Adding upstream version 1:9.18.19.upstream/1%9.18.19upstream

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>

1 files changed, 294 insertions, 0 deletions

diff --git a/lib/isc/symtab.c b/lib/isc/symtab.c
new file mode 100644
index 0000000..ff022a2
--- /dev/null
+++ b/lib/isc/symtab.c
@@ -0,0 +1,294 @@
+/*
+ * Copyright (C) Internet Systems Consortium, Inc. ("ISC")
+ *
+ * SPDX-License-Identifier: MPL-2.0
+ *
+ * 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 https://mozilla.org/MPL/2.0/.
+ *
+ * See the COPYRIGHT file distributed with this work for additional
+ * information regarding copyright ownership.
+ */
+
+/*! \file */
+
+#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_mem_get(mctx, sizeof(*symtab));
+
+	symtab->mctx = NULL;
+	isc_mem_attach(mctx, &symtab->mctx);
+	symtab->table = isc_mem_get(mctx, size * sizeof(eltlist_t));
+	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;
+	*symtabp = NULL;
+	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));
+}
+
+static 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));
+
+	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 = isc_mem_get(symtab->mctx, sizeof(*elt));
+		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);
+}