bin2raw: Convert R vectors to/from the raw binary format

Description

Convert R vectors of any type to and from the raw binary format, stored as vector of type "raw".

Usage

r = bin2raw(x, size=NA, endian=.Platform$endian)
  x = raw2bin(r, what, size=NA, signed = TRUE, endian=.Platform$endian)

Arguments

vector or any structure that can be converted to a vector by as.vector function. Strings are also allowed.

vector of type "raw"

what

Either an object whose mode will give the mode of the vector to be created, or a character vector of length one describing the mode: one of '"numeric", "double", "integer", "int", "logical", "complex", "character", "raw".

size

integer. The number of bytes per element in the byte stream stored in r. The default, 'NA', uses the natural size. See details.

signed

logical. Only used for integers of sizes 1 and 2, when it determines if the quantity stored as raw should be regarded as a signed or unsigned integer.

endian

If provided, can be used to swap endian-ness. Using '"swap"' will force swapping of byte order. Use '"big"' (big-endian, aka IEEE, aka "network") or '"little"' (little-endian, format used on PC/Intel machines) to indicate type of data

Value

Function bin2raw returns vector of raw values (see r above), where each 1-byte raw value correspond to 1-byte of 1-byte of the binary form of other types. Length of the vector is going to be "number of bytes of a single element in array x" times length(x). Function raw2bin returns vector of appropriate mode and length (see x above), where each 1-byte raw value correspond to 1-byte of the binary form of other types. Length of the vector is going to be number of bytes per element in array x times length(x). If parameter what is equal to "character" than a string (of length 1) is returned instead of vector f characters.

Details

Quoting from readBin documentation: "If 'size' is specified and not the natural size of the object, each element of the vector is coerced to an appropriate type before being written or as it is read. Possible sizes are 1, 2, 4 and possibly 8 for integer or logical vectors, and 4, 8 and possibly 12/16 for numeric vectors. (Note that coercion occurs as signed types except if 'signed = FALSE' when reading integers of sizes 1 and 2.) Changing sizes is unlikely to preserve 'NA's, and the extended precision sizes are unlikely to be portable across platforms." Default sizes for different types: logical - 4, integer - 4, double - 8 , complex - 16, character - 2, raw - 1.

Examples

Run this code

print(x <- (1:5)*pi)      
   print(y <- bin2raw(x))
   print(z <- raw2bin(y,"double"))
  
   x = (10*runif(10)>5) # logical
   for (i in c(NA, 1, 2, 4)) {
     y = bin2raw(x, size=i)
     z = raw2bin(y,typeof(x), size=i)
     stopifnot(x==z)
   }
   print("Checked bin2raw and raw2bin conversion for logical type")
   
   x = as.integer(1:10) # integer
   for (i in c(NA, 1, 2, 4)) {
     y = bin2raw(x, size=i)
     z = raw2bin(y,typeof(x), size=i)
     stopifnot(x==z)
   }
   print("Checked bin2raw and raw2bin conversion for integer type")
  
   x = (1:10)*pi        # double
   for (i in c(NA, 4, 8)) {
     y = bin2raw(x, size=i)
     z = raw2bin(y,typeof(x), size=i)
     stopifnot(mean(abs(x-z))<1e-5)
   }
   print("Checked bin2raw and raw2bin conversion for double type")
   
   x = log(as.complex(-(1:10)*pi))        # complex
   y = bin2raw(x)
   z = raw2bin(y,typeof(x))
   stopifnot(x==z)
   print("Checked bin2raw and raw2bin conversion for complex type")
   
   x = "Chance favors the prepared mind" # character
   y = bin2raw(x)
   z = raw2bin(y,typeof(x))
   stopifnot(x==z)
   print("Checked bin2raw and raw2bin conversion for character type")