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uses a single list to keep allocated strings.

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This commit is contained in:
Roberto Ierusalimschy 1994-11-16 16:09:11 -02:00
parent a5862498a1
commit d6a1699e37
1 changed files with 42 additions and 88 deletions
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130
tree.c
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@ -3,7 +3,7 @@
** TecCGraf - PUC-Rio ** TecCGraf - PUC-Rio
*/ */
char *rcs_tree="$Id: tree.c,v 1.5 1994/11/16 16:03:48 roberto Exp roberto $"; char *rcs_tree="$Id: tree.c,v 1.6 1994/11/16 17:38:08 roberto Exp roberto $";
#include <string.h> #include <string.h>
@ -17,13 +17,21 @@ char *rcs_tree="$Id: tree.c,v 1.5 1994/11/16 16:03:48 roberto Exp roberto $";
#define lua_strcmp(a,b) (a[0]<b[0]?(-1):(a[0]>b[0]?(1):strcmp(a,b))) #define lua_strcmp(a,b) (a[0]<b[0]?(-1):(a[0]>b[0]?(1):strcmp(a,b)))
static TreeNode *string_root = NULL; typedef struct StringNode {
struct StringNode *next;
Word mark;
char str[1];
} StringNode;
static StringNode *string_root = NULL;
static TreeNode *constant_root = NULL; static TreeNode *constant_root = NULL;
/* /*
** Insert a new string/constant/variable at the tree. ** Insert a new constant/variable at the tree.
*/ */
static TreeNode *tree_create (TreeNode **node, char *str, int *created) static TreeNode *tree_create (TreeNode **node, char *str)
{ {
if (*node == NULL) if (*node == NULL)
{ {
@ -31,16 +39,15 @@ static TreeNode *tree_create (TreeNode **node, char *str, int *created)
(*node)->left = (*node)->right = NULL; (*node)->left = (*node)->right = NULL;
strcpy((*node)->str, str); strcpy((*node)->str, str);
(*node)->varindex = (*node)->constindex = UNMARKED_STRING; (*node)->varindex = (*node)->constindex = UNMARKED_STRING;
*created = 1;
return *node; return *node;
} }
else else
{ {
int c = lua_strcmp(str, (*node)->str); int c = lua_strcmp(str, (*node)->str);
if (c < 0) if (c < 0)
return tree_create(&(*node)->left, str, created); return tree_create(&(*node)->left, str);
else if (c > 0) else if (c > 0)
return tree_create(&(*node)->right, str, created); return tree_create(&(*node)->right, str);
else else
return *node; return *node;
} }
@ -48,101 +55,48 @@ static TreeNode *tree_create (TreeNode **node, char *str, int *created)
char *lua_strcreate (char *str) char *lua_strcreate (char *str)
{ {
int created=0; StringNode *newString = (StringNode *)luaI_malloc(sizeof(StringNode)+
TreeNode *t = tree_create(&string_root, str, &created); strlen(str));
if (created) newString->mark = UNMARKED_STRING;
{ strcpy(newString->str, str);
newString->next = string_root;
string_root = newString;
if (lua_nentity == lua_block) lua_pack (); if (lua_nentity == lua_block) lua_pack ();
lua_nentity++; lua_nentity++;
} return newString->str;
return t->str;
} }
TreeNode *lua_constcreate (char *str) TreeNode *lua_constcreate (char *str)
{ {
int created; return tree_create(&constant_root, str);
return tree_create(&constant_root, str, &created);
}
/*
** Free a node of the tree
*/
static TreeNode *lua_strfree (TreeNode *parent)
{
if (parent->left == NULL && parent->right == NULL) /* no child */
{
luaI_free(parent);
return NULL;
}
else if (parent->left == NULL) /* only right child */
{
TreeNode *p = parent->right;
luaI_free(parent);
return p;
}
else if (parent->right == NULL) /* only left child */
{
TreeNode *p = parent->left;
luaI_free(parent);
return p;
}
else /* two children */
{
TreeNode *p = parent, *r = parent->right;
while (r->left != NULL)
{
p = r;
r = r->left;
}
if (p == parent)
{
r->left = parent->left;
parent->left = NULL;
parent->right = r->right;
r->right = lua_strfree(parent);
}
else
{
TreeNode *t = r->right;
r->left = parent->left;
r->right = parent->right;
parent->left = NULL;
parent->right = t;
p->left = lua_strfree(parent);
}
return r;
}
}
/*
** Traverse tree for garbage collection
*/
static TreeNode *lua_travcollector (TreeNode *r)
{
if (r == NULL) return NULL;
r->right = lua_travcollector(r->right);
r->left = lua_travcollector(r->left);
if (r->constindex == UNMARKED_STRING)
{
++lua_recovered;
return lua_strfree(r);
}
else
{
r->constindex = UNMARKED_STRING;
return r;
}
} }
/* /*
** Garbage collection function. ** Garbage collection function.
** This function traverse the tree freening unindexed strings ** This function traverse the string list freeing unindexed strings
*/ */
void lua_strcollector (void) void lua_strcollector (void)
{ {
string_root = lua_travcollector(string_root); StringNode *curr = string_root, *prev = NULL;
while (curr)
{
StringNode *next = curr->next;
if (curr->mark == UNMARKED_STRING)
{
if (prev == NULL) string_root = next;
else prev->next = next;
luaI_free(curr);
++lua_recovered;
}
else
{
curr->mark = UNMARKED_STRING;
prev = curr;
}
curr = next;
}
} }
/* /*