io/file/open.fz
# This file is part of the Fuzion language implementation.
#
# The Fuzion language implementation is free software: you can redistribute it
# and/or modify it under the terms of the GNU General Public License as published
# by the Free Software Foundation, version 3 of the License.
#
# The Fuzion language implementation is distributed in the hope that it will be
# useful, but WITHOUT ANY WARRANTY; without even the implied warranty of
# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public
# License for more details.
#
# You should have received a copy of the GNU General Public License along with The
# Fuzion language implementation. If not, see <https://www.gnu.org/licenses/>.
# -----------------------------------------------------------------------
#
# Tokiwa Software GmbH, Germany
#
# Source code of Fuzion standard library feature io.file.open
#
# -----------------------------------------------------------------------
# effect for manipulating open files
# T is used to distinguish several open files
#
module:public open(public T type,
private fd i64,
public file_name String) : simple_effect is
# writes the content of an array of bytes to a file opened as fd
#
# this might overwrite parts or all of an existing file.
#
public write(content Sequence u8) ! io.file.write =>
io.file.write.write fd content.as_array
# reads all bytes from the file in the path
# returns outcome array u8, a byte array representing the content of the file if the operation was successful
# returns an error in case the operation fails
#
public read outcome (array u8) ! io.file.read =>
io.file.read.read_file fd
# seek in file
#
public seek(
# the offset to seek from the beginning of the stream pointer
offset i64) =>
io.file.seek.seek fd offset
# get the current byte position in the file
#
public file_position =>
io.file.seek.file_position fd
# install mmap effect an run code
#
# note: the offset must be a multiple of the pagesize which usually is 4096, windows 65536?
# note: offset+size must not exceed size of file
#
# example usage:
# _ := io.file.use unit "/some_file" io.file.mode.append ()->
# io.file.open.mmap (i64 0) (i64 100) ()->
# io.file.open.mmap[99] := 42
#
public mmap(R type, offset i64, size i64, code mapped_buffer->R) outcome R
pre offset % 4096 = 0 # NYI get real page size instead of 4096.
=>
arr := fuzion.sys.internal_array_init i32 1
mapped_memory := fuzion.sys.fileio.mmap fd offset size arr.data
res := arr.as_array
if res[0] = -1
error "mmap failed"
else
r := code (mapped_buffer mapped_memory size)
if fuzion.sys.fileio.munmap mapped_memory size = 0
r
else
error "error closing the memory mapped file"
# get a byte from a given mapped buffer
#
module mapped_buffer_get(memory fuzion.sys.Pointer, i i64) =>
open.this.env.replace
fuzion.sys.fileio.mapped_buffer_get memory i
# set a byte of a given mapped buffer
#
module mapped_buffer_set(memory fuzion.sys.Pointer, i i64, o u8) =>
open.this.env.replace
fuzion.sys.fileio.mapped_buffer_set memory i o
# mapped buffer gives access to the memory region a file is mapped
# to via `mmap`.
#
module:public mapped_buffer
(# internal pointer to the mapped memory
private memory fuzion.sys.Pointer,
# the length of this buffer
public length i64
)
: container.Buffer u8 (io.file.open T) is
# get byte at given index i
#
public index [ ] (i i64) u8 ! open T
pre
safety: i64 0 ≤ i < length
=>
mapped_buffer_get memory i
# set byte at given index i to given value o
#
public set [ ] (i i64, o u8) unit ! io.file.open T
pre
safety: i64 0 ≤ i < length
=>
mapped_buffer_set memory i o
# short hand to get the currently
# installed open effect
# for type T from the environment.
# see `use` on how to use this.
#
public open(T type) =>
(open T).env
# unit type used internally by open- and use-
# short hands which can be used when one does not need
# to distinguish between several open files.
private:public open_unique_type is
# short hand to get the currently
# installed open effect
# from the environment.
# see `use` on how to use this.
#
public open =>
(open open_unique_type).env