1 files changed, 146 insertions, 0 deletions
diff --git a/scope.c b/scope.c
new file mode 100644
index 0000000..6706765
--- /dev/null
+++ b/scope.c
@@ -0,0 +1,146 @@
+#include <stdio.h>
+#include <stdlib.h>
+#include <assert.h>
+#include <string.h>
+
+#include "node.h"
+#include "scope.h"
+
+scope* mkscope()
+{
+	int i;
+	
+	scope *p = malloc(sizeof(scope));
+	assert(p);
+
+	for (i = 0; i < HASH_SIZE; i++)
+		p->table[i] = NULL;
+
+	p->prev = NULL;
+	p->ret_var= NULL;
+
+	return p;
+}
+
+void free_scope(s)
+scope *s;
+{
+	int i;
+
+	if (!s)
+		return;
+
+	for (i = 0; i < HASH_SIZE; i++) {
+		free_list(s->table[i]);
+	}
+
+	free(s);
+	s = NULL;
+}
+
+/*Copied from Compilers, Aho*/
+#define EOS '\0'
+int hashpjw(s)
+char* s;
+{
+	char *p;
+	unsigned h = 0, g;
+
+	for (p = s; *p != EOS; p++) {
+		h = (h<<4) + *p;
+		if (g = h & 0xf0000000) {
+			h^= g>>24;
+			h^= g;
+		}
+	}
+
+	return h % HASH_SIZE;
+}
+
+void push_scope(root)
+scope **root;
+{
+	scope *tmp = mkscope();
+	
+	assert(tmp);
+
+	tmp->prev = *root;
+	*root = tmp;
+}
+
+void pop_scope(root)
+scope **root;
+{
+	scope *tmp;
+
+	if (!*root)
+		return;
+
+	tmp = *root;
+	*root = (*root)->prev;
+
+	free_scope(tmp);
+}
+
+node* scope_insert(root, name)
+scope *root;
+char *name;
+{
+	int hash = hashpjw(name);
+
+	node *tmp = root->table[hash];
+	return root->table[hash] = list_insert(tmp, name);
+}
+
+node* scope_search(root, name)
+scope *root;
+char *name;
+{
+	int hash = hashpjw(name);
+
+	node *tmp = root->table[hash];
+	return list_search(tmp, name);
+}
+
+node* scope_search_all(root, name)
+scope *root;
+char *name;
+{
+	scope *p;
+	node *tmp;
+
+	for (p = root; p; p = p->prev)
+		if (tmp = scope_search(p, name))
+			return tmp;
+
+	return NULL;
+}
+
+node* scope_safe_search(root, name)
+scope *root;
+char *name;
+{
+	scope *p;
+	node *tmp;
+
+	for (p = root; p; p = p->prev) {
+		if (tmp = scope_search(p, name))
+			return tmp;
+		if (p->ret_var)
+			return NULL;
+	}
+
+	return NULL;
+}
+
+void print_scope(s)
+scope *s;
+{
+	int i;
+	node * tmp;
+	for (i = 0; i < HASH_SIZE; i++) {
+		for( tmp=s->table[i]; tmp; tmp = tmp->next) {
+			fprintf(stderr, "\t%s\n", tmp->name);
+		}
+	}
+}