Switch ID code to use a hash table instead of a skip list (#52)

* Brings hash table ID code over from Bitbucket branch

* Includes reformatting via clang.

* Excludes uthash.h from reformatting.

* Still has the failing test issue in tid.c. This should only be a
  problem if a custom ID type is used and its free function deletes
  other IDs.

* Fixes munged H5_GCC_DIAG_ON/OFF macros in H5I.c

The H5_GCC_DIAG_ON/OFF macros used to turn off fallthrough warnings
in uthash.h (external code) were munged when formatting with clang
due to their lack of quotes.

e.g.;

    H5_GCC_DIAG_OFF(implicit-fallthrough)

was munged to:

    H5_GCC_DIAG_OFF(implicit - fallthrough)

which compiles, but is useless. So, with quotes, this is now:

    H5_GCC_DIAG_OFF("implicit-fallthrough")

which survives reformatting with clang.

* Fixes issues with user callbacks in the ID hash tables

The skip lists (previously) used to handle IDs use a mark-and-sweep
scheme to deal with user-defined ID delete callbacks which themselves delete
other IDs in the list. The uthash hash table implementation used to manage
the IDs in this feature branch does not have this ability.

This commit restores the skip lists for non-library ID types in lieu of
significantly modifying the uthash code. The hash tables are used to
manage the library IDs as those do not delete other IDs when they are
closed.

* Adds uthash.h to MANIFEST

* Removes implicit-fallthrough diagnostic disable

Removing -Wimplicit-fallthrough=5 means that the uthash code
no longer raises warnings so the H5_GCC_DIAG_OFF/ON macros
that disabled those warnings have been removed from H5I.c.

