fully ordered by insert only. Preserving this ordering
in face of deletions is more tricky tho. As we currently don't use
ordered maps, the "delete" operation maintains compactness of the item
arrays in the simplest way by breaking the ordering. It would be
possible to implement an order-preserving delete although at some cost,
like allowing the items array to become non-dense until the next rehash.

Finally, in face of these two major changes, all code used in khash.h
has been integrated into map.c and friends. Given the heavy edits it
makes no sense to "layer" the code into a vendored and a wrapper part.
Rather, the layered cake follows the specialization depth: code shared
for all maps, code specialized to a key type (and its equivalence
relation), and finally code specialized to value+key type.

1 files changed, 0 insertions, 733 deletions

diff --git a/src/klib/khash.h b/src/klib/khash.h
deleted file mode 100644
index eb1714c471..0000000000
--- a/src/klib/khash.h
+++ /dev/null
@@ -1,733 +0,0 @@
-/* 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.
- */
-
-/*
-   Example:
-
- #include "nvim/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 NVIM_LIB_KHASH_H
-#define NVIM_LIB_KHASH_H
-
-/*!
-   @header
-
-   Generic hash table library.
- */
-
-#define AC_VERSION_KHASH_H "0.2.8"
-
-#include <limits.h>
-#include <stdint.h>
-#include <stdlib.h>
-#include <string.h>
-
-#include "nvim/func_attr.h"
-#include "nvim/memory.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]&=~(khint_t)(1ul<<((i&0xfU)<<1)))
-#define __ac_set_isempty_false(flag, i) (flag[i>>4]&=~(khint_t)(2ul<<((i&0xfU)<<1)))
-#define __ac_set_isboth_false(flag, i) (flag[i>>4]&=~(khint_t)(3ul<<((i&0xfU)<<1)))
-#define __ac_set_isdel_true(flag, i) (flag[i>>4]|=(khint_t)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) xcalloc(N, Z)
-#endif
-#ifndef kmalloc
-# define kmalloc(Z) xmalloc(Z)
-#endif
-#ifndef krealloc
-# define krealloc(P, Z) xrealloc(P, Z)
-#endif
-#ifndef kfree
-# define kfree(P) XFREE_CLEAR(P)
-#endif
-
-#define __ac_HASH_UPPER 0.77
-
-// This is only used for stack temporaries. Heap allocation is done with precise sizes.
-#define KHASH_MAX_VAL_SIZE 32
-
-#define __KHASH_TYPE(name, khkey_t) \
-  typedef struct { \
-    khint_t n_buckets, size, n_occupied, upper_bound; \
-    khint32_t *flags; \
-    khkey_t *keys; \
-    char *vals_buf; \
-  } kh_##name##_t;
-
-#define __KHASH_PROTOTYPES(name, khkey_t) \
-  extern kh_##name##_t *kh_init_##name(void); \
-  extern void kh_dealloc_##name(kh_##name##_t *h); \
-  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 void kh_resize_##name(kh_##name##_t *h, khint_t new_n_buckets, size_t val_size); \
-  extern khint_t kh_put_##name(kh_##name##_t *h, khkey_t key, int *ret, size_t val_size); \
-  extern void kh_del_##name(kh_##name##_t *h, khint_t x);
-
-#define kh_bval(h, x) (&(h)->vals_buf[val_size*(x)])
-#define kh_copyval(to, from) memcpy(to, from, val_size)
-
-#define __KHASH_IMPL(name, SCOPE, khkey_t, __hash_func, __hash_equal) \
-  SCOPE kh_##name##_t *kh_init_##name(void) \
-    REAL_FATTR_UNUSED; \
-  SCOPE kh_##name##_t *kh_init_##name(void) { \
-    return (kh_##name##_t *)kcalloc(1, sizeof(kh_##name##_t)); \
-  } \
-  SCOPE void kh_dealloc_##name(kh_##name##_t *h) \
-    REAL_FATTR_UNUSED; \
-  SCOPE void kh_dealloc_##name(kh_##name##_t *h) \
-  { \
-    kfree(h->keys); \
-    kfree(h->flags); \
-    kfree(h->vals_buf); \
-  } \
-  SCOPE void kh_destroy_##name(kh_##name##_t *h) \
-    REAL_FATTR_UNUSED; \
-  SCOPE void kh_destroy_##name(kh_##name##_t *h) \
-  { \
-    if (h) { \
-      kh_dealloc_##name(h); \
-      kfree(h); \
-    } \
-  } \
-  SCOPE void kh_clear_##name(kh_##name##_t *h) \
-    REAL_FATTR_UNUSED; \
-  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) \
-    REAL_FATTR_UNUSED; \
-  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 void kh_resize_##name(kh_##name##_t *h, khint_t new_n_buckets, size_t val_size) \
-    REAL_FATTR_UNUSED; \
-  SCOPE void kh_resize_##name(kh_##name##_t *h, khint_t new_n_buckets, size_t val_size) \
-  {  /* 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; \
-      } \
-      /* requested size is too small */ \
-      if (h->size >= (khint_t)(new_n_buckets * __ac_HASH_UPPER + 0.5)) { \
-        j = 0; \
-      } else {  /* hash table size to be changed (shrink or expand); rehash */ \
-        new_flags = (khint32_t *)kmalloc(__ac_fsize(new_n_buckets) \
