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XPath: Store string length inside string object

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When xpath_string is heap-allocated we always know the length of the
string at some point - it is now stored in the object. This reduces
redundant string length calculations and makes string_value() much faster
in case it has to concatenate strings.

git-svn-id: https://pugixml.googlecode.com/svn/trunk@1053 99668b35-9821-0410-8761-19e4c4f06640
This commit is contained in:
Arseny Kapoulkine 2014-10-05 07:58:05 +00:00
parent 5239fcbd00
commit 89f2f00da4
1 changed files with 44 additions and 44 deletions
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88
src/pugixml.cpp
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@ -6595,6 +6595,7 @@ PUGI__NS_BEGIN
{
const char_t* _buffer;
bool _uses_heap;
size_t _length_heap;
static char_t* duplicate_string(const char_t* string, size_t length, xpath_allocator* alloc)
{
@ -6607,36 +6608,34 @@ PUGI__NS_BEGIN
return result;
}
static char_t* duplicate_string(const char_t* string, xpath_allocator* alloc)
xpath_string(const char_t* buffer, bool uses_heap_, size_t length_heap): _buffer(buffer), _uses_heap(uses_heap_), _length_heap(length_heap)
{
return duplicate_string(string, strlength(string), alloc);
}
public:
xpath_string(): _buffer(PUGIXML_TEXT("")), _uses_heap(false)
static xpath_string from_const(const char_t* str)
{
return xpath_string(str, false, 0);
}
explicit xpath_string(const char_t* str, xpath_allocator* alloc)
static xpath_string from_heap_preallocated(const char_t* begin, const char_t* end)
{
bool empty_ = (*str == 0);
assert(begin <= end && *end == 0);
_buffer = empty_ ? PUGIXML_TEXT("") : duplicate_string(str, alloc);
_uses_heap = !empty_;
return xpath_string(begin, true, static_cast<size_t>(end - begin));
}
explicit xpath_string(const char_t* str, bool use_heap): _buffer(str), _uses_heap(use_heap)
{
}
xpath_string(const char_t* begin, const char_t* end, xpath_allocator* alloc)
static xpath_string from_heap(const char_t* begin, const char_t* end, xpath_allocator* alloc)
{
assert(begin <= end);
bool empty_ = (begin == end);
size_t length = static_cast<size_t>(end - begin);
_buffer = empty_ ? PUGIXML_TEXT("") : duplicate_string(begin, static_cast<size_t>(end - begin), alloc);
_uses_heap = !empty_;
return length == 0 ? xpath_string() : xpath_string(duplicate_string(begin, length, alloc), true, length);
}
xpath_string(): _buffer(PUGIXML_TEXT("")), _uses_heap(false), _length_heap(0)
{
}
void append(const xpath_string& o, xpath_allocator* alloc)
@ -6652,8 +6651,8 @@ PUGI__NS_BEGIN
else
{
// need to make heap copy
size_t target_length = strlength(_buffer);
size_t source_length = strlength(o._buffer);
size_t target_length = length();
size_t source_length = o.length();
size_t result_length = target_length + source_length;
// allocate new buffer
@ -6670,6 +6669,7 @@ PUGI__NS_BEGIN
// finalize
_buffer = result;
_uses_heap = true;
_length_heap = result_length;
}
}
@ -6680,7 +6680,7 @@ PUGI__NS_BEGIN
size_t length() const
{
return strlength(_buffer);
return _uses_heap ? _length_heap : strlength(_buffer);
}
char_t* data(xpath_allocator* alloc)
@ -6688,8 +6688,11 @@ PUGI__NS_BEGIN
// make private heap copy
if (!_uses_heap)
{
_buffer = duplicate_string(_buffer, alloc);
size_t length_ = strlength(_buffer);
_buffer = duplicate_string(_buffer, length_, alloc);
_uses_heap = true;
_length_heap = length_;
}
return const_cast<char_t*>(_buffer);
@ -6715,11 +6718,6 @@ PUGI__NS_BEGIN
return _uses_heap;
}
};
PUGI__FN xpath_string xpath_string_const(const char_t* str)
{
return xpath_string(str, false);
}
PUGI__NS_END
PUGI__NS_BEGIN
@ -6762,7 +6760,7 @@ PUGI__NS_BEGIN
PUGI__FN xpath_string string_value(const xpath_node& na, xpath_allocator* alloc)
{
if (na.attribute())
return xpath_string_const(na.attribute().value());
return xpath_string::from_const(na.attribute().value());
else
{
xml_node n = na.node();
@ -6773,7 +6771,7 @@ PUGI__NS_BEGIN
case node_cdata:
case node_comment:
case node_pi:
return xpath_string_const(n.value());
return xpath_string::from_const(n.value());
case node_document:
case node_element:
@ -6785,7 +6783,7 @@ PUGI__NS_BEGIN
while (cur && cur != n)
{
if (cur.type() == node_pcdata || cur.type() == node_cdata)
result.append(xpath_string_const(cur.value()), alloc);
result.append(xpath_string::from_const(cur.value()), alloc);
if (cur.first_child())
cur = cur.first_child();
