hphp/util/fast_strtoll_base10.h

   1 /*
   2    +----------------------------------------------------------------------+
   3    | HipHop for PHP                                                       |
   4    +----------------------------------------------------------------------+
   5    | Copyright (c) 2010-present Facebook, Inc. (http://www.facebook.com)  |
   6    +----------------------------------------------------------------------+
   7    | This source file is subject to version 3.01 of the PHP license,      |
   8    | that is bundled with this package in the file LICENSE, and is        |
   9    | available through the world-wide-web at the following url:           |
  10    | http://www.php.net/license/3_01.txt                                  |
  11    | If you did not receive a copy of the PHP license and are unable to   |
  12    | obtain it through the world-wide-web, please send a note to          |
  13    | license@php.net so we can mail you a copy immediately.               |
  14    +----------------------------------------------------------------------+
  15 */
  16
  17 #ifndef incl_HPHP_UTIL_FAST_STRTOLL_BASE10_H_
  18 #define incl_HPHP_UTIL_FAST_STRTOLL_BASE10_H_
  19
  20 namespace HPHP {
  21
  22 // This a fast version of strtoll() specialized for base 10. This version
  23 // does not skip leading white space. It does not check for overflow/underflow,
  24 // in which case the return value becomes different from strtoll(3c) that
  25 // sets the result to LLONG_MAX/LLONG_MIN and errno to ERANGE.
  26 // This function never sets errno.  Thus a caller is responsible for making
  27 // sure the value fits in [LLONG_MIN, LLONG_MAX] range.
  28 inline int64_t fast_strtoll_base10(const char* p) {
  29   int64_t x = 0;
  30   bool neg = false;
  31
  32   if (*p == '-') {
  33     neg = true;
  34     ++p;
  35   } else if (*p == '+') {
  36     ++p;
  37   }
  38   while (*p >= '0' && *p <= '9') {
  39     x = (x * 10) + ('0' - *p);
  40     ++p;
  41   }
  42   if (!neg) {
  43     x = -x;
  44   }
  45
  46   return x;
  47 }
  48
  49 }
  50
  51 #endif