diff options
Diffstat (limited to 'src/pugixml.cpp')
| -rw-r--r-- | src/pugixml.cpp | 38 |
1 files changed, 20 insertions, 18 deletions
diff --git a/src/pugixml.cpp b/src/pugixml.cpp index e0bd32c..390a843 100644 --- a/src/pugixml.cpp +++ b/src/pugixml.cpp @@ -288,7 +288,6 @@ PUGI__NS_BEGIN xml_memory_page* result = static_cast<xml_memory_page*>(memory); result->allocator = 0; - result->memory = 0; result->prev = 0; result->next = 0; result->busy_size = 0; @@ -299,15 +298,11 @@ PUGI__NS_BEGIN 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 @@ -324,28 +319,32 @@ PUGI__NS_BEGIN xml_memory_page* allocate_page(size_t data_size) { - size_t size = offsetof(xml_memory_page, data) + data_size; + size_t size = sizeof(xml_memory_page) + data_size; // allocate block with some alignment, leaving memory for worst-case padding void* memory = xml_memory::allocate(size + xml_memory_page_alignment); if (!memory) return 0; - // align upwards to page boundary - void* page_memory = reinterpret_cast<void*>((reinterpret_cast<uintptr_t>(memory) + (xml_memory_page_alignment - 1)) & ~(xml_memory_page_alignment - 1)); + // align upwards to page boundary (note: this guarantees at least 1 usable byte before the page) + char* page_memory = reinterpret_cast<char*>((reinterpret_cast<uintptr_t>(memory) + xml_memory_page_alignment) & ~(xml_memory_page_alignment - 1)); // prepare page structure xml_memory_page* page = xml_memory_page::construct(page_memory); assert(page); - page->memory = memory; page->allocator = _root->allocator; + // record the offset for freeing the memory block + page_memory[-1] = static_cast<char>(page_memory - static_cast<char*>(memory)); + return page; } static void deallocate_page(xml_memory_page* page) { - xml_memory::deallocate(page->memory); + char* page_memory = reinterpret_cast<char*>(page); + + xml_memory::deallocate(page_memory - page_memory[-1]); } void* allocate_memory_oob(size_t size, xml_memory_page*& out_page); @@ -354,7 +353,7 @@ PUGI__NS_BEGIN { if (_busy_size + size > xml_memory_page_size) return allocate_memory_oob(size, out_page); - void* buf = _root->data + _busy_size; + void* buf = reinterpret_cast<char*>(_root) + sizeof(xml_memory_page) + _busy_size; _busy_size += size; @@ -367,7 +366,7 @@ PUGI__NS_BEGIN { if (page == _root) page->busy_size = _busy_size; - assert(ptr >= page->data && ptr < page->data + page->busy_size); + assert(ptr >= reinterpret_cast<char*>(page) + sizeof(xml_memory_page) && ptr < reinterpret_cast<char*>(page) + sizeof(xml_memory_page) + page->busy_size); (void)!ptr; page->freed_size += size; @@ -412,7 +411,7 @@ PUGI__NS_BEGIN if (!header) return 0; // setup header - ptrdiff_t page_offset = reinterpret_cast<char*>(header) - page->data; + ptrdiff_t page_offset = reinterpret_cast<char*>(header) - reinterpret_cast<char*>(page) - sizeof(xml_memory_page); assert(page_offset >= 0 && page_offset < (1 << 16)); header->page_offset = static_cast<uint16_t>(page_offset); @@ -435,7 +434,7 @@ PUGI__NS_BEGIN xml_memory_string_header* header = static_cast<xml_memory_string_header*>(static_cast<void*>(string)) - 1; // deallocate - size_t page_offset = offsetof(xml_memory_page, data) + header->page_offset; + size_t page_offset = sizeof(xml_memory_page) + header->page_offset; xml_memory_page* page = reinterpret_cast<xml_memory_page*>(static_cast<void*>(reinterpret_cast<char*>(header) - page_offset)); // if full_size == 0 then this string occupies the whole page @@ -484,7 +483,7 @@ PUGI__NS_BEGIN // allocate inside page page->busy_size = size; - return page->data; + return reinterpret_cast<char*>(page) + sizeof(xml_memory_page); } PUGI__NS_END @@ -5872,7 +5871,7 @@ namespace pugi assert(!_root); // initialize sentinel page - PUGI__STATIC_ASSERT(sizeof(impl::xml_memory_page) + sizeof(impl::xml_document_struct) + impl::xml_memory_page_alignment <= sizeof(_memory)); + PUGI__STATIC_ASSERT(sizeof(impl::xml_memory_page) + sizeof(impl::xml_document_struct) + impl::xml_memory_page_alignment - sizeof(void*) <= sizeof(_memory)); // align upwards to page boundary void* page_memory = reinterpret_cast<void*>((reinterpret_cast<uintptr_t>(_memory) + (impl::xml_memory_page_alignment - 1)) & ~(impl::xml_memory_page_alignment - 1)); @@ -5884,11 +5883,14 @@ namespace pugi page->busy_size = impl::xml_memory_page_size; // allocate new root - _root = new (page->data) impl::xml_document_struct(page); + _root = new (reinterpret_cast<char*>(page) + sizeof(impl::xml_memory_page)) impl::xml_document_struct(page); _root->prev_sibling_c = _root; // setup sentinel page page->allocator = static_cast<impl::xml_document_struct*>(_root); + + // verify the document allocation + assert(reinterpret_cast<char*>(_root) + sizeof(impl::xml_document_struct) <= _memory + sizeof(_memory)); } PUGI__FN void xml_document::destroy() @@ -5910,7 +5912,7 @@ namespace pugi // destroy dynamic storage, leave sentinel page (it's in static memory) impl::xml_memory_page* root_page = reinterpret_cast<impl::xml_memory_page*>(_root->header & impl::xml_memory_page_pointer_mask); - assert(root_page && !root_page->prev && !root_page->memory); + assert(root_page && !root_page->prev); for (impl::xml_memory_page* page = root_page->next; page; ) { |