blob: 5868a3677fcc70b5ae99a09abc6184ab5e6045de [file] [log] [blame]
package datokenizer
/**
* The file reader is basically a port of foma2js,
* licensed under the Apache License, version 2,
* and written by Mans Hulden.
*/
import (
"bufio"
"compress/gzip"
"fmt"
"io"
"os"
"strconv"
"strings"
"unicode/utf8"
)
const (
PROPS = 1
SIGMA = 2
STATES = 3
NONE = 4
NEWLINE = '\u000a'
)
// Special symbols in sigma
var EPSILON = -1
var UNKNOWN = -1
var IDENTITY = -1
var FINAL = -1
type mapping struct {
source int
target int
}
type edge struct {
in int
out int
target int
}
type Tokenizer struct {
sigma map[rune]int
sigma_rev map[int]rune
arccount int
statecount int
sigmacount int
maxsize int
array []int
transitions []map[int]*edge
}
func parse_file(file string) *Tokenizer {
f, err := os.Open(file)
if err != nil {
panic(err)
}
defer f.Close()
gz, err := gzip.NewReader(f)
if err != nil {
panic(err)
}
defer gz.Close()
return parse(gz)
}
func parse(ior io.Reader) *Tokenizer {
r := bufio.NewReader(ior)
tok := &Tokenizer{
sigma: make(map[rune]int),
sigma_rev: make(map[int]rune),
}
final := false
var arrstate, arrin, arrout, arrtarget, arrfinal int
mode := 0
var elem []string
var elemint [5]int
for {
line, err := r.ReadString('\n')
if err != nil {
if err == io.EOF {
break
}
panic(err)
}
if strings.HasPrefix(line, "##foma-net") {
continue
}
if strings.HasPrefix(line, "##props##") {
mode = PROPS
continue
}
if strings.HasPrefix(line, "##states##") {
mode = STATES
// Adds a final transition symbol to sigma
// written as '#' in Mizobuchi et al (2000)
tok.sigmacount++
FINAL = tok.sigmacount
continue
}
if strings.HasPrefix(line, "##sigma##") {
mode = SIGMA
continue
}
if strings.HasPrefix(line, "##end##") {
mode = NONE
continue
}
switch mode {
case PROPS:
{
elem = strings.Split(line, " ")
/*
fmt.Println("arity: " + elem[0])
fmt.Println("arccount: " + elem[1])
fmt.Println("statecount: " + elem[2])
fmt.Println("linecount: " + elem[3])
fmt.Println("finalcount: " + elem[4])
fmt.Println("pathcount: " + elem[5])
fmt.Println("is_deterministic: " + elem[6])
fmt.Println("is_pruned: " + elem[7])
fmt.Println("is_minimized: " + elem[8])
fmt.Println("is_epsilon_free: " + elem[9])
fmt.Println("is_loop_free: " + elem[10])
fmt.Println("extras: " + elem[11])
fmt.Println("name: " + elem[12])
*/
if elem[6] != "1" {
panic("The FST needs to be deterministic")
}
if elem[9] != "1" {
panic("The FST needs to be epsilon free")
}
elemint[0], err = strconv.Atoi(elem[1])
if err != nil {
panic("Can't read arccount")
}
tok.arccount = elemint[0]
// States start at 1 in Mizobuchi et al (2000),
// as the state 0 is associated with a fail.
// Initialize states and transitions
elemint[0], err = strconv.Atoi(elem[2])
if err != nil {
panic("Can't read statecount")
}
tok.statecount = elemint[0]
tok.transitions = make([]map[int]*edge, elemint[0]+1)
continue
}
case STATES:
{
elem = strings.Split(line[0:len(line)-1], " ")
if elem[0] == "-1" {
continue
}
elemint[0], err = strconv.Atoi(elem[0])
if err != nil {
break
}
if len(elem) > 1 {
elemint[1], err = strconv.Atoi(elem[1])
if err != nil {
break
}
if len(elem) > 2 {
elemint[2], err = strconv.Atoi(elem[2])
if err != nil {
break
}
if len(elem) > 3 {
elemint[3], err = strconv.Atoi(elem[3])
if err != nil {
break
}
if len(elem) > 4 {
elemint[4], err = strconv.Atoi(elem[4])
if err != nil {
break
}
}
}
}
}
switch len(elem) {
case 5:
{
arrstate = elemint[0]
arrin = elemint[1]
arrout = elemint[2]
arrtarget = elemint[3]
arrfinal = elemint[4]
}
case 4:
{
if elemint[1] == -1 {
arrstate = elemint[0]
arrfinal = elemint[3]
} else {
arrstate = elemint[0]
arrin = elemint[1]
arrtarget = elemint[2]
arrfinal = elemint[3]
arrout = arrin
}
}
case 3:
{
arrin = elemint[0]
arrout = elemint[1]
arrtarget = elemint[2]
}
case 2:
{
arrin = elemint[0]
arrtarget = elemint[1]
arrout = arrin
}
}
// This collects all edges until arrstate changes
if arrfinal == 1 {
final = true
} else {
final = false
}
// While the states in foma start with 0, the states in the
// Mizobuchi FSA start with one - so we increase every state by 1.
