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authorArseny Kapoulkine <arseny.kapoulkine@gmail.com>2014-10-26 10:07:01 -0700
committerArseny Kapoulkine <arseny.kapoulkine@gmail.com>2014-10-26 10:11:22 -0700
commit11ce004e040937e17755b3bdf2a1d7f846214f3f (patch)
tree2e06754d291d8cc7a2dc8322f496dcf8f199f177 /src
parentd5e29292c67c24b5cd7ac4f6afce2f8ec293144a (diff)
XPath: Unify ast_filter/ast_predicate structure
Now expression is always _right for filter/predicate nodes to make optimize() simpler. Additionally we now use predicate metadata to make is_posinv_step() faster. This introduces a weak ordering dependency in rewrite rules to optimize() - classification has to be performed before other optimizations.
Diffstat (limited to 'src')
-rw-r--r--src/pugixml.cpp31
1 files changed, 16 insertions, 15 deletions
diff --git a/src/pugixml.cpp b/src/pugixml.cpp
index ac36a31..d66f9f9 100644
--- a/src/pugixml.cpp
+++ b/src/pugixml.cpp
@@ -8581,9 +8581,9 @@ PUGI__NS_BEGIN
assert(pred->_type == ast_predicate);
if (pred->_test == predicate_constant || pred->_test == predicate_constant_one)
- apply_predicate_const(ns, first, pred->_left, stack);
+ apply_predicate_const(ns, first, pred->_right, stack);
else
- apply_predicate(ns, first, pred->_left, stack, !pred->_next && last_once);
+ apply_predicate(ns, first, pred->_right, stack, !pred->_next && last_once);
}
}
@@ -9066,6 +9066,12 @@ PUGI__NS_BEGIN
_data.nodetest = contents;
}
+ xpath_ast_node(ast_type_t type, xpath_ast_node* left, xpath_ast_node* right, predicate_t test):
+ _type(static_cast<char>(type)), _rettype(xpath_type_node_set), _axis(0), _test(static_cast<char>(test)), _left(left), _right(right), _next(0)
+ {
+ assert(type == ast_filter || type == ast_predicate);
+ }
+
void set_next(xpath_ast_node* value)
{
_next = value;
@@ -9771,16 +9777,14 @@ PUGI__NS_BEGIN
// Classify filter/predicate ops to perform various optimizations during evaluation
if (_type == ast_filter || _type == ast_predicate)
{
- xpath_ast_node* expr = (_type == ast_filter) ? _right : _left;
+ assert(_test == predicate_default);
- if (expr->_type == ast_number_constant && expr->_data.number == 1.0)
+ if (_right->_type == ast_number_constant && _right->_data.number == 1.0)
_test = predicate_constant_one;
- else if (expr->_type == ast_number_constant || expr->_type == ast_variable)
+ else if (_right->_type == ast_number_constant || _right->_type == ast_variable)
_test = predicate_constant;
- else if (expr->rettype() != xpath_type_number && expr->is_posinv_expr())
+ else if (_right->_rettype != xpath_type_number && _right->is_posinv_expr())
_test = predicate_posinv;
- else
- _test = predicate_default;
}
// Replace descendant-or-self::node()/child::foo with descendant::foo
@@ -9814,7 +9818,7 @@ PUGI__NS_BEGIN
// Use optimized path for @attr = 'value' or @attr = $value
if (_type == ast_op_equal &&
_left->_type == ast_step && _left->_axis == axis_attribute && _left->_test == nodetest_name && !_left->_left && !_left->_right &&
- (_right->_type == ast_string_constant || (_right->_type == ast_variable && _right->rettype() == xpath_type_string)))
+ (_right->_type == ast_string_constant || (_right->_type == ast_variable && _right->_rettype == xpath_type_string)))
{
_type = ast_opt_compare_attribute;
}
@@ -9859,10 +9863,7 @@ PUGI__NS_BEGIN
{
assert(n->_type == ast_predicate);
- xpath_ast_node* expr = n->_left;
- bool posinv = expr->rettype() != xpath_type_number && expr->is_posinv_expr();
-
- if (!posinv)
+ if (n->_test != predicate_posinv)
return false;
}
@@ -10282,7 +10283,7 @@ PUGI__NS_BEGIN
if (n->rettype() != xpath_type_node_set) throw_error("Predicate has to be applied to node set");
- n = new (alloc_node()) xpath_ast_node(ast_filter, xpath_type_node_set, n, expr);
+ n = new (alloc_node()) xpath_ast_node(ast_filter, n, expr, predicate_default);
if (_lexer.current() != lex_close_square_brace)
throw_error("Unmatched square brace");
@@ -10426,7 +10427,7 @@ PUGI__NS_BEGIN
xpath_ast_node* expr = parse_expression();
- xpath_ast_node* pred = new (alloc_node()) xpath_ast_node(ast_predicate, xpath_type_node_set, expr);
+ xpath_ast_node* pred = new (alloc_node()) xpath_ast_node(ast_predicate, 0, expr, predicate_default);
if (_lexer.current() != lex_close_square_brace)
throw_error("Unmatched square brace");