vectorfill

NEWVALUES = VECTORFILL(VALUES, FILLVALUE)

NEWVALUES = VECTORFILL(VALUES, FILLVALUE,DIRECTION)

NEWVALUES = VECTORFILL(VALUES, FILLVALUE,DIRECTION,INDICES)

DIRECTION can be either -1,0, or 1, and specifies whether to fill the numbers with the last non-FILLVALUE (-1) or the next non-FILLVALUE (1), or the nearest non-FILLVALUE (0 - default). The user can also specify which indices of VALUES operate on (default is all indices).

Example:
x = vectorfill([2 2 -1 3 3 3 3 -1 4 4 4], -1, 1)

x =
2 2 3 3 3 3 3 4 4 4 4

Written in c, so the operation is fast. Type "mex vectorfill.c" in matlab before use.

You might need a free compiler if it was not installed with your matlab:
http://www.mathworks.com/support/compilers/R2012b/win64.html