Is it possible to use short ints (16-bit) in PHP?

[gomez]

Background: I have a large 2D array of integers that I need to load into memory in PHP for each Apache request. I want it to take up less memory.PHP stores ints in PHP_INT_SIZE bytes, which is 32 bits on most systems. All the integers are less than 2^16, which means they could be a short int (eg in C). Am I right in thinking that storing ints as short would take up half the RAM?Ideally I'd like to be able to do:$s = (short) 1234; // takes up 2 bytes instead of 4More info: The array takes up about 100mb of RAM and is generated by including a 30MB var_export() dumpThe array is written in a cron process. Only the reading needs to be memory efficient (and quick)The only operations I need to do on the integers are comparing all of them (<, >, ===) and then reading a few of them (similar to the Floyd-Warshall algorithm)Reading each value from a DB is way too slow as there are a few hundred million reads per requestSome crazy ideas:Use pack() / unpack() but that would still store the values as 32 bit ints when they were unpackedStore the values as pixels in an image and use PHP's GD library to read them (would this be slow)Use shmop_read() and have the Apache processes share the arrayMemcached might work but I have no experience with it and I guess it would be many times slower than a native PHP arrayLearn C++ and write a PHP extensionRecompile PHP (or HipHop?) to use 2 bytes for intsUse Igbinary (useful, but will have same problem as pack())