1 files changed, 153 insertions, 0 deletions
diff --git a/libc-top-half/musl/src/search/hsearch.c b/libc-top-half/musl/src/search/hsearch.c
new file mode 100644
index 0000000..b3ac879
--- /dev/null
+++ b/libc-top-half/musl/src/search/hsearch.c
@@ -0,0 +1,153 @@
+#define _GNU_SOURCE
+#include <stdlib.h>
+#include <string.h>
+#include <search.h>
+
+/*
+open addressing hash table with 2^n table size
+quadratic probing is used in case of hash collision
+tab indices and hash are size_t
+after resize fails with ENOMEM the state of tab is still usable
+
+with the posix api items cannot be iterated and length cannot be queried
+*/
+
+#define MINSIZE 8
+#define MAXSIZE ((size_t)-1/2 + 1)
+
+struct __tab {
+	ENTRY *entries;
+	size_t mask;
+	size_t used;
+};
+
+static struct hsearch_data htab;
+
+static int __hcreate_r(size_t, struct hsearch_data *);
+static void __hdestroy_r(struct hsearch_data *);
+static int __hsearch_r(ENTRY, ACTION, ENTRY **, struct hsearch_data *);
+
+static size_t keyhash(char *k)
+{
+	unsigned char *p = (void *)k;
+	size_t h = 0;
+
+	while (*p)
+		h = 31*h + *p++;
+	return h;
+}
+
+static int resize(size_t nel, struct hsearch_data *htab)
+{
+	size_t newsize;
+	size_t i, j;
+	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->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->key) {
+			for (i=keyhash(e->key),j=1; ; i+=j++) {
+				newe = htab->__tab->entries + (i & htab->__tab->mask);
+				if (!newe->key)
+					break;
+			}
+			*newe = *e;
+		}
+	free(oldtab);
+	return 1;
+}
+
+int hcreate(size_t nel)
+{
+	return __hcreate_r(nel, &htab);
+}
+
+void hdestroy(void)
+{
+	__hdestroy_r(&htab);
+}
+
+static ENTRY *lookup(char *key, size_t hash, struct hsearch_data *htab)
+{
+	size_t i, j;
+	ENTRY *e;
+
+	for (i=hash,j=1; ; i+=j++) {
+		e = htab->__tab->entries + (i & htab->__tab->mask);
+		if (!e->key || strcmp(e->key, key) == 0)
+			break;
+	}
+	return e;
+}
+
+ENTRY *hsearch(ENTRY item, ACTION action)
+{
+	ENTRY *e;
+
+	__hsearch_r(item, action, &e, &htab);
+	return e;
+}
+
+static int __hcreate_r(size_t nel, struct hsearch_data *htab)
+{
+	int r;
+
+	htab->__tab = calloc(1, sizeof *htab->__tab);
+	if (!htab->__tab)
+		return 0;
+	r = resize(nel, htab);
+	if (r == 0) {
+		free(htab->__tab);
+		htab->__tab = 0;
+	}
+	return r;
+}
+weak_alias(__hcreate_r, hcreate_r);
+
+static void __hdestroy_r(struct hsearch_data *htab)
+{
+	if (htab->__tab) free(htab->__tab->entries);
+	free(htab->__tab);
+	htab->__tab = 0;
+}
+weak_alias(__hdestroy_r, hdestroy_r);
+
+static int __hsearch_r(ENTRY item, ACTION action, ENTRY **retval, struct hsearch_data *htab)
+{
+	size_t hash = keyhash(item.key);
+	ENTRY *e = lookup(item.key, hash, htab);
+
+	if (e->key) {
+		*retval = e;
+		return 1;
+	}
+	if (action == FIND) {
+		*retval = 0;
+		return 0;
+	}
+	*e = item;
+	if (++htab->__tab->used > htab->__tab->mask - htab->__tab->mask/4) {
+		if (!resize(2*htab->__tab->used, htab)) {
+			htab->__tab->used--;
+			e->key = 0;
+			*retval = 0;
+			return 0;
+		}
+		e = lookup(item.key, hash, htab);
+	}
+	*retval = e;
+	return 1;
+}
+weak_alias(__hsearch_r, hsearch_r);