An IO buffer is an array of bytes
b0 b1 b2 ... br ... bw ... bn-1
^ ^ ^
rp wp n
rp: read pointer
wp: write pointer
n: size of the buffer
Invariant: 0 <= rp <= wp <= n
rp = wp: no more to read
wp = n: buffer is fullval alloc : int -> talloc size allocates an io buffer of size and set its read pointer and write pointer to 0.
val getc : t -> char optiongetc b reads the character at the read pointer of the buffer b, advances the read pointer and returns the character. If the read pointer is at the position of the write pointer, then None is retured.
val putc : t -> char -> unit optionputc b ch appends the character c at the position of the write pointer and advances the write pointer. If the write pointer is already at the end None is returned.
val capacity : t -> intThe capacity of the buffer.
val length : t -> intThe length of the content of the buffer.
val read_pointer : t -> intPosition of the next character to read.
val write_pointer : t -> intPosition of the next character to write.
val is_empty : t -> boolIs the buffer empty? read_pointer = write_pointer
val is_full : t -> boolIs the buffer full?
val reset : t -> unitSet the read and the write pointer to zero.
val set_read_pointer : t -> int -> unitSet the read pointer.
val set_write_pointer : t -> int -> unitSet the write pointer.
copy src s0 s1 dst d0 copies the data from the buffer src between position s0 and s1 (excluding s1 to the buffer dst starting at position d0. Overlapping is handled properly.
module Read (W : Fmlib.Module_types.WRITABLE) : sig ... endmodule Write (R : Fmlib.Module_types.READABLE) : sig ... end