* Adds a test to ensure you can delete IDs in the H5Iiterate() callback

1 files changed, 1150 insertions, 0 deletions

diff --git a/src/uthash.h b/src/uthash.h
new file mode 100644
index 0000000..5e5866a
--- /dev/null
+++ b/src/uthash.h
@@ -0,0 +1,1150 @@
+/*
+Copyright (c) 2003-2018, Troy D. Hanson     http://troydhanson.github.com/uthash/
+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.
+
+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.
+*/
+
+#ifndef UTHASH_H
+#define UTHASH_H
+
+#define UTHASH_VERSION 2.1.0
+
+#include <string.h>   /* memcmp, memset, strlen */
+#include <stddef.h>   /* ptrdiff_t */
+#include <stdlib.h>   /* exit */
+
+/* These macros use decltype or the earlier __typeof GNU extension.
+   As decltype is only available in newer compilers (VS2010 or gcc 4.3+
+   when compiling c++ source) this code uses whatever method is needed
+   or, for VS2008 where neither is available, uses casting workarounds. */
+#if !defined(DECLTYPE) && !defined(NO_DECLTYPE)
+#if defined(_MSC_VER)   /* MS compiler */
+#if _MSC_VER >= 1600 && defined(__cplusplus)  /* VS2010 or newer in C++ mode */
+#define DECLTYPE(x) (decltype(x))
+#else                   /* VS2008 or older (or VS2010 in C mode) */
+#define NO_DECLTYPE
+#endif
+#elif defined(__BORLANDC__) || defined(__ICCARM__) || defined(__LCC__) || defined(__WATCOMC__)
+#define NO_DECLTYPE
+#else                   /* GNU, Sun and other compilers */
+#define DECLTYPE(x) (__typeof(x))
+#endif
+#endif
+
+#ifdef NO_DECLTYPE
+#define DECLTYPE(x)
+#define DECLTYPE_ASSIGN(dst,src)                                                 \
+do {                                                                             \
+  char **_da_dst = (char**)(&(dst));                                             \
+  *_da_dst = (char*)(src);                                                       \
+} while (0)
+#else
+#define DECLTYPE_ASSIGN(dst,src)                                                 \
+do {                                                                             \
+  (dst) = DECLTYPE(dst)(src);                                                    \
+} while (0)
+#endif
+
+/* a number of the hash function use uint32_t which isn't defined on Pre VS2010 */
+#if defined(_WIN32)
+#if defined(_MSC_VER) && _MSC_VER >= 1600
+#include <stdint.h>
+#elif defined(__WATCOMC__) || defined(__MINGW32__) || defined(__CYGWIN__)
+#include <stdint.h>
+#else
+typedef unsigned int uint32_t;
+typedef unsigned char uint8_t;
+#endif
+#elif defined(__GNUC__) && !defined(__VXWORKS__)
+#include <stdint.h>
+#else
+typedef unsigned int uint32_t;
+typedef unsigned char uint8_t;
+#endif
+
+#ifndef uthash_malloc
+#define uthash_malloc(sz) malloc(sz)      /* malloc fcn                      */
+#endif
+#ifndef uthash_free
+#define uthash_free(ptr,sz) free(ptr)     /* free fcn                        */
+#endif
+#ifndef uthash_bzero
+#define uthash_bzero(a,n) memset(a,'\0',n)
+#endif
+#ifndef uthash_strlen
+#define uthash_strlen(s) strlen(s)
+#endif
+
+#ifdef uthash_memcmp
+/* This warning will not catch programs that define uthash_memcmp AFTER including uthash.h. */
+#warning "uthash_memcmp is deprecated; please use HASH_KEYCMP instead"
+#else
+#define uthash_memcmp(a,b,n) memcmp(a,b,n)
+#endif
+
+#ifndef HASH_KEYCMP
+#define HASH_KEYCMP(a,b,n) uthash_memcmp(a,b,n)
+#endif
+
+#ifndef uthash_noexpand_fyi
+#define uthash_noexpand_fyi(tbl)          /* can be defined to log noexpand  */
+#endif
+#ifndef uthash_expand_fyi
+#define uthash_expand_fyi(tbl)            /* can be defined to log expands   */
+#endif
+
+#ifndef HASH_NONFATAL_OOM
+#define HASH_NONFATAL_OOM 0
+#endif
+
+#if HASH_NONFATAL_OOM
+/* malloc failures can be recovered from */
+
+#ifndef uthash_nonfatal_oom
+#define uthash_nonfatal_oom(obj) do {} while (0)    /* non-fatal OOM error */
+#endif
+
+#define HASH_RECORD_OOM(oomed) do { (oomed) = 1; } while (0)
+#define IF_HASH_NONFATAL_OOM(x) x
+
+#else
+/* malloc failures result in lost memory, hash tables are unusable */
+
+#ifndef uthash_fatal
+#define uthash_fatal(msg) exit(-1)        /* fatal OOM error */
+#endif
+
+#define HASH_RECORD_OOM(oomed) uthash_fatal("out of memory")
+#define IF_HASH_NONFATAL_OOM(x)
+
+#endif
+
+/* initial number of buckets */
+#define HASH_INITIAL_NUM_BUCKETS 32U     /* initial number of buckets        */
+#define HASH_INITIAL_NUM_BUCKETS_LOG2 5U /* lg2 of initial number of buckets */
+#define HASH_BKT_CAPACITY_THRESH 10U     /* expand when bucket count reaches */
+
+/* calculate the element whose hash handle address is hhp */
+#define ELMT_FROM_HH(tbl,hhp) ((void*)(((char*)(hhp)) - ((tbl)->hho)))
+/* calculate the hash handle from element address elp */
+#define HH_FROM_ELMT(tbl,elp) ((UT_hash_handle*)(void*)(((char*)(elp)) + ((tbl)->hho)))
+
+#define HASH_ROLLBACK_BKT(hh, head, itemptrhh)                                   \
+do {                                                                             \
+  struct UT_hash_handle *_hd_hh_item = (itemptrhh);                              \
+  unsigned _hd_bkt;                                                              \
+  HASH_TO_BKT(_hd_hh_item->hashv, (head)->hh.tbl->num_buckets, _hd_bkt);         \
+  (head)->hh.tbl->buckets[_hd_bkt].count++;                                      \
+  _hd_hh_item->hh_next = NULL;                                                   \
+  _hd_hh_item->hh_prev = NULL;                                                   \
+} while (0)
+
+#define HASH_VALUE(keyptr,keylen,hashv)                                          \
+do {                                                                             \
+  HASH_FCN(keyptr, keylen, hashv);                                               \
+} while (0)
+
+#define HASH_FIND_BYHASHVALUE(hh,head,keyptr,keylen,hashval,out)                 \
+do {                                                                             \
+  (out) = NULL;                                                                  \
+  if (head) {                                                                    \
+    unsigned _hf_bkt;                                                            \
+    HASH_TO_BKT(hashval, (head)->hh.tbl->num_buckets, _hf_bkt);                  \
+    if (HASH_BLOOM_TEST((head)->hh.tbl, hashval) != 0) {                         \
+      HASH_FIND_IN_BKT((head)->hh.tbl, hh, (head)->hh.tbl->buckets[ _hf_bkt ], keyptr, keylen, hashval, out); \
+    }                                                                            \
+  }                                                                              \
+} while (0)
+
+#define HASH_FIND(hh,head,keyptr,keylen,out)                                     \
+do {                                                                             \
+  (out) = NULL;                                                                  \
+  if (head) {                                                                    \
+    unsigned _hf_hashv;                                                          \
+    HASH_VALUE(keyptr, keylen, _hf_hashv);                                       \
+    HASH_FIND_BYHASHVALUE(hh, head, keyptr, keylen, _hf_hashv, out);             \
+  }                                                                              \
+} while (0)
+
+#ifdef HASH_BLOOM
+#define HASH_BLOOM_BITLEN (1UL << HASH_BLOOM)
+#define HASH_BLOOM_BYTELEN (HASH_BLOOM_BITLEN/8UL) + (((HASH_BLOOM_BITLEN%8UL)!=0UL) ? 1UL : 0UL)
+#define HASH_BLOOM_MAKE(tbl,oomed)                                               \
+do {                                                                             \
+  (tbl)->bloom_nbits = HASH_BLOOM;                                               \
+  (tbl)->bloom_bv = (uint8_t*)uthash_malloc(HASH_BLOOM_BYTELEN);                 \
+  if (!(tbl)->bloom_bv) {                                                        \
+    HASH_RECORD_OOM(oomed);                                                      \
+  } else {                                                                       \
+    uthash_bzero((tbl)->bloom_bv, HASH_BLOOM_BYTELEN);                           \
+    (tbl)->bloom_sig = HASH_BLOOM_SIGNATURE;                                     \
+  }                                                                              \
+} while (0)
+
+#define HASH_BLOOM_FREE(tbl)                                                     \
+do {                                                                             \
+  uthash_free((tbl)->bloom_bv, HASH_BLOOM_BYTELEN);                              \
+} while (0)
+
+#define HASH_BLOOM_BITSET(bv,idx) (bv[(idx)/8U] |= (1U << ((idx)%8U)))
+#define HASH_BLOOM_BITTEST(bv,idx) (bv[(idx)/8U] & (1U << ((idx)%8U)))
+
+#define HASH_BLOOM_ADD(tbl,hashv)                                                \
+  HASH_BLOOM_BITSET((tbl)->bloom_bv, ((hashv) & (uint32_t)((1UL << (tbl)->bloom_nbits) - 1U)))
+
+#define HASH_BLOOM_TEST(tbl,hashv)                                               \
+  HASH_BLOOM_BITTEST((tbl)->bloom_bv, ((hashv) & (uint32_t)((1UL << (tbl)->bloom_nbits) - 1U)))
+
+#else
+#define HASH_BLOOM_MAKE(tbl,oomed)
+#define HASH_BLOOM_FREE(tbl)
+#define HASH_BLOOM_ADD(tbl,hashv)
+#define HASH_BLOOM_TEST(tbl,hashv) (1)
+#define HASH_BLOOM_BYTELEN 0U
+#endif
+
+#define HASH_MAKE_TABLE(hh,head,oomed)                                           \
+do {                                                                             \
+  (head)->hh.tbl = (UT_hash_table*)uthash_malloc(sizeof(UT_hash_table));         \
+  if (!(head)->hh.tbl) {                                                         \
+    HASH_RECORD_OOM(oomed);                                                      \
+  } else {                                                                       \
+    uthash_bzero((head)->hh.tbl, sizeof(UT_hash_table));                         \
+    (head)->hh.tbl->tail = &((head)->hh);                                        \
+    (head)->hh.tbl->num_buckets = HASH_INITIAL_NUM_BUCKETS;                      \
+    (head)->hh.tbl->log2_num_buckets = HASH_INITIAL_NUM_BUCKETS_LOG2;            \
+    (head)->hh.tbl->hho = (char*)(&(head)->hh) - (char*)(head);                  \
+    (head)->hh.tbl->buckets = (UT_hash_bucket*)uthash_malloc(                    \
+        HASH_INITIAL_NUM_BUCKETS * sizeof(struct UT_hash_bucket));               \
+    (head)->hh.tbl->signature = HASH_SIGNATURE;                                  \
+    if (!(head)->hh.tbl->buckets) {                                              \
+      HASH_RECORD_OOM(oomed);                                                    \
