remove struct elem entirely from hsearch.c

There are two changes here, both of which make sense to be done in a
single patch:

- Remove hash from struct elem and compute it at runtime wherever
  necessary.
- Eliminate struct elem and use ENTRY directly.

As a result we cut down on the memory usage as each element in the
hash table now contains only an ENTRY not an ENTRY + size_t for the
hash. The downside is that the hash needs to be computed at runtime.

diff --git a/src/search/hsearch.c b/src/search/hsearch.c
index 88edb2634b533853ddf9356f83e804689f83e18a..5c8965114bdcb320562ae4661c05ac8bd9374a66 100644 (file)
--- a/src/search/hsearch.c
+++ b/src/search/hsearch.c
@@ -16,13 +16,8 @@ with the posix api items cannot be iterated and length cannot be queried
 #define MINSIZE 8
 #define MAXSIZE ((size_t)-1/2 + 1)
 
-struct elem {
-       ENTRY item;
-       size_t hash;
-};
-
 struct __tab {
-       struct elem *elems;
+       ENTRY *entries;
        size_t mask;
        size_t used;
 };
@@ -47,26 +42,26 @@ static int resize(size_t nel, struct hsearch_data *htab)
 {
        size_t newsize;
        size_t i, j;
-       struct elem *e, *newe;
-       struct elem *oldtab = htab->__tab->elems;
-       struct elem *oldend = htab->__tab->elems + htab->__tab->mask + 1;
+       ENTRY *e, *newe;
+       ENTRY *oldtab = htab->__tab->entries;
+       ENTRY *oldend = htab->__tab->entries + htab->__tab->mask + 1;
 
        if (nel > MAXSIZE)
                nel = MAXSIZE;
        for (newsize = MINSIZE; newsize < nel; newsize *= 2);
-       htab->__tab->elems = calloc(newsize, sizeof *htab->__tab->elems);
-       if (!htab->__tab->elems) {
-               htab->__tab->elems = oldtab;
+       htab->__tab->entries = calloc(newsize, sizeof *htab->__tab->entries);
+       if (!htab->__tab->entries) {
+               htab->__tab->entries = oldtab;
                return 0;
        }
        htab->__tab->mask = newsize - 1;
        if (!oldtab)
                return 1;
        for (e = oldtab; e < oldend; e++)
-               if (e->item.key) {
-                       for (i=e->hash,j=1; ; i+=j++) {
-                               newe = htab->__tab->elems + (i & htab->__tab->mask);
-                               if (!newe->item.key)
+               if (e->key) {
+                       for (i=keyhash(e->key),j=1; ; i+=j++) {
+                               newe = htab->__tab->entries + (i & htab->__tab->mask);
+                               if (!newe->key)
                                        break;
                        }
                        *newe = *e;
@@ -85,15 +80,14 @@ void hdestroy(void)
        __hdestroy_r(&htab);
 }
 
-static struct elem *lookup(char *key, size_t hash, struct hsearch_data *htab)
+static ENTRY *lookup(char *key, size_t hash, struct hsearch_data *htab)
 {
        size_t i, j;
-       struct elem *e;
+       ENTRY *e;
 
        for (i=hash,j=1; ; i+=j++) {
-               e = htab->__tab->elems + (i & htab->__tab->mask);
-               if (!e->item.key ||
-                   (e->hash==hash && strcmp(e->item.key, key)==0))
+               e = htab->__tab->entries + (i & htab->__tab->mask);
+               if (!e->key || strcmp(e->key, key) == 0)
                        break;
        }
        return e;
@@ -125,7 +119,7 @@ weak_alias(__hcreate_r, hcreate_r);
 
 void __hdestroy_r(struct hsearch_data *htab)
 {
-       if (htab->__tab) free(htab->__tab->elems);
+       if (htab->__tab) free(htab->__tab->entries);
        free(htab->__tab);
        htab->__tab = 0;
 }
@@ -134,28 +128,27 @@ weak_alias(__hdestroy_r, hdestroy_r);
 int __hsearch_r(ENTRY item, ACTION action, ENTRY **retval, struct hsearch_data *htab)
 {
        size_t hash = keyhash(item.key);
-       struct elem *e = lookup(item.key, hash, htab);
+       ENTRY *e = lookup(item.key, hash, htab);
 
-       if (e->item.key) {
-               *retval = &e->item;
+       if (e->key) {
+               *retval = e;
                return 1;
        }
        if (action == FIND) {
                *retval = 0;
                return 0;
        }
-       e->item = item;
-       e->hash = hash;
+       *e = item;
        if (++htab->__tab->used > htab->__tab->mask - htab->__tab->mask/4) {
                if (!resize(2*htab->__tab->used, htab)) {
                        htab->__tab->used--;
-                       e->item.key = 0;
+                       e->key = 0;
                        *retval = 0;
                        return 0;
                }
                e = lookup(item.key, hash, htab);
        }
-       *retval = &e->item;
+       *retval = e;
        return 1;
 }
 weak_alias(__hsearch_r, hsearch_r);