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class atoi_func
{
public:
atoi_func(): value_() {}
inline int value() const { return value_; }
inline bool operator() (const char *str, size_t len)
{
value_ = 0;
int sign = 1;
if (str[0] == '-') { // handle negative
sign = -1;
++str;
--len;
}
switch (len) { // handle up to 10 digits, assume we're 32-bit
case 10: value_ += (str[len-10] - '0') * 1000000000;
case 9: value_ += (str[len- 9] - '0') * 100000000;
case 8: value_ += (str[len- 8] - '0') * 10000000;
case 7: value_ += (str[len- 7] - '0') * 1000000;
case 6: value_ += (str[len- 6] - '0') * 100000;
case 5: value_ += (str[len- 5] - '0') * 10000;
case 4: value_ += (str[len- 4] - '0') * 1000;
case 3: value_ += (str[len- 3] - '0') * 100;
case 2: value_ += (str[len- 2] - '0') * 10;
case 1: value_ += (str[len- 1] - '0');
value_ *= sign;
return value_ > 0;
default:
return false;
}
}
private:
int value_;
};
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