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Eliminate redundant strlen calls during set_value/set

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Since we use manual integer conversion we know the length of the string.

This makes set_value(int) ~30% faster for 4-digit numbers.
This commit is contained in:
Arseny Kapoulkine 2015-09-20 00:24:07 -07:00
parent 5750b7cc19
commit 9c539f92ab
1 changed files with 19 additions and 16 deletions
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35
src/pugixml.cpp
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@ -4541,25 +4541,24 @@ PUGI__NS_BEGIN
#endif #endif
template <typename U> template <typename U>
PUGI__FN char_t* integer_to_string(char_t (&buf)[64], U value, bool negative) PUGI__FN char_t* integer_to_string(char_t* begin, char_t* end, U value, bool negative)
{ {
char_t* end = buf + sizeof(buf) / sizeof(buf[0]) - 1; char_t* result = end - 1;
U rest = negative ? 0 - value : value; U rest = negative ? 0 - value : value;
*end-- = 0;
do do
{ {
*end-- = static_cast<char_t>('0' + (rest % 10)); *result-- = static_cast<char_t>('0' + (rest % 10));
rest /= 10; rest /= 10;
} }
while (rest); while (rest);
assert(end >= buf); assert(result >= begin);
(void)begin;
*end = '-'; *result = '-';
return end + !negative; return result + !negative;
} }
// set value with conversion functions // set value with conversion functions
@ -4580,18 +4579,20 @@ PUGI__NS_BEGIN
PUGI__FN bool set_value_convert(String& dest, Header& header, uintptr_t header_mask, int value) PUGI__FN bool set_value_convert(String& dest, Header& header, uintptr_t header_mask, int value)
{ {
char_t buf[64]; char_t buf[64];
char_t* begin = integer_to_string<unsigned int>(buf, value, value < 0); char_t* end = buf + sizeof(buf) / sizeof(buf[0]);
char_t* begin = integer_to_string<unsigned int>(buf, end, value, value < 0);
return strcpy_insitu(dest, header, header_mask, begin, strlength(begin)); return strcpy_insitu(dest, header, header_mask, begin, end - begin);
} }
template <typename String, typename Header> template <typename String, typename Header>
PUGI__FN bool set_value_convert(String& dest, Header& header, uintptr_t header_mask, unsigned int value) PUGI__FN bool set_value_convert(String& dest, Header& header, uintptr_t header_mask, unsigned int value)
{ {
char_t buf[64]; char_t buf[64];
char_t* begin = integer_to_string<unsigned int>(buf, value, false); char_t* end = buf + sizeof(buf) / sizeof(buf[0]);
char_t* begin = integer_to_string<unsigned int>(buf, end, value, false);
return strcpy_insitu(dest, header, header_mask, begin, strlength(begin)); return strcpy_insitu(dest, header, header_mask, begin, end - begin);
} }
template <typename String, typename Header> template <typename String, typename Header>
@ -4623,18 +4624,20 @@ PUGI__NS_BEGIN
PUGI__FN bool set_value_convert(String& dest, Header& header, uintptr_t header_mask, long long value) PUGI__FN bool set_value_convert(String& dest, Header& header, uintptr_t header_mask, long long value)
{ {
char_t buf[64]; char_t buf[64];
char_t* begin = integer_to_string<unsigned long long>(buf, value, value < 0); char_t* end = buf + sizeof(buf) / sizeof(buf[0]);
char_t* begin = integer_to_string<unsigned long long>(buf, end, value, value < 0);
return strcpy_insitu(dest, header, header_mask, begin, strlength(begin)); return strcpy_insitu(dest, header, header_mask, begin, end - begin);
} }
template <typename String, typename Header> template <typename String, typename Header>
PUGI__FN bool set_value_convert(String& dest, Header& header, uintptr_t header_mask, unsigned long long value) PUGI__FN bool set_value_convert(String& dest, Header& header, uintptr_t header_mask, unsigned long long value)
{ {
char_t buf[64]; char_t buf[64];
char_t* begin = integer_to_string<unsigned long long>(buf, value, false); char_t* end = buf + sizeof(buf) / sizeof(buf[0]);
char_t* begin = integer_to_string<unsigned long long>(buf, end, value, false);
return strcpy_insitu(dest, header, header_mask, begin, strlength(begin)); return strcpy_insitu(dest, header, header_mask, begin, end - begin);
} }
#endif #endif