Support for tokenend MCS symbol
diff --git a/datokenizer.go b/datokenizer.go
index 0c763c8..919c611 100644
--- a/datokenizer.go
+++ b/datokenizer.go
@@ -10,11 +10,18 @@
// with a loadfactor of ~70, this means roughly 70 million
// states in the FSA, which is sufficient for the current
// job.
+//
+// Serialization is little endian.
// TODO:
// - replace maxSize with the check value
// - Strip first state and make everything start with 0!
// - Add checksum to serialization.
+// - Mark epsilon transitions in bytes
+// - Introduce methods on BC array entries instead of
+// jumping into the entries all the time!
+// - Instead of memoizing the loadFactor, better remember
+// the number of set transitions
import (
"bufio"
@@ -36,15 +43,15 @@
SIGMA = 2
STATES = 3
NONE = 4
- NEWLINE = '\u000a'
DEBUG = false
MAGIC = "DATOK"
VERSION = uint16(1)
- firstBit uint32 = 1 << 31
- secondBit uint32 = 1 << 30
- restBit uint32 = ^uint32(0) &^ (firstBit | secondBit)
+ FIRSTBIT uint32 = 1 << 31
+ SECONDBIT uint32 = 1 << 30
+ RESTBIT uint32 = ^uint32(0) &^ (FIRSTBIT | SECONDBIT)
)
+// Serialization is always little endian
var bo binary.ByteOrder = binary.LittleEndian
type mapping struct {
@@ -60,8 +67,9 @@
tokenend bool
}
+// Tokenizer is the intermediate representation
+// of the tokenizer.
type Tokenizer struct {
- // sigma map[rune]int
sigmaRev map[int]rune
arcCount int
stateCount int
@@ -73,10 +81,12 @@
unknown int
identity int
final int
+ tokenend int
}
+// DaTokenizer represents a tokenizer implemented as a
+// Double Array FSA.
type DaTokenizer struct {
- // sigmaRev map[int]rune
sigma map[rune]int
maxSize int
loadFactor float64
@@ -88,8 +98,12 @@
unknown int
identity int
final int
+ tokenend int
}
+// ParseFoma reads the FST from a foma file
+// and creates an internal representation,
+// in case it follows the tokenizer's convention.
func LoadFomaFile(file string) *Tokenizer {
f, err := os.Open(file)
if err != nil {
@@ -108,6 +122,9 @@
return ParseFoma(gz)
}
+// ParseFoma reads the FST from a foma file reader
+// and creates an internal representation,
+// in case it follows the tokenizer's convention.
func ParseFoma(ior io.Reader) *Tokenizer {
r := bufio.NewReader(ior)
@@ -117,16 +134,19 @@
unknown: -1,
identity: -1,
final: -1,
+ tokenend: -1,
}
- checkmap := make(map[string]bool)
-
var state, inSym, outSym, end, final int
mode := 0
var elem []string
var elemint [5]int
+ // Iterate over all lines of the file.
+ // This is mainly based on foma2js,
+ // licensed under the Apache License, version 2,
+ // and written by Mans Hulden.
for {
line, err := r.ReadString('\n')
if err != nil {
@@ -300,7 +320,7 @@
if inSym != outSym {
- if tok.sigmaRev[outSym] == NEWLINE {
+ if outSym == tok.tokenend {
tokenend = true
} else if outSym == tok.epsilon {
nontoken = true
@@ -326,16 +346,7 @@
os.Exit(1)
}
- // This collects all edges until arrstate changes
-
- // TODO:
- // if arrin == EPSILON && arrout == TOKENEND, mark state as newline
- // if the next transition is the same, remove TOKENEND and add SENTENCEEND
- // This requires to remove the transition alltogether and marks the state instead.
