1 files changed, 303 insertions, 0 deletions
diff --git a/lib/isc/symtab.c b/lib/isc/symtab.c
new file mode 100644
index 0000000..b6466d3
--- /dev/null
+++ b/lib/isc/symtab.c
@@ -0,0 +1,303 @@
+/*
+ * Copyright (C) Internet Systems Consortium, Inc. ("ISC")
+ *
+ * This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/.
+ *
+ * See the COPYRIGHT file distributed with this work for additional
+ * information regarding copyright ownership.
+ */
+
+
+/*! \file */
+
+#include <config.h>
+
+#include <ctype.h>
+#include <stdbool.h>
+
+#include <isc/magic.h>
+#include <isc/mem.h>
+#include <isc/string.h>
+#include <isc/symtab.h>
+#include <isc/util.h>
+
+typedef struct elt {
+	char *				key;
+	unsigned int			type;
+	isc_symvalue_t			value;
+	LINK(struct elt)		link;
+} elt_t;
+
+typedef LIST(elt_t)			eltlist_t;
+
+#define SYMTAB_MAGIC			ISC_MAGIC('S', 'y', 'm', 'T')
+#define VALID_SYMTAB(st)		ISC_MAGIC_VALID(st, SYMTAB_MAGIC)
+
+struct isc_symtab {
+	/* Unlocked. */
+	unsigned int			magic;
+	isc_mem_t *			mctx;
+	unsigned int			size;
+	unsigned int			count;
+	unsigned int			maxload;
+	eltlist_t *			table;
+	isc_symtabaction_t		undefine_action;
+	void *				undefine_arg;
+	bool			case_sensitive;
+};
+
+isc_result_t
+isc_symtab_create(isc_mem_t *mctx, unsigned int size,
+		  isc_symtabaction_t undefine_action,
+		  void *undefine_arg,
+		  bool case_sensitive,
+		  isc_symtab_t **symtabp)
+{
+	isc_symtab_t *symtab;
+	unsigned int i;
+
+	REQUIRE(mctx != NULL);
+	REQUIRE(symtabp != NULL && *symtabp == NULL);
+	REQUIRE(size > 0);	/* Should be prime. */
+
+	symtab = (isc_symtab_t *)isc_mem_get(mctx, sizeof(*symtab));
+	if (symtab == NULL)
+		return (ISC_R_NOMEMORY);
+
+	symtab->mctx = NULL;
+	isc_mem_attach(mctx, &symtab->mctx);
+	symtab->table = (eltlist_t *)isc_mem_get(mctx,
+						 size * sizeof(eltlist_t));
+	if (symtab->table == NULL) {
+		isc_mem_putanddetach(&symtab->mctx, symtab, sizeof(*symtab));
+		return (ISC_R_NOMEMORY);
+	}
+	for (i = 0; i < size; i++)
+		INIT_LIST(symtab->table[i]);
+	symtab->size = size;
+	symtab->count = 0;
+	symtab->maxload = size * 3 / 4;
+	symtab->undefine_action = undefine_action;
+	symtab->undefine_arg = undefine_arg;
+	symtab->case_sensitive = case_sensitive;
+	symtab->magic = SYMTAB_MAGIC;
+
+	*symtabp = symtab;
+
+	return (ISC_R_SUCCESS);
+}
+
+void
+isc_symtab_destroy(isc_symtab_t **symtabp) {
+	isc_symtab_t *symtab;
+	unsigned int i;
+	elt_t *elt, *nelt;
+
+	REQUIRE(symtabp != NULL);
+	symtab = *symtabp;
+	REQUIRE(VALID_SYMTAB(symtab));
+
+	for (i = 0; i < symtab->size; i++) {
+		for (elt = HEAD(symtab->table[i]); elt != NULL; elt = nelt) {
+			nelt = NEXT(elt, link);
+			if (symtab->undefine_action != NULL)
+			       (symtab->undefine_action)(elt->key,
+							 elt->type,
+							 elt->value,
+							 symtab->undefine_arg);
+			isc_mem_put(symtab->mctx, elt, sizeof(*elt));
+		}
+	}
+	isc_mem_put(symtab->mctx, symtab->table,
+		    symtab->size * sizeof(eltlist_t));
+	symtab->magic = 0;
+	isc_mem_putanddetach(&symtab->mctx, symtab, sizeof(*symtab));
+
+	*symtabp = NULL;
+}
+
+static inline unsigned int
+hash(const char *key, bool case_sensitive) {
+	const char *s;
+	unsigned int h = 0;
+	int c;
+
+	/*
+	 * This hash function is similar to the one Ousterhout
+	 * uses in Tcl.
