module Opal::SourceMap::VLQ
Ported from github.com/maccman/sourcemap
Adopted from ConradIrwin/ruby-source_map
https://github.com/ConradIrwin/ruby-source_map/blob/master/lib/source_map/vlq.rb
Resources
http://en.wikipedia.org/wiki/Variable-length_quantity https://docs.google.com/document/d/1U1RGAehQwRypUTovF1KRlpiOFze0b-_2gc6fAH0KY0k/edit https://github.com/mozilla/source-map/blob/master/lib/source-map/base64-vlq.js
Constants
- BASE64_DIGITS
- BASE64_VALUES
- VLQ_BASE
- VLQ_BASE_MASK
- VLQ_BASE_SHIFT
- VLQ_CONTINUATION_BIT
Public Class Methods
decode(str)
click to toggle source
Public: Decode a VLQ
string.
str - VLQ
encoded String
Returns an Array of Integers.
# File lib/opal/source_map/vlq.rb, line 47 def self.decode(str) result = [] chars = str.split('') while chars.any? vlq = 0 shift = 0 continuation = true while continuation char = chars.shift raise ArgumentError unless char digit = BASE64_VALUES[char] continuation = false if (digit & VLQ_CONTINUATION_BIT) == 0 digit &= VLQ_BASE_MASK vlq += digit << shift shift += VLQ_BASE_SHIFT end result << (vlq & 1 == 1 ? -(vlq >> 1) : vlq >> 1) end result end
decode_mappings(str)
click to toggle source
Public: Decode a VLQ
string into mapping numbers.
str - VLQ
encoded String
Returns an two dimensional Array of Integers.
# File lib/opal/source_map/vlq.rb, line 86 def self.decode_mappings(str) mappings = [] str.split(';').each_with_index do |group, index| mappings[index] = [] group.split(',').each do |segment| mappings[index] << decode(segment) end end mappings end
encode(ary)
click to toggle source
Public: Encode a list of numbers into a compact VLQ
string.
ary - An Array of Integers
Returns a VLQ
String.
# File lib/opal/source_map/vlq.rb, line 26 def self.encode(ary) result = [] ary.each do |n| vlq = n < 0 ? ((-n) << 1) + 1 : n << 1 loop do digit = vlq & VLQ_BASE_MASK vlq >>= VLQ_BASE_SHIFT digit |= VLQ_CONTINUATION_BIT if vlq > 0 result << BASE64_DIGITS[digit] break unless vlq > 0 end end result.join end
encode_mappings(ary)
click to toggle source
Public: Encode a mapping array into a compact VLQ
string.
ary - Two dimensional Array of Integers.
Returns a VLQ
encoded String seperated by , and ;.
# File lib/opal/source_map/vlq.rb, line 73 def self.encode_mappings(ary) ary.map { |group| group.map { |segment| encode(segment) }.join(',') }.join(';') end