-                                         * sizeof(khint32_t)); \
-        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)); \
-          h->keys = new_keys; \
-          if (val_size) { \
-            char *new_vals = krealloc( h->vals_buf, new_n_buckets * val_size); \
-            h->vals_buf = new_vals; \
-          } \
-        }  /* otherwise shrink */ \
-      } \
-    } \
-    char cval[KHASH_MAX_VAL_SIZE]; \
-    char ctmp[KHASH_MAX_VAL_SIZE]; \
-    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]; \
-          khint_t new_mask; \
-          new_mask = new_n_buckets - 1; \
-          if (val_size) { \
-            kh_copyval(cval, kh_bval(h, j)); \
-          } \
-          __ac_set_isdel_true(h->flags, j); \
-          /* kick-out process; sort of like in Cuckoo hashing */ \
-          while (1) { \
-            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); \
-            /* kick out the existing element */ \
-            if (i < h->n_buckets && __ac_iseither(h->flags, i) == 0) { \
-              { \
-                khkey_t tmp = h->keys[i]; \
-                h->keys[i] = key; \
-                key = tmp; \
-              } \
-              if (val_size) { \
-                kh_copyval(ctmp, kh_bval(h, i)); \
-                kh_copyval(kh_bval(h, i), cval); \
-                kh_copyval(cval, ctmp); \
-              } \
-              /* mark it as deleted in the old hash table */ \
-              __ac_set_isdel_true(h->flags, i); \
-            } else {  /* write the element and jump out of the loop */ \
-              h->keys[i] = key; \
-              if (val_size) { \
-                kh_copyval(kh_bval(h, i), cval); \
-              } \
-              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 (val_size) { \
-          h->vals_buf = krealloc((void *)h->vals_buf, new_n_buckets * val_size); \
-        } \
-      } \
-      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); \
-    } \
-  } \
-  SCOPE khint_t kh_put_##name(kh_##name##_t *h, khkey_t key, int *ret, size_t val_size) \
-    REAL_FATTR_UNUSED; \
-  SCOPE khint_t kh_put_##name(kh_##name##_t *h, khkey_t key, int *ret, size_t val_size) \
-  { \
-    khint_t x; \
-    if (h->n_occupied >= h->upper_bound) {  /* update the hash table */ \
-      if (h->n_buckets > (h->size << 1)) { \
-        kh_resize_##name(h, h->n_buckets - 1, val_size);  /* clear "deleted" elements */ \
-      } else { \
-        kh_resize_##name(h, h->n_buckets + 1, val_size);  /* expand the hash table */ \
-      } \
-    }  /* TODO: 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) \
-    REAL_FATTR_UNUSED; \
-  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(khkey_t) \
-  __KHASH_TYPE(khkey_t, khkey_t) \
-  __KHASH_PROTOTYPES(khkey_t, khkey_t)
-
-#define KHASH_INIT2(name, SCOPE, khkey_t, khval_t, __hash_func, __hash_equal) \
-  __KHASH_TYPE(name, khkey_t, khval_t) \
-  __KHASH_IMPL(name, SCOPE, khkey_t, khval_t, __hash_func, __hash_equal)
-
-#define KHASH_INIT(name, khkey_t, khval_t, __hash_func, __hash_equal) \
-  KHASH_INIT2(name, static kh_inline, khkey_t, khval_t, __hash_func, __hash_equal)
-
-// --- BEGIN OF HASH FUNCTIONS ---
-
-/*! @function
-   @abstract     Integer hash function
-   @param  key   The integer [khint32_t]
-   @return       The hash value [khint_t]
- */
-#define kh_int_hash_func(key) (khint32_t)(key)
-/*! @function
-   @abstract     Integer comparison function
- */
-#define kh_int_hash_equal(a, b) ((a) == (b))
-/*! @function
-   @abstract     64-bit integer hash function
-   @param  key   The integer [khint64_t]
-   @return       The hash value [khint_t]
- */
-#define kh_int64_hash_func(key) (khint32_t)((key)>>33^(key)^(key)<<11)
-/*! @function
-   @abstract     64-bit integer comparison function
- */
-#define kh_int64_hash_equal(a, b) ((a) == (b))
-/*! @function
-   @abstract     const char* hash function
-   @param  s     Pointer to a null terminated string
-   @return       The hash value
- */
-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 + (uint8_t)*s; }
-  }
-  return h;
-}
-/*! @function
-   @abstract     Another interface to const char* hash function
-   @param  key   Pointer to a null terminated string [const char*]
-   @return       The hash value [khint_t]
- */
-#define kh_str_hash_func(key) __ac_X31_hash_string(key)
-/*! @function
-   @abstract     Const char* comparison function
- */
-#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...
