Posted by shodan

Sometimes you need to work with big numbers in PHP (gulp). For example, sometimes 32-bit identifiers are not enough and you have to use BIGINT 64-bit ids; e.g. if you are encoding additional information like the server ID into high bits of the ID.

I had already written about the mess that 64-bit integers are in PHP. But if the numbers you use do not cover 64-bit range fully, floats might save the day. The trick is that PHP floats are in fact doubles, i.e. double-precision 64-bit numbers. They have 52 bits for mantissa, and integer values up to 2^53-1 can be stored exactly. So if you’re using up to 53 bits, you’re OK with floats.

However, there’s a conversion caveat you should be aware of.
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