@ -7098,7 +7096,7 @@ PUGI__NS_BEGIN
{
// try special number conversion
const char_t* special = convert_number_to_string_special(value);
if (special) return xpath_string_const(special);
if (special) return xpath_string::from_const(special);
// get mantissa + exponent form
char mantissa_buffer[32];
@ -7158,7 +7156,7 @@ PUGI__NS_BEGIN
assert(s < result + result_size);
*s = 0;
return xpath_string(result, true);
return xpath_string::from_heap_preallocated(result, s);
}
PUGI__FN bool check_string_to_number_format(const char_t* string)
@ -9181,7 +9179,7 @@ PUGI__NS_BEGIN
*ri = 0;
return xpath_string(result, true);
return xpath_string::from_heap_preallocated(result, ri);
}
xpath_string eval_string(const xpath_context& c, const xpath_stack& stack)
@ -9189,13 +9187,13 @@ PUGI__NS_BEGIN
switch (_type)
{
case ast_string_constant:
return xpath_string_const(_data.string);
return xpath_string::from_const(_data.string);
case ast_func_local_name_0:
{
xpath_node na = c.n;
return xpath_string_const(local_name(na));
return xpath_string::from_const(local_name(na));
}
case ast_func_local_name_1:
@ -9205,14 +9203,14 @@ PUGI__NS_BEGIN
xpath_node_set_raw ns = _left->eval_node_set(c, stack);
xpath_node na = ns.first();
return xpath_string_const(local_name(na));
return xpath_string::from_const(local_name(na));
}
case ast_func_name_0:
{
xpath_node na = c.n;
return xpath_string_const(qualified_name(na));
return xpath_string::from_const(qualified_name(na));
}
case ast_func_name_1:
@ -9222,14 +9220,14 @@ PUGI__NS_BEGIN
xpath_node_set_raw ns = _left->eval_node_set(c, stack);
xpath_node na = ns.first();
return xpath_string_const(qualified_name(na));
return xpath_string::from_const(qualified_name(na));
}
case ast_func_namespace_uri_0:
{
xpath_node na = c.n;
return xpath_string_const(namespace_uri(na));
return xpath_string::from_const(namespace_uri(na));
}
case ast_func_namespace_uri_1:
@ -9239,7 +9237,7 @@ PUGI__NS_BEGIN
xpath_node_set_raw ns = _left->eval_node_set(c, stack);
xpath_node na = ns.first();
return xpath_string_const(namespace_uri(na));
return xpath_string::from_const(namespace_uri(na));
}
case ast_func_string_0:
@ -9262,7 +9260,7 @@ PUGI__NS_BEGIN
const char_t* pos = find_substring(s.c_str(), p.c_str());
return pos ? xpath_string(s.c_str(), pos, stack.result) : xpath_string();
return pos ? xpath_string::from_heap(s.c_str(), pos, stack.result) : xpath_string();
}
case ast_func_substring_after:
@ -9279,7 +9277,7 @@ PUGI__NS_BEGIN
const char_t* result = pos + p.length();
return s.uses_heap() ? xpath_string(result, stack.result) : xpath_string_const(result);
return s.uses_heap() ? xpath_string::from_heap(result, s.c_str() + s.length(), stack.result) : xpath_string::from_const(result);
}
case ast_func_substring_2:
@ -9301,7 +9299,7 @@ PUGI__NS_BEGIN
const char_t* rbegin = s.c_str() + (pos - 1);
return s.uses_heap() ? xpath_string(rbegin, stack.result) : xpath_string_const(rbegin);
return s.uses_heap() ? xpath_string::from_heap(rbegin, s.c_str() + s.length(), stack.result) : xpath_string::from_const(rbegin);
}
case ast_func_substring_3:
@ -9328,7 +9326,7 @@ PUGI__NS_BEGIN
const char_t* rbegin = s.c_str() + (pos - 1);
const char_t* rend = s.c_str() + (end - 1);
return (end == s_length + 1 && !s.uses_heap()) ? xpath_string_const(rbegin) : xpath_string(rbegin, rend, stack.result);
return (end == s_length + 1 && !s.uses_heap()) ? xpath_string::from_const(rbegin) : xpath_string::from_heap(rbegin, rend, stack.result);
}
case ast_func_normalize_space_0:
@ -9378,7 +9376,7 @@ PUGI__NS_BEGIN
assert(_rettype == _data.variable->type());
if (_rettype == xpath_type_string)
return xpath_string_const(_data.variable->get_string());
return xpath_string::from_const(_data.variable->get_string());
// fallthrough to type conversion
}
@ -9388,7 +9386,7 @@ PUGI__NS_BEGIN
switch (_rettype)
{
case xpath_type_boolean:
return xpath_string_const(eval_boolean(c, stack) ? PUGIXML_TEXT("true") : PUGIXML_TEXT("false"));
return xpath_string::from_const(eval_boolean(c, stack) ? PUGIXML_TEXT("true") : PUGIXML_TEXT("false"));
case xpath_type_number:
return convert_number_to_string(eval_number(c, stack), stack.result);
@ -10973,7 +10971,9 @@ namespace pugi
{
impl::xpath_stack_data sd;
return impl::evaluate_string_impl(static_cast<impl::xpath_query_impl*>(_impl), n, sd).c_str();
impl::xpath_string r = impl::evaluate_string_impl(static_cast<impl::xpath_query_impl*>(_impl), n, sd);
return string_t(r.c_str(), r.length());
}
#endif