cqfn/eo

# The MIT License (MIT)
#
# Copyright (c) 2016-2024 Objectionary.com
#
# Permission is hereby granted, free of charge, to any person obtaining a copy
# of this software and associated documentation files (the "Software"), to deal
# in the Software without restriction, including without limitation the rights
# to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
# copies of the Software, and to permit persons to whom the Software is
# furnished to do so, subject to the following conditions:
#
# The above copyright notice and this permission notice shall be included
# in all copies or substantial portions of the Software.
#
# THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
# IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
# FITNESS FOR A PARTICULAR PURPOSE AND NON-INFRINGEMENT. IN NO EVENT SHALL THE
# AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
# LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
# OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
# SOFTWARE.

+architect yegor256@gmail.com
+home https://github.com/objectionary/eo
+package org.eolang
+rt jvm org.eolang:eo-runtime:0.0.0
+version 0.0.0

# The `malloc` object is an abstraction of a storage of data in heap
# memory. The implementation of `malloc` is platform dependent. It may
# use either OS-level or VM-level memory management mechanism.
#
# There are two ways of usage `malloc`:
#
# First, when the size of required memory block is known upfront:
#
# ```
# malloc.of
#   8
#   [m]
#     m.put 10 > @
# ```
#
# Here, the first argument is a size of allocated block in memory, the second argument
# is the scope where memory block is available for reading and writing. When `malloc.of` is
# dataized it dataizes the scope, take the data from the block in memory, clears the block and
# returns the data. So there's no need for end-user to care about clearing memory after allocation.
#
# Second, when the size is not known upfront, but there exists
# an object ready to be dataized and placed into the memory block
# (the size of the block will be equal to the amount of bytes
# produced by the dataization of the object):
#
# ```
# malloc.for
#   "Hello world!"
#   [m]
#     m.put "Hello, Jeff!" > @
# ```
#
# Here, the first argument is an object which will be dataized, then a block in memory of given data
# size is allocated and the data is written to the block. The second argument is the same scope as
# in the p.1.
#
# The void attribute in the scope object is memory-block object which provides API to write and read
# data to the memory.
#
# ```
# malloc.of
#   8                         # allocate 8 bytes length block in memory
#   [m]
#     seq > @
#       *
#         m.write 2 "Hello"   # write object "Hello" with offset 2
#         m.read 3 4          # read 4 bytes from offset 3 -> "ello"
#         m.put 42            # write object 42 with offset 0
#         m.get               # just get all the data from the memory block -> 42
#         m.size              # get size of the block
#         m.id                # get identifier of the block
#         m.@                 # the same as m.get
# ```
[] > malloc
  # Allocates block in memory for given `object`. After allocation the provided object is dataized
  # and the data are written into memory.
  [object scope] > for
    (dataized object).as-bytes > bts
    malloc.of > @
      bts.size
      [m] >>
        seq > @
          *
            m.write 0 ^.bts
            ^.scope m

  # Allocates block in memory of given `size`. After allocation the `size` zero bytes bytes are
  # written into memory.
  [size scope] > of
    [] > @ /bytes

    # Allocated block in memory that provides an API for writing and reading.
    [id] > allocated
      ^.size > size
      get > @

      # Read `length` bytes with `offset` from the allocated block in memory.
      [offset length] > read /bytes

      # Write `data` with `offset` to the allocated block in memory.
      [offset data] > write /true

      # Just get all the data from the allocated block in memory.
      ^.read 0 ^.size > [] > get

      # Put `object` into the allocated block in memory. The `object` is supposed to be dataizable.
      [object] > put
        seq > @
          *
            ^.write 0 object
            ^.get