From ece914761160ed83f41e826443f96a5513eb2744 Mon Sep 17 00:00:00 2001 From: "arseny.kapoulkine" Date: Tue, 25 May 2010 07:55:44 +0000 Subject: Changed memory management so that the document node lives inside document; this way a default-constructed document does not allocate any dynamic memory git-svn-id: http://pugixml.googlecode.com/svn/trunk@445 99668b35-9821-0410-8761-19e4c4f06640 --- src/pugixml.cpp | 125 ++++++++++++++++++++++++++++++++------------------------ 1 file changed, 72 insertions(+), 53 deletions(-) (limited to 'src/pugixml.cpp') diff --git a/src/pugixml.cpp b/src/pugixml.cpp index 60e0b2f..ff2be33 100644 --- a/src/pugixml.cpp +++ b/src/pugixml.cpp @@ -238,12 +238,47 @@ namespace pugi namespace pugi { + static const size_t xml_memory_page_size = 32768; + static const uintptr_t xml_memory_page_alignment = 32; static const uintptr_t xml_memory_page_pointer_mask = ~(xml_memory_page_alignment - 1); static const uintptr_t xml_memory_page_name_allocated_mask = 16; static const uintptr_t xml_memory_page_value_allocated_mask = 8; static const uintptr_t xml_memory_page_type_mask = 7; + struct xml_allocator; + + struct xml_memory_page + { + static xml_memory_page* construct(void* memory) + { + if (!memory) return 0; + + xml_memory_page* result = static_cast(memory); + + result->allocator = 0; + result->memory = 0; + result->prev = 0; + result->next = 0; + result->busy_size = 0; + result->freed_size = 0; + + return result; + } + + xml_allocator* allocator; + + void* memory; + + xml_memory_page* prev; + xml_memory_page* next; + + size_t busy_size; + size_t freed_size; + + char data[1]; + }; + struct xml_memory_string_header { xml_memory_page* page; @@ -258,13 +293,7 @@ namespace pugi xml_memory_page* allocate_page(size_t data_size) { - #ifdef __GNUC__ - // To avoid offsetof warning (xml_memory_page is not POD) - xml_memory_page* dummy_page = 0; - size_t size = ((size_t)(uintptr_t)&dummy_page->data) + data_size; - #else size_t size = offsetof(xml_memory_page, data) + data_size; - #endif // allocate block with some alignment, leaving memory for worst-case padding void* memory = global_allocate(size + xml_memory_page_alignment); @@ -273,7 +302,7 @@ namespace pugi void* page_memory = reinterpret_cast((reinterpret_cast(memory) + (xml_memory_page_alignment - 1)) & ~(xml_memory_page_alignment - 1)); // prepare page structure - xml_memory_page* page = new (page_memory) xml_memory_page(); + xml_memory_page* page = xml_memory_page::construct(page_memory); page->memory = memory; page->allocator = _root->allocator; @@ -451,6 +480,13 @@ namespace pugi xml_allocator allocator; const char_t* buffer; }; + + inline xml_allocator& get_allocator(const xml_node_struct* node) + { + assert(node); + + return *reinterpret_cast(node->header & xml_memory_page_pointer_mask)->allocator; + } } // Low-level DOM operations @@ -3305,13 +3341,6 @@ namespace pugi return !_root; } - xml_allocator& xml_node::get_allocator() const - { - assert(_root); - - return *reinterpret_cast(_root->header & xml_memory_page_pointer_mask)->allocator; - } - const char_t* xml_node::name() const { return (_root && _root->name) ? _root->name : PUGIXML_TEXT(""); @@ -3524,7 +3553,7 @@ namespace pugi { if (type() != node_element && type() != node_declaration) return xml_attribute(); - xml_attribute a(append_attribute_ll(_root, get_allocator())); + xml_attribute a(append_attribute_ll(_root, get_allocator(_root))); a.set_name(name); return a; @@ -3541,7 +3570,7 @@ namespace pugi if (cur != _root->first_attribute) return xml_attribute(); - xml_attribute a(allocate_attribute(get_allocator())); + xml_attribute a(allocate_attribute(get_allocator(_root))); a.set_name(name); if (attr._attr->prev_attribute_c->next_attribute) @@ -3567,7 +3596,7 @@ namespace pugi if (cur != _root->first_attribute) return xml_attribute(); - xml_attribute a(allocate_attribute(get_allocator())); + xml_attribute a(allocate_attribute(get_allocator(_root))); a.set_name(name); if (attr._attr->next_attribute) @@ -3616,7 +3645,7 @@ namespace pugi { if ((this->type() != node_element && this->type() != node_document) || type == node_document || type == node_null) return xml_node(); - return