v.support

I am in trouble using v.support command because I cannot make clear about
the methods used to build areas and isles.
Following you can find a few little examples (dig_ascii file format) where
the results are not clear:

Example 1:
A 5
  1.0 1.0
  1.0 3.0
  3.0 3.0
  3.0 1.0
  1.0 1.0
--> Aree: 1
  Isole: 1

Example 2:
  1.0 1.0
  1.0 5.0
  5.0 5.0
  5.0 1.0
  1.0 1.0
A 5
  2.0 2.0
  2.0 4.0
  4.0 4.0
  4.0 2.0
  2.0 2.0
--> Areas: 2
  Isles: 2

Example 3:
A 5
  1.0 1.0
  1.0 5.0
  5.0 5.0
  5.0 1.0
  1.0 1.0
A 2
  1.0 1.0
  2.0 2.0
--> Areas: 0
  Isles: 1

Examples 4:
A 5
  1.0 1.0
  1.0 5.0
  5.0 5.0
  5.0 1.0
  1.0 1.0
A 2
  1.5 1.5
  2.0 2.0
--> Areas: 1
  Isles: 1

Examples 5:
A 5
  1.0 1.0
  1.0 5.0
  5.0 5.0
  5.0 1.0
  1.0 1.0
A 2
  5.0 5.0
  4.0 4.0

--> Areas: 1
  Isles: 1

Probably a detailed programmers documentation about isles and areas could
help me to understand how v.support works. Could someone help me to find it ?

Thank You in advance!
Elena
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