Validate CBOR

Checks that x holds well-formed, valid CBOR within the given limits, without building any R value. This is exactly the check cbor_decode() runs before it builds anything, so the two agree about the bytes; they disagree only where the bytes are valid but R cannot hold the value, such as a text string containing U+0000.

Usage

cbor_validate(
  x,
  sequence = FALSE,
  deterministic = FALSE,
  duplicate_keys = FALSE,
  max_depth = 256L,
  max_size = 64 * 1024^2,
  max_items = 1e+06,
  error = FALSE
)

Arguments

x

A raw vector.

sequence

If TRUE, x is an RFC 8742 CBOR sequence of zero or more items; if FALSE, it must be exactly one item.

deterministic

If TRUE, also require RFC 8949 section 4.2.1 core deterministic encoding: shortest integers, lengths and floats, definite lengths, map keys in bytewise order, and bignums in preferred form.

duplicate_keys

If FALSE (the default), a map with the same key twice is invalid.

max_depth

Deepest nesting allowed, counting arrays, maps and tags. At most zucbor_info()$max_depth_cap.

max_size

Largest input allowed, in bytes, or Inf.

max_items

Most data items allowed, counting every tag and every chunk of an indefinite-length string, or Inf.

error

If TRUE, raise the classed condition describing the fault instead of returning FALSE; see zucbor-conditions.

Value

TRUE or FALSE; with error = TRUE, TRUE invisibly or an error.

Details

The check covers well-formedness (RFC 8949 section 3), UTF-8 in text strings, the content of the tags RFC 8949, RFC 8943 and RFC 8746 restrict (their content type, the date text of tags 0 and 1004, the length of a typed array, the shape of a multi-dimensional array), duplicate map keys (compared by value, so 1 encoded in one byte and in two is the same key), and the limits.

Examples

cbor_validate(as.raw(c(0x83, 0x01, 0x02, 0x03)))   # [1, 2, 3]
#> [1] TRUE
cbor_validate(as.raw(c(0x83, 0x01, 0x02)))         # truncated
#> [1] FALSE
cbor_validate(as.raw(c(0xa2, 0x01, 0x00, 0x01, 0x00)))  # {1: 0, 1: 0}
#> [1] FALSE
cbor_validate(as.raw(c(0x01, 0x02)), sequence = TRUE)
#> [1] TRUE