Read a vector of one type from bytes

bin_decode() reads n consecutive values of one type from the raw vector x, starting at the 0-based byte offset: bin_decode(x, "u32", offset = 4) is a header field, bin_decode(x, "f32", offset = 64, n = 1e6) is a column. It is readBin() generalised to every width and both byte orders, exact or an error; bin_encode() is its inverse. Offsets are 0-based.

Usage

bin_decode(
  x,
  type,
  offset = 0,
  n = NULL,
  endian = c("little", "big", "native"),
  int64 = c("double", "integer64"),
  na = c("error", "allow")
)

Arguments

x

A raw vector.

type

Any type token of bin_layout() except padding ("u8", "i128", "f16", "c64", "bool", "b16", "s8", ...), optionally with a .le or .be suffix.

offset

The 0-based byte position of the first record.

n

The number of values, or NULL for every whole value that fits.

endian

The byte order: "little", "big", or "native".

int64

How i64, u64, i128 and u128 fields are returned: "double", exact or an error; or "integer64", a double vector carrying the 64-bit pattern with class integer64, as the bit64 package defines it.

na

"error", or "allow" to read -2^31 in an i32 field as NA_integer_ (and -2^63 in integer64 mode as NA).

Value

A vector of the type's R type (see bin_layout()): integer, double, integer64, complex, logical, character, or a list of raw vectors for b<n>.

Examples

x <- as.raw(c(0x01, 0x00, 0x02, 0x00, 0xff, 0xff))
bin_decode(x, "u16")
#> [1]     1     2 65535
bin_decode(x, "i16")
#> [1]  1  2 -1
bin_decode(x, "u16", endian = "big", offset = 2, n = 1)
#> [1] 512