1 files changed, 316 insertions, 0 deletions
diff --git a/vendor/github.com/couchbase/vellum/regexp/compile.go b/vendor/github.com/couchbase/vellum/regexp/compile.go
new file mode 100644
index 0000000000..6922b749db
--- /dev/null
+++ b/vendor/github.com/couchbase/vellum/regexp/compile.go
@@ -0,0 +1,316 @@
+//  Copyright (c) 2017 Couchbase, Inc.
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+// 		http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package regexp
+
+import (
+	"regexp/syntax"
+	"unicode"
+
+	"github.com/couchbase/vellum/utf8"
+)
+
+type compiler struct {
+	sizeLimit uint
+	insts     prog
+}
+
+func newCompiler(sizeLimit uint) *compiler {
+	return &compiler{
+		sizeLimit: sizeLimit,
+	}
+}
+
+func (c *compiler) compile(ast *syntax.Regexp) (prog, error) {
+	err := c.c(ast)
+	if err != nil {
+		return nil, err
+	}
+	c.insts = append(c.insts, &inst{
+		op: OpMatch,
+	})
+	return c.insts, nil
+}
+
+func (c *compiler) c(ast *syntax.Regexp) error {
+	if ast.Flags&syntax.NonGreedy > 1 {
+		return ErrNoLazy
+	}
+
+	switch ast.Op {
+	case syntax.OpEndLine, syntax.OpBeginLine,
+		syntax.OpBeginText, syntax.OpEndText:
+		return ErrNoEmpty
+	case syntax.OpWordBoundary, syntax.OpNoWordBoundary:
+		return ErrNoWordBoundary
+	case syntax.OpEmptyMatch:
+		return nil
+	case syntax.OpLiteral:
+		for _, r := range ast.Rune {
+			if ast.Flags&syntax.FoldCase > 0 {
+				next := syntax.Regexp{
+					Op:    syntax.OpCharClass,
+					Flags: ast.Flags & syntax.FoldCase,
+					Rune0: [2]rune{r, r},
+				}
+				next.Rune = next.Rune0[0:2]
+				return c.c(&next)
+			}
+			seqs, err := utf8.NewSequences(r, r)
+			if err != nil {
+				return err
+			}
+			for _, seq := range seqs {
+				c.compileUtf8Ranges(seq)
+			}
+		}
+	case syntax.OpAnyChar:
+		next := syntax.Regexp{
+			Op:    syntax.OpCharClass,
+			Flags: ast.Flags & syntax.FoldCase,
+			Rune0: [2]rune{0, unicode.MaxRune},
+		}
+		next.Rune = next.Rune0[:2]
+		return c.c(&next)
+	case syntax.OpAnyCharNotNL:
+		next := syntax.Regexp{
+			Op:    syntax.OpCharClass,
+			Flags: ast.Flags & syntax.FoldCase,
+			Rune:  []rune{0, 0x09, 0x0B, unicode.MaxRune},
+		}
+		return c.c(&next)
+	case syntax.OpCharClass:
+		return c.compileClass(ast)
+	case syntax.OpCapture:
+		return c.c(ast.Sub[0])
+	case syntax.OpConcat:
+		for _, sub := range ast.Sub {
+			err := c.c(sub)
+			if err != nil {
+				return err
+			}
+		}
+		return nil
+	case syntax.OpAlternate:
+		if len(ast.Sub) == 0 {
+			return nil
+		}
+		jmpsToEnd := []uint{}
+
+		// does not handle last entry
+		for i := 0; i < len(ast.Sub)-1; i++ {
+			sub := ast.Sub[i]
+			split := c.emptySplit()
+			j1 := c.top()
+			err := c.c(sub)
+			if err != nil {
+				return err
+			}
+			jmpsToEnd = append(jmpsToEnd, c.emptyJump())
+			j2 := c.top()
+			c.setSplit(split, j1, j2)
+		}
+		// handle last entry
+		err := c.c(ast.Sub[len(ast.Sub)-1])
+		if err != nil {
+			return err
+		}
+		end := uint(len(c.insts))
+		for _, jmpToEnd := range jmpsToEnd {
+			c.setJump(jmpToEnd, end)
+		}
+	case syntax.OpQuest:
+		split := c.emptySplit()
+		j1 := c.top()
+		err := c.c(ast.Sub[0])
+		if err != nil {
+			return err
+		}
+		j2 := c.top()
+		c.setSplit(split, j1, j2)
+
+	case syntax.OpStar:
+		j1 := c.top()
+		split := c.emptySplit()
+		j2 := c.top()
+		err := c.c(ast.Sub[0])
