Module Bin_prot.Utils

size_header_length is the standard number of bytes allocated for the size header in size-prefixed bin-io payloads. This size-prefixed layout is used by the bin_dump and bin_read_stream functions below, as well as:

• Core.Bigstring.{read,write}_bin_prot
• Core.Unpack_buffer.unpack_bin_prot
• Async.{Reader,Writer}.{read,write}_bin_prot among others.

The size prefix is always 8 bytes at present. This is exposed so your program does not have to know this fact too.

We do not use a variable length header because we want to know how many bytes to read to get the size without having to peek into the payload.

bin_read_size_header and bin_write_size_header are bin-prot serializers for the size header described above.

bin_dump ?header writer v uses writer to first compute the size of v in the binary protocol, then allocates a buffer of exactly this size, and then writes out the value. If header is true, the size of the resulting binary string will be prefixed as a signed 64bit integer.

• returns

  the buffer containing the written out value.

• parameter header

  default = false

• raises Failure

  if the size of the value changes during writing, and any other exceptions that the binary writer in writer can raise.

bin_read_stream ?max_size ~read reader reads binary protocol data from a stream as generated by the read function, which places data of a given length into a given buffer. Requires a header. The reader type class will be used for conversion to OCaml-values.

• parameter max_size

  default = nothing

• raises Failure

  if the size of the value disagrees with the one specified in the header, and any other exceptions that the binary reader associated with reader can raise.

• raises Failure

  if the size reported in the data header is longer than max_size.