add string_table to manage container STAB data

src/string-table.c

@@ -0,0 +1,110 @@
+#include "string-table.h"
+
+#include <blue/core/hash.h>
+#include <stdlib.h>
+#include <string.h>
+
+struct string_table_entry {
+	b_btree_node e_hash_node;
+	b_btree_node e_offset_node;
+	size_t e_hash;
+	size_t e_offset;
+	char e_str[];
+};
+
+B_BTREE_DEFINE_SIMPLE_INSERT(
+	struct string_table_entry,
+	e_hash_node,
+	e_hash,
+	put_string_by_hash)
+
+B_BTREE_DEFINE_SIMPLE_INSERT(
+	struct string_table_entry,
+	e_offset_node,
+	e_offset,
+	put_string_by_offset)
+
+struct string_table_entry *get_string(const b_btree *hash_tree, const char *s)
+{
+	size_t key = b_hash_string(s);
+
+	b_btree_node *cur = hash_tree->b_root;
+	while (cur) {
+		struct string_table_entry *cur_node
+			= b_unbox(struct string_table_entry, cur, e_hash_node);
+
+		if (key == cur_node->e_hash && !strcmp(s, cur_node->e_str)) {
+			return cur_node;
+		}
+
+		if (key >= cur_node->e_hash) {
+			cur = b_btree_right(cur);
+		} else {
+			cur = b_btree_left(cur);
+		}
+	}
+
+	return NULL;
+}
+
+static struct string_table_entry *create_entry(const char *s)
+{
+	struct string_table_entry *out = NULL;
+
+	size_t s_len = strlen(s);
+	size_t entry_len = s_len + 1 + sizeof *out;
+
+	out = malloc(entry_len);
+
+	if (!out) {
+		return NULL;
+	}
+
+	memset(out, 0x0, entry_len);
+	memcpy(out->e_str, s, s_len);
+
+	out->e_hash = b_hash_string(s);
+
+	return out;
+}
+
+void string_table_init(struct string_table *out)
+{
+	memset(out, 0x0, sizeof *out);
+}
+
+void string_table_finish(struct string_table *tab)
+{
+	b_btree_iterator it;
+	b_btree_iterator_begin(&tab->s_hash_tree, &it);
+
+	while (b_btree_iterator_is_valid(&it)) {
+		struct string_table_entry *entry = b_unbox(
+			struct string_table_entry,
+			it.node,
+			e_hash_node);
+		b_btree_iterator_erase(&it);
+		free(entry);
+	}
+
+	free(tab);
+}
+
+size_t string_table_get(struct string_table *tab, const char *s)
+{
+	struct string_table_entry *entry = get_string(&tab->s_hash_tree, s);
+	if (entry) {
+		return entry->e_offset;
+	}
+
+	entry = create_entry(s);
+
+	entry->e_offset = tab->s_next_offset;
+
+	tab->s_next_offset += strlen(s) + 1;
+
+	put_string_by_hash(&tab->s_hash_tree, entry);
+	put_string_by_offset(&tab->s_offset_tree, entry);
+
+	return entry->e_offset;
+}

src/string-table.h

@@ -0,0 +1,17 @@
+#ifndef STRING_TABLE_H_
+#define STRING_TABLE_H_
+
+#include <blue/core/btree.h>
+
+struct string_table {
+	b_btree s_hash_tree;
+	b_btree s_offset_tree;
+	size_t s_next_offset;
+};
+
+extern void string_table_init(struct string_table *out);
+extern void string_table_finish(struct string_table *tab);
+
+extern size_t string_table_get(struct string_table *tab, const char *s);
+
+#endif