commonMain.kotlinx.serialization.json.internal.StringOps.kt Maven / Gradle / Ivy

Go to download
/*
 * Copyright 2017-2019 JetBrains s.r.o. Use of this source code is governed by the Apache 2.0 license.
 */

package kotlinx.serialization.json.internal

import kotlin.native.concurrent.SharedImmutable

private fun toHexChar(i: Int) : Char {
    val d = i and 0xf
    return if (d < 10) (d + '0'.toInt()).toChar()
    else (d - 10 + 'a'.toInt()).toChar()
}

/*
 * Even though the actual size of this array is 92, it has to be the power of two, otherwise
 * JVM cannot perform advanced range-check elimination and vectorization in printQuoted
 */
@SharedImmutable
private val ESCAPE_CHARS: Array = arrayOfNulls(128).apply {
    for (c in 0..0x1f) {
        val c1 = toHexChar(c shr 12)
        val c2 = toHexChar(c shr 8)
        val c3 = toHexChar(c shr 4)
        val c4 = toHexChar(c)
        this[c] = "\\u$c1$c2$c3$c4"
    }
    this['"'.toInt()] = "\\\""
    this['\\'.toInt()] = "\\\\"
    this['\t'.toInt()] = "\\t"
    this['\b'.toInt()] = "\\b"
    this['\n'.toInt()] = "\\n"
    this['\r'.toInt()] = "\\r"
    this[0x0c] = "\\f"
}

internal fun StringBuilder.printQuoted(value: String) {
    append(STRING)
    var lastPos = 0
    val length = value.length
    for (i in 0 until length) {
        val c = value[i].toInt()
        // Do not replace this constant with C2ESC_MAX (which is smaller than ESCAPE_CHARS size),
        // otherwise JIT won't eliminate range check and won't vectorize this loop
        if (c >= ESCAPE_CHARS.size) continue // no need to escape
        val esc = ESCAPE_CHARS[c] ?: continue
        append(value, lastPos, i) // flush prev
        append(esc)
        lastPos = i + 1
    }
    append(value, lastPos, length)
    append(STRING)
}

/**
 * Returns `true` if the contents of this string is equal to the word "true", ignoring case, `false` if content equals "false",
 * and throws [IllegalStateException] otherwise.
 */
internal fun String.toBooleanStrict(): Boolean = toBooleanStrictOrNull() ?: throw IllegalStateException("$this does not represent a Boolean")

/**
 * Returns `true` if the contents of this string is equal to the word "true", ignoring case, `false` if content equals "false",
 * and returns `null` otherwise.
 */
internal fun String.toBooleanStrictOrNull(): Boolean? = when {
    this.equals("true", ignoreCase = true) -> true
    this.equals("false", ignoreCase = true) -> false
    else -> null
}

internal fun shouldBeQuoted(str: String): Boolean {
    if (str == NULL) return true
    for (ch in str) {
        if (charToTokenClass(ch) != TC_OTHER) return true
    }

    return false
}