+      uthash_free((head)->hh.tbl, sizeof(UT_hash_table));                        \
+    } else {                                                                     \
+      uthash_bzero((head)->hh.tbl->buckets,                                      \
+          HASH_INITIAL_NUM_BUCKETS * sizeof(struct UT_hash_bucket));             \
+      HASH_BLOOM_MAKE((head)->hh.tbl, oomed);                                    \
+      IF_HASH_NONFATAL_OOM(                                                      \
+        if (oomed) {                                                             \
+          uthash_free((head)->hh.tbl->buckets,                                   \
+              HASH_INITIAL_NUM_BUCKETS*sizeof(struct UT_hash_bucket));           \
+          uthash_free((head)->hh.tbl, sizeof(UT_hash_table));                    \
+        }                                                                        \
+      )                                                                          \
+    }                                                                            \
+  }                                                                              \
+} while (0)
+
+#define HASH_REPLACE_BYHASHVALUE_INORDER(hh,head,fieldname,keylen_in,hashval,add,replaced,cmpfcn) \
+do {                                                                             \
+  (replaced) = NULL;                                                             \
+  HASH_FIND_BYHASHVALUE(hh, head, &((add)->fieldname), keylen_in, hashval, replaced); \
+  if (replaced) {                                                                \
+    HASH_DELETE(hh, head, replaced);                                             \
+  }                                                                              \
+  HASH_ADD_KEYPTR_BYHASHVALUE_INORDER(hh, head, &((add)->fieldname), keylen_in, hashval, add, cmpfcn); \
+} while (0)
+
+#define HASH_REPLACE_BYHASHVALUE(hh,head,fieldname,keylen_in,hashval,add,replaced) \
+do {                                                                             \
+  (replaced) = NULL;                                                             \
+  HASH_FIND_BYHASHVALUE(hh, head, &((add)->fieldname), keylen_in, hashval, replaced); \
+  if (replaced) {                                                                \
+    HASH_DELETE(hh, head, replaced);                                             \
+  }                                                                              \
+  HASH_ADD_KEYPTR_BYHASHVALUE(hh, head, &((add)->fieldname), keylen_in, hashval, add); \
+} while (0)
+
+#define HASH_REPLACE(hh,head,fieldname,keylen_in,add,replaced)                   \
+do {                                                                             \
+  unsigned _hr_hashv;                                                            \
+  HASH_VALUE(&((add)->fieldname), keylen_in, _hr_hashv);                         \
+  HASH_REPLACE_BYHASHVALUE(hh, head, fieldname, keylen_in, _hr_hashv, add, replaced); \
+} while (0)
+
+#define HASH_REPLACE_INORDER(hh,head,fieldname,keylen_in,add,replaced,cmpfcn)    \
+do {                                                                             \
+  unsigned _hr_hashv;                                                            \
+  HASH_VALUE(&((add)->fieldname), keylen_in, _hr_hashv);                         \
+  HASH_REPLACE_BYHASHVALUE_INORDER(hh, head, fieldname, keylen_in, _hr_hashv, add, replaced, cmpfcn); \
+} while (0)
+
+#define HASH_APPEND_LIST(hh, head, add)                                          \
+do {                                                                             \
+  (add)->hh.next = NULL;                                                         \
+  (add)->hh.prev = ELMT_FROM_HH((head)->hh.tbl, (head)->hh.tbl->tail);           \
+  (head)->hh.tbl->tail->next = (add);                                            \
+  (head)->hh.tbl->tail = &((add)->hh);                                           \
+} while (0)
+
+#define HASH_AKBI_INNER_LOOP(hh,head,add,cmpfcn)                                 \
+do {                                                                             \
+  do {                                                                           \
+    if (cmpfcn(DECLTYPE(head)(_hs_iter), add) > 0) {                             \
+      break;                                                                     \
+    }                                                                            \
+  } while ((_hs_iter = HH_FROM_ELMT((head)->hh.tbl, _hs_iter)->next));           \
+} while (0)
+
+#ifdef NO_DECLTYPE
+#undef HASH_AKBI_INNER_LOOP
+#define HASH_AKBI_INNER_LOOP(hh,head,add,cmpfcn)                                 \
+do {                                                                             \
+  char *_hs_saved_head = (char*)(head);                                          \
+  do {                                                                           \
+    DECLTYPE_ASSIGN(head, _hs_iter);                                             \
+    if (cmpfcn(head, add) > 0) {                                                 \
+      DECLTYPE_ASSIGN(head, _hs_saved_head);                                     \
+      break;                                                                     \
+    }                                                                            \
+    DECLTYPE_ASSIGN(head, _hs_saved_head);                                       \
+  } while ((_hs_iter = HH_FROM_ELMT((head)->hh.tbl, _hs_iter)->next));           \
+} while (0)
+#endif
+
+#if HASH_NONFATAL_OOM
+
+#define HASH_ADD_TO_TABLE(hh,head,keyptr,keylen_in,hashval,add,oomed)            \
+do {                                                                             \
+  if (!(oomed)) {                                                                \
+    unsigned _ha_bkt;                                                            \
+    (head)->hh.tbl->num_items++;                                                 \
+    HASH_TO_BKT(hashval, (head)->hh.tbl->num_buckets, _ha_bkt);                  \
+    HASH_ADD_TO_BKT((head)->hh.tbl->buckets[_ha_bkt], hh, &(add)->hh, oomed);    \
+    if (oomed) {                                                                 \
+      HASH_ROLLBACK_BKT(hh, head, &(add)->hh);                                   \
+      HASH_DELETE_HH(hh, head, &(add)->hh);                                      \
+      (add)->hh.tbl = NULL;                                                      \
+      uthash_nonfatal_oom(add);                                                  \
+    } else {                                                                     \
+      HASH_BLOOM_ADD((head)->hh.tbl, hashval);                                   \
+      HASH_EMIT_KEY(hh, head, keyptr, keylen_in);                                \
+    }                                                                            \
+  } else {                                                                       \
+    (add)->hh.tbl = NULL;                                                        \
+    uthash_nonfatal_oom(add);                                                    \
+  }                                                                              \
+} while (0)
+
+#else
+
+#define HASH_ADD_TO_TABLE(hh,head,keyptr,keylen_in,hashval,add,oomed)            \
+do {                                                                             \
+  unsigned _ha_bkt;                                                              \
+  (head)->hh.tbl->num_items++;                                                   \
+  HASH_TO_BKT(hashval, (head)->hh.tbl->num_buckets, _ha_bkt);                    \
+  HASH_ADD_TO_BKT((head)->hh.tbl->buckets[_ha_bkt], hh, &(add)->hh, oomed);      \
+  HASH_BLOOM_ADD((head)->hh.tbl, hashval);                                       \
+  HASH_EMIT_KEY(hh, head, keyptr, keylen_in);                                    \
+} while (0)
+
+#endif
+
+
+#define HASH_ADD_KEYPTR_BYHASHVALUE_INORDER(hh,head,keyptr,keylen_in,hashval,add,cmpfcn) \
+do {                                                                             \
+  IF_HASH_NONFATAL_OOM( int _ha_oomed = 0; )                                     \
+  (add)->hh.hashv = (hashval);                                                   \
+  (add)->hh.key = (char*) (keyptr);                                              \
+  (add)->hh.keylen = (unsigned) (keylen_in);                                     \
+  if (!(head)) {                                                                 \
+    (add)->hh.next = NULL;                                                       \
+    (add)->hh.prev = NULL;                                                       \
+    HASH_MAKE_TABLE(hh, add, _ha_oomed);                                         \
+    IF_HASH_NONFATAL_OOM( if (!_ha_oomed) { )                                    \
+      (head) = (add);                                                            \
+    IF_HASH_NONFATAL_OOM( } )                                                    \
+  } else {                                                                       \
+    void *_hs_iter = (head);                                                     \
+    (add)->hh.tbl = (head)->hh.tbl;                                              \
+    HASH_AKBI_INNER_LOOP(hh, head, add, cmpfcn);                                 \
+    if (_hs_iter) {                                                              \
+      (add)->hh.next = _hs_iter;                                                 \
+      if (((add)->hh.prev = HH_FROM_ELMT((head)->hh.tbl, _hs_iter)->prev)) {     \
+        HH_FROM_ELMT((head)->hh.tbl, (add)->hh.prev)->next = (add);              \
+      } else {                                                                   \
+        (head) = (add);                                                          \
+      }                                                                          \
+      HH_FROM_ELMT((head)->hh.tbl, _hs_iter)->prev = (add);                      \
+    } else {                                                                     \
+      HASH_APPEND_LIST(hh, head, add);                                           \
+    }                                                                            \
+  }                                                                              \
+  HASH_ADD_TO_TABLE(hh, head, keyptr, keylen_in, hashval, add, _ha_oomed);       \
