Module Core.Bigstring

read ?min_len fd ?pos ?len bstr reads at least min_len (must be greater than or equal zero) and at most len (must be greater than or equal to min_len) bytes from file descriptor fd, and writes them to bigstring bstr starting at position pos.

• Returns the number of bytes actually read.

  read returns zero only if len = 0. If len > 0 and there's nothing left to read, read raises to indicate EOF even if min_len = 0.

  NOTE: even if len is zero, there may still be errors when reading from the descriptor!

• Raises Invalid_argument: if the designated ranges are out of bounds.
• Raises IOError: in the case of input errors, or on EOF if the minimum length could not be read.
• Parameter pos: default = 0
• Parameter min_len: default = 0
• Parameter len: default = length bstr - pos

really_read fd ?pos ?len bstr reads len bytes from file descriptor fd, and writes them to bigstring bstr starting at position pos.

• Raises Invalid_argument: if the designated range is out of bounds.
• Raises IOError: in the case of input errors, or on EOF.
• Parameter pos: default = 0
• Parameter len: default = length bstr - pos

really_recv sock ?pos ?len bstr receives len bytes from socket sock, and writes them to bigstring bstr starting at position pos. If len is zero, the function returns immediately without performing the underlying system call.

• Raises Invalid_argument: if the designated range is out of bounds.
• Raises IOError: in the case of input errors, or on EOF.
• Parameter pos: default = 0
• Parameter len: default = length bstr - pos

recvfrom_assume_fd_is_nonblocking sock ?pos ?len bstr reads up to len bytes into bigstring bstr starting at position pos from socket sock without yielding to other OCaml-threads.

• Returns the number of bytes actually read and the socket address of the client.
• Raises Unix_error: in the case of input errors.
• Raises Invalid_argument: if the designated range is out of bounds.
• Parameter pos: default = 0
• Parameter len: default = length bstr - pos

read_assume_fd_is_nonblocking fd ?pos ?len bstr reads up to len bytes into bigstring bstr starting at position pos from file descriptor fd without yielding to other OCaml-threads.

• Returns the number of bytes actually read.
• Raises Invalid_argument: if the designated range is out of bounds.
• Parameter pos: default = 0
• Parameter len: default = length bstr - pos

pread_assume_fd_is_nonblocking fd ~offset ?pos ?len bstr reads up to len bytes from file descriptor fd at offset offset, and writes them to bigstring bstr starting at position pos. The fd must be capable of seeking, and the current file offset used for a regular read() is unchanged. Please see 'man pread' for more information.

• Returns the number of bytes actually read.
• Raises Invalid_argument: if the designated range is out of bounds.
• Raises Unix_error: in the case of input errors.
• Parameter pos: default = 0
• Parameter len: default = length bstr - pos

input ?min_len ic ?pos ?len bstr tries to read len bytes (guarantees to read at least min_len bytes (must be greater than or equal to zero and smaller or equal to len), if possible, before returning) from input channel ic, and writes them to bigstring bstr starting at position pos.

• Returns the number of bytes actually read.

  NOTE: even if len is zero, there may still be errors when reading from the descriptor, which will be done if the internal buffer is empty!

  NOTE: if at least len characters are available in the input channel buffer and if len is not zero, data will only be fetched from the channel buffer. Otherwise data will be read until at least min_len characters are available.

• Raises Invalid_argument: if the designated range is out of bounds.
• Raises IOError: in the case of input errors, or on premature EOF.
• Parameter pos: default = 0
• Parameter min_len: default = 0
• Parameter len: default = length bstr - pos

really_input ic ?pos ?len bstr reads exactly len bytes from input channel ic, and writes them to bigstring bstr starting at position pos.

• Raises Invalid_argument: if the designated range is out of bounds.
• Raises IOError: in the case of input errors, or on premature EOF.
• Parameter pos: default = 0
• Parameter len: default = length bstr - pos

really_write fd ?pos ?len bstr writes len bytes in bigstring bstr starting at position pos to file descriptor fd.

