From 131c1a159c672ee651fa14efe41ee6ea6fd7ebf8 Mon Sep 17 00:00:00 2001
From: Arseny Kapoulkine <arseny.kapoulkine@gmail.com>
Date: Sun, 20 Sep 2015 00:03:02 -0700
Subject: Implement integer to string conversion manually
This reduces the amount of non-standard C++ functionality pugixml may be using
by avoiding sprintf with %lld; additionally this implementation is significantly
faster (4-5x) than sprintf, mostly due to avoiding format string parsing and
stream setup that commonly happens in CRT implementations.
This comes at the expense of requiring long long division/remainder operations
if PUGIXML_USE_LONG_LONG is defined which will surely bite me one day.
---
src/pugixml.cpp | 52 +++++++++++++++++++++++++++++++++++++---------------
1 file changed, 37 insertions(+), 15 deletions(-)
(limited to 'src')
diff --git a/src/pugixml.cpp b/src/pugixml.cpp
index 2ad2f15..e817690 100644
--- a/src/pugixml.cpp
+++ b/src/pugixml.cpp
@@ -4540,6 +4540,28 @@ PUGI__NS_BEGIN
}
#endif
+ template <typename U>
+ PUGI__FN char_t* integer_to_string(char_t (&buf)[64], U value, bool negative)
+ {
+ char_t* end = buf + sizeof(buf) / sizeof(buf[0]) - 1;
+ U rest = negative ? 0 - value : value;
+
+ *end-- = 0;
+
+ do
+ {
+ *end-- = static_cast<char_t>('0' + (rest % 10));
+ rest /= 10;
+ }
+ while (rest);
+
+ assert(end >= buf);
+
+ *end = '-';
+
+ return end + !negative;
+ }
+
// set value with conversion functions
template <typename String, typename Header>
PUGI__FN bool set_value_buffer(String& dest, Header& header, uintptr_t header_mask, char (&buf)[128])
@@ -4557,19 +4579,19 @@ PUGI__NS_BEGIN
template <typename String, typename Header>
PUGI__FN bool set_value_convert(String& dest, Header& header, uintptr_t header_mask, int value)
{
- char buf[128];
- sprintf(buf, "%d", value);
-
- return set_value_buffer(dest, header, header_mask, buf);
+ char_t buf[64];
+ char_t* begin = integer_to_string<unsigned int>(buf, value, value < 0);
+
+ return strcpy_insitu(dest, header, header_mask, begin);
}
template <typename String, typename Header>
PUGI__FN bool set_value_convert(String& dest, Header& header, uintptr_t header_mask, unsigned int value)
{
- char buf[128];
- sprintf(buf, "%u", value);
+ char_t buf[64];
+ char_t* begin = integer_to_string<unsigned int>(buf, value, false);
- return set_value_buffer(dest, header, header_mask, buf);
+ return strcpy_insitu(dest, header, header_mask, begin);
}
template <typename String, typename Header>
@@ -4600,19 +4622,19 @@ PUGI__NS_BEGIN
template <typename String, typename Header>
PUGI__FN bool set_value_convert(String& dest, Header& header, uintptr_t header_mask, long long value)
{
- char buf[128];
- sprintf(buf, "%lld", value);
-
- return set_value_buffer(dest, header, header_mask, buf);
+ char_t buf[64];
+ char_t* begin = integer_to_string<unsigned long long>(buf, value, value < 0);
+
+ return strcpy_insitu(dest, header, header_mask, begin);
}
template <typename String, typename Header>
PUGI__FN bool set_value_convert(String& dest, Header& header, uintptr_t header_mask, unsigned long long value)
{
- char buf[128];
- sprintf(buf, "%llu", value);
-
- return set_value_buffer(dest, header, header_mask, buf);
+ char_t buf[64];
+ char_t* begin = integer_to_string<unsigned long long>(buf, value, false);
+
+ return strcpy_insitu(dest, header, header_mask, begin);
}
#endif
--
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