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Rework compact_pointer implementation

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Split the implementation into a generic one with adjustable range and a
special implementation for parent (may need to use 2 bytes on that one
later).

Optimize compact_string and compact_pointer to use minimal amount of math
and move slow hash paths into no-inline functions so that compiler can
inline the fast-paths.

Merge compact_pointer_generic and compact_pointer_forward and optimize.
This commit is contained in:
Arseny Kapoulkine 2014-10-07 20:16:32 -07:00
parent 43622107d7
commit 80d6f5a7d0
1 changed files with 106 additions and 86 deletions
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156
src/pugixml.cpp
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@ -639,6 +639,8 @@ PUGI__NS_BEGIN
} }
}; };
static const unsigned int compact_alignment_log2 = 2;
typedef uint32_t compact_alignment; typedef uint32_t compact_alignment;
class compact_header class compact_header
@ -681,14 +683,24 @@ PUGI__NS_BEGIN
unsigned char flags; unsigned char flags;
}; };
xml_memory_page* compact_get_page(const void* object, int header_offset) PUGI__FN xml_memory_page* compact_get_page(const void* object, int header_offset)
{ {
const compact_header* header = reinterpret_cast<const compact_header*>(static_cast<const char*>(object) - header_offset); const compact_header* header = reinterpret_cast<const compact_header*>(static_cast<const char*>(object) - header_offset);
return header->get_page(); return header->get_page();
} }
template <typename T, int header_offset, int direction, int tag> class compact_pointer template <int header_offset, typename T> PUGI__FN_NO_INLINE T* compact_get_value(const void* object)
{
return static_cast<T*>(*compact_get_page(object, header_offset)->allocator->_hash->find(object));
}
template <int header_offset, int tag, typename T> PUGI__FN_NO_INLINE void compact_set_value(const void* object, T* value)
{
*compact_get_page(object, header_offset)->allocator->_hash->insert(object, tag) = value;
}
template <typename T, int header_offset, int tag, int start = -126> class compact_pointer
{ {
public: public:
compact_pointer(): _data(0) compact_pointer(): _data(0)
@ -700,6 +712,63 @@ PUGI__NS_BEGIN
*this = rhs + 0; *this = rhs + 0;
} }
void operator=(T* value)
{
if (value)
{
ptrdiff_t offset = ((reinterpret_cast<char*>(value) - reinterpret_cast<char*>(this) + int(sizeof(compact_alignment) - 1)) >> compact_alignment_log2) - start;
if (static_cast<uintptr_t>(offset) <= 253)
_data = static_cast<unsigned char>(offset + 1);
else
{
compact_set_value<header_offset, tag>(this, value);
_data = 255;
}
}
else
_data = 0;
}
operator T* const() const
{
if (_data)
{
if (_data < 255)
{
uintptr_t base = reinterpret_cast<uintptr_t>(this) & ~(sizeof(compact_alignment) - 1);
return reinterpret_cast<T*>(base + ((_data - (1 - start)) << compact_alignment_log2));
}
else
return compact_get_value<header_offset, T>(this);
}
else
return 0;
}
T* operator->() const
{
return operator T* const();
}
private:
unsigned char _data;
};
template <typename T, int header_offset, int tag> class compact_pointer_parent
{
public:
compact_pointer_parent(): _data(0)
{
}
void operator=(const compact_pointer_parent& rhs)
{
*this = rhs + 0;
}
void operator=(T* value_) void operator=(T* value_)
{ {
if (value_) if (value_)
@ -707,19 +776,6 @@ PUGI__NS_BEGIN
compact_alignment* base = get_base(); compact_alignment* base = get_base();
compact_alignment* value = reinterpret_cast<compact_alignment*>(value_); compact_alignment* value = reinterpret_cast<compact_alignment*>(value_);
if (direction > 0)
{
if (value >= base && value <= base + 253)
_data = static_cast<unsigned char>((value - base) + 1);
else
{
*compact_get_page(this, header_offset)->allocator->_hash->insert(this, tag) = value;
_data = 255;
}
}
else if (direction < 0)
{
if (value <= base && value >= base - 252) if (value <= base && value >= base - 252)
_data = static_cast<unsigned char>((base - value) + 1); _data = static_cast<unsigned char>((base - value) + 1);
else else
@ -737,19 +793,7 @@ PUGI__NS_BEGIN
} }
else else
{ {
*page->allocator->_hash->insert(this, tag) = value; compact_set_value<header_offset, tag>(this, value);
_data = 255;
}
}
}
else
{
if (value >= base - 126 && value <= base + 127)
_data = static_cast<unsigned char>((value - base) + 127);
else
{
*compact_get_page(this, header_offset)->allocator->_hash->insert(this, tag) = value;
_data = 255; _data = 255;
} }
} }
@ -763,19 +807,14 @@ PUGI__NS_BEGIN
if (_data) if (_data)
{ {
if (_data == 255) if (_data == 255)
return static_cast<T*>(*compact_get_page(this, header_offset)->allocator->_hash->find(this)); return compact_get_value<header_offset, T>(this);