-
- // TODO:
- // if arrout == EPSILON, mark the transition as NOTOKEN
-
+ // Create an edge based on the collected information
targetObj := &edge{
inSym: inSym,
outSym: outSym,
@@ -356,18 +367,11 @@
// Add final transition
if final == 1 {
- // TODO: maybe this is irrelevant for tokenizers
+ // TODO:
+ // Maybe this is less relevant for tokenizers
tok.transitions[state+1][tok.final] = &edge{}
}
- test := fmt.Sprint(state+1) + ":" + fmt.Sprint(inSym)
- if checkmap[test] {
- fmt.Println("Path already defined!", test)
- os.Exit(0)
- } else {
- checkmap[test] = true
- }
-
if DEBUG {
fmt.Println("Add",
state+1, "->", end+1,
@@ -430,6 +434,12 @@
tok.identity = number
continue
}
+
+ case "@_TOKEN_SYMBOL_@":
+ {
+ tok.tokenend = number
+ continue
+ }
default:
{
log.Error().Msg("MCS not supported: " + line)
@@ -447,7 +457,7 @@
log.Error().Msg("MCS not supported:" + line)
os.Exit(0)
}
- symbol = rune(NEWLINE)
+ symbol = rune('\n')
}
tok.sigmaRev[number] = symbol
@@ -479,6 +489,7 @@
unknown: tok.unknown,
identity: tok.identity,
epsilon: tok.epsilon,
+ tokenend: tok.tokenend,
// lastFilledBase: 1,
}
@@ -612,43 +623,43 @@
// Returns true if a state is separate pointing to a representative
func (dat *DaTokenizer) isSeparate(p uint32) bool {
- return dat.array[p*2]&firstBit != 0
+ return dat.array[p*2]&FIRSTBIT != 0
}
// Mark a state as separate pointing to a representative
func (dat *DaTokenizer) setSeparate(p uint32, sep bool) {
if sep {
- dat.array[p*2] |= firstBit
+ dat.array[p*2] |= FIRSTBIT
} else {
- dat.array[p*2] &= (restBit | secondBit)
+ dat.array[p*2] &= (RESTBIT | SECONDBIT)
}
}
// Returns true if a state is the target of a nontoken transition
func (dat *DaTokenizer) isNonToken(p uint32) bool {
- return dat.array[p*2+1]&firstBit != 0
+ return dat.array[p*2+1]&FIRSTBIT != 0
}
// Mark a state as being the target of a nontoken transition
func (dat *DaTokenizer) setNonToken(p uint32, sep bool) {
if sep {
- dat.array[p*2+1] |= firstBit
+ dat.array[p*2+1] |= FIRSTBIT
} else {
- dat.array[p*2+1] &= (restBit | secondBit)
+ dat.array[p*2+1] &= (RESTBIT | SECONDBIT)
}
}
// Returns true if a state is the target of a tokenend transition
func (dat *DaTokenizer) isTokenEnd(p uint32) bool {
- return dat.array[p*2+1]&secondBit != 0
+ return dat.array[p*2+1]&SECONDBIT != 0
}
// Mark a state as being the target of a tokenend transition
func (dat *DaTokenizer) setTokenEnd(p uint32, sep bool) {
if sep {
- dat.array[p*2+1] |= secondBit
+ dat.array[p*2+1] |= SECONDBIT
} else {
- dat.array[p*2+1] &= (restBit | firstBit)
+ dat.array[p*2+1] &= (RESTBIT | FIRSTBIT)
}
}
@@ -657,7 +668,7 @@
if int(p*2) >= len(dat.array) {
return 0
}
- return dat.array[p*2] & restBit
+ return dat.array[p*2] & RESTBIT
}
// Set check value in double array
@@ -675,7 +686,7 @@
if int((p*2)+1) >= len(dat.array) {
return 0
}
- return dat.array[(p*2)+1] & restBit
+ return dat.array[(p*2)+1] & RESTBIT
}
// Set size of double array
@@ -1190,9 +1201,7 @@
t0 = t
if dat.getCheck(dat.getBase(t0)+uint32(dat.epsilon)) == t0 {
- if DEBUG {
- fmt.Println("Remember for epsilon tu:charcount", t0, buffo)
- }
+ // Remember state for backtracking to last tokenend state
epsilonState = t0
epsilonOffset = buffo
}