1============
  2These pieces of code were ported from dotnet/corefx:
  3
  4syntax/charclass.go (from RegexCharClass.cs): ported to use the built-in Go unicode classes.  Canonicalize is 
  5    a direct port, but most of the other code required large changes because the C# implementation 
  6    used a string to represent the CharSet data structure and I cleaned that up in my implementation.
  7
  8syntax/code.go (from RegexCode.cs): ported literally with various cleanups and layout to make it more Go-ish.
  9
 10syntax/escape.go (from RegexParser.cs): ported Escape method and added some optimizations.  Unescape is inspired by 
 11    the C# implementation but couldn't be directly ported because of the lack of do-while syntax in Go.
 12
 13syntax/parser.go (from RegexpParser.cs and RegexOptions.cs): ported parser struct and associated methods as 
 14    literally as possible. Several language differences required changes.  E.g. lack pre/post-fix increments as 
 15    expressions, lack of do-while loops, lack of overloads, etc.
 16
 17syntax/prefix.go (from RegexFCD.cs and RegexBoyerMoore.cs): ported as literally as possible and added support
 18    for unicode chars that are longer than the 16-bit char in C# for the 32-bit rune in Go.
 19
 20syntax/replacerdata.go (from RegexReplacement.cs): conceptually ported and re-organized to handle differences 
 21    in charclass implementation, and fix odd code layout between RegexParser.cs, Regex.cs, and RegexReplacement.cs.
 22
 23syntax/tree.go (from RegexTree.cs and RegexNode.cs): ported literally as possible.
 24
 25syntax/writer.go (from RegexWriter.cs): ported literally with minor changes to make it more Go-ish.
 26
 27match.go (from RegexMatch.cs): ported, simplified, and changed to handle Go's lack of inheritence.
 28
 29regexp.go (from Regex.cs and RegexOptions.cs): conceptually serves the same "starting point", but is simplified 
 30    and changed to handle differences in C# strings and Go strings/runes.  
 31
 32replace.go (from RegexReplacement.cs): ported closely and then cleaned up to combine the MatchEvaluator and 
 33    simple string replace implementations.
 34
 35runner.go (from RegexRunner.cs): ported literally as possible.
 36
 37regexp_test.go (from CaptureTests.cs and GroupNamesAndNumbers.cs): conceptually ported, but the code was 
 38    manually structured like Go tests.
 39
 40replace_test.go (from RegexReplaceStringTest0.cs): conceptually ported
 41
 42rtl_test.go (from RightToLeft.cs): conceptually ported
 43---
 44dotnet/corefx was released under this license:
 45
 46The MIT License (MIT)
 47
 48Copyright (c) Microsoft Corporation
 49
 50Permission is hereby granted, free of charge, to any person obtaining a copy
 51of this software and associated documentation files (the "Software"), to deal
 52in the Software without restriction, including without limitation the rights
 53to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
 54copies of the Software, and to permit persons to whom the Software is
 55furnished to do so, subject to the following conditions:
 56
 57The above copyright notice and this permission notice shall be included in all
 58copies or substantial portions of the Software.
 59
 60THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
 61IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
 62FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
 63AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
 64LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
 65OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
 66SOFTWARE.
 67
 68============
 69These pieces of code are copied from the Go framework:
 70
 71- The overall directory structure of regexp2 was inspired by the Go runtime regexp package.
 72- The optimization in the escape method of syntax/escape.go is from the Go runtime QuoteMeta() func in regexp/regexp.go
 73- The method signatures in regexp.go are designed to match the Go framework regexp methods closely
 74- func regexp2.MustCompile and func quote are almost identifical to the regexp package versions
 75- BenchmarkMatch* and TestProgramTooLong* funcs in regexp_performance_test.go were copied from the framework 
 76    regexp/exec_test.go
 77---
 78The Go framework was released under this license:
 79
 80Copyright (c) 2012 The Go Authors. All rights reserved.
 81
 82Redistribution and use in source and binary forms, with or without
 83modification, are permitted provided that the following conditions are
 84met:
 85
 86   * Redistributions of source code must retain the above copyright
 87notice, this list of conditions and the following disclaimer.
 88   * Redistributions in binary form must reproduce the above
 89copyright notice, this list of conditions and the following disclaimer
 90in the documentation and/or other materials provided with the
 91distribution.
 92   * Neither the name of Google Inc. nor the names of its
 93contributors may be used to endorse or promote products derived from
 94this software without specific prior written permission.
 95
 96THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
 97"AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
 98LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
 99A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
100OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
101SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
102LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
103DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
104THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
105(INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
106OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
107
108============
109Some test data were gathered from the Mono project.
110
111regexp_mono_test.go: ported from https://github.com/mono/mono/blob/master/mcs/class/System/Test/System.Text.RegularExpressions/PerlTrials.cs
112---
113Mono tests released under this license:
114
115Permission is hereby granted, free of charge, to any person obtaining
116a copy of this software and associated documentation files (the
117"Software"), to deal in the Software without restriction, including
118without limitation the rights to use, copy, modify, merge, publish,
119distribute, sublicense, and/or sell copies of the Software, and to
120permit persons to whom the Software is furnished to do so, subject to
121the following conditions:
122
123The above copyright notice and this permission notice shall be
124included in all copies or substantial portions of the Software.
125
126THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
127EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
128MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
129NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE
130LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION
131OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION
132WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
133