External/pugixml
8
0
Fork 0
Code Issues Pull Requests Packages Projects Releases Wiki Activity

XPath: Number to string conversion uses ecvt_s under MSVC8+ (major speedup), minor conversion refactoring

Browse Source 
git-svn-id: http://pugixml.googlecode.com/svn/trunk@649 99668b35-9821-0410-8761-19e4c4f06640
This commit is contained in:
arseny.kapoulkine 2010-08-29 15:15:21 +00:00
parent 7aadde4229
commit 3284cc2f1b
1 changed files with 29 additions and 8 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

37
src/pugixpath.cpp
View File

@ -337,11 +337,35 @@ namespace
return (value != 0 && !is_nan(value)); return (value != 0 && !is_nan(value));
} }
void truncate_zeros(char* begin, char* end)
{
while (begin != end && end[-1] == '0') end--;
*end = 0;
}
// gets mantissa digits in the form of 0.xxxxx with 0. implied and the exponent // gets mantissa digits in the form of 0.xxxxx with 0. implied and the exponent
void convert_number_to_mantissa_exponent(double value, char* buffer, char** out_mantissa, int* out_exponent) #if defined(_MSC_VER) && _MSC_VER >= 1400
void convert_number_to_mantissa_exponent(double value, char* buffer, size_t buffer_size, char** out_mantissa, int* out_exponent)
{
// get base values
int sign, exponent;
_ecvt_s(buffer, buffer_size, value, DBL_DIG + 1, &exponent, &sign);
// truncate redundant zeros
truncate_zeros(buffer, buffer + strlen(buffer));
// fill results
*out_mantissa = buffer;
*out_exponent = exponent;
}
#else
void convert_number_to_mantissa_exponent(double value, char* buffer, size_t buffer_size, char** out_mantissa, int* out_exponent)
{ {
// get a scientific notation value with IEEE DBL_DIG decimals // get a scientific notation value with IEEE DBL_DIG decimals
sprintf(buffer, "%.15e", value); sprintf(buffer, "%.*e", DBL_DIG, value);
assert(strlen(buffer) < buffer_size);
(void)!buffer_size;
// get the exponent (possibly negative) // get the exponent (possibly negative)
char* exponent_string = strchr(buffer, 'e'); char* exponent_string = strchr(buffer, 'e');
@ -359,16 +383,13 @@ namespace
exponent++; exponent++;
// remove extra mantissa digits and zero-terminate mantissa // remove extra mantissa digits and zero-terminate mantissa
char* mantissa_end = exponent_string; truncate_zeros(mantissa, exponent_string);
while (mantissa != mantissa_end && *(mantissa_end - 1) == '0') --mantissa_end;
*mantissa_end = 0;
// fill results // fill results
*out_mantissa = mantissa; *out_mantissa = mantissa;
*out_exponent = exponent; *out_exponent = exponent;
} }
#endif
string_t convert_number_to_string(double value) string_t convert_number_to_string(double value)
{ {
@ -381,7 +402,7 @@ namespace
char* mantissa; char* mantissa;
int exponent; int exponent;
convert_number_to_mantissa_exponent(value, mantissa_buffer, &mantissa, &exponent); convert_number_to_mantissa_exponent(value, mantissa_buffer, sizeof(mantissa_buffer), &mantissa, &exponent);
// make the number! // make the number!
char_t result[512]; char_t result[512];