+  HASH_FSCK(hh, head, "HASH_ADD_KEYPTR_BYHASHVALUE_INORDER");                    \
+} while (0)
+
+#define HASH_ADD_KEYPTR_INORDER(hh,head,keyptr,keylen_in,add,cmpfcn)             \
+do {                                                                             \
+  unsigned _hs_hashv;                                                            \
+  HASH_VALUE(keyptr, keylen_in, _hs_hashv);                                      \
+  HASH_ADD_KEYPTR_BYHASHVALUE_INORDER(hh, head, keyptr, keylen_in, _hs_hashv, add, cmpfcn); \
+} while (0)
+
+#define HASH_ADD_BYHASHVALUE_INORDER(hh,head,fieldname,keylen_in,hashval,add,cmpfcn) \
+  HASH_ADD_KEYPTR_BYHASHVALUE_INORDER(hh, head, &((add)->fieldname), keylen_in, hashval, add, cmpfcn)
+
+#define HASH_ADD_INORDER(hh,head,fieldname,keylen_in,add,cmpfcn)                 \
+  HASH_ADD_KEYPTR_INORDER(hh, head, &((add)->fieldname), keylen_in, add, cmpfcn)
+
+#define HASH_ADD_KEYPTR_BYHASHVALUE(hh,head,keyptr,keylen_in,hashval,add)        \
+do {                                                                             \
+  IF_HASH_NONFATAL_OOM( int _ha_oomed = 0; )                                     \
+  (add)->hh.hashv = (hashval);                                                   \
+  (add)->hh.key = (char*) (keyptr);                                              \
+  (add)->hh.keylen = (unsigned) (keylen_in);                                     \
+  if (!(head)) {                                                                 \
+    (add)->hh.next = NULL;                                                       \
+    (add)->hh.prev = NULL;                                                       \
+    HASH_MAKE_TABLE(hh, add, _ha_oomed);                                         \
+    IF_HASH_NONFATAL_OOM( if (!_ha_oomed) { )                                    \
+      (head) = (add);                                                            \
+    IF_HASH_NONFATAL_OOM( } )                                                    \
+  } else {                                                                       \
+    (add)->hh.tbl = (head)->hh.tbl;                                              \
+    HASH_APPEND_LIST(hh, head, add);                                             \
+  }                                                                              \
+  HASH_ADD_TO_TABLE(hh, head, keyptr, keylen_in, hashval, add, _ha_oomed);       \
+  HASH_FSCK(hh, head, "HASH_ADD_KEYPTR_BYHASHVALUE");                            \
+} while (0)
+
+#define HASH_ADD_KEYPTR(hh,head,keyptr,keylen_in,add)                            \
+do {                                                                             \
+  unsigned _ha_hashv;                                                            \
+  HASH_VALUE(keyptr, keylen_in, _ha_hashv);                                      \
+  HASH_ADD_KEYPTR_BYHASHVALUE(hh, head, keyptr, keylen_in, _ha_hashv, add);      \
+} while (0)
+
+#define HASH_ADD_BYHASHVALUE(hh,head,fieldname,keylen_in,hashval,add)            \
+  HASH_ADD_KEYPTR_BYHASHVALUE(hh, head, &((add)->fieldname), keylen_in, hashval, add)
+
+#define HASH_ADD(hh,head,fieldname,keylen_in,add)                                \
+  HASH_ADD_KEYPTR(hh, head, &((add)->fieldname), keylen_in, add)
+
+#define HASH_TO_BKT(hashv,num_bkts,bkt)                                          \
+do {                                                                             \
+  bkt = ((hashv) & ((num_bkts) - 1U));                                           \
+} while (0)
+
+/* delete "delptr" from the hash table.
+ * "the usual" patch-up process for the app-order doubly-linked-list.
+ * The use of _hd_hh_del below deserves special explanation.
+ * These used to be expressed using (delptr) but that led to a bug
+ * if someone used the same symbol for the head and deletee, like
+ *  HASH_DELETE(hh,users,users);
+ * We want that to work, but by changing the head (users) below
+ * we were forfeiting our ability to further refer to the deletee (users)
+ * in the patch-up process. Solution: use scratch space to
+ * copy the deletee pointer, then the latter references are via that
+ * scratch pointer rather than through the repointed (users) symbol.
+ */
+#define HASH_DELETE(hh,head,delptr)                                              \
+    HASH_DELETE_HH(hh, head, &(delptr)->hh)
+
+#define HASH_DELETE_HH(hh,head,delptrhh)                                         \
+do {                                                                             \
+  struct UT_hash_handle *_hd_hh_del = (delptrhh);                                \
+  if ((_hd_hh_del->prev == NULL) && (_hd_hh_del->next == NULL)) {                \
+    HASH_BLOOM_FREE((head)->hh.tbl);                                             \
+    uthash_free((head)->hh.tbl->buckets,                                         \
+                (head)->hh.tbl->num_buckets * sizeof(struct UT_hash_bucket));    \
+    uthash_free((head)->hh.tbl, sizeof(UT_hash_table));                          \
+    (head) = NULL;                                                               \
+  } else {                                                                       \
+    unsigned _hd_bkt;                                                            \
+    if (_hd_hh_del == (head)->hh.tbl->tail) {                                    \
+      (head)->hh.tbl->tail = HH_FROM_ELMT((head)->hh.tbl, _hd_hh_del->prev);     \
+    }                                                                            \
+    if (_hd_hh_del->prev != NULL) {                                              \
+      HH_FROM_ELMT((head)->hh.tbl, _hd_hh_del->prev)->next = _hd_hh_del->next;   \
+    } else {                                                                     \
+      DECLTYPE_ASSIGN(head, _hd_hh_del->next);                                   \
+    }                                                                            \
+    if (_hd_hh_del->next != NULL) {                                              \
+      HH_FROM_ELMT((head)->hh.tbl, _hd_hh_del->next)->prev = _hd_hh_del->prev;   \
+    }                                                                            \
+    HASH_TO_BKT(_hd_hh_del->hashv, (head)->hh.tbl->num_buckets, _hd_bkt);        \
+    HASH_DEL_IN_BKT((head)->hh.tbl->buckets[_hd_bkt], _hd_hh_del);               \
+    (head)->hh.tbl->num_items--;                                                 \
+  }                                                                              \
+  HASH_FSCK(hh, head, "HASH_DELETE_HH");                                         \
+} while (0)
+
+/* convenience forms of HASH_FIND/HASH_ADD/HASH_DEL */
+#define HASH_FIND_STR(head,findstr,out)                                          \
+do {                                                                             \
+    unsigned _uthash_hfstr_keylen = (unsigned)uthash_strlen(findstr);            \
+    HASH_FIND(hh, head, findstr, _uthash_hfstr_keylen, out);                     \
+} while (0)
+#define HASH_ADD_STR(head,strfield,add)                                          \
+do {                                                                             \
+    unsigned _uthash_hastr_keylen = (unsigned)uthash_strlen((add)->strfield);    \
+    HASH_ADD(hh, head, strfield[0], _uthash_hastr_keylen, add);                  \
+} while (0)
+#define HASH_REPLACE_STR(head,strfield,add,replaced)                             \
+do {                                                                             \
+    unsigned _uthash_hrstr_keylen = (unsigned)uthash_strlen((add)->strfield);    \
+    HASH_REPLACE(hh, head, strfield[0], _uthash_hrstr_keylen, add, replaced);    \
+} while (0)
+#define HASH_FIND_INT(head,findint,out)                                          \
+    HASH_FIND(hh,head,findint,sizeof(int),out)
+#define HASH_ADD_INT(head,intfield,add)                                          \
+    HASH_ADD(hh,head,intfield,sizeof(int),add)
+#define HASH_REPLACE_INT(head,intfield,add,replaced)                             \
+    HASH_REPLACE(hh,head,intfield,sizeof(int),add,replaced)
+#define HASH_FIND_PTR(head,findptr,out)                                          \
+    HASH_FIND(hh,head,findptr,sizeof(void *),out)
+#define HASH_ADD_PTR(head,ptrfield,add)                                          \
+    HASH_ADD(hh,head,ptrfield,sizeof(void *),add)
+#define HASH_REPLACE_PTR(head,ptrfield,add,replaced)                             \
+    HASH_REPLACE(hh,head,ptrfield,sizeof(void *),add,replaced)
+#define HASH_DEL(head,delptr)                                                    \
+    HASH_DELETE(hh,head,delptr)
+
+/* HASH_FSCK checks hash integrity on every add/delete when HASH_DEBUG is defined.
+ * This is for uthash developer only; it compiles away if HASH_DEBUG isn't defined.
+ */
+#ifdef HASH_DEBUG
+#include <stdio.h>   /* fprintf, stderr */
+#define HASH_OOPS(...) do { fprintf(stderr, __VA_ARGS__); exit(-1); } while (0)
+#define HASH_FSCK(hh,head,where)                                                 \
+do {                                                                             \
+  struct UT_hash_handle *_thh;                                                   \
+  if (head) {                                                                    \
+    unsigned _bkt_i;                                                             \
+    unsigned _count = 0;                                                         \
+    char *_prev;                                                                 \
+    for (_bkt_i = 0; _bkt_i < (head)->hh.tbl->num_buckets; ++_bkt_i) {           \
+      unsigned _bkt_count = 0;                                                   \
+      _thh = (head)->hh.tbl->buckets[_bkt_i].hh_head;                            \
+      _prev = NULL;                                                              \
+      while (_thh) {                                                             \
+        if (_prev != (char*)(_thh->hh_prev)) {                                   \
+          HASH_OOPS("%s: invalid hh_prev %p, actual %p\n",                       \
+              (where), (void*)_thh->hh_prev, (void*)_prev);                      \
+        }                                                                        \
+        _bkt_count++;                                                            \
+        _prev = (char*)(_thh);                                                   \
+        _thh = _thh->hh_next;                                                    \
