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Unified Diff: pkg/compiler/lib/src/io/line_column_provider.dart

Issue 830703004: Emit to StreamCodeOutput instead of CodeBuffer. (Closed) Base URL: https://dart.googlecode.com/svn/branches/bleeding_edge/dart
Patch Set: Updated cf. comments Created 5 years, 11 months ago
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Index: pkg/compiler/lib/src/io/line_column_provider.dart
diff --git a/pkg/compiler/lib/src/io/line_column_provider.dart b/pkg/compiler/lib/src/io/line_column_provider.dart
new file mode 100644
index 0000000000000000000000000000000000000000..5aa700cca4a738e5a909b00bf1e7e1c7070a678a
--- /dev/null
+++ b/pkg/compiler/lib/src/io/line_column_provider.dart
@@ -0,0 +1,73 @@
+// Copyright (c) 2012, 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.
+
+library dart2js.io.line_column;
+
+import 'code_output.dart';
+
+/// Interface for providing line/column information.
+abstract class LineColumnProvider {
+ /// Returns the line number (0-based) for [offset].
+ int getLine(int offset);
+
+ /// Returns the column number (0-based) for [offset] at the given [line].
+ int getColumn(int line, int offset);
+}
+
+/// [CodeOutputListener] that collects line information.
+class LineColumnCollector extends CodeOutputListener
+ implements LineColumnProvider {
+ int lastLineStart = 0;
+ List<int> lineStarts = <int>[0];
+
+ void _collect(String text) {
+ int offset = lastLineStart;
+ int index = 0;
+ while (index < text.length) {
+ // Unix uses '\n' and Windows uses '\r\n', so this algorithm works for
+ // both platforms.
+ index = text.indexOf('\n', index) + 1;
+ if (index <= 0) break;
+ lastLineStart = offset + index;
+ lineStarts.add(lastLineStart);
+ }
+ }
+
+ @override
+ void onText(String text) {
+ _collect(text);
+ }
+
+ @override
+ int getLine(int offset) {
+ List<int> starts = lineStarts;
+ if (offset < 0 || starts.last <= offset) {
+ throw 'bad position #$offset in buffer with length ${lineStarts.last}.';
+ }
+ int first = 0;
+ int count = starts.length;
+ while (count > 1) {
+ int step = count ~/ 2;
+ int middle = first + step;
+ int lineStart = starts[middle];
+ if (offset < lineStart) {
+ count = step;
+ } else {
+ first = middle;
+ count -= step;
+ }
+ }
+ return first;
+ }
+
+ @override
+ int getColumn(int line, int offset) {
+ return offset - lineStarts[line];
+ }
+
+ @override
+ void onDone(int length) {
+ lineStarts.add(length);
+ }
+}
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