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package moe.nea.firmament.util
import java.util.*
import net.minecraft.nbt.AbstractNbtNumber
import net.minecraft.nbt.NbtByte
import net.minecraft.nbt.NbtCompound
import net.minecraft.nbt.NbtDouble
import net.minecraft.nbt.NbtElement
import net.minecraft.nbt.NbtFloat
import net.minecraft.nbt.NbtInt
import net.minecraft.nbt.NbtList
import net.minecraft.nbt.NbtLong
import net.minecraft.nbt.NbtShort
import net.minecraft.nbt.NbtString
class LegacyTagParser private constructor(string: String) {
data class TagParsingException(val baseString: String, val offset: Int, val mes0: String) :
Exception("$mes0 at $offset in `$baseString`.")
class StringRacer(val backing: String) {
var idx = 0
val stack = Stack<Int>()
fun pushState() {
stack.push(idx)
}
fun popState() {
idx = stack.pop()
}
fun discardState() {
stack.pop()
}
fun peek(count: Int): String {
return backing.substring(minOf(idx, backing.length), minOf(idx + count, backing.length))
}
fun finished(): Boolean {
return peek(1).isEmpty()
}
fun peekReq(count: Int): String? {
val p = peek(count)
if (p.length != count)
return null
return p
}
fun consumeCountReq(count: Int): String? {
val p = peekReq(count)
if (p != null)
idx += count
return p
}
fun tryConsume(string: String): Boolean {
val p = peek(string.length)
if (p != string)
return false
idx += p.length
return true
}
fun consumeWhile(shouldConsumeThisString: (String) -> Boolean): String {
var lastString: String = ""
while (true) {
val nextString = lastString + peek(1)
if (!shouldConsumeThisString(nextString)) {
return lastString
}
idx++
lastString = nextString
}
}
fun expect(search: String, errorMessage: String) {
if (!tryConsume(search))
error(errorMessage)
}
fun error(errorMessage: String): Nothing {
throw TagParsingException(backing, idx, errorMessage)
}
}
val racer = StringRacer(string)
val baseTag = parseTag()
companion object {
val digitRange = "0123456789-"
fun parse(string: String): NbtCompound {
return LegacyTagParser(string).baseTag
}
}
fun skipWhitespace() {
racer.consumeWhile { Character.isWhitespace(it.last()) } // Only check last since other chars are always checked before.
}
fun parseTag(): NbtCompound {
skipWhitespace()
racer.expect("{", "Expected '{’ at start of tag")
skipWhitespace()
val tag = NbtCompound()
while (!racer.tryConsume("}")) {
skipWhitespace()
val lhs = parseIdentifier()
skipWhitespace()
racer.expect(":", "Expected ':' after identifier in tag")
skipWhitespace()
val rhs = parseAny()
tag.put(lhs, rhs)
racer.tryConsume(",")
skipWhitespace()
}
return tag
}
private fun parseAny(): NbtElement {
skipWhitespace()
val nextChar = racer.peekReq(1) ?: racer.error("Expected new object, found EOF")
return when {
nextChar == "{" -> parseTag()
nextChar == "[" -> parseList()
nextChar == "\"" -> parseStringTag()
nextChar.first() in (digitRange) -> parseNumericTag()
else -> racer.error("Unexpected token found. Expected start of new element")
}
}
fun parseList(): NbtList {
skipWhitespace()
racer.expect("[", "Expected '[' at start of tag")
skipWhitespace()
val list = NbtList()
while (!racer.tryConsume("]")) {
skipWhitespace()
racer.pushState()
val lhs = racer.consumeWhile { it.all { it in digitRange } }
skipWhitespace()
if (!racer.tryConsume(":") || lhs.isEmpty()) { // No prefixed 0:
racer.popState()
list.add(parseAny()) // Reparse our number (or not a number) as actual tag
} else {
racer.discardState()
skipWhitespace()
list.add(parseAny()) // Ignore prefix indexes. They should not be generated out of order by any vanilla implementation (which is what NEU should export). Instead append where it appears in order.
}
skipWhitespace()
racer.tryConsume(",")
}
return list
}
fun parseQuotedString(): String {
skipWhitespace()
racer.expect("\"", "Expected '\"' at string start")
val sb = StringBuilder()
while (true) {
when (val peek = racer.consumeCountReq(1)) {
"\"" -> break
"\\" -> {
val escaped = racer.consumeCountReq(1) ?: racer.error("Unfinished backslash escape")
if (escaped != "\"" && escaped != "\\") {
// Surprisingly i couldn't find unicode escapes to be generated by the original minecraft 1.8.9 implementation
racer.idx--
racer.error("Invalid backslash escape '$escaped'")
}
sb.append(escaped)
}
null -> racer.error("Unfinished string")
else -> {
sb.append(peek)
}
}
}
return sb.toString()
}
fun parseStringTag(): NbtString {
return NbtString.of(parseQuotedString())
}
object Patterns {
val DOUBLE = "([-+]?[0-9]*\\.?[0-9]+)[d|D]".toRegex()
val FLOAT = "([-+]?[0-9]*\\.?[0-9]+)[f|F]".toRegex()
val BYTE = "([-+]?[0-9]+)[b|B]".toRegex()
val LONG = "([-+]?[0-9]+)[l|L]".toRegex()
val SHORT = "([-+]?[0-9]+)[s|S]".toRegex()
val INTEGER = "([-+]?[0-9]+)".toRegex()
val DOUBLE_UNTYPED = "([-+]?[0-9]*\\.?[0-9]+)".toRegex()
val ROUGH_PATTERN = "[-+]?[0-9]*\\.?[0-9]*[dDbBfFlLsS]?".toRegex()
}
fun parseNumericTag(): AbstractNbtNumber {
skipWhitespace()
val textForm = racer.consumeWhile { Patterns.ROUGH_PATTERN.matchEntire(it) != null }
if (textForm.isEmpty()) {
racer.error("Expected numeric tag (starting with either -, +, . or a digit")
}
val floatMatch = Patterns.FLOAT.matchEntire(textForm)
if (floatMatch != null) {
return NbtFloat.of(floatMatch.groups[1]!!.value.toFloat())
}
val byteMatch = Patterns.BYTE.matchEntire(textForm)
if (byteMatch != null) {
return NbtByte.of(byteMatch.groups[1]!!.value.toByte())
}
val longMatch = Patterns.LONG.matchEntire(textForm)
if (longMatch != null) {
return NbtLong.of(longMatch.groups[1]!!.value.toLong())
}
val shortMatch = Patterns.SHORT.matchEntire(textForm)
if (shortMatch != null) {
return NbtShort.of(shortMatch.groups[1]!!.value.toShort())
}
val integerMatch = Patterns.INTEGER.matchEntire(textForm)
if (integerMatch != null) {
return NbtInt.of(integerMatch.groups[1]!!.value.toInt())
}
val doubleMatch = Patterns.DOUBLE.matchEntire(textForm) ?: Patterns.DOUBLE_UNTYPED.matchEntire(textForm)
if (doubleMatch != null) {
return NbtDouble.of(doubleMatch.groups[1]!!.value.toDouble())
}
throw IllegalStateException("Could not properly parse numeric tag '$textForm', despite passing rough verification. This is a bug in the LegacyTagParser")
}
private fun parseIdentifier(): String {
skipWhitespace()
if (racer.peek(1) == "\"") {
return parseQuotedString()
}
return racer.consumeWhile {
val x = it.last()
x != ':' && !Character.isWhitespace(x)
}
}
}
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