+      }                                                                          \
+      _count += _bkt_count;                                                      \
+      if ((head)->hh.tbl->buckets[_bkt_i].count !=  _bkt_count) {                \
+        HASH_OOPS("%s: invalid bucket count %u, actual %u\n",                    \
+            (where), (head)->hh.tbl->buckets[_bkt_i].count, _bkt_count);         \
+      }                                                                          \
+    }                                                                            \
+    if (_count != (head)->hh.tbl->num_items) {                                   \
+      HASH_OOPS("%s: invalid hh item count %u, actual %u\n",                     \
+          (where), (head)->hh.tbl->num_items, _count);                           \
+    }                                                                            \
+    _count = 0;                                                                  \
+    _prev = NULL;                                                                \
+    _thh =  &(head)->hh;                                                         \
+    while (_thh) {                                                               \
+      _count++;                                                                  \
+      if (_prev != (char*)_thh->prev) {                                          \
+        HASH_OOPS("%s: invalid prev %p, actual %p\n",                            \
+            (where), (void*)_thh->prev, (void*)_prev);                           \
+      }                                                                          \
+      _prev = (char*)ELMT_FROM_HH((head)->hh.tbl, _thh);                         \
+      _thh = (_thh->next ? HH_FROM_ELMT((head)->hh.tbl, _thh->next) : NULL);     \
+    }                                                                            \
+    if (_count != (head)->hh.tbl->num_items) {                                   \
+      HASH_OOPS("%s: invalid app item count %u, actual %u\n",                    \
+          (where), (head)->hh.tbl->num_items, _count);                           \
+    }                                                                            \
+  }                                                                              \
+} while (0)
+#else
+#define HASH_FSCK(hh,head,where)
+#endif
+
+/* When compiled with -DHASH_EMIT_KEYS, length-prefixed keys are emitted to
+ * the descriptor to which this macro is defined for tuning the hash function.
+ * The app can #include <unistd.h> to get the prototype for write(2). */
+#ifdef HASH_EMIT_KEYS
+#define HASH_EMIT_KEY(hh,head,keyptr,fieldlen)                                   \
+do {                                                                             \
+  unsigned _klen = fieldlen;                                                     \
+  write(HASH_EMIT_KEYS, &_klen, sizeof(_klen));                                  \
+  write(HASH_EMIT_KEYS, keyptr, (unsigned long)fieldlen);                        \
+} while (0)
+#else
+#define HASH_EMIT_KEY(hh,head,keyptr,fieldlen)
+#endif
+
+/* default to Jenkin's hash unless overridden e.g. DHASH_FUNCTION=HASH_SAX */
+#ifdef HASH_FUNCTION
+#define HASH_FCN HASH_FUNCTION
+#else
+#define HASH_FCN HASH_JEN
+#endif
+
+/* The Bernstein hash function, used in Perl prior to v5.6. Note (x<<5+x)=x*33. */
+#define HASH_BER(key,keylen,hashv)                                               \
+do {                                                                             \
+  unsigned _hb_keylen = (unsigned)keylen;                                        \
+  const unsigned char *_hb_key = (const unsigned char*)(key);                    \
+  (hashv) = 0;                                                                   \
+  while (_hb_keylen-- != 0U) {                                                   \
+    (hashv) = (((hashv) << 5) + (hashv)) + *_hb_key++;                           \
+  }                                                                              \
+} while (0)
+
+
+/* SAX/FNV/OAT/JEN hash functions are macro variants of those listed at
+ * http://eternallyconfuzzled.com/tuts/algorithms/jsw_tut_hashing.aspx */
+#define HASH_SAX(key,keylen,hashv)                                               \
+do {                                                                             \
+  unsigned _sx_i;                                                                \
+  const unsigned char *_hs_key = (const unsigned char*)(key);                    \
+  hashv = 0;                                                                     \
+  for (_sx_i=0; _sx_i < keylen; _sx_i++) {                                       \
+    hashv ^= (hashv << 5) + (hashv >> 2) + _hs_key[_sx_i];                       \
+  }                                                                              \
+} while (0)
+/* FNV-1a variation */
+#define HASH_FNV(key,keylen,hashv)                                               \
+do {                                                                             \
+  unsigned _fn_i;                                                                \
+  const unsigned char *_hf_key = (const unsigned char*)(key);                    \
+  (hashv) = 2166136261U;                                                         \
+  for (_fn_i=0; _fn_i < keylen; _fn_i++) {                                       \
+    hashv = hashv ^ _hf_key[_fn_i];                                              \
+    hashv = hashv * 16777619U;                                                   \
+  }                                                                              \
+} while (0)
+
+#define HASH_OAT(key,keylen,hashv)                                               \
+do {                                                                             \
+  unsigned _ho_i;                                                                \
+  const unsigned char *_ho_key=(const unsigned char*)(key);                      \
+  hashv = 0;                                                                     \
+  for(_ho_i=0; _ho_i < keylen; _ho_i++) {                                        \
+      hashv += _ho_key[_ho_i];                                                   \
+      hashv += (hashv << 10);                                                    \
+      hashv ^= (hashv >> 6);                                                     \
+  }                                                                              \
+  hashv += (hashv << 3);                                                         \
+  hashv ^= (hashv >> 11);                                                        \
+  hashv += (hashv << 15);                                                        \
+} while (0)
+
+#define HASH_JEN_MIX(a,b,c)                                                      \
+do {                                                                             \
+  a -= b; a -= c; a ^= ( c >> 13 );                                              \
+  b -= c; b -= a; b ^= ( a << 8 );                                               \
+  c -= a; c -= b; c ^= ( b >> 13 );                                              \
+  a -= b; a -= c; a ^= ( c >> 12 );                                              \
+  b -= c; b -= a; b ^= ( a << 16 );                                              \
+  c -= a; c -= b; c ^= ( b >> 5 );                                               \
+  a -= b; a -= c; a ^= ( c >> 3 );                                               \
+  b -= c; b -= a; b ^= ( a << 10 );                                              \
+  c -= a; c -= b; c ^= ( b >> 15 );                                              \
+} while (0)
+
+#define HASH_JEN(key,keylen,hashv)                                               \
+do {                                                                             \
+  unsigned _hj_i,_hj_j,_hj_k;                                                    \
+  unsigned const char *_hj_key=(unsigned const char*)(key);                      \
+  hashv = 0xfeedbeefu;                                                           \
+  _hj_i = _hj_j = 0x9e3779b9u;                                                   \
+  _hj_k = (unsigned)(keylen);                                                    \
+  while (_hj_k >= 12U) {                                                         \
+    _hj_i +=    (_hj_key[0] + ( (unsigned)_hj_key[1] << 8 )                      \
+        + ( (unsigned)_hj_key[2] << 16 )                                         \
+        + ( (unsigned)_hj_key[3] << 24 ) );                                      \
+    _hj_j +=    (_hj_key[4] + ( (unsigned)_hj_key[5] << 8 )                      \
+        + ( (unsigned)_hj_key[6] << 16 )                                         \
+        + ( (unsigned)_hj_key[7] << 24 ) );                                      \
+    hashv += (_hj_key[8] + ( (unsigned)_hj_key[9] << 8 )                         \
+        + ( (unsigned)_hj_key[10] << 16 )                                        \
+        + ( (unsigned)_hj_key[11] << 24 ) );                                     \
+                                                                                 \
+     HASH_JEN_MIX(_hj_i, _hj_j, hashv);                                          \
+                                                                                 \
+     _hj_key += 12;                                                              \
+     _hj_k -= 12U;                                                               \
+  }                                                                              \
+  hashv += (unsigned)(keylen);                                                   \
+  switch ( _hj_k ) {                                                             \
+    case 11: hashv += ( (unsigned)_hj_key[10] << 24 ); /* FALLTHROUGH */         \
+    case 10: hashv += ( (unsigned)_hj_key[9] << 16 );  /* FALLTHROUGH */         \
+    case 9:  hashv += ( (unsigned)_hj_key[8] << 8 );   /* FALLTHROUGH */         \
+    case 8:  _hj_j += ( (unsigned)_hj_key[7] << 24 );  /* FALLTHROUGH */         \
+    case 7:  _hj_j += ( (unsigned)_hj_key[6] << 16 );  /* FALLTHROUGH */         \
+    case 6:  _hj_j += ( (unsigned)_hj_key[5] << 8 );   /* FALLTHROUGH */         \
+    case 5:  _hj_j += _hj_key[4];                      /* FALLTHROUGH */         \
+    case 4:  _hj_i += ( (unsigned)_hj_key[3] << 24 );  /* FALLTHROUGH */         \
+    case 3:  _hj_i += ( (unsigned)_hj_key[2] << 16 );  /* FALLTHROUGH */         \
