1 files changed, 115 insertions, 0 deletions
diff --git a/utils/static_utoa.h b/utils/static_utoa.h
new file mode 100755
index 00000000..fe5f6d92
--- /dev/null
+++ b/utils/static_utoa.h
@@ -0,0 +1,115 @@
+#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