• Raises Invalid_argument: if the designated range is out of bounds.
• Raises IOError: in the case of output errors.
• Parameter pos: default = 0
• Parameter len: default = length bstr - pos

really_send_no_sigpipe sock ?pos ?len bstr sends len bytes in bigstring bstr starting at position pos to socket sock without blocking and ignoring SIGPIPE.

• Raises Invalid_argument: if the designated range is out of bounds.
• Raises IOError: in the case of output errors.
• Parameter pos: default = 0

• Parameter len: default = length bstr - pos

  really_send_no_sigpipe is not implemented on some platforms, in which case it is an Error value that indicates that it is unimplemented.

send_nonblocking_no_sigpipe sock ?pos ?len bstr tries to send len bytes in bigstring bstr starting at position pos to socket sock.

• Returns bytes_written.
• Raises Invalid_argument: if the designated range is out of bounds.
• Parameter pos: default = 0
• Parameter len: default = length bstr - pos

sendto_nonblocking_no_sigpipe sock ?pos ?len bstr sockaddr tries to send len bytes in bigstring bstr starting at position pos to socket sock using address addr.

• Returns bytes_written.
• Raises Invalid_argument: if the designated range is out of bounds.
• Parameter pos: default = 0
• Parameter len: default = length bstr - pos

write fd ?pos ?len bstr writes len bytes in bigstring bstr starting at position pos to file descriptor fd.

• Returns the number of bytes actually written.
• Raises Unix_error: in the case of output errors.
• Raises Invalid_argument: if the designated range is out of bounds.
• Parameter pos: default = 0
• Parameter len: default = length bstr - pos

pwrite_assume_fd_is_nonblocking fd ~offset ?pos ?len bstr writes up to len bytes of bigstring bstr starting at position pos to file descriptor fd at position offset. The fd must be capable of seeking, and the current file offset used for non-positional read()/write() calls is unchanged.

• Returns the number of bytes written.
• Raises Invalid_argument: if the designated range is out of bounds.
• Raises Unix_error: in the case of input errors.
• Parameter pos: default = 0
• Parameter len: default = length bstr - pos

write_assume_fd_is_nonblocking fd ?pos ?len bstr writes len bytes in bigstring bstr starting at position pos to file descriptor fd without yielding to other OCaml-threads.

• Returns the number of bytes actually written.
• Raises Unix_error: in the case of output errors.
• Raises Invalid_argument: if the designated range is out of bounds.
• Parameter pos: default = 0
• Parameter len: default = length bstr - pos

writev fd ?count iovecs writes countiovecs of bigstrings to file descriptor fd.

• Returns the number of bytes written.
• Raises Unix_error: in the case of output errors.
• Raises Invalid_argument: if count is out of range.
• Parameter count: default = Array.length iovecs

writev_assume_fd_is_nonblocking fd ?count iovecs writes countiovecs of bigstrings to file descriptor fd without yielding to other OCaml-threads.

• Returns the number of bytes actually written.
• Raises Unix_error: in the case of output errors.
• Raises Invalid_argument: if the designated range is out of bounds.
• Parameter count: default = Array.length iovecs

recvmmsg_assume_fd_is_nonblocking fd iovecs ~count ~lens receives up to count messages into iovecs from file descriptor fd without yielding to other OCaml threads. If ~count is supplied, it must be that 0 <= count <= Array.length iovecs. If ~srcs is supplied, save the source addresses for corresponding received messages there. If supplied, Array.length srcs must be >= count. Save the lengths of the received messages in lens. It is required that Array.length lens >= count.

If an IOVec isn't long enough for its corresponding message, excess bytes may be discarded, depending on the type of socket the message is received from. While the recvmmsg system call itself does return details of such truncation, etc., those details are not (yet) passed through this interface.

• See recvmmsg(2)re. the underlying system call.
• Returns the number of messages actually read, or a negative number to indicate EWOULDBLOCK or EAGAIN. This is a compromise to mitigate the exception overhead for what ends up being a very common result with our use of recvmmsg.
• Raises Unix_error: in the case of output errors.
• Raises Invalid_argument: if the designated range is out of bounds.
• Parameter count: default = Array.length iovecs

sendmsg_nonblocking_no_sigpipe sock ?count iovecs sends countiovecs of bigstrings to socket sock.

