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#ifndef STATIC_UTOA_H
#define STATIC_UTOA_H
#include "threadlocal.h"
#include <cstring>
#define DIGIT_LOOKUP_TABLE 0
namespace {
THREADLOCAL char utoa_buf[] = "01234567890123456789"; // to put end of string character at buf[20]
const unsigned utoa_bufsize=sizeof(utoa_buf);
const unsigned utoa_bufsizem1=utoa_bufsize-1;
#ifdef DIGIT_LOOKUP_TABLE
char digits[] = "0123456789";
#endif
}
inline char digit_to_char(int d) {
return
#ifdef DIGIT_LOOKUP_TABLE
digits[d];
#else
'0'+d;
#endif
}
// returns n in string [return,num); *num=0 yourself calling if you want a c_str
inline char *utoa(char *num,unsigned n) {
if ( !n ) {
*--num='0';
} else {
unsigned rem;
// 3digit lookup table, divide by 1000 faster?
while ( n ) {
#if 1
rem = n;
n /= 10;
rem -= 10*n; // maybe this is faster than mod because we are already dividing
#else
rem = n%10; // would optimizer combine these together?
n = n/10;
#endif
*--num = digit_to_char(rem);
}
}
return num;
}
inline char *static_utoa(unsigned n) {
return utoa(utoa_buf+utoa_bufsizem1,n);
}
//returns position of '\0' terminating number written starting at to
inline char* append_utoa(char *to,unsigned n) {
char *s=static_utoa(n);
int ns=(utoa_buf+utoa_bufsize)-s;
std::memcpy(to,s,ns);
return to+ns;
}
#endif
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