Integer overflow in snd_mem.c

[miried]

ResampleSfx() and ResampleSfxRaw() in snd_mem.c resample the input audio file to the audio driver's sampling rate. The multiplication by 256=2^8 and subsequent bitshift by 8 bits to the right of the buffer offset allow for an upscaling of input frequencies as low as 1/256 of the target sampling rate, but they reduce the resulting maximum number of samples by 8 bits. This allows only for 95 seconds of playtime at 44.1 khz or 190 seconds at 22 khz. After that, samplefrac overflows.

One "fix" would be to change 2^8 and 8 to smaller values, maybe 2^3=8 and 3, and add a warning message if the sampling rate is too small.

[zturtleman]

Fixed by #230, closing.