pkgs/io_file/lib/src/internal_constants.dart

// Copyright (c) 2025, the Dart project authors.  Please see the AUTHORS file
// for details. All rights reserved. Use of this source code is governed by a
// BSD-style license that can be found in the LICENSE file.

/// The maximum number of bytes to read in a single call to `read`.
///
/// On macOS, it is an error to call
/// `read/_read(fildes, buf, nbyte)` with `nbyte >= INT_MAX`.
///
/// The POSIX specification states that the behavior of `read` is
/// implementation-defined if `nbyte > SSIZE_MAX`. On Linux, the `read` will
/// transfer at most 0x7ffff000 bytes and return the number of bytes actually.
/// transfered.
///
//// A smaller value has the advantage of making vm-service clients
/// (e.g. debugger) more responsive.
///
/// A bigger value reduces the number of system calls.
const int maxReadSize = 16 * 1024 * 1024; // 16MB.

/// If the size of a file is unknown, read in blocks of this size.
const int blockSize = 64 * 1024;

/// The maximum number of bytes to read in a single call to `read`.
///
/// `write` on FreeBSD returns `EINVAL` if nbytes is greater than
/// `INT_MAX`.
/// See https://man.freebsd.org/cgi/man.cgi?write(2)
///
/// A smaller value has the advantage of making vm-service clients
/// (e.g. debugger) more responsive.
///
/// A bigger value reduces the number of system calls.
const int maxWriteSize = 16 * 1024 * 1024; // 16MB.