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.