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#ifndef STATIC_UTOA_H
#define STATIC_UTOA_H
#include "threadlocal.h"
#include <string>
#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 before 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;
}
// so named to avoid gcc segfault when named itoa
inline char *itoa(char *p,int n) {
if (n<0) {
p=utoa(p,-n); // TODO: check that (unsigned)(-INT_MIN) == 0x1000000 in 2s complement and not == 0
*--p='-';
return p;
} else
return utoa(p,n);
}
inline char *static_itoa(int n) {
return itoa(utoa_buf+utoa_bufsizem1,n);
}
inline std::string utos(unsigned n) {
const int bufsz=20;
char buf[bufsz];
char *end=buf+bufsz;
char *p=utoa(end,n);
return std::string(p,end);
}
inline std::string itos(int n) {
const int bufsz=20;
char buf[bufsz];
char *end=buf+bufsz;
char *p=itoa(end,n);
return std::string(p,end);
}
#ifdef ITOA_SAMPLE
# include <cstdio>
# include <sstream>
# include <iostream>
using namespace std;
int main(int argc,char *argv[]) {
printf("d U d U d U\n");
for (int i=1;i<argc;++i) {
int n;
unsigned un;
sscanf(argv[i],"%d",&n);
sscanf(argv[i],"%u",&un);
printf("%d %u %s",n,un,static_itoa(n));
printf(" %s %s %s\n",static_utoa(un),itos(n).c_str(),utos(un).c_str());
}
return 0;
}
#endif
#endif
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