+    case 2:  _hj_i += ( (unsigned)_hj_key[1] << 8 );   /* FALLTHROUGH */         \
+    case 1:  _hj_i += _hj_key[0];                                                \
+  }                                                                              \
+  HASH_JEN_MIX(_hj_i, _hj_j, hashv);                                             \
+} while (0)
+
+/* The Paul Hsieh hash function */
+#undef get16bits
+#if (defined(__GNUC__) && defined(__i386__)) || defined(__WATCOMC__)             \
+  || defined(_MSC_VER) || defined (__BORLANDC__) || defined (__TURBOC__)
+#define get16bits(d) (*((const uint16_t *) (d)))
+#endif
+
+#if !defined (get16bits)
+#define get16bits(d) ((((uint32_t)(((const uint8_t *)(d))[1])) << 8)             \
+                       +(uint32_t)(((const uint8_t *)(d))[0]) )
+#endif
+#define HASH_SFH(key,keylen,hashv)                                               \
+do {                                                                             \
+  unsigned const char *_sfh_key=(unsigned const char*)(key);                     \
+  uint32_t _sfh_tmp, _sfh_len = (uint32_t)keylen;                                \
+                                                                                 \
+  unsigned _sfh_rem = _sfh_len & 3U;                                             \
+  _sfh_len >>= 2;                                                                \
+  hashv = 0xcafebabeu;                                                           \
+                                                                                 \
+  /* Main loop */                                                                \
+  for (;_sfh_len > 0U; _sfh_len--) {                                             \
+    hashv    += get16bits (_sfh_key);                                            \
+    _sfh_tmp  = ((uint32_t)(get16bits (_sfh_key+2)) << 11) ^ hashv;              \
+    hashv     = (hashv << 16) ^ _sfh_tmp;                                        \
+    _sfh_key += 2U*sizeof (uint16_t);                                            \
+    hashv    += hashv >> 11;                                                     \
+  }                                                                              \
+                                                                                 \
+  /* Handle end cases */                                                         \
+  switch (_sfh_rem) {                                                            \
+    case 3: hashv += get16bits (_sfh_key);                                       \
+            hashv ^= hashv << 16;                                                \
+            hashv ^= (uint32_t)(_sfh_key[sizeof (uint16_t)]) << 18;              \
+            hashv += hashv >> 11;                                                \
+            break;                                                               \
+    case 2: hashv += get16bits (_sfh_key);                                       \
+            hashv ^= hashv << 11;                                                \
+            hashv += hashv >> 17;                                                \
+            break;                                                               \
+    case 1: hashv += *_sfh_key;                                                  \
+            hashv ^= hashv << 10;                                                \
+            hashv += hashv >> 1;                                                 \
+  }                                                                              \
+                                                                                 \
+  /* Force "avalanching" of final 127 bits */                                    \
+  hashv ^= hashv << 3;                                                           \
+  hashv += hashv >> 5;                                                           \
+  hashv ^= hashv << 4;                                                           \
+  hashv += hashv >> 17;                                                          \
+  hashv ^= hashv << 25;                                                          \
+  hashv += hashv >> 6;                                                           \
+} while (0)
+
+/* iterate over items in a known bucket to find desired item */
+#define HASH_FIND_IN_BKT(tbl,hh,head,keyptr,keylen_in,hashval,out)               \
+do {                                                                             \
+  if ((head).hh_head != NULL) {                                                  \
+    DECLTYPE_ASSIGN(out, ELMT_FROM_HH(tbl, (head).hh_head));                     \
+  } else {                                                                       \
+    (out) = NULL;                                                                \
+  }                                                                              \
+  while ((out) != NULL) {                                                        \
+    if ((out)->hh.hashv == (hashval) && (out)->hh.keylen == (keylen_in)) {       \
+      if (HASH_KEYCMP((out)->hh.key, keyptr, keylen_in) == 0) {              \
+        break;                                                                   \
+      }                                                                          \
+    }                                                                            \
+    if ((out)->hh.hh_next != NULL) {                                             \
+      DECLTYPE_ASSIGN(out, ELMT_FROM_HH(tbl, (out)->hh.hh_next));                \
+    } else {                                                                     \
+      (out) = NULL;                                                              \
+    }                                                                            \
+  }                                                                              \
+} while (0)
+
+/* add an item to a bucket  */
+#define HASH_ADD_TO_BKT(head,hh,addhh,oomed)                                     \
+do {                                                                             \
+  UT_hash_bucket *_ha_head = &(head);                                            \
+  _ha_head->count++;                                                             \
+  (addhh)->hh_next = _ha_head->hh_head;                                          \
+  (addhh)->hh_prev = NULL;                                                       \
+  if (_ha_head->hh_head != NULL) {                                               \
+    _ha_head->hh_head->hh_prev = (addhh);                                        \
+  }                                                                              \
+  _ha_head->hh_head = (addhh);                                                   \
+  if ((_ha_head->count >= ((_ha_head->expand_mult + 1U) * HASH_BKT_CAPACITY_THRESH)) \
+      && !(addhh)->tbl->noexpand) {                                              \
+    HASH_EXPAND_BUCKETS(addhh,(addhh)->tbl, oomed);                              \
+    IF_HASH_NONFATAL_OOM(                                                        \
+      if (oomed) {                                                               \
+        HASH_DEL_IN_BKT(head,addhh);                                             \
+      }                                                                          \
+    )                                                                            \
+  }                                                                              \
+} while (0)
+
+/* remove an item from a given bucket */
+#define HASH_DEL_IN_BKT(head,delhh)                                              \
+do {                                                                             \
+  UT_hash_bucket *_hd_head = &(head);                                            \
+  _hd_head->count--;                                                             \
+  if (_hd_head->hh_head == (delhh)) {                                            \
+    _hd_head->hh_head = (delhh)->hh_next;                                        \
+  }                                                                              \
+  if ((delhh)->hh_prev) {                                                        \
+    (delhh)->hh_prev->hh_next = (delhh)->hh_next;                                \
+  }                                                                              \
+  if ((delhh)->hh_next) {                                                        \
+    (delhh)->hh_next->hh_prev = (delhh)->hh_prev;                                \
+  }                                                                              \
+} while (0)
+
+/* Bucket expansion has the effect of doubling the number of buckets
+ * and redistributing the items into the new buckets. Ideally the
+ * items will distribute more or less evenly into the new buckets
+ * (the extent to which this is true is a measure of the quality of
+ * the hash function as it applies to the key domain).
+ *
+ * With the items distributed into more buckets, the chain length
+ * (item count) in each bucket is reduced. Thus by expanding buckets
+ * the hash keeps a bound on the chain length. This bounded chain
+ * length is the essence of how a hash provides constant time lookup.
+ *
+ * The calculation of tbl->ideal_chain_maxlen below deserves some
+ * explanation. First, keep in mind that we're calculating the ideal
+ * maximum chain length based on the *new* (doubled) bucket count.
+ * In fractions this is just n/b (n=number of items,b=new num buckets).
+ * Since the ideal chain length is an integer, we want to calculate
+ * ceil(n/b). We don't depend on floating point arithmetic in this
+ * hash, so to calculate ceil(n/b) with integers we could write
+ *
+ *      ceil(n/b) = (n/b) + ((n%b)?1:0)
+ *
+ * and in fact a previous version of this hash did just that.
+ * But now we have improved things a bit by recognizing that b is
+ * always a power of two. We keep its base 2 log handy (call it lb),
+ * so now we can write this with a bit shift and logical AND:
+ *
+ *      ceil(n/b) = (n>>lb) + ( (n & (b-1)) ? 1:0)
+ *
+ */
+#define HASH_EXPAND_BUCKETS(hh,tbl,oomed)                                        \
+do {                                                                             \
+  unsigned _he_bkt;                                                              \
+  unsigned _he_bkt_i;                                                            \
+  struct UT_hash_handle *_he_thh, *_he_hh_nxt;                                   \
