From a3aa5d39b82c33b651d5e61094ec4e9ef87de455 Mon Sep 17 00:00:00 2001 From: "arseny.kapoulkine@gmail.com" <arseny.kapoulkine@gmail.com@99668b35-9821-0410-8761-19e4c4f06640> Date: Sun, 18 Nov 2012 23:11:59 +0000 Subject: [PATCH] XPath stack optimization: Reduce convert_number_to_string stack usage by reducing mantissa_buffer size and filling resulting string on heap without an extra copy from stack. git-svn-id: http://pugixml.googlecode.com/svn/trunk@933 99668b35-9821-0410-8761-19e4c4f06640 --- src/pugixml.cpp | 12 ++++++++---- 1 file changed, 8 insertions(+), 4 deletions(-) diff --git a/src/pugixml.cpp b/src/pugixml.cpp index 83f53291..163ac48b 100644 --- a/src/pugixml.cpp +++ b/src/pugixml.cpp @@ -6341,14 +6341,18 @@ PUGI__NS_BEGIN if (special) return xpath_string_const(special); // get mantissa + exponent form - char mantissa_buffer[64]; + char mantissa_buffer[32]; char* mantissa; int exponent; convert_number_to_mantissa_exponent(value, mantissa_buffer, sizeof(mantissa_buffer), &mantissa, &exponent); + // allocate a buffer of suitable length for the number + size_t result_size = strlen(mantissa_buffer) + (exponent > 0 ? exponent : -exponent) + 4; + char_t* result = static_cast<char_t*>(alloc->allocate(sizeof(char_t) * result_size)); + assert(result); + // make the number! - char_t result[512]; char_t* s = result; // sign @@ -6391,10 +6395,10 @@ PUGI__NS_BEGIN } // zero-terminate - assert(s < result + sizeof(result) / sizeof(result[0])); + assert(s < result + result_size); *s = 0; - return xpath_string(result, alloc); + return xpath_string(result, true); } PUGI__FN bool check_string_to_number_format(const char_t* string) -- GitLab