string to number code in C++ template

 

template<class IntType>    bool AtoI(WCHAR *sz, IntType *out) {  int i = 0;  bool sign = false;  if (sz[i] == '-') {    ++i;    sign = true;  }  int base = 10;  if(sz[i] == '0' && tolower(sz[i+1]) == 'x') {    i += 2;    base = 16;  } else if (sz[i] == '0' && sz[i+1] != '/0') {    ++i;    base = 8;  }  IntType res = 0;  int chars = 0;  while (sz[i] != '/0') {    WCHAR c = tolower(sz[i++]);    if (c >= '0' && c <= '9')      c = c - '0';    else if (c >= 'a' && c <= 'f')      c = c - 'a' + 10;    else      return false;    if (c >= base)      return false;    IntType res_sav = res;    res *= (IntType)base;    if (res / (IntType)base != res_sav) {      // Overflow!      return false;    }    res_sav = res;    res += (IntType)c;    if (res < res_sav) {      // Overflow!      return false;    }    ++chars;  }  if (chars == 0)    return false;  *out = sign ? -res : res;  return true;}