package links
include module type of struct include Buffer end
Unsynchronized accesses
Unsynchronized accesses to a buffer may lead to an invalid buffer state. Thus, concurrent accesses to a buffer must be synchronized (for instance with a Mutex.t
).
type t = Buffer.t
The abstract type of buffers.
val create : int -> t
create n
returns a fresh buffer, initially empty. The n
parameter is the initial size of the internal byte sequence that holds the buffer contents. That byte sequence is automatically reallocated when more than n
characters are stored in the buffer, but shrinks back to n
characters when reset
is called. For best performance, n
should be of the same order of magnitude as the number of characters that are expected to be stored in the buffer (for instance, 80 for a buffer that holds one output line). Nothing bad will happen if the buffer grows beyond that limit, however. In doubt, take n = 16
for instance. If n
is not between 1 and Sys.max_string_length
, it will be clipped to that interval.
val contents : t -> string
Return a copy of the current contents of the buffer. The buffer itself is unchanged.
val to_bytes : t -> bytes
Return a copy of the current contents of the buffer. The buffer itself is unchanged.
val sub : t -> int -> int -> string
Buffer.sub b off len
returns a copy of len
bytes from the current contents of the buffer b
, starting at offset off
.
val blit : t -> int -> bytes -> int -> int -> unit
Buffer.blit src srcoff dst dstoff len
copies len
characters from the current contents of the buffer src
, starting at offset srcoff
to dst
, starting at character dstoff
.
val nth : t -> int -> char
Get the n-th character of the buffer.
val length : t -> int
Return the number of characters currently contained in the buffer.
val clear : t -> unit
Empty the buffer.
val reset : t -> unit
Empty the buffer and deallocate the internal byte sequence holding the buffer contents, replacing it with the initial internal byte sequence of length n
that was allocated by Buffer.create
n
. For long-lived buffers that may have grown a lot, reset
allows faster reclamation of the space used by the buffer.
val output_buffer : out_channel -> t -> unit
output_buffer oc b
writes the current contents of buffer b
on the output channel oc
.
val truncate : t -> int -> unit
truncate b len
truncates the length of b
to len
Note: the internal byte sequence is not shortened.
Appending
Note: all add_*
operations can raise Failure
if the internal byte sequence of the buffer would need to grow beyond Sys.max_string_length
.
val add_char : t -> char -> unit
add_char b c
appends the character c
at the end of buffer b
.
add_utf_8_uchar b u
appends the UTF-8 encoding of u
at the end of buffer b
.
add_utf_16le_uchar b u
appends the UTF-16LE encoding of u
at the end of buffer b
.
add_utf_16be_uchar b u
appends the UTF-16BE encoding of u
at the end of buffer b
.
val add_string : t -> string -> unit
add_string b s
appends the string s
at the end of buffer b
.
val add_bytes : t -> bytes -> unit
add_bytes b s
appends the byte sequence s
at the end of buffer b
.
val add_substring : t -> string -> int -> int -> unit
add_substring b s ofs len
takes len
characters from offset ofs
in string s
and appends them at the end of buffer b
.
val add_subbytes : t -> bytes -> int -> int -> unit
add_subbytes b s ofs len
takes len
characters from offset ofs
in byte sequence s
and appends them at the end of buffer b
.
add_buffer b1 b2
appends the current contents of buffer b2
at the end of buffer b1
. b2
is not modified.
val add_channel : t -> in_channel -> int -> unit
add_channel b ic n
reads at most n
characters from the input channel ic
and stores them at the end of buffer b
.
Buffers and Sequences
Iterate on the buffer, in increasing order.
The behavior is not specified if the buffer is modified during iteration.
Iterate on the buffer, in increasing order, yielding indices along chars.
The behavior is not specified if the buffer is modified during iteration.
Binary encoding of integers
The functions in this section append binary encodings of integers to buffers.
Little-endian (resp. big-endian) encoding means that least (resp. most) significant bytes are stored first. Big-endian is also known as network byte order. Native-endian encoding is either little-endian or big-endian depending on Sys.big_endian
.
32-bit and 64-bit integers are represented by the int32
and int64
types, which can be interpreted either as signed or unsigned numbers.
8-bit and 16-bit integers are represented by the int
type, which has more bits than the binary encoding. Functions that encode these values truncate their inputs to their least significant bytes.
val add_uint8 : t -> int -> unit
add_uint8 b i
appends a binary unsigned 8-bit integer i
to b
.
val add_int8 : t -> int -> unit
add_int8 b i
appends a binary signed 8-bit integer i
to b
.
val add_uint16_ne : t -> int -> unit
add_uint16_ne b i
appends a binary native-endian unsigned 16-bit integer i
to b
.
val add_uint16_be : t -> int -> unit
add_uint16_be b i
appends a binary big-endian unsigned 16-bit integer i
to b
.
val add_uint16_le : t -> int -> unit
add_uint16_le b i
appends a binary little-endian unsigned 16-bit integer i
to b
.
val add_int16_ne : t -> int -> unit
add_int16_ne b i
appends a binary native-endian signed 16-bit integer i
to b
.
val add_int16_be : t -> int -> unit
add_int16_be b i
appends a binary big-endian signed 16-bit integer i
to b
.
val add_int16_le : t -> int -> unit
add_int16_le b i
appends a binary little-endian signed 16-bit integer i
to b
.
val add_int32_ne : t -> int32 -> unit
add_int32_ne b i
appends a binary native-endian 32-bit integer i
to b
.
val add_int32_be : t -> int32 -> unit
add_int32_be b i
appends a binary big-endian 32-bit integer i
to b
.
val add_int32_le : t -> int32 -> unit
add_int32_le b i
appends a binary little-endian 32-bit integer i
to b
.
val add_int64_ne : t -> int64 -> unit
add_int64_ne b i
appends a binary native-endian 64-bit integer i
to b
.
val add_int64_be : t -> int64 -> unit
add_int64_be b i
appends a binary big-endian 64-bit integer i
to b
.
val add_int64_le : t -> int64 -> unit
add_int64_ne b i
appends a binary little-endian 64-bit integer i
to b
.
val add_substitute : t -> (string -> string) -> string -> unit