/usr/share/gocode/src/github.com/dlclark/regexp2/syntax/code.go is in golang-github-dlclark-regexp2-dev 1.1.6-1.
This file is owned by root:root, with mode 0o644.
The actual contents of the file can be viewed below.
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import (
"bytes"
"fmt"
"math"
)
// similar to prog.go in the go regex package...also with comment 'may not belong in this package'
// File provides operator constants for use by the Builder and the Machine.
// Implementation notes:
//
// Regexps are built into RegexCodes, which contain an operation array,
// a string table, and some constants.
//
// Each operation is one of the codes below, followed by the integer
// operands specified for each op.
//
// Strings and sets are indices into a string table.
type InstOp int
const (
// lef/back operands description
Onerep InstOp = 0 // lef,back char,min,max a {n}
Notonerep = 1 // lef,back char,min,max .{n}
Setrep = 2 // lef,back set,min,max [\d]{n}
Oneloop = 3 // lef,back char,min,max a {,n}
Notoneloop = 4 // lef,back char,min,max .{,n}
Setloop = 5 // lef,back set,min,max [\d]{,n}
Onelazy = 6 // lef,back char,min,max a {,n}?
Notonelazy = 7 // lef,back char,min,max .{,n}?
Setlazy = 8 // lef,back set,min,max [\d]{,n}?
One = 9 // lef char a
Notone = 10 // lef char [^a]
Set = 11 // lef set [a-z\s] \w \s \d
Multi = 12 // lef string abcd
Ref = 13 // lef group \#
Bol = 14 // ^
Eol = 15 // $
Boundary = 16 // \b
Nonboundary = 17 // \B
Beginning = 18 // \A
Start = 19 // \G
EndZ = 20 // \Z
End = 21 // \Z
Nothing = 22 // Reject!
// Primitive control structures
Lazybranch = 23 // back jump straight first
Branchmark = 24 // back jump branch first for loop
Lazybranchmark = 25 // back jump straight first for loop
Nullcount = 26 // back val set counter, null mark
Setcount = 27 // back val set counter, make mark
Branchcount = 28 // back jump,limit branch++ if zero<=c<limit
Lazybranchcount = 29 // back jump,limit same, but straight first
Nullmark = 30 // back save position
Setmark = 31 // back save position
Capturemark = 32 // back group define group
Getmark = 33 // back recall position
Setjump = 34 // back save backtrack state
Backjump = 35 // zap back to saved state
Forejump = 36 // zap backtracking state
Testref = 37 // backtrack if ref undefined
Goto = 38 // jump just go
Prune = 39 // prune it baby
Stop = 40 // done!
ECMABoundary = 41 // \b
NonECMABoundary = 42 // \B
// Modifiers for alternate modes
Mask = 63 // Mask to get unmodified ordinary operator
Rtl = 64 // bit to indicate that we're reverse scanning.
Back = 128 // bit to indicate that we're backtracking.
Back2 = 256 // bit to indicate that we're backtracking on a second branch.
Ci = 512 // bit to indicate that we're case-insensitive.
)
type Code struct {
Codes []int // the code
Strings [][]rune // string table
Sets []*CharSet //character set table
TrackCount int // how many instructions use backtracking
Caps map[int]int // mapping of user group numbers -> impl group slots
Capsize int // number of impl group slots
FcPrefix *Prefix // the set of candidate first characters (may be null)
BmPrefix *BmPrefix // the fixed prefix string as a Boyer-Moore machine (may be null)
Anchors AnchorLoc // the set of zero-length start anchors (RegexFCD.Bol, etc)
RightToLeft bool // true if right to left
}
func opcodeBacktracks(op InstOp) bool {
op &= Mask
switch op {
case Oneloop, Notoneloop, Setloop, Onelazy, Notonelazy, Setlazy, Lazybranch, Branchmark, Lazybranchmark,
Nullcount, Setcount, Branchcount, Lazybranchcount, Setmark, Capturemark, Getmark, Setjump, Backjump,
Forejump, Goto:
return true
default:
return false
}
}
func opcodeSize(op InstOp) int {
op &= Mask
switch op {