-
-/*!
-   @abstract Type of the hash table.
-   @param  name  Name of the hash table [symbol]
- */
-#define khash_t(name) kh_##name##_t
-
-/*! @function
-   @abstract     Initiate a hash table.
-   @param  name  Name of the hash table [symbol]
-   @return       Pointer to the hash table [khash_t(name)*]
- */
-#define kh_init(name) kh_init_##name()
-
-/*! @function
-   @abstract     Destroy a hash table.
-   @param  name  Name of the hash table [symbol]
-   @param  h     Pointer to the hash table [khash_t(name)*]
- */
-#define kh_destroy(name, h) kh_destroy_##name(h)
-
-/*! @function
-   @abstract     Free memory referenced directly inside a hash table.
-   @param  name  Name of the hash table [symbol]
-   @param  h     Pointer to the hash table [khash_t(name)*]
- */
-#define kh_dealloc(name, h) kh_dealloc_##name(h)
-
-/*! @function
-   @abstract     Reset a hash table without deallocating memory.
-   @param  name  Name of the hash table [symbol]
-   @param  h     Pointer to the hash table [khash_t(name)*]
- */
-#define kh_clear(name, h) kh_clear_##name(h)
-
-/*! @function
-   @abstract     Resize a hash table.
-   @param  name  Name of the hash table [symbol]
-   @param  h     Pointer to the hash table [khash_t(name)*]
-   @param  s     New size [khint_t]
- */
-#define kh_resize(name, h, s) kh_resize_##name(h, s)
-
-/*! @function
-   @abstract     Insert a key to the hash table.
-   @param  name  Name of the hash table [symbol]
-   @param  h     Pointer to the hash table [khash_t(name)*]
-   @param  k     Key [type of keys]
-   @param  r     Extra return code: -1 if the operation failed;
-                0 if the key is present in the hash table;
-                1 if the bucket is empty (never used); 2 if the element in
-                the bucket has been deleted [int*]
-   @return       Iterator to the inserted element [khint_t]
- */
-#define kh_put(name, h, k, r, vs) kh_put_##name(h, k, r, vs)
-
-/*! @function
-   @abstract     Retrieve a key from the hash table.
-   @param  name  Name of the hash table [symbol]
-   @param  h     Pointer to the hash table [khash_t(name)*]
-   @param  k     Key [type of keys]
-   @return       Iterator to the found element, or kh_end(h) if the element is absent [khint_t]
- */
-#define kh_get(name, h, k) kh_get_##name(h, k)
-
-/*! @function
-   @abstract     Remove a key from the hash table.
-   @param  name  Name of the hash table [symbol]
-   @param  h     Pointer to the hash table [khash_t(name)*]
-   @param  k     Iterator to the element to be deleted [khint_t]
- */
-#define kh_del(name, h, k) kh_del_##name(h, k)
-
-/*! @function
-   @abstract     Test whether a bucket contains data.
-   @param  h     Pointer to the hash table [khash_t(name)*]
-   @param  x     Iterator to the bucket [khint_t]
-   @return       1 if containing data; 0 otherwise [int]
- */
-#define kh_exist(h, x) (!__ac_iseither((h)->flags, (x)))
-
-/*! @function
-   @abstract     Get key given an iterator
-   @param  h     Pointer to the hash table [khash_t(name)*]
-   @param  x     Iterator to the bucket [khint_t]
-   @return       Key [type of keys]
- */
-#define kh_key(h, x) ((h)->keys[x])
-
-/*! @function
-   @abstract     Get value given an iterator
-   @param  h     Pointer to the hash table [khash_t(name)*]
-   @param  x     Iterator to the bucket [khint_t]
-   @return       Value [type of values]
-   @discussion   For hash sets, calling this results in segfault.