+	 */
+
+	if (case_sensitive) {
+		for (s = key; *s != '\0'; s++) {
+			h += (h << 3) + *s;
+		}
+	} else {
+		for (s = key; *s != '\0'; s++) {
+			c = *s;
+			c = tolower((unsigned char)c);
+			h += (h << 3) + c;
+		}
+	}
+
+	return (h);
+}
+
+#define FIND(s, k, t, b, e) \
+	b = hash((k), (s)->case_sensitive) % (s)->size; \
+	if ((s)->case_sensitive) { \
+		for (e = HEAD((s)->table[b]); e != NULL; e = NEXT(e, link)) { \
+			if (((t) == 0 || e->type == (t)) && \
+			    strcmp(e->key, (k)) == 0) \
+				break; \
+		} \
+	} else { \
+		for (e = HEAD((s)->table[b]); e != NULL; e = NEXT(e, link)) { \
+			if (((t) == 0 || e->type == (t)) && \
+			    strcasecmp(e->key, (k)) == 0) \
+				break; \
+		} \
+	}
+
+isc_result_t
+isc_symtab_lookup(isc_symtab_t *symtab, const char *key, unsigned int type,
+		  isc_symvalue_t *value)
+{
+	unsigned int bucket;
+	elt_t *elt;
+
+	REQUIRE(VALID_SYMTAB(symtab));
+	REQUIRE(key != NULL);
+
+	FIND(symtab, key, type, bucket, elt);
+
+	if (elt == NULL)
+		return (ISC_R_NOTFOUND);
+
+	if (value != NULL)
+		*value = elt->value;
+
+	return (ISC_R_SUCCESS);
+}
+
+static void
+grow_table(isc_symtab_t *symtab) {
+	eltlist_t *newtable;
+	unsigned int i, newsize, newmax;
+
+	REQUIRE(symtab != NULL);
+
+	newsize = symtab->size * 2;
+	newmax = newsize * 3 / 4;
+	INSIST(newsize > 0U && newmax > 0U);
+
+	newtable = isc_mem_get(symtab->mctx, newsize * sizeof(eltlist_t));
+	if (newtable == NULL)
+		return;
+
+	for (i = 0; i < newsize; i++)
+		INIT_LIST(newtable[i]);
+
+	for (i = 0; i < symtab->size; i++) {
+		elt_t *elt, *nelt;
+
+		for (elt = HEAD(symtab->table[i]); elt != NULL; elt = nelt) {
+			unsigned int hv;
+
+			nelt = NEXT(elt, link);
+
+			UNLINK(symtab->table[i], elt, link);
+			hv = hash(elt->key, symtab->case_sensitive);
+			APPEND(newtable[hv % newsize], elt, link);
+		}
+	}
+
+	isc_mem_put(symtab->mctx, symtab->table,
+		    symtab->size * sizeof(eltlist_t));
+
+	symtab->table = newtable;
+	symtab->size = newsize;
+	symtab->maxload = newmax;
+}
+
+isc_result_t
+isc_symtab_define(isc_symtab_t *symtab, const char *key, unsigned int type,
+		  isc_symvalue_t value, isc_symexists_t exists_policy)
+{
+	unsigned int bucket;
+	elt_t *elt;
+
+	REQUIRE(VALID_SYMTAB(symtab));
+	REQUIRE(key != NULL);
+	REQUIRE(type != 0);
+
+	FIND(symtab, key, type, bucket, elt);
+
+	if (exists_policy != isc_symexists_add && elt != NULL) {
+		if (exists_policy == isc_symexists_reject)
+			return (ISC_R_EXISTS);
+		INSIST(exists_policy == isc_symexists_replace);
+		UNLINK(symtab->table[bucket], elt, link);
+		if (symtab->undefine_action != NULL)
+			(symtab->undefine_action)(elt->key, elt->type,
+						  elt->value,
+						  symtab->undefine_arg);
+	} else {
+		elt = (elt_t *)isc_mem_get(symtab->mctx, sizeof(*elt));
+		if (elt == NULL)
+			return (ISC_R_NOMEMORY);
+		ISC_LINK_INIT(elt, link);
+		symtab->count++;
+	}
+
+	/*
+	 * Though the "key" can be const coming in, it is not stored as const
+	 * so that the calling program can easily have writable access to
+	 * it in its undefine_action function.  In the event that it *was*
+	 * truly const coming in and then the caller modified it anyway ...
+	 * well, don't do that!
+	 */
+	DE_CONST(key, elt->key);
+	elt->type = type;
+	elt->value = value;
+
+	/*
+	 * We prepend so that the most recent definition will be found.
+	 */
+	PREPEND(symtab->table[bucket], elt, link);
+
+	if (symtab->count > symtab->maxload)
+		grow_table(symtab);
+
+	return (ISC_R_SUCCESS);
+}
+
+isc_result_t
+isc_symtab_undefine(isc_symtab_t *symtab, const char *key, unsigned int type) {
+	unsigned int bucket;
+	elt_t *elt;
+
+	REQUIRE(VALID_SYMTAB(symtab));
+	REQUIRE(key != NULL);
+
+	FIND(symtab, key, type, bucket, elt);
+
+	if (elt == NULL)
+		return (ISC_R_NOTFOUND);
+
+	if (symtab->undefine_action != NULL)
+		(symtab->undefine_action)(elt->key, elt->type,
+					  elt->value, symtab->undefine_arg);
+	UNLINK(symtab->table[bucket], elt, link);
+	isc_mem_put(symtab->mctx, elt, sizeof(*elt));
+	symtab->count--;
+
+	return (ISC_R_SUCCESS);
+}
+
+unsigned int
+isc_symtab_count(isc_symtab_t *symtab) {
+	REQUIRE(VALID_SYMTAB(symtab));
+	return (symtab->count);
+}