Ryan Macnak
e1f5039854
This assumption will soon become false with compressed pointers. TEST=ci Change-Id: Ia95ffdcd0c55d649190fcd4764dc3878ecdeb6a4 Reviewed-on: https://dart-review.googlesource.com/c/sdk/+/184540 Reviewed-by: Daco Harkes <dacoharkes@google.com> Commit-Queue: Ryan Macnak <rmacnak@google.com>
53 lines
1.7 KiB
Dart
53 lines
1.7 KiB
Dart
// Copyright (c) 2021, the Dart project authors. Please see the AUTHORS file
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// for details. All rights reserved. Use of this source code is governed by a
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// BSD-style license that can be found in the LICENSE file.
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import 'dart:convert';
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import 'dart:ffi';
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import 'dart:typed_data';
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import 'package:ffi/ffi.dart';
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extension Utf8InPool on String {
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/// Convert a [String] to a Utf8-encoded null-terminated C string.
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///
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/// If 'string' contains NULL bytes, the converted string will be truncated
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/// prematurely. See [Utf8Encoder] for details on encoding.
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///
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/// Returns a [allocator]-allocated pointer to the result.
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Pointer<Utf8> toUtf8(Allocator allocator) {
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final units = utf8.encode(this);
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final Pointer<Uint8> result = allocator<Uint8>(units.length + 1);
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final Uint8List nativeString = result.asTypedList(units.length + 1);
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nativeString.setAll(0, units);
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nativeString[units.length] = 0;
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return result.cast();
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}
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}
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extension Utf8Helpers on Pointer<Utf8> {
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/// The length of a null-terminated string — the number of (one-byte)
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/// characters before the first null byte.
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int get strlen {
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final Pointer<Uint8> array = this.cast<Uint8>();
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int length = 0;
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while (array[length] != 0) {
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length++;
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}
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return length;
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}
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/// Creates a [String] containing the characters UTF-8 encoded in [this].
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///
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/// [this] must be a zero-terminated byte sequence of valid UTF-8
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/// encodings of Unicode code points. See [Utf8Decoder] for details on
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/// decoding.
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///
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/// Returns a Dart string containing the decoded code points.
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String contents() {
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final int length = strlen;
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return utf8.decode(Uint8List.view(
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this.cast<Uint8>().asTypedList(length).buffer, 0, length));
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}
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}
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