• Returns Some bytes_written, or None if the operation would have blocked. This system call will not cause signal SIGPIPE if an attempt is made to write to a socket that was closed by the other side.
• Raises Unix_error: in the case of output errors.
• Raises Invalid_argument: if count is out of range.
• Parameter count: default = Array.length iovecs

output ?min_len oc ?pos ?len bstr tries to output len bytes (guarantees to write at least min_len bytes (must be equal to or greater than zero), if possible, before returning) from bigstring bstr starting at position pos to output channel oc.

• Returns the number of bytes actually written.

  NOTE: you may need to flush oc to make sure that the data is actually sent.

  NOTE: if len characters fit into the channel buffer completely, they will be buffered. Otherwise writes will be attempted until at least min_len characters have been sent.

• Raises Invalid_argument: if the designated range is out of bounds.
• Raises IOError: in the case of output errors. The IOError-argument counting the number of successful bytes includes those that have been transferred to the channel buffer before the error.
• Parameter pos: default = 0
• Parameter min_len: default = 0
• Parameter len: default = length bstr - pos

really_output oc ?pos ?len bstr outputs exactly len bytes from bigstring bstr starting at position pos to output channel oc.

• Raises Invalid_argument: if the designated range is out of bounds.
• Raises IOError: in the case of output errors. The IOError-argument counting the number of successful bytes includes those that have been transferred to the channel buffer before the error.
• Parameter pos: default = 0
• Parameter len: default = length bstr - pos

unsafe_read_assume_fd_is_nonblocking fd ~pos ~len bstr similar to Bigstring.read_assume_fd_is_nonblocking, but does not perform any bounds checks. Will crash on bounds errors!

unsafe_write fd ~pos ~len bstr similar to Bigstring.write, but does not perform any bounds checks. Will crash on bounds errors!

unsafe_write_assume_fd_is_nonblocking fd ~pos ~len bstr similar to Bigstring.write_assume_fd_is_nonblocking, but does not perform any bounds checks. Will crash on bounds errors!

unsafe_read ~min_len fd ~pos ~len bstr similar to Bigstring.read, but does not perform any bounds checks. Will crash on bounds errors!

unsafe_really_recv sock ~pos ~len bstr similar to Bigstring.really_recv, but does not perform any bounds checks. Will crash on bounds errors!

unsafe_really_write fd ~pos ~len bstr similar to Bigstring.write, but does not perform any bounds checks. Will crash on bounds errors!

unsafe_really_send_no_sigpipe sock ~pos ~len bstr similar to Bigstring.send, but does not perform any bounds checks. Will crash on bounds errors!

unsafe_send_nonblocking_no_sigpipe sock ~pos ~len bstr similar to Bigstring.send_nonblocking_no_sigpipe, but does not perform any bounds checks. Will crash on bounds errors!

unsafe_writev fd iovecs count similar to Bigstring.writev, but does not perform any bounds checks. Will crash on bounds errors!

unsafe_sendmsg_nonblocking_no_sigpipe fd iovecs count similar to Bigstring.sendmsg_nonblocking_no_sigpipe, but does not perform any bounds checks. Will crash on bounds errors!

unsafe_input ~min_len ic ~pos ~len bstr similar to Bigstring.input, but does not perform any bounds checks. Will crash on bounds errors!

unsafe_output ~min_len oc ~pos ~len bstr similar to Bigstring.output, but does not perform any bounds checks. Will crash on bounds errors!

map_file shared fd n memory-maps n characters of the data associated with descriptor fd to a bigstring. Iff shared is true, all changes to the bigstring will be reflected in the file.

Users must keep in mind that operations on the resulting bigstring may result in disk operations which block the runtime. This is true for pure OCaml operations (such as t.

<- 1), and for calls to blit. While some I/O operations may release the OCaml lock, users should not expect this to be done for all operations on a bigstring returned from map_file.