Counting Week Data - Replicate, Transform and Percent Agreggation

I need to transform some data from a specific initial and end date to weekdays or days counting.

https://i.stack.imgur.com/aBOSF.png to this https://i.stack.imgur.com/KqS3L.png

Example: Code table

structure(list(year.month = structure(c(1L, 2L, 2L, 2L, 2L), .Label = c("2016-05", 
"2016-08"), class = "factor"), id = 1:5, begin = structure(c(2L, 
1L, 3L, 5L, 4L), .Label = c("02/07/2016", "13/04/2016", "24/07/2016", 
"25/07/2016", "30/06/2016"), class = "factor"), end = structure(c(1L, 
2L, 2L, 2L, 2L), .Label = c("01/05/2016", "01/08/2016"), class = "factor"), 
    value = c(4L, 7L, 3L, 4L, 6L)), .Names = c("year.month", 
"id", "begin", "end", "value"), class = "data.frame", row.names = c(NA, 
-5L))

For each row, I need to calculate weeks that hapenned to be in the specific begin and end time. This way , begin date 13-04 and end date 01-05 passed between the weeks starting in 11-04, 18-04 and 25-04, each of them with different contributions, first with 5 days (wed-dom), second with 7 days (seg-dom) and third with 7 days (seg-dom)

For each week, also i need to calculate the percent of days compared to total period of that id.

I manage to do this but only creating a loop for each row (using strftime and as.POSIXlt) and this gets extremely slow for a big dataset (several hours). Is there another way of doing this by matrix commands or transforming the whole data at once?

Thanks,