/*
if arrin != arrout && arrin != EPSILON && tok.sigma_rev[arrin] != '\n' {
panic("Problem: " + strconv.Itoa(arrstate) + " -> " + strconv.Itoa(arrtarget) + " (" + strconv.Itoa(arrin) + ":" + strconv.Itoa(arrout) + ") ")
}
*/
if arrin != arrout {
if arrin == EPSILON && tok.sigma_rev[arrout] == NEWLINE {
} else if arrin != EPSILON && arrout == EPSILON {
} else {
panic(
"Problem: " +
strconv.Itoa(arrstate) +
" -> " + strconv.Itoa(arrtarget) +
" (" +
strconv.Itoa(arrin) +
":" +
strconv.Itoa(arrout) +
") (" +
string(tok.sigma_rev[arrin]) +
":" +
string(tok.sigma_rev[arrout]) +
")")
}
}
// 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
targetObj := &edge{
in: arrin,
out: arrout,
target: arrtarget + 1,
}
// Initialize outgoing state
if tok.transitions[arrstate+1] == nil {
tok.transitions[arrstate+1] = make(map[int]*edge)
}
if arrin >= 0 {
tok.transitions[arrstate+1][arrin] = targetObj
}
if final {
tok.transitions[arrstate+1][FINAL] = &edge{}
}
fmt.Println("Add",
arrstate+1, "->", arrtarget+1,
"(",
arrin,
":",
arrout,
") (",
string(tok.sigma_rev[arrin]),
":",
string(tok.sigma_rev[arrout]),
")")
continue
}
case SIGMA:
{
elem = strings.SplitN(line[0:len(line)-1], " ", 2)
// Turn string into sigma id
number, err := strconv.Atoi(elem[0])
if err != nil {
panic(err)
}
tok.sigmacount = number
var symbol rune
// Read rune
if utf8.RuneCountInString(elem[1]) == 1 {
symbol = []rune(elem[1])[0]
// Probably a MCS
} else if utf8.RuneCountInString(elem[1]) > 1 {
switch elem[1] {
case "@_EPSILON_SYMBOL_@":
{
EPSILON = number
continue
}
case "@_UNKNOWN_SYMBOL_@":
{
UNKNOWN = number
continue
}
case "@_IDENTITY_SYMBOL_@":
{
IDENTITY = number
continue
}
default:
panic("MCS not supported: " + line)
}
// Probably a new line symbol
} else {
line, err = r.ReadString('\n')
if err != nil {
panic(err)
}
if len(line) != 1 {
panic("MCS not supported:" + line)
}
symbol = rune('\n')
}
tok.sigma[symbol] = number
tok.sigma_rev[number] = symbol
}
}
}
return tok
}
// Implementation of Mizobuchi et al (2000), p.128
func (tok *Tokenizer) buildDA() *Tokenizer {
mark := 0
size := 0
// Create a mapping from s to t
table := make([]*mapping, tok.arccount+1)
table[size] = &mapping{source: 1, target: 1}
size++
A := make([]int, 0, 256)
for mark < size {
s := table[mark].source // This is a state in Ms
t := table[mark].target // This is a state in Mt
mark++
// fmt.Println("Increase mark", mark)
// St := append(St, t)
A = A[:0]
tok.get_set(s, &A)
// fmt.Println("Outgoing arcs from t", t, A)
// tok.array[t].base = tok.x_check(A)
tok.set_base(t, tok.x_check(A))
for _, a := range A {
if a != FINAL {
s1 := tok.transitions[s][a].target // g(s, a)
// fmt.Println("Found", s, "to", s1, "via", a)
t1 := tok.get_base(t) + a
tok.set_check(t1, t)
r := in_table(s1, table, size)
if r == 0 {
// fmt.Println("Increase size", t1)
table[size] = &mapping{source: s1, target: t1}
size++
} else {
//fmt.Println("Rep is there", t1, r)
tok.set_base(t1, -1*r)
// tok.array[t1].base = -1 * r
}
} else {
fmt.Println("I set a final")
// t1 := tok.array[t].base + FINAL
t1 := tok.get_base(t) + FINAL
// tok.array[t1].check = t
tok.set_check(t1, t)
}
}
}
// Following Mizobuchi et al (2000) the size of the
// FSA should be stored in check(1).
