1 files changed, 109 insertions, 0 deletions
diff --git a/ptrmap.c b/ptrmap.c
new file mode 100644
index 00000000..ff07e19a
--- /dev/null
+++ b/ptrmap.c
@@ -0,0 +1,109 @@
+// SPDX-License-Identifier: MIT
+/*
+ * Stupid implementation of pointer -> pointer map.
+ *
+ * Copyright (c) 2017 Luc Van Oostenryck.
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a copy
+ * of this software and associated documentation files (the "Software"), to deal
+ * in the Software without restriction, including without limitation the rights
+ * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+ * copies of the Software, and to permit persons to whom the Software is
+ * furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be included in
+ * all copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+ * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+ * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
+ * THE SOFTWARE.
+ */
+
+#include "ptrmap.h"
+#include "allocate.h"
+#include <stddef.h>
+
+#define	MAP_NR	7
+
+struct ptrpair {
+	void *key;
+	void *val;
+};
+struct ptrmap {
+	struct ptrmap *next;
+	int nr;
+	struct ptrpair pairs[MAP_NR];
+};
+
+DECLARE_ALLOCATOR(ptrmap);
+ALLOCATOR(ptrmap, "ptrmap");
+
+void __ptrmap_add(struct ptrmap **mapp, void *key, void *val)
+{
+	struct ptrmap *head = *mapp;
+	struct ptrmap *newmap;
+	struct ptrmap *map;
+	struct ptrpair *pair;
+	int nr;
+
+	if ((map = head)) {
+		struct ptrmap *next = map->next;
+		if (next)		// head is full
+			map = next;
+		if ((nr = map->nr) < MAP_NR)
+			goto oldmap;
+	}
+
+	// need a new block
+	newmap = __alloc_ptrmap(0);
+	if (!head) {
+		*mapp = newmap;
+	} else {
+		newmap->next = head->next;
+		head->next = newmap;
+	}
+	map = newmap;
+	nr = 0;
+
+oldmap:
+	pair = &map->pairs[nr];
+	pair->key = key;
+	pair->val = val;
+	map->nr = ++nr;
+}
+
+void *__ptrmap_lookup(struct ptrmap *map, void *key)
+{
+	for (; map; map = map->next) {
+		int i, n = map->nr;
+		for (i = 0; i < n; i++) {
+			struct ptrpair *pair = &map->pairs[i];
+			if (pair->key == key)
+				return pair->val;
+		}
+	}
+	return NULL;
+}
+
+void __ptrmap_update(struct ptrmap **mapp, void *key, void *val)
+{
+	struct ptrmap *map = *mapp;
+
+	for (; map; map = map->next) {
+		int i, n = map->nr;
+		for (i = 0; i < n; i++) {
+			struct ptrpair *pair = &map->pairs[i];
+			if (pair->key == key) {
+				if (pair->val != val)
+					pair->val = val;
+				return;
+			}
+		}
+	}
+
+	__ptrmap_add(mapp, key, val);
+}