+		if err != nil {
+			return err
+		}
+		jmp := c.emptyJump()
+		j3 := uint(len(c.insts))
+
+		c.setJump(jmp, j1)
+		c.setSplit(split, j2, j3)
+
+	case syntax.OpPlus:
+		j1 := c.top()
+		err := c.c(ast.Sub[0])
+		if err != nil {
+			return err
+		}
+		split := c.emptySplit()
+		j2 := c.top()
+		c.setSplit(split, j1, j2)
+
+	case syntax.OpRepeat:
+		if ast.Max == -1 {
+			for i := 0; i < ast.Min; i++ {
+				err := c.c(ast.Sub[0])
+				if err != nil {
+					return err
+				}
+			}
+			next := syntax.Regexp{
+				Op:    syntax.OpStar,
+				Flags: ast.Flags,
+				Sub:   ast.Sub,
+				Sub0:  ast.Sub0,
+				Rune:  ast.Rune,
+				Rune0: ast.Rune0,
+			}
+			return c.c(&next)
+		}
+		for i := 0; i < ast.Min; i++ {
+			err := c.c(ast.Sub[0])
+			if err != nil {
+				return err
+			}
+		}
+		var splits, starts []uint
+		for i := ast.Min; i < ast.Max; i++ {
+			splits = append(splits, c.emptySplit())
+			starts = append(starts, uint(len(c.insts)))
+			err := c.c(ast.Sub[0])
+			if err != nil {
+				return err
+			}
+		}
+		end := uint(len(c.insts))
+		for i := 0; i < len(splits); i++ {
+			c.setSplit(splits[i], starts[i], end)
+		}
+
+	}
+
+	return c.checkSize()
+}
+
+func (c *compiler) checkSize() error {
+	if uint(len(c.insts)*instSize) > c.sizeLimit {
+		return ErrCompiledTooBig
+	}
+	return nil
+}
+
+func (c *compiler) compileClass(ast *syntax.Regexp) error {
+	if len(ast.Rune) == 0 {
+		return nil
+	}
+	var jmps []uint
+
+	// does not do last pair
+	for i := 0; i < len(ast.Rune)-2; i += 2 {
+		rstart := ast.Rune[i]
+		rend := ast.Rune[i+1]
+
+		split := c.emptySplit()
+		j1 := c.top()
+		err := c.compileClassRange(rstart, rend)
+		if err != nil {
+			return err
+		}
+		jmps = append(jmps, c.emptyJump())
+		j2 := c.top()
+		c.setSplit(split, j1, j2)
+	}
+	// handle last pair
+	rstart := ast.Rune[len(ast.Rune)-2]
+	rend := ast.Rune[len(ast.Rune)-1]
+	err := c.compileClassRange(rstart, rend)
+	if err != nil {
+		return err
+	}
+	end := c.top()
+	for _, jmp := range jmps {
+		c.setJump(jmp, end)
+	}
+	return nil
+}
+
+func (c *compiler) compileClassRange(startR, endR rune) error {
+	seqs, err := utf8.NewSequences(startR, endR)
+	if err != nil {
+		return err
+	}
+	var jmps []uint
+
+	// does not do last entry
+	for i := 0; i < len(seqs)-1; i++ {
+		seq := seqs[i]
+		split := c.emptySplit()
+		j1 := c.top()
+		c.compileUtf8Ranges(seq)
+		jmps = append(jmps, c.emptyJump())
+		j2 := c.top()
+		c.setSplit(split, j1, j2)
+	}
+	// handle last entry
+	c.compileUtf8Ranges(seqs[len(seqs)-1])
+	end := c.top()
+	for _, jmp := range jmps {
+		c.setJump(jmp, end)
+	}
+
+	return nil
+}
+
+func (c *compiler) compileUtf8Ranges(seq utf8.Sequence) {
+	for _, r := range seq {
+		c.insts = append(c.insts, &inst{
+			op:         OpRange,
+			rangeStart: r.Start,
+			rangeEnd:   r.End,
+		})
+	}
+}
+
+func (c *compiler) emptySplit() uint {
+	c.insts = append(c.insts, &inst{
+		op: OpSplit,
+	})
+	return c.top() - 1
+}
+
+func (c *compiler) emptyJump() uint {
+	c.insts = append(c.insts, &inst{
+		op: OpJmp,
+	})
+	return c.top() - 1
+}
+
+func (c *compiler) setSplit(i, pc1, pc2 uint) {
+	split := c.insts[i]
+	split.splitA = pc1
+	split.splitB = pc2
+}
+
+func (c *compiler) setJump(i, pc uint) {
+	jmp := c.insts[i]
+	jmp.to = pc
+}
+
+func (c *compiler) top() uint {
+	return uint(len(c.insts))
+}