+  UT_hash_bucket *_he_new_buckets, *_he_newbkt;                                  \
+  _he_new_buckets = (UT_hash_bucket*)uthash_malloc(                              \
+           2UL * (tbl)->num_buckets * sizeof(struct UT_hash_bucket));            \
+  if (!_he_new_buckets) {                                                        \
+    HASH_RECORD_OOM(oomed);                                                      \
+  } else {                                                                       \
+    uthash_bzero(_he_new_buckets,                                                \
+        2UL * (tbl)->num_buckets * sizeof(struct UT_hash_bucket));               \
+    (tbl)->ideal_chain_maxlen =                                                  \
+       ((tbl)->num_items >> ((tbl)->log2_num_buckets+1U)) +                      \
+       ((((tbl)->num_items & (((tbl)->num_buckets*2U)-1U)) != 0U) ? 1U : 0U);    \
+    (tbl)->nonideal_items = 0;                                                   \
+    for (_he_bkt_i = 0; _he_bkt_i < (tbl)->num_buckets; _he_bkt_i++) {           \
+      _he_thh = (tbl)->buckets[ _he_bkt_i ].hh_head;                             \
+      while (_he_thh != NULL) {                                                  \
+        _he_hh_nxt = _he_thh->hh_next;                                           \
+        HASH_TO_BKT(_he_thh->hashv, (tbl)->num_buckets * 2U, _he_bkt);           \
+        _he_newbkt = &(_he_new_buckets[_he_bkt]);                                \
+        if (++(_he_newbkt->count) > (tbl)->ideal_chain_maxlen) {                 \
+          (tbl)->nonideal_items++;                                               \
+          if (_he_newbkt->count > _he_newbkt->expand_mult * (tbl)->ideal_chain_maxlen) { \
+            _he_newbkt->expand_mult++;                                           \
+          }                                                                      \
+        }                                                                        \
+        _he_thh->hh_prev = NULL;                                                 \
+        _he_thh->hh_next = _he_newbkt->hh_head;                                  \
+        if (_he_newbkt->hh_head != NULL) {                                       \
+          _he_newbkt->hh_head->hh_prev = _he_thh;                                \
+        }                                                                        \
+        _he_newbkt->hh_head = _he_thh;                                           \
+        _he_thh = _he_hh_nxt;                                                    \
+      }                                                                          \
+    }                                                                            \
+    uthash_free((tbl)->buckets, (tbl)->num_buckets * sizeof(struct UT_hash_bucket)); \
+    (tbl)->num_buckets *= 2U;                                                    \
+    (tbl)->log2_num_buckets++;                                                   \
+    (tbl)->buckets = _he_new_buckets;                                            \
+    (tbl)->ineff_expands = ((tbl)->nonideal_items > ((tbl)->num_items >> 1)) ?   \
+        ((tbl)->ineff_expands+1U) : 0U;                                          \
+    if ((tbl)->ineff_expands > 1U) {                                             \
+      (tbl)->noexpand = 1;                                                       \
+      uthash_noexpand_fyi(tbl);                                                  \
+    }                                                                            \
+    uthash_expand_fyi(tbl);                                                      \
+  }                                                                              \
+} while (0)
+
+
+/* This is an adaptation of Simon Tatham's O(n log(n)) mergesort */
+/* Note that HASH_SORT assumes the hash handle name to be hh.
+ * HASH_SRT was added to allow the hash handle name to be passed in. */
+#define HASH_SORT(head,cmpfcn) HASH_SRT(hh,head,cmpfcn)
+#define HASH_SRT(hh,head,cmpfcn)                                                 \
+do {                                                                             \
+  unsigned _hs_i;                                                                \
+  unsigned _hs_looping,_hs_nmerges,_hs_insize,_hs_psize,_hs_qsize;               \
+  struct UT_hash_handle *_hs_p, *_hs_q, *_hs_e, *_hs_list, *_hs_tail;            \
+  if (head != NULL) {                                                            \
+    _hs_insize = 1;                                                              \
+    _hs_looping = 1;                                                             \
+    _hs_list = &((head)->hh);                                                    \
+    while (_hs_looping != 0U) {                                                  \
+      _hs_p = _hs_list;                                                          \
+      _hs_list = NULL;                                                           \
+      _hs_tail = NULL;                                                           \
+      _hs_nmerges = 0;                                                           \
+      while (_hs_p != NULL) {                                                    \
+        _hs_nmerges++;                                                           \
+        _hs_q = _hs_p;                                                           \
+        _hs_psize = 0;                                                           \
+        for (_hs_i = 0; _hs_i < _hs_insize; ++_hs_i) {                           \
+          _hs_psize++;                                                           \
+          _hs_q = ((_hs_q->next != NULL) ?                                       \
+            HH_FROM_ELMT((head)->hh.tbl, _hs_q->next) : NULL);                   \
+          if (_hs_q == NULL) {                                                   \
+            break;                                                               \
+          }                                                                      \
+        }                                                                        \
+        _hs_qsize = _hs_insize;                                                  \
+        while ((_hs_psize != 0U) || ((_hs_qsize != 0U) && (_hs_q != NULL))) {    \
+          if (_hs_psize == 0U) {                                                 \
+            _hs_e = _hs_q;                                                       \
+            _hs_q = ((_hs_q->next != NULL) ?                                     \
+              HH_FROM_ELMT((head)->hh.tbl, _hs_q->next) : NULL);                 \
+            _hs_qsize--;                                                         \
+          } else if ((_hs_qsize == 0U) || (_hs_q == NULL)) {                     \
+            _hs_e = _hs_p;                                                       \
+            if (_hs_p != NULL) {                                                 \
+              _hs_p = ((_hs_p->next != NULL) ?                                   \
+                HH_FROM_ELMT((head)->hh.tbl, _hs_p->next) : NULL);               \
+            }                                                                    \
+            _hs_psize--;                                                         \
+          } else if ((cmpfcn(                                                    \
+                DECLTYPE(head)(ELMT_FROM_HH((head)->hh.tbl, _hs_p)),             \
+                DECLTYPE(head)(ELMT_FROM_HH((head)->hh.tbl, _hs_q))              \
+                )) <= 0) {                                                       \
+            _hs_e = _hs_p;                                                       \
+            if (_hs_p != NULL) {                                                 \
+              _hs_p = ((_hs_p->next != NULL) ?                                   \
+                HH_FROM_ELMT((head)->hh.tbl, _hs_p->next) : NULL);               \
+            }                                                                    \
+            _hs_psize--;                                                         \
+          } else {                                                               \
+            _hs_e = _hs_q;                                                       \
+            _hs_q = ((_hs_q->next != NULL) ?                                     \
+              HH_FROM_ELMT((head)->hh.tbl, _hs_q->next) : NULL);                 \
+            _hs_qsize--;                                                         \
+          }                                                                      \
+          if ( _hs_tail != NULL ) {                                              \
+            _hs_tail->next = ((_hs_e != NULL) ?                                  \
+              ELMT_FROM_HH((head)->hh.tbl, _hs_e) : NULL);                       \
+          } else {                                                               \
+            _hs_list = _hs_e;                                                    \
+          }                                                                      \
+          if (_hs_e != NULL) {                                                   \
+            _hs_e->prev = ((_hs_tail != NULL) ?                                  \
+              ELMT_FROM_HH((head)->hh.tbl, _hs_tail) : NULL);                    \
+          }                                                                      \
+          _hs_tail = _hs_e;                                                      \
+        }                                                                        \
+        _hs_p = _hs_q;                                                           \
+      }                                                                          \
+      if (_hs_tail != NULL) {                                                    \
+        _hs_tail->next = NULL;                                                   \
+      }                                                                          \
+      if (_hs_nmerges <= 1U) {                                                   \
+        _hs_looping = 0;                                                         \
+        (head)->hh.tbl->tail = _hs_tail;                                         \
+        DECLTYPE_ASSIGN(head, ELMT_FROM_HH((head)->hh.tbl, _hs_list));           \
+      }                                                                          \
