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XPath: Always allocate xpath_strings on temporary stack for concat

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The static_buffer optimization seems to come from the time where the
on-heap buffer was allocated using global memory operations. At this
point the temporary buffer and temporary string storage all come from
the evaluation stack (that can be partially allocated on heap...), so
the extra logic isn't relevant for performance.
This commit is contained in:
Arseny Kapoulkine 2017-11-13 19:10:36 -08:00
parent 7c6d0010b3
commit 344c74a74c
1 changed files with 3 additions and 10 deletions
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13
src/pugixml.cpp
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@ -10442,16 +10442,9 @@ PUGI__NS_BEGIN
size_t count = 1;
for (xpath_ast_node* nc = _right; nc; nc = nc->_next) count++;
// gather all strings
xpath_string static_buffer[4];
xpath_string* buffer = static_buffer;
// allocate on-heap for large concats
if (count > sizeof(static_buffer) / sizeof(static_buffer[0]))
{
buffer = static_cast<xpath_string*>(stack.temp->allocate(count * sizeof(xpath_string)));
if (!buffer) return xpath_string();
}
// allocate a buffer for temporary string objects
xpath_string* buffer = static_cast<xpath_string*>(stack.temp->allocate(count * sizeof(xpath_string)));
if (!buffer) return xpath_string();
// evaluate all strings to temporary stack
xpath_stack swapped_stack = {stack.temp, stack.result};