1 files changed, 63 insertions, 0 deletions
diff --git a/decoder/static_utoa.h b/decoder/static_utoa.h
new file mode 100755
index 00000000..0dbe111f
--- /dev/null
+++ b/decoder/static_utoa.h
@@ -0,0 +1,63 @@
+#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