I am working in PHP and I want to check if a given user submitted input is not too big or too small, where the input represents an amount in Bitcoins (don't worry I am sanitising the data and not blindly using it).
1. I am storing the amounts in the database as 64 bit integers (multiply them by 10^8 to avoid rounding errors in future calculations). I am limiting the amounts so that they cannot exceed the following precision: no more than 4 numbers after the decimal point. Also since no-one can have more than 100 million bitcoins, I also want to specify no more than 8 numbers precending the decimal point. How can I achieve this neatly?
My current approach seems a bit hack-ish:
//Check for existence of decimal point in string using strpos
//explode the string by the decimal point
//do a strlen on both the strings and check they dont exceed 8 and 4 respectively
//if no decimal point, simply do a strelen and check it's not greater than 8
2. Also, I don't want the inputted data to be smaller than 0.0001. I am proficient in php for web design not familiar with the math functions of php is there an easy way to handle this?
Thanks for any tips
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