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optimization: rs274ngc: parse numbers with std::from_chars #4491

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Merged
grandixximo merged 1 commit into from
Sep 2, 2026
+23 −9
Merged

optimization: rs274ngc: parse numbers with std::from_chars #4491

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32 changes: 23 additions & 9 deletions src/emc/rs274ngc/interp_read.cc
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Original file line number Diff line number Diff line change
Expand Up @@ -22,7 +22,8 @@
#include <ctype.h>
#include <sys/types.h>
#include <sys/stat.h>
#include <sstream>
#include <charconv>
#include <string>
#include "rs274ngc.hh"
#include "rs274ngc_return.hh"
#include "interp_internal.hh"
Expand Down Expand Up @@ -740,7 +741,9 @@ int Interp::read_integer_unsigned(char *line, //!< string: line of RS274 code
break;
}
CHKS((n == *counter), NCE_BAD_FORMAT_UNSIGNED_INTEGER);
if (sscanf(line + *counter, "%d", integer_ptr) == 0)
// the digits are already delimited above, so from_chars needs no sscanf
std::from_chars_result r = std::from_chars(line + *counter, line + n, *integer_ptr);
if (r.ec != std::errc())
ERS(NCE_SSCANF_FAILED);
*counter = n;
return INTERP_OK;
Expand Down Expand Up @@ -2749,14 +2752,25 @@ int Interp::read_real_number(char *line, //!< string: line of RS274/NGC code bei

start = line + *counter;

after = strspn(start, "+-");
after = strspn(start+after, "0123456789.") + after;
size_t signs = strspn(start, "+-");
after = strspn(start+signs, "0123456789.") + signs;

std::string st(start, start+after);
std::stringstream s(st);
double val;
if(!(s >> val)) ERS(_("bad number format (conversion failed) parsing '%s'"), st.c_str());
if(s.get() != std::char_traits<char>::eof()) ERS(_("bad number format (trailing characters) parsing '%s'"), st.c_str());
const char *first = start + ((signs == 1 && *start == '+') ? 1 : 0);
const char *last = start + after;
double val = 0;
std::from_chars_result r{first, std::errc::invalid_argument};
if (signs <= 1) r = std::from_chars(first, last, val);

if (r.ec != std::errc()) {
// No number there, or a magnitude that does not fit a double; the stream
// conversion set failbit for the former and for an overflow.
std::string st(start, after);
ERS(_("bad number format (conversion failed) parsing '%s'"), st.c_str());
}
if (r.ptr != last) {
std::string st(start, after);
ERS(_("bad number format (trailing characters) parsing '%s'"), st.c_str());
}

*double_ptr = val;
*counter = start + after - line;
Expand Down