From 613301ce5143f0ce5f00f914d27d309b2e2efd75 Mon Sep 17 00:00:00 2001
From: Arseny Kapoulkine <arseny.kapoulkine@gmail.com>
Date: Sat, 2 May 2015 14:52:27 -0700
Subject: Optimize compact_string
First assignment uses a fast path; second assignment uses a specialized
path as well.
---
src/pugixml.cpp | 35 +++++++++++++++++++++++++----------
1 file changed, 25 insertions(+), 10 deletions(-)
(limited to 'src')
diff --git a/src/pugixml.cpp b/src/pugixml.cpp
index eab6e6c..c98ee40 100644
--- a/src/pugixml.cpp
+++ b/src/pugixml.cpp
@@ -527,7 +527,8 @@ PUGI__NS_BEGIN
void* allocate_memory(size_t size, xml_memory_page*& out_page)
{
- if (_busy_size + size > xml_memory_page_size) return allocate_memory_oob(size, out_page);
+ if (PUGI__UNLIKELY(_busy_size + size > xml_memory_page_size))
+ return allocate_memory_oob(size, out_page);
void* buf = reinterpret_cast<char*>(_root) + sizeof(xml_memory_page) + _busy_size;
@@ -916,16 +917,9 @@ PUGI__NS_BEGIN
if (PUGI__UNLIKELY(page->compact_string_base == 0))
page->compact_string_base = value;
- uint16_t* base = reinterpret_cast<uint16_t*>(reinterpret_cast<char*>(this) - base_offset);
-
ptrdiff_t offset = value - page->compact_string_base;
- if (*base == 0)
- *base = static_cast<uint16_t>(offset >> 7) + 1;
-
- ptrdiff_t remainder = offset - ((*base - 1) << 7);
-
- if (PUGI__UNLIKELY(static_cast<uintptr_t>(remainder) >= 254 || *base == 0))
+ if (PUGI__UNLIKELY(static_cast<uintptr_t>(offset) >= (65535 << 7)))
{
compact_set_value<header_offset>(this, value);
@@ -933,7 +927,28 @@ PUGI__NS_BEGIN
}
else
{
- _data = static_cast<unsigned char>(remainder + 1);
+ uint16_t* base = reinterpret_cast<uint16_t*>(reinterpret_cast<char*>(this) - base_offset);
+
+ if (PUGI__UNLIKELY(*base))
+ {
+ ptrdiff_t remainder = offset - ((*base - 1) << 7);
+
+ if (PUGI__UNLIKELY(static_cast<uintptr_t>(remainder) >= 254))
+ {
+ compact_set_value<header_offset>(this, value);
+
+ _data = 255;
+ }
+ else
+ {
+ _data = static_cast<unsigned char>(remainder + 1);
+ }
+ }
+ else
+ {
+ *base = static_cast<uint16_t>((offset >> 7) + 1);
+ _data = static_cast<unsigned char>((offset & 127) + 1);
+ }
}
}
else
--
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