case Nothing, Bol, Eol, Boundary, Nonboundary, ECMABoundary, NonECMABoundary, Beginning, Start, EndZ,
End, Nullmark, Setmark, Getmark, Setjump, Backjump, Forejump, Stop:
return 1
case One, Notone, Multi, Ref, Testref, Goto, Nullcount, Setcount, Lazybranch, Branchmark, Lazybranchmark,
Prune, Set:
return 2
case Capturemark, Branchcount, Lazybranchcount, Onerep, Notonerep, Oneloop, Notoneloop, Onelazy, Notonelazy,
Setlazy, Setrep, Setloop:
return 3
default:
panic(fmt.Errorf("Unexpected op code: %v", op))
}
}
var codeStr = []string{
"Onerep", "Notonerep", "Setrep",
"Oneloop", "Notoneloop", "Setloop",
"Onelazy", "Notonelazy", "Setlazy",
"One", "Notone", "Set",
"Multi", "Ref",
"Bol", "Eol", "Boundary", "Nonboundary", "Beginning", "Start", "EndZ", "End",
"Nothing",
"Lazybranch", "Branchmark", "Lazybranchmark",
"Nullcount", "Setcount", "Branchcount", "Lazybranchcount",
"Nullmark", "Setmark", "Capturemark", "Getmark",
"Setjump", "Backjump", "Forejump", "Testref", "Goto",
"Prune", "Stop",
"ECMABoundary", "NonECMABoundary",
}
func operatorDescription(op InstOp) string {
desc := codeStr[op&Mask]
if (op & Ci) != 0 {
desc += "-Ci"
}
if (op & Rtl) != 0 {
desc += "-Rtl"
}
if (op & Back) != 0 {
desc += "-Back"
}
if (op & Back2) != 0 {
desc += "-Back2"
}
return desc
}
// OpcodeDescription is a humman readable string of the specific offset
func (c *Code) OpcodeDescription(offset int) string {
buf := &bytes.Buffer{}
op := InstOp(c.Codes[offset])
fmt.Fprintf(buf, "%06d ", offset)
if opcodeBacktracks(op & Mask) {
buf.WriteString("*")
} else {
buf.WriteString(" ")
}
buf.WriteString(operatorDescription(op))
buf.WriteString("(")
op &= Mask
switch op {
case One, Notone, Onerep, Notonerep, Oneloop, Notoneloop, Onelazy, Notonelazy:
buf.WriteString("Ch = ")
buf.WriteString(CharDescription(rune(c.Codes[offset+1])))
case Set, Setrep, Setloop, Setlazy:
buf.WriteString("Set = ")
buf.WriteString(c.Sets[c.Codes[offset+1]].String())
case Multi:
fmt.Fprintf(buf, "String = %s", string(c.Strings[c.Codes[offset+1]]))
case Ref, Testref:
fmt.Fprintf(buf, "Index = %d", c.Codes[offset+1])
case Capturemark:
fmt.Fprintf(buf, "Index = %d", c.Codes[offset+1])
if c.Codes[offset+2] != -1 {
fmt.Fprintf(buf, ", Unindex = %d", c.Codes[offset+2])
}
case Nullcount, Setcount:
fmt.Fprintf(buf, "Value = %d", c.Codes[offset+1])
case Goto, Lazybranch, Branchmark, Lazybranchmark, Branchcount, Lazybranchcount:
fmt.Fprintf(buf, "Addr = %d", c.Codes[offset+1])
}
switch op {
case Onerep, Notonerep, Oneloop, Notoneloop, Onelazy, Notonelazy, Setrep, Setloop, Setlazy:
buf.WriteString(", Rep = ")
if c.Codes[offset+2] == math.MaxInt32 {
buf.WriteString("inf")
} else {
fmt.Fprintf(buf, "%d", c.Codes[offset+2])
}
case Branchcount, Lazybranchcount:
buf.WriteString(", Limit = ")
if c.Codes[offset+2] == math.MaxInt32 {
buf.WriteString("inf")
} else {
fmt.Fprintf(buf, "%d", c.Codes[offset+2])
}
}
buf.WriteString(")")
return buf.String()
}
func (c *Code) Dump() string {
buf := &bytes.Buffer{}
if c.RightToLeft {
fmt.Fprintln(buf, "Direction: right-to-left")
} else {
fmt.Fprintln(buf, "Direction: left-to-right")
}
if c.FcPrefix == nil {
fmt.Fprintln(buf, "Firstchars: n/a")
} else {
fmt.Fprintf(buf, "Firstchars: %v\n", c.FcPrefix.PrefixSet.String())
}
if c.BmPrefix == nil {
fmt.Fprintln(buf, "Prefix: n/a")
} else {
fmt.Fprintf(buf, "Prefix: %v\n", Escape(c.BmPrefix.String()))
}
fmt.Fprintf(buf, "Anchors: %v\n", c.Anchors)
fmt.Fprintln(buf)
if c.BmPrefix != nil {
fmt.Fprintln(buf, "BoyerMoore:")
fmt.Fprintln(buf, c.BmPrefix.Dump(" "))
}
for i := 0; i < len(c.Codes); i += opcodeSize(InstOp(c.Codes[i])) {
fmt.Fprintln(buf, c.OpcodeDescription(i))
}
return buf.String()
}
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