else if (direction < 0 && _data == 254) else if (_data == 254)
return static_cast<T*>(compact_get_page(this, header_offset)->compact_parent); return static_cast<T*>(compact_get_page(this, header_offset)->compact_parent);
else else
{ {
compact_alignment* base = get_base(); compact_alignment* base = get_base();
if (direction > 0)
return reinterpret_cast<T*>(base + (_data - 1));
else if (direction < 0)
return reinterpret_cast<T*>(base - (_data - 1)); return reinterpret_cast<T*>(base - (_data - 1));
else
return reinterpret_cast<T*>(base + (_data - 127));
} }
} }
else else
@ -792,9 +831,6 @@ PUGI__NS_BEGIN
compact_alignment* get_base() const compact_alignment* get_base() const
{ {
if (direction > 0)
return reinterpret_cast<compact_alignment*>((reinterpret_cast<uintptr_t>(this) + sizeof(compact_alignment)) & ~(sizeof(compact_alignment) - 1));
else
return reinterpret_cast<compact_alignment*>(reinterpret_cast<uintptr_t>(this) & ~(sizeof(compact_alignment) - 1)); return reinterpret_cast<compact_alignment*>(reinterpret_cast<uintptr_t>(this) & ~(sizeof(compact_alignment) - 1));
} }
}; };
@ -818,34 +854,22 @@ PUGI__NS_BEGIN
xml_memory_page* page = compact_get_page(this, header_offset); xml_memory_page* page = compact_get_page(this, header_offset);
if (page->compact_string_base == 0) if (page->compact_string_base == 0)
{
page->compact_string_base = value; page->compact_string_base = value;
_data0 = 1;
_data1 = 0;
_data2 = 0;
}
else
{
ptrdiff_t offset = value - page->compact_string_base; ptrdiff_t offset = value - page->compact_string_base;
if (offset >= 0 && offset <= 1677213) if (static_cast<uintptr_t>(offset) >= 16777213)
{ {
compact_set_value<header_offset, tag>(this, value);
offset = 16777214;
}
_data0 = static_cast<unsigned char>(offset + 1); _data0 = static_cast<unsigned char>(offset + 1);
_data1 = static_cast<unsigned char>((offset + 1) >> 8); _data1 = static_cast<unsigned char>((offset + 1) >> 8);
_data2 = static_cast<unsigned char>((offset + 1) >> 16); _data2 = static_cast<unsigned char>((offset + 1) >> 16);
} }
else else
{
*page->allocator->_hash->insert(this, tag) = value;
_data0 = 255;
_data1 = 255;
_data2 = 255;
}
}
}
else
{ {
_data0 = 0; _data0 = 0;
_data1 = 0; _data1 = 0;
@ -862,13 +886,9 @@ PUGI__NS_BEGIN
xml_memory_page* page = compact_get_page(this, header_offset); xml_memory_page* page = compact_get_page(this, header_offset);
if (data < 16777215) if (data < 16777215)
{
return page->compact_string_base + (data - 1); return page->compact_string_base + (data - 1);
}
else else
{ return compact_get_value<header_offset, char_t>(this);
return static_cast<char_t*>(*page->allocator->_hash->find(this));
}
} }
else else
return 0; return 0;
@ -904,8 +924,8 @@ namespace pugi
impl::compact_string<4, /*tag*/11> name; ///< Pointer to attribute name. impl::compact_string<4, /*tag*/11> name; ///< Pointer to attribute name.
impl::compact_string<7, /*tag*/12> value; ///< Pointer to attribute value. impl::compact_string<7, /*tag*/12> value; ///< Pointer to attribute value.
impl::compact_pointer<xml_attribute_struct, 10, 0, /*tag*/13> prev_attribute_c; ///< Previous attribute (cyclic list) impl::compact_pointer<xml_attribute_struct, 10, /*tag*/13> prev_attribute_c; ///< Previous attribute (cyclic list)
impl::compact_pointer<xml_attribute_struct, 11, +1, /*tag*/14> next_attribute; ///< Next attribute impl::compact_pointer<xml_attribute_struct, 11, /*tag*/14, 0> next_attribute; ///< Next attribute
}; };
/// An XML document tree node. /// An XML document tree node.
@ -926,14 +946,14 @@ namespace pugi
impl::compact_string<4, /*tag*/21> contents; ///< Pointer to element name. impl::compact_string<4, /*tag*/21> contents; ///< Pointer to element name.
impl::compact_pointer<xml_node_struct, 7, -1, /*tag*/22> parent; ///< Pointer to parent impl::compact_pointer_parent<xml_node_struct, 7, /*tag*/22> parent; ///< Pointer to parent
impl::compact_pointer<xml_node_struct, 8, +1, /*tag*/23> first_child; ///< First child impl::compact_pointer<xml_node_struct, 8, /*tag*/23, 0> first_child; ///< First child
impl::compact_pointer<xml_node_struct, 9, 0, /*tag*/24> prev_sibling_c; ///< Left brother (cyclic list) impl::compact_pointer<xml_node_struct, 9, /*tag*/24> prev_sibling_c; ///< Left brother (cyclic list)
impl::compact_pointer<xml_node_struct, 10, +1, /*tag*/25> next_sibling; ///< Right brother impl::compact_pointer<xml_node_struct, 10, /*tag*/25, 0> next_sibling; ///< Right brother
impl::compact_pointer<xml_attribute_struct, 11, +1, /*tag*/26> first_attribute; ///< First attribute impl::compact_pointer<xml_attribute_struct, 11, /*tag*/26, 0> first_attribute; ///< First attribute
}; };
} }
#else #else