+      _hs_insize *= 2U;                                                          \
+    }                                                                            \
+    HASH_FSCK(hh, head, "HASH_SRT");                                             \
+  }                                                                              \
+} while (0)
+
+/* This function selects items from one hash into another hash.
+ * The end result is that the selected items have dual presence
+ * in both hashes. There is no copy of the items made; rather
+ * they are added into the new hash through a secondary hash
+ * hash handle that must be present in the structure. */
+#define HASH_SELECT(hh_dst, dst, hh_src, src, cond)                              \
+do {                                                                             \
+  unsigned _src_bkt, _dst_bkt;                                                   \
+  void *_last_elt = NULL, *_elt;                                                 \
+  UT_hash_handle *_src_hh, *_dst_hh, *_last_elt_hh=NULL;                         \
+  ptrdiff_t _dst_hho = ((char*)(&(dst)->hh_dst) - (char*)(dst));                 \
+  if ((src) != NULL) {                                                           \
+    for (_src_bkt=0; _src_bkt < (src)->hh_src.tbl->num_buckets; _src_bkt++) {    \
+      for (_src_hh = (src)->hh_src.tbl->buckets[_src_bkt].hh_head;               \
+        _src_hh != NULL;                                                         \
+        _src_hh = _src_hh->hh_next) {                                            \
+        _elt = ELMT_FROM_HH((src)->hh_src.tbl, _src_hh);                         \
+        if (cond(_elt)) {                                                        \
+          IF_HASH_NONFATAL_OOM( int _hs_oomed = 0; )                             \
+          _dst_hh = (UT_hash_handle*)(void*)(((char*)_elt) + _dst_hho);          \
+          _dst_hh->key = _src_hh->key;                                           \
+          _dst_hh->keylen = _src_hh->keylen;                                     \
+          _dst_hh->hashv = _src_hh->hashv;                                       \
+          _dst_hh->prev = _last_elt;                                             \
+          _dst_hh->next = NULL;                                                  \
+          if (_last_elt_hh != NULL) {                                            \
+            _last_elt_hh->next = _elt;                                           \
+          }                                                                      \
+          if ((dst) == NULL) {                                                   \
+            DECLTYPE_ASSIGN(dst, _elt);                                          \
+            HASH_MAKE_TABLE(hh_dst, dst, _hs_oomed);                             \
+            IF_HASH_NONFATAL_OOM(                                                \
+              if (_hs_oomed) {                                                   \
+                uthash_nonfatal_oom(_elt);                                       \
+                (dst) = NULL;                                                    \
+                continue;                                                        \
+              }                                                                  \
+            )                                                                    \
+          } else {                                                               \
+            _dst_hh->tbl = (dst)->hh_dst.tbl;                                    \
+          }                                                                      \
+          HASH_TO_BKT(_dst_hh->hashv, _dst_hh->tbl->num_buckets, _dst_bkt);      \
+          HASH_ADD_TO_BKT(_dst_hh->tbl->buckets[_dst_bkt], hh_dst, _dst_hh, _hs_oomed); \
+          (dst)->hh_dst.tbl->num_items++;                                        \
+          IF_HASH_NONFATAL_OOM(                                                  \
+            if (_hs_oomed) {                                                     \
+              HASH_ROLLBACK_BKT(hh_dst, dst, _dst_hh);                           \
+              HASH_DELETE_HH(hh_dst, dst, _dst_hh);                              \
+              _dst_hh->tbl = NULL;                                               \
+              uthash_nonfatal_oom(_elt);                                         \
+              continue;                                                          \
+            }                                                                    \
+          )                                                                      \
+          HASH_BLOOM_ADD(_dst_hh->tbl, _dst_hh->hashv);                          \
+          _last_elt = _elt;                                                      \
+          _last_elt_hh = _dst_hh;                                                \
+        }                                                                        \
+      }                                                                          \
+    }                                                                            \
+  }                                                                              \
+  HASH_FSCK(hh_dst, dst, "HASH_SELECT");                                         \
+} while (0)
+
+#define HASH_CLEAR(hh,head)                                                      \
+do {                                                                             \
+  if ((head) != NULL) {                                                          \
+    HASH_BLOOM_FREE((head)->hh.tbl);                                             \
+    uthash_free((head)->hh.tbl->buckets,                                         \
+                (head)->hh.tbl->num_buckets*sizeof(struct UT_hash_bucket));      \
+    uthash_free((head)->hh.tbl, sizeof(UT_hash_table));                          \
+    (head) = NULL;                                                               \
+  }                                                                              \
+} while (0)
+
+#define HASH_OVERHEAD(hh,head)                                                   \
+ (((head) != NULL) ? (                                                           \
+ (size_t)(((head)->hh.tbl->num_items   * sizeof(UT_hash_handle))   +             \
+          ((head)->hh.tbl->num_buckets * sizeof(UT_hash_bucket))   +             \
+           sizeof(UT_hash_table)                                   +             \
+           (HASH_BLOOM_BYTELEN))) : 0U)
+
+#ifdef NO_DECLTYPE
+#define HASH_ITER(hh,head,el,tmp)                                                \
+for(((el)=(head)), ((*(char**)(&(tmp)))=(char*)((head!=NULL)?(head)->hh.next:NULL)); \
+  (el) != NULL; ((el)=(tmp)), ((*(char**)(&(tmp)))=(char*)((tmp!=NULL)?(tmp)->hh.next:NULL)))
+#else
+#define HASH_ITER(hh,head,el,tmp)                                                \
+for(((el)=(head)), ((tmp)=DECLTYPE(el)((head!=NULL)?(head)->hh.next:NULL));      \
+  (el) != NULL; ((el)=(tmp)), ((tmp)=DECLTYPE(el)((tmp!=NULL)?(tmp)->hh.next:NULL)))
+#endif
+
+/* obtain a count of items in the hash */
+#define HASH_COUNT(head) HASH_CNT(hh,head)
+#define HASH_CNT(hh,head) ((head != NULL)?((head)->hh.tbl->num_items):0U)
+
+typedef struct UT_hash_bucket {
+   struct UT_hash_handle *hh_head;
+   unsigned count;
+
+   /* expand_mult is normally set to 0. In this situation, the max chain length
+    * threshold is enforced at its default value, HASH_BKT_CAPACITY_THRESH. (If
+    * the bucket's chain exceeds this length, bucket expansion is triggered).
+    * However, setting expand_mult to a non-zero value delays bucket expansion
+    * (that would be triggered by additions to this particular bucket)
+    * until its chain length reaches a *multiple* of HASH_BKT_CAPACITY_THRESH.
+    * (The multiplier is simply expand_mult+1). The whole idea of this
+    * multiplier is to reduce bucket expansions, since they are expensive, in
+    * situations where we know that a particular bucket tends to be overused.
+    * It is better to let its chain length grow to a longer yet-still-bounded
+    * value, than to do an O(n) bucket expansion too often.
+    */
+   unsigned expand_mult;
+
+} UT_hash_bucket;
+
+/* random signature used only to find hash tables in external analysis */
+#define HASH_SIGNATURE 0xa0111fe1u
+#define HASH_BLOOM_SIGNATURE 0xb12220f2u
+
+typedef struct UT_hash_table {
+   UT_hash_bucket *buckets;
+   unsigned num_buckets, log2_num_buckets;
+   unsigned num_items;
+   struct UT_hash_handle *tail; /* tail hh in app order, for fast append    */
+   ptrdiff_t hho; /* hash handle offset (byte pos of hash handle in element */
+
+   /* in an ideal situation (all buckets used equally), no bucket would have
+    * more than ceil(#items/#buckets) items. that's the ideal chain length. */
+   unsigned ideal_chain_maxlen;
+
+   /* nonideal_items is the number of items in the hash whose chain position
+    * exceeds the ideal chain maxlen. these items pay the penalty for an uneven
+    * hash distribution; reaching them in a chain traversal takes >ideal steps */
+   unsigned nonideal_items;
+
+   /* ineffective expands occur when a bucket doubling was performed, but
+    * afterward, more than half the items in the hash had nonideal chain
+    * positions. If this happens on two consecutive expansions we inhibit any
+    * further expansion, as it's not helping; this happens when the hash
+    * function isn't a good fit for the key domain. When expansion is inhibited
+    * the hash will still work, albeit no longer in constant time. */
+   unsigned ineff_expands, noexpand;
+
+   uint32_t signature; /* used only to find hash tables in external analysis */
+#ifdef HASH_BLOOM
+   uint32_t bloom_sig; /* used only to test bloom exists in external analysis */
+   uint8_t *bloom_bv;
+   uint8_t bloom_nbits;
+#endif
+
+} UT_hash_table;
+
+typedef struct UT_hash_handle {
+   struct UT_hash_table *tbl;
+   void *prev;                       /* prev element in app order      */
+   void *next;                       /* next element in app order      */
+   struct UT_hash_handle *hh_prev;   /* previous hh in bucket order    */
+   struct UT_hash_handle *hh_next;   /* next hh in bucket order        */
+   void *key;                        /* ptr to enclosing struct's key  */
+   unsigned keylen;                  /* enclosing struct's key len     */
+   unsigned hashv;                   /* result of hash-fcn(key)        */
+} UT_hash_handle;
+
+#endif /* UTHASH_H */