/**

public int strToInt(String str) {

str = str.trim();

if (str.length() == 0) {

return 0;

}

// mark number is negative or not.

boolean isNegative = str.charAt(0) == '-';

int ret = 0;

for (int i = 0; i < str.length(); i++) {

char chr = str.charAt(i);

// skip '+' or '-' in begin.

if (i == 0 && (chr == '+' || chr == '-')) {

continue;

}

// current character isn't valid,

// stop transfer.

if (chr < '0' || chr > '9') {

break;

}

// if number is out of limit, directly return.

if (ret > Integer.MAX_VALUE / 10

|| (ret == Integer.MAX_VALUE / 10 && chr - '0' > 7)) {

return isNegative ? Integer.MIN_VALUE : Integer.MAX_VALUE;

}

// calculate number.

ret = ret * 10 + (chr - '0');

}

return isNegative ? -ret : ret;

}

}