Module Stdlib.Buffer

Contents

Instructions: Use this module in your project

In the IDE (CLion, Visual Studio Code, Xcode, etc.) you use for your DkSDK project:

  1. Add the following to your project's dependencies/CMakeLists.txt:

    Copy
    DkSDKProject_DeclareAvailable(ocaml
        CONSTRAINT "= 4.14.0"
        FINDLIBS str unix runtime_events threads dynlink)
    DkSDKProject_MakeAvailable(ocaml)
  2. Add the Findlib::ocaml library to any desired targets in src/*/CMakeLists.txt:

    Copy
    target_link_libraries(YourPackage_YourLibraryName
         # ... existing libraries, if any ...
         Findlib::ocaml)
  3. Click your IDE's Build button

Not using DkSDK?

FIRST, do one or all of the following:

  1. Run:

    Copy
    opam install ocaml.4.14.0
  2. Edit your dune-project and add:

    Copy
    (package
      (name YourExistingPackage)
      (depends
      ; ... existing dependenices ...
      (ocaml (>= 4.14.0))))

    Then run:

    Copy
    dune build *.opam # if this fails, run: dune build
  3. Edit your <package>.opam file and add:

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    depends: [
      # ... existing dependencies ...
      "ocaml" {>= "4.14.0"}
    ]

    Then run:

    Copy
    opam install . --deps-only

FINALLY, add the library to any desired (library)and/or (executable) targets in your **/dune files:

Copy
(library
  (name YourLibrary)
  ; ... existing library options ...
  (libraries
    ; ... existing libraries ...
    ))

(executable
  (name YourExecutable)
  ; ... existing executable options ...
  (libraries
    ; ... existing libraries ...
    ))
type t

The abstract type of buffers.

valcreate : ``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.

valcontents :t -> string

Return a copy of the current contents of the buffer. The buffer itself is unchanged.

valto_bytes :t -> bytes

Return a copy of the current contents of the buffer. The buffer itself is unchanged.

  • since 4.02
valsub :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.

  • raises Invalid_argument

    if off and len do not designate a valid range of b.

valblit :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.

  • raises Invalid_argument

    if srcoff and len do not designate a valid range of src, or if dstoff and len do not designate a valid range of dst.

  • since 3.11.2

valnth :t ->``int-> char

Get the n-th character of the buffer.

  • raises Invalid_argument

    if index out of bounds

vallength :t -> int

Return the number of characters currently contained in the buffer.

valclear :t -> unit

Empty the buffer.

valreset :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.

valoutput_buffer :out_channel -> t -> unit

output_buffer oc b writes the current contents of buffer b on the output channel oc.

valtruncate :t ->``int-> unit

truncate b len truncates the length of b to len Note: the internal byte sequence is not shortened.

  • raises Invalid_argument

    if len < 0 or len > length b.

  • since 4.05.0

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.

valadd_char :t ->``char-> unit

add_char b c appends the character c at the end of buffer b.

valadd_utf_8_uchar :t -> Uchar.t -> unit

add_utf_8_uchar b u appends the UTF-8 encoding of u at the end of buffer b.

  • since 4.06.0
valadd_utf_16le_uchar :t -> Uchar.t -> unit

add_utf_16le_uchar b u appends the UTF-16LE encoding of u at the end of buffer b.

  • since 4.06.0
valadd_utf_16be_uchar :t -> Uchar.t -> unit

add_utf_16be_uchar b u appends the UTF-16BE encoding of u at the end of buffer b.

  • since 4.06.0
valadd_string :t ->``string-> unit

add_string b s appends the string s at the end of buffer b.

valadd_bytes :t ->``bytes-> unit

add_bytes b s appends the byte sequence s at the end of buffer b.

  • since 4.02
valadd_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.

  • raises Invalid_argument

    if ofs and len do not designate a valid range of s.

valadd_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.