tok.set_check(1, tok.maxsize+1)
tok.array = tok.array[:tok.maxsize+1]
return tok
}
func (tok *Tokenizer) resize(l int) {
if len(tok.array) <= l {
tok.array = append(tok.array, make([]int, l)...)
}
}
func (tok *Tokenizer) set_base(p int, v int) {
l := p*2 + 1
tok.resize(l)
if tok.maxsize < l {
tok.maxsize = l
}
tok.array[p*2] = v
}
func (tok *Tokenizer) get_base(p int) int {
if p*2 >= len(tok.array) {
return 0
}
return tok.array[p*2]
}
func (tok *Tokenizer) set_check(p int, v int) {
l := p*2 + 1
tok.resize(l)
if tok.maxsize < l {
tok.maxsize = l
}
tok.array[(p*2)+1] = v
}
func (tok *Tokenizer) get_check(p int) int {
if (p*2)+1 >= len(tok.array) {
return 0
}
return tok.array[(p*2)+1]
}
// Check the table if a mapping of s
// exists and return this as a representative
func in_table(s int, table []*mapping, size int) int {
for x := 0; x < size; x++ {
if table[x].source == s {
return table[x].target
}
}
return 0
}
// Set alphabet A to the list of all symbols
// outgoing from s
func (tok *Tokenizer) get_set(s int, A *[]int) {
for a := range tok.transitions[s] {
*A = append(*A, a)
}
}
// Based on Mizobuchi et al (2000), p. 124
// This iterates for every state through the complete double array
// structure until it finds a gap that fits all outgoing transitions
// of the state. This is extremely slow, but is only necessary in the
// construction phase of the tokenizer.
func (tok *Tokenizer) x_check(symbols []int) int {
// see https://github.com/bramstein/datrie/blob/master/lib/trie.js
base := 1
// fmt.Println("Resize", len(tok.linarray), "<", ((base + FINAL + 1) * 2))
OVERLAP:
tok.resize((base + FINAL) * 2)
for _, a := range symbols {
// if tok.array[base+a].check != 0 {
if tok.get_check(base+a) != 0 {
base++
goto OVERLAP
}
}
// fmt.Println("Found a nice place at", base, "for", len(symbols))
return base
}
// Based on Mizobuchi et al (2000), p. 129
func (tok *Tokenizer) match(input string) bool {
t := 1 // Start position
chars := []rune(input)
i := 0
// fmt.Println("Length of string is", len(chars))
for ; i < len(chars); i++ {
a, ok := tok.sigma[chars[i]]
// Support identity symbol if char not in sigma
if !ok && IDENTITY != -1 {
fmt.Println("IDENTITY symbol", chars[i], "->", IDENTITY)
a = IDENTITY
}
tu := t
CHECK:
t = tok.get_base(tu) + a
if t > tok.get_check(1) || tok.get_check(t) != tu {
fmt.Println("Match is not fine!", t, "and", tok.get_check(t), "vs", tu)
// Try again with unknown symbol, in case identity failed
if !ok && a == IDENTITY {
a = UNKNOWN
goto CHECK
}
break
} else if tok.get_base(t) < 0 {
// Move to representative state
t = -1 * tok.get_base(t)
}
}
if i == len(chars) {
fmt.Println("At the end")
} else {
fmt.Println("Not at the end")
return false
}
fmt.Println("Hmm...", tok.get_check(tok.get_base(t)+FINAL), "-", t)
if tok.get_check(tok.get_base(t)+FINAL) == t {
return true
}
return false
}
// In the final realization, the states can only have 30 bits:
// base[1] -> is final
// base[2] -> is_separate
// check[1] -> translates to epsilon
// check[2] -> appends newine (Maybe)
// If check[1] && check[2] is set, this translates to a sentence split (Maybe)