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Unified Diff: pkg/source_maps/lib/src/vlq.dart

Issue 814113004: Pull args, intl, logging, shelf, and source_maps out of the SDK. (Closed) Base URL: https://dart.googlecode.com/svn/branches/bleeding_edge/dart
Patch Set: Also csslib. Created 6 years ago
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Index: pkg/source_maps/lib/src/vlq.dart
diff --git a/pkg/source_maps/lib/src/vlq.dart b/pkg/source_maps/lib/src/vlq.dart
deleted file mode 100644
index e4ab4eb69c5aa28dc2009c560623344a7f43bcb0..0000000000000000000000000000000000000000
--- a/pkg/source_maps/lib/src/vlq.dart
+++ /dev/null
@@ -1,103 +0,0 @@
-// Copyright (c) 2013, 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.
-
-
-/// Utilities to encode and decode VLQ values used in source maps.
-///
-/// Sourcemaps are encoded with variable length numbers as base64 encoded
-/// strings with the least significant digit coming first. Each base64 digit
-/// encodes a 5-bit value (0-31) and a continuation bit. Signed values can be
-/// represented by using the least significant bit of the value as the sign bit.
-///
-/// For more details see the source map [version 3 documentation][spec].
-/// [spec]: https://docs.google.com/a/google.com/document/d/1U1RGAehQwRypUTovF1KRlpiOFze0b-_2gc6fAH0KY0k/edit
-library source_maps.src.vlq;
-
-import 'dart:math';
-
-const int VLQ_BASE_SHIFT = 5;
-
-const int VLQ_BASE_MASK = (1 << 5) - 1;
-
-const int VLQ_CONTINUATION_BIT = 1 << 5;
-
-const int VLQ_CONTINUATION_MASK = 1 << 5;
-
-const String BASE64_DIGITS =
- 'ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/';
-
-final Map<String, int> _digits = () {
- var map = <String, int>{};
- for (int i = 0; i < 64; i++) {
- map[BASE64_DIGITS[i]] = i;
- }
- return map;
-}();
-
-final int MAX_INT32 = pow(2, 31) - 1;
-final int MIN_INT32 = -pow(2, 31);
-
-/// Creates the VLQ encoding of [value] as a sequence of characters
-Iterable<String> encodeVlq(int value) {
- if (value < MIN_INT32 || value > MAX_INT32) {
- throw new ArgumentError('expected 32 bit int, got: $value');
- }
- var res = <String>[];
- int signBit = 0;
- if (value < 0) {
- signBit = 1;
- value = -value;
- }
- value = (value << 1) | signBit;
- do {
- int digit = value & VLQ_BASE_MASK;
- value >>= VLQ_BASE_SHIFT;
- if (value > 0) {
- digit |= VLQ_CONTINUATION_BIT;
- }
- res.add(BASE64_DIGITS[digit]);
- } while (value > 0);
- return res;
-}
-
-/// Decodes a value written as a sequence of VLQ characters. The first input
-/// character will be `chars.current` after calling `chars.moveNext` once. The
-/// iterator is advanced until a stop character is found (a character without
-/// the [VLQ_CONTINUATION_BIT]).
-int decodeVlq(Iterator<String> chars) {
- int result = 0;
- bool stop = false;
- int shift = 0;
- while (!stop) {
- if (!chars.moveNext()) throw new StateError('incomplete VLQ value');
- var char = chars.current;
- if (!_digits.containsKey(char)) {
- throw new FormatException('invalid character in VLQ encoding: $char');
- }
- var digit = _digits[char];
- stop = (digit & VLQ_CONTINUATION_BIT) == 0;
- digit &= VLQ_BASE_MASK;
- result += (digit << shift);
- shift += VLQ_BASE_SHIFT;
- }
-
- // Result uses the least significant bit as a sign bit. We convert it into a
- // two-complement value. For example,
- // 2 (10 binary) becomes 1
- // 3 (11 binary) becomes -1
- // 4 (100 binary) becomes 2
- // 5 (101 binary) becomes -2
- // 6 (110 binary) becomes 3
- // 7 (111 binary) becomes -3
- bool negate = (result & 1) == 1;
- result = result >> 1;
- result = negate ? -result : result;
-
- // TODO(sigmund): can we detect this earlier?
- if (result < MIN_INT32 || result > MAX_INT32) {
- throw new FormatException(
- 'expected an encoded 32 bit int, but we got: $result');
- }
- return result;
-}
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