  • raises Invalid_argument

    if ofs and len do not designate a valid range of s.

  • since 4.02

valadd_substitute :t ->``(``string->string)``->``string-> unit

add_substitute b f s appends the string pattern s at the end of buffer b with substitution. The substitution process looks for variables into the pattern and substitutes each variable name by its value, as obtained by applying the mapping f to the variable name. Inside the string pattern, a variable name immediately follows a non-escaped $ character and is one of the following:

  • a non empty sequence of alphanumeric or _ characters,

  • an arbitrary sequence of characters enclosed by a pair of matching parentheses or curly brackets. An escaped $ character is a $ that immediately follows a backslash character; it then stands for a plain $.

  • raises Not_found

    if the closing character of a parenthesized variable cannot be found.

valadd_buffer :t -> t -> unit

add_buffer b1 b2 appends the current contents of buffer b2 at the end of buffer b1. b2 is not modified.

valadd_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.

  • raises End_of_file

    if the channel contains fewer than n characters. In this case, the characters are still added to the buffer, so as to avoid loss of data.

  • raises Invalid_argument

    if len < 0 or len > Sys.max_string_length.

Buffers and Sequences

valto_seq :t ->``charSeq.t

Iterate on the buffer, in increasing order.

The behavior is not specified if the buffer is modified during iteration.

  • since 4.07
valto_seqi :t ->``(int * char)``Seq.t

Iterate on the buffer, in increasing order, yielding indices along chars.

The behavior is not specified if the buffer is modified during iteration.

  • since 4.07
valadd_seq :t ->``charSeq.t -> unit

Add chars to the buffer

  • since 4.07
valof_seq : ``charSeq.t -> t

Create a buffer from the generator

  • since 4.07

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.

valadd_uint8 :t ->``int-> unit

add_uint8 b i appends a binary unsigned 8-bit integer i to b.

  • since 4.08
valadd_int8 :t ->``int-> unit

add_int8 b i appends a binary signed 8-bit integer i to b.

  • since 4.08
valadd_uint16_ne :t ->``int-> unit

add_uint16_ne b i appends a binary native-endian unsigned 16-bit integer i to b.

  • since 4.08
valadd_uint16_be :t ->``int-> unit

add_uint16_be b i appends a binary big-endian unsigned 16-bit integer i to b.

  • since 4.08
valadd_uint16_le :t ->``int-> unit

add_uint16_le b i appends a binary little-endian unsigned 16-bit integer i to b.

  • since 4.08
valadd_int16_ne :t ->``int-> unit

add_int16_ne b i appends a binary native-endian signed 16-bit integer i to b.

  • since 4.08
valadd_int16_be :t ->``int-> unit

add_int16_be b i appends a binary big-endian signed 16-bit integer i to b.

  • since 4.08
valadd_int16_le :t ->``int-> unit

add_int16_le b i appends a binary little-endian signed 16-bit integer i to b.

  • since 4.08
valadd_int32_ne :t ->``int32-> unit

add_int32_ne b i appends a binary native-endian 32-bit integer i to b.

  • since 4.08
valadd_int32_be :t ->``int32-> unit

add_int32_be b i appends a binary big-endian 32-bit integer i to b.

  • since 4.08
valadd_int32_le :t ->``int32-> unit

add_int32_le b i appends a binary little-endian 32-bit integer i to b.

  • since 4.08
valadd_int64_ne :t ->``int64-> unit

add_int64_ne b i appends a binary native-endian 64-bit integer i to b.

  • since 4.08
valadd_int64_be :t ->``int64-> unit

add_int64_be b i appends a binary big-endian 64-bit integer i to b.

  • since 4.08
valadd_int64_le :t ->``int64-> unit

add_int64_ne b i appends a binary little-endian 64-bit integer i to b.

  • since 4.08

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          1. Module type Logs_lwt.LOG
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            1. Module type Lwt_io.NumberIO
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