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Code Issues Releases Wiki Activity

Factor out expr tree rotation into its own function

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This commit is contained in:
John Johansen
2010-11-09 11:48:29 -08:00
parent ac9553de19
commit 0ad84d93f9
1 changed files with 13 additions and 8 deletions
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21
parser/libapparmor_re/regexp.y
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@@ -562,16 +562,25 @@ static EpsNode epsnode;
* a b c T * a b c T
* *
*/ */
static void rotate_node(Node *t, int dir) {
// (a | b) | c -> a | (b | c)
// (ab)c -> a(bc)
Node *left = t->child[dir];
t->child[dir] = left->child[dir];
left->child[dir] = left->child[!dir];
left->child[!dir] = t->child[!dir];
t->child[!dir] = left;
}
void normalize_tree(Node *t, int dir) void normalize_tree(Node *t, int dir)
{ {
if (dynamic_cast<ImportantNode *>(t)) if (dynamic_cast<LeafNode *>(t))
return; return;
for (;;) { for (;;) {
if ((&epsnode == t->child[dir]) && if ((&epsnode == t->child[dir]) &&
(&epsnode != t->child[!dir]) && (&epsnode != t->child[!dir]) &&
(dynamic_cast<AltNode *>(t) || dynamic_cast<TwoChildNode *>(t)) {
dynamic_cast<CatNode *>(t))) {
// (E | a) -> (a | E) // (E | a) -> (a | E)
// Ea -> aE // Ea -> aE
Node *c = t->child[dir]; Node *c = t->child[dir];
@@ -585,11 +594,7 @@ void normalize_tree(Node *t, int dir)
dynamic_cast<CatNode *>(t->child[dir]))) { dynamic_cast<CatNode *>(t->child[dir]))) {
// (a | b) | c -> a | (b | c) // (a | b) | c -> a | (b | c)
// (ab)c -> a(bc) // (ab)c -> a(bc)
Node *c = t->child[dir]; rotate_node(t, dir);
t->child[dir] = c->child[dir];
c->child[dir] = c->child[!dir];
c->child[!dir] = t->child[!dir];
t->child[!dir] = c;
} else if (dynamic_cast<AltNode *>(t) && } else if (dynamic_cast<AltNode *>(t) &&
dynamic_cast<CharSetNode *>(t->child[dir]) && dynamic_cast<CharSetNode *>(t->child[dir]) &&
dynamic_cast<CharNode *>(t->child[!dir])) { dynamic_cast<CharNode *>(t->child[!dir])) {