1 files changed, 103 insertions, 0 deletions
diff --git a/vendor/github.com/mattermost/rsc/regexp/regmerge/merge.go b/vendor/github.com/mattermost/rsc/regexp/regmerge/merge.go
new file mode 100644
index 000000000..15f51cfa7
--- /dev/null
+++ b/vendor/github.com/mattermost/rsc/regexp/regmerge/merge.go
@@ -0,0 +1,103 @@
+// Copyright 2011 The Go Authors.  All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+// Code to merge (join) multiple regexp progs into a single prog.
+// New code; not copied from anywhere.
+
+package main
+
+import "regexp/syntax"
+
+func joinProgs(progs []*syntax.Prog) *syntax.Prog {
+	all := &syntax.Prog{}
+	for i, p := range progs {
+		n := len(all.Inst)
+		all.Inst = append(all.Inst, p.Inst...)
+		match := shiftInst(all.Inst[n:], n)
+		if match < 0 {
+			// no match instruction; give up
+			all.Inst = []syntax.Inst{{Op: syntax.InstFail}}
+			all.Start = 0
+			return all
+		}
+		match += n
+		m := len(all.Inst)
+		all.Inst = append(all.Inst,
+			syntax.Inst{Op: syntax.InstAlt, Out: uint32(p.Start+n), Arg: uint32(m+1)},
+			syntax.Inst{Op: instByteRange, Arg: 0x00FF, Out: uint32(m)},
+			syntax.Inst{Op: instByteRange, Arg: 0x00FF, Out: uint32(match)},
+			syntax.Inst{Op: syntax.InstMatch},
+		)
+		all.Inst[match] = syntax.Inst{Op: syntax.InstAlt, Out: uint32(m+2), Arg: uint32(m+3)}
+
+		if i == 0 {
+			all.Start = m
+		} else {
+			old := all.Start
+			all.Start = len(all.Inst)
+			all.Inst = append(all.Inst, syntax.Inst{Op: syntax.InstAlt, Out: uint32(old), Arg: uint32(m)})
+		}
+	}
+
+	return all
+}
+
+func shiftInst(inst []syntax.Inst, n int) int {
+	match := -1
+	for i := range inst {
+		ip := &inst[i]
+		ip.Out += uint32(n)
+		if ip.Op == syntax.InstMatch {
+			if match >= 0 {
+				panic("double match")
+			}
+			match = i
+		}
+		if ip.Op == syntax.InstAlt || ip.Op == syntax.InstAltMatch {
+			ip.Arg += uint32(n)
+		}
+	}
+	return match
+}
+
+func (m *matcher) crunchProg() {
+	var rewrite [256]byte
+
+	for i := range m.prog.Inst {
+		ip := &m.prog.Inst[i]
+		switch ip.Op {
+		case instByteRange:
+			lo, hi := byte(ip.Arg>>8), byte(ip.Arg)
+			rewrite[lo] = 1
+			if hi < 255 {
+				rewrite[hi+1] = 1
+			}
+		case syntax.InstEmptyWidth:
+			switch op := syntax.EmptyOp(ip.Arg); {
+			case op&(syntax.EmptyBeginLine|syntax.EmptyEndLine) != 0:
+				rewrite['\n'] = 1
+				rewrite['\n'+1] = 1
+			case op&(syntax.EmptyWordBoundary|syntax.EmptyNoWordBoundary) != 0:
+				rewrite['A'] = 1
+				rewrite['Z'+1] = 1
+				rewrite['a'] = 1
+				rewrite['z'+1] = 1
+				rewrite['0'] = 1
+				rewrite['9'+1] = 1
+				rewrite['_'] = 1
+				rewrite['_'+1] = 1
+			}
+		}
+	}
+
+	rewrite[0] = 0
+	for i := 1; i < 256; i++ {
+		rewrite[i] += rewrite[i-1]
+	}
+	m.numByte = int(rewrite[255]) + 1
+
+	for i := 255; i >= 0; i-- {
+		m.undo[rewrite[i]] = byte(i)
+	}
+}