This case occurs often enough (around 45% of conversion specs executed
in our regression tests are just "%s") that it's worth an extra test
per conversion spec to allow skipping all the logic associated with
field widths and padding when it happens.
Discussion: https://postgr.es/m/26193.
1538582367@sss.pgh.pa.us
/* Process conversion spec starting at *format */
format++;
+
+ /* Fast path for conversion spec that is exactly %s */
+ if (*format == 's')
+ {
+ format++;
+ strvalue = va_arg(args, char *);
+ Assert(strvalue != NULL);
+ dostr(strvalue, strlen(strvalue), target);
+ if (target->failed)
+ break;
+ continue;
+ }
+
fieldwidth = precision = zpad = leftjust = forcesign = 0;
longflag = longlongflag = pointflag = 0;
fmtpos = accum = 0;