xml_node(append_node(_root, get_allocator(), type)); + return xml_node(append_node(_root, get_allocator(_root), type)); } xml_node xml_node::insert_child_before(xml_node_type type, const xml_node& node) @@ -3624,7 +3653,7 @@ namespace pugi if ((this->type() != node_element && this->type() != node_document) || type == node_document || type == node_null) return xml_node(); if (node.parent() != *this) return xml_node(); - xml_node n(allocate_node(get_allocator(), type)); + xml_node n(allocate_node(get_allocator(_root), type)); n._root->parent = _root; if (node._root->prev_sibling_c->next_sibling) @@ -3644,7 +3673,7 @@ namespace pugi if ((this->type() != node_element && this->type() != node_document) || type == node_document || type == node_null) return xml_node(); if (node.parent() != *this) return xml_node(); - xml_node n(allocate_node(get_allocator(), type)); + xml_node n(allocate_node(get_allocator(_root), type)); n._root->parent = _root; if (node._root->next_sibling) @@ -3708,7 +3737,7 @@ namespace pugi if (a._attr->prev_attribute_c->next_attribute) a._attr->prev_attribute_c->next_attribute = a._attr->next_attribute; else _root->first_attribute = a._attr->next_attribute; - destroy_attribute(a._attr, get_allocator()); + destroy_attribute(a._attr, get_allocator(_root)); } void xml_node::remove_child(const char_t* name) @@ -3726,7 +3755,7 @@ namespace pugi if (n._root->prev_sibling_c->next_sibling) n._root->prev_sibling_c->next_sibling = n._root->next_sibling; else _root->first_child = n._root->next_sibling; - destroy_node(n._root, get_allocator()); + destroy_node(n._root, get_allocator(_root)); } xml_node xml_node::find_child_by_attribute(const char_t* name, const char_t* attr_name, const char_t* attr_value) const @@ -4102,10 +4131,6 @@ namespace pugi return temp; } - xml_memory_page::xml_memory_page(): allocator(0), memory(0), prev(0), next(0), busy_size(0), freed_size(0) - { - } - const char* xml_parse_result::description() const { switch (status) @@ -4141,13 +4166,6 @@ namespace pugi xml_document::~xml_document() { destroy(); - - if (_memory.next) - { - assert(!_memory.next->next); - - xml_allocator::deallocate_page(_memory.next); - } } void xml_document::create() @@ -4155,22 +4173,26 @@ namespace pugi destroy(); // initialize sentinel page - _memory.busy_size = xml_memory_page_size; + assert(offsetof(xml_memory_page, data) + sizeof(xml_document_struct) + xml_memory_page_alignment <= sizeof(_memory)); - // allocate new root - xml_allocator alloc(_memory.next ? _memory.next : &_memory); - - _root = allocate_document(alloc); + // align upwards to page boundary + void* page_memory = reinterpret_cast((reinterpret_cast(_memory) + (xml_memory_page_alignment - 1)) & ~(xml_memory_page_alignment - 1)); + + // prepare page structure + xml_memory_page* page = xml_memory_page::construct(page_memory); + page->busy_size = xml_memory_page_size; + + // allocate new root + _root = new (page->data) xml_document_struct(page); _root->prev_sibling_c = _root; // setup allocator xml_allocator& a = static_cast(_root)->allocator; - a = alloc; + a = xml_allocator(page); - // setup page - assert(_memory.next); - _memory.next->allocator = &a; + // setup sentinel page + page->allocator = &a; } void xml_document::destroy() @@ -4182,13 +4204,14 @@ namespace pugi _buffer = 0; } - // destroy dynamic storage, leave sentinel page and next page (if any) + // destroy dynamic storage, leave sentinel page (it's in static memory) if (_root) { - assert(_memory.next); + xml_memory_page* root_page = reinterpret_cast(_root->header & xml_memory_page_pointer_mask); + assert(root_page && !root_page->prev && !root_page->memory); // destroy all pages - for (xml_memory_page* page = _memory.next->next; page; ) + for (xml_memory_page* page = root_page->next; page; ) { xml_memory_page* next = page->next; @@ -4197,17 +4220,13 @@ namespace pugi page = next; } - // cleanup next page - _memory.next->allocator = 0; - _memory.next->next = 0; - _memory.next->busy_size = _memory.next->freed_size = 0; + // cleanup root page + root_page->allocator = 0; + root_page->next = 0; + root_page->busy_size = root_page->freed_size = 0; _root = 0; } - else - { - assert(!_memory.next); - } } #ifndef PUGIXML_NO_STL -- cgit v1.2.3