- */
-#define kh_val(type, h, x) (*(type *)(&(h)->vals_buf[(x)*(sizeof (type))]))
-
-/*! @function
-   @abstract     Get the start iterator
-   @param  h     Pointer to the hash table [khash_t(name)*]
-   @return       The start iterator [khint_t]
- */
-#define kh_begin(h) (khint_t)(0)
-
-/*! @function
-   @abstract     Get the end iterator
-   @param  h     Pointer to the hash table [khash_t(name)*]
-   @return       The end iterator [khint_t]
- */
-#define kh_end(h) ((h)->n_buckets)
-
-/*! @function
-   @abstract     Get the number of elements in the hash table
-   @param  h     Pointer to the hash table [khash_t(name)*]
-   @return       Number of elements in the hash table [khint_t]
- */
-#define kh_size(h) ((h)->size)
-
-/*! @function
-   @abstract     Get the number of buckets in the hash table
-   @param  h     Pointer to the hash table [khash_t(name)*]
-   @return       Number of buckets in the hash table [khint_t]
- */
-#define kh_n_buckets(h) ((h)->n_buckets)
-
-/*! @function
-   @abstract     Iterate over the entries in the hash table
-   @param  h     Pointer to the hash table [khash_t(name)*]
-   @param  kvar  Variable to which key will be assigned
-   @param  vvar  Variable to which value will be assigned
-   @param  code  Block of code to execute
- */
-#define kh_foreach(type, 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(type, h,__i); \
-    code; \
-  } \
-}
-
-/*! @function
-   @abstract     Iterate over the values in the hash table
-   @param  h     Pointer to the hash table [khash_t(name)*]
-   @param  vvar  Variable to which value will be assigned
-   @param  code  Block of code to execute
- */
-#define kh_foreach_value(type, 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(type, h,__i); \
-    code; \
-  } \
-}
-
-/*! @function
-   @abstract     Iterate over the keys in the hash table
-   @param  h     Pointer to the hash table [khash_t(name)*]
-   @param  kvar  Variable to which value will be assigned
-   @param  code  Block of code to execute
- */
-#define kh_foreach_key(h, kvar, 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); \
-      code; \
-    } \
-  }
-
-// More convenient interfaces
-
-/*! @function
-   @abstract     Instantiate a hash set containing integer keys
-   @param  name  Name of the hash table [symbol]
- */
-#define KHASH_SET_INIT_INT(name) \
-  KHASH_INIT(name, khint32_t, char, 0, kh_int_hash_func, kh_int_hash_equal)
-
-/*! @function
-   @abstract     Instantiate a hash map containing integer keys
-   @param  name  Name of the hash table [symbol]
-   @param  khval_t  Type of values [type]
- */
-#define KHASH_MAP_INIT_INT(name, khval_t) \
-  KHASH_INIT(name, khint32_t, khval_t, 1, kh_int_hash_func, kh_int_hash_equal)
-
-/*! @function
-   @abstract     Instantiate a hash map containing 64-bit integer keys
-   @param  name  Name of the hash table [symbol]
- */
-#define KHASH_SET_INIT_INT64(name) \
-  KHASH_INIT(name, khint64_t, char, 0, kh_int64_hash_func, kh_int64_hash_equal)
-
-/*! @function
-   @abstract     Instantiate a hash map containing 64-bit integer keys
-   @param  name  Name of the hash table [symbol]
-   @param  khval_t  Type of values [type]
- */
-#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;
-/*! @function
-   @abstract     Instantiate a hash map containing const char* keys
-   @param  name  Name of the hash table [symbol]
- */
-#define KHASH_SET_INIT_STR(name) \
-  KHASH_INIT(name, kh_cstr_t, char, 0, kh_str_hash_func, kh_str_hash_equal)
-
-/*! @function
-   @abstract     Instantiate a hash map containing const char* keys
-   @param  name  Name of the hash table [symbol]
-   @param  khval_t  Type of values [type]
- */
-#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)
-
-/*! @function
-   @abstract     Return a literal for an empty hash table.
-   @param  name  Name of the hash table [symbol]
- */
-#define KHASH_EMPTY_TABLE(name) \
-  ((kh_##name##_t) { \
-    .n_buckets = 0, \
-    .size = 0, \
-    .n_occupied = 0, \
-    .upper_bound = 0, \
-    .flags = NULL, \
-    .keys = NULL, \
-    .vals_buf = NULL, \
-  })
-#endif  // NVIM_LIB_KHASH_H