This function does the conversion, if there is no space between the number and the units:
convert_to_bytes <- function(value) {
digits <- gsub("[^0-9.]", "", value)
units <- gsub("[0-9.]", "", value)
multiplier <- switch (units,
'GiB' = 1024^3,
'MiB' = 1024^2,
'KiB'= 1024,
'B' = 1)
as.double(digits) * multiplier
}