Rapid statistics for subareas of a raster map?

[hnw at mtqgrass.ESD.ORNL.GOV]

I need to calculate n, mean, std, max, and min for a number of patches
in a raster map.

I am currently masking the patch, zooming with g.region, and then using
r.stats to spew the cells to an awk program which calculates the
statistics.

But it takes a long time for g.region to "walk" the edges of the window
down to each individual patch.  But if I don't window in the current
region, it takes r.stats a long time to filter through all of the
masked cells to get to the cells that are in the current patch.

Does anybody know of a better, faster approach for getting summary
stats for patches in a raster map?

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