From 8815105bf2462787885214a12af927d484226f21 Mon Sep 17 00:00:00 2001 From: Torsten Grote Date: Thu, 30 Jul 2020 16:40:23 -0300 Subject: Split out common code into multiplatform Kotlin library --- .../commonMain/kotlin/net/taler/common/Amount.kt | 198 +++++++++++++++++++++ .../src/commonMain/kotlin/net/taler/common/Time.kt | 81 +++++++++ .../commonMain/kotlin/net/taler/common/Version.kt | 70 ++++++++ 3 files changed, 349 insertions(+) create mode 100644 taler-kotlin-common/src/commonMain/kotlin/net/taler/common/Amount.kt create mode 100644 taler-kotlin-common/src/commonMain/kotlin/net/taler/common/Time.kt create mode 100644 taler-kotlin-common/src/commonMain/kotlin/net/taler/common/Version.kt (limited to 'taler-kotlin-common/src/commonMain') diff --git a/taler-kotlin-common/src/commonMain/kotlin/net/taler/common/Amount.kt b/taler-kotlin-common/src/commonMain/kotlin/net/taler/common/Amount.kt new file mode 100644 index 0000000..84d10c5 --- /dev/null +++ b/taler-kotlin-common/src/commonMain/kotlin/net/taler/common/Amount.kt @@ -0,0 +1,198 @@ +/* + * This file is part of GNU Taler + * (C) 2020 Taler Systems S.A. + * + * GNU Taler is free software; you can redistribute it and/or modify it under the + * terms of the GNU General Public License as published by the Free Software + * Foundation; either version 3, or (at your option) any later version. + * + * GNU Taler is distributed in the hope that it will be useful, but WITHOUT ANY + * WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR + * A PARTICULAR PURPOSE. See the GNU General Public License for more details. + * + * You should have received a copy of the GNU General Public License along with + * GNU Taler; see the file COPYING. If not, see + */ + +package net.taler.common + +import kotlinx.serialization.Decoder +import kotlinx.serialization.Encoder +import kotlinx.serialization.KSerializer +import kotlinx.serialization.Serializable +import kotlinx.serialization.Serializer +import kotlin.math.floor +import kotlin.math.pow +import kotlin.math.roundToInt + +class AmountParserException(msg: String? = null, cause: Throwable? = null) : Exception(msg, cause) +class AmountOverflowException(msg: String? = null, cause: Throwable? = null) : Exception(msg, cause) + +@Serializable(with = KotlinXAmountSerializer::class) +data class Amount( + /** + * name of the currency using either a three-character ISO 4217 currency code, + * or a regional currency identifier starting with a "*" followed by at most 10 characters. + * ISO 4217 exponents in the name are not supported, + * although the "fraction" is corresponds to an ISO 4217 exponent of 6. + */ + val currency: String, + + /** + * The integer part may be at most 2^52. + * Note that "1" here would correspond to 1 EUR or 1 USD, depending on currency, not 1 cent. + */ + val value: Long, + + /** + * Unsigned 32 bit fractional value to be added to value representing + * an additional currency fraction, in units of one hundred millionth (1e-8) + * of the base currency value. For example, a fraction + * of 50_000_000 would correspond to 50 cents. + */ + val fraction: Int +) : Comparable { + + companion object { + + private const val FRACTIONAL_BASE: Int = 100000000 // 1e8 + + private val REGEX_CURRENCY = Regex("""^[-_*A-Za-z0-9]{1,12}$""") + val MAX_VALUE = 2.0.pow(52).toLong() + private const val MAX_FRACTION_LENGTH = 8 + const val MAX_FRACTION = 99_999_999 + + fun zero(currency: String): Amount { + return Amount(checkCurrency(currency), 0, 0) + } + + fun fromJSONString(str: String): Amount { + val split = str.split(":") + if (split.size != 2) throw AmountParserException("Invalid Amount Format") + return fromString(split[0], split[1]) + } + + fun fromString(currency: String, str: String): Amount { + // value + val valueSplit = str.split(".") + val value = checkValue(valueSplit[0].toLongOrNull()) + // fraction + val fraction: Int = if (valueSplit.size > 1) { + val fractionStr = valueSplit[1] + if (fractionStr.length > MAX_FRACTION_LENGTH) + throw AmountParserException("Fraction $fractionStr too long") + val fraction = "0.$fractionStr".toDoubleOrNull() + ?.times(FRACTIONAL_BASE) + ?.roundToInt() + checkFraction(fraction) + } else 0 + return Amount(checkCurrency(currency), value, fraction) + } + + fun min(currency: String): Amount = Amount(currency, 0, 1) + fun max(currency: String): Amount = Amount(currency, MAX_VALUE, MAX_FRACTION) + + + internal fun checkCurrency(currency: String): String { + if (!REGEX_CURRENCY.matches(currency)) + throw AmountParserException("Invalid currency: $currency") + return currency + } + + internal fun checkValue(value: Long?): Long { + if (value == null || value > MAX_VALUE) + throw AmountParserException("Value $value greater than $MAX_VALUE") + return value + } + + internal fun checkFraction(fraction: Int?): Int { + if (fraction == null || fraction > MAX_FRACTION) + throw AmountParserException("Fraction $fraction greater than $MAX_FRACTION") + return fraction + } + + } + + val amountStr: String + get() = if (fraction == 0) "$value" else { + var f = fraction + var fractionStr = "" + while (f > 0) { + fractionStr += f / (FRACTIONAL_BASE / 10) + f = (f * 10) % FRACTIONAL_BASE + } + "$value.$fractionStr" + } + + operator fun plus(other: Amount): Amount { + check(currency == other.currency) { "Can only subtract from same currency" } + val resultValue = value + other.value + floor((fraction + other.fraction).toDouble() / FRACTIONAL_BASE).toLong() + if (resultValue > MAX_VALUE) + throw AmountOverflowException() + val resultFraction = (fraction + other.fraction) % FRACTIONAL_BASE + return Amount(currency, resultValue, resultFraction) + } + + operator fun times(factor: Int): Amount { + // TODO consider replacing with a faster implementation + if (factor == 0) return zero(currency) + var result = this + for (i in 1 until factor) result += this + return result + } + + operator fun minus(other: Amount): Amount { + check(currency == other.currency) { "Can only subtract from same currency" } + var resultValue = value + var resultFraction = fraction + if (resultFraction < other.fraction) { + if (resultValue < 1L) + throw AmountOverflowException() + resultValue-- + resultFraction += FRACTIONAL_BASE + } + check(resultFraction >= other.fraction) + resultFraction -= other.fraction + if (resultValue < other.value) + throw AmountOverflowException() + resultValue -= other.value + return Amount(currency, resultValue, resultFraction) + } + + fun isZero(): Boolean { + return value == 0L && fraction == 0 + } + + fun toJSONString(): String { + return "$currency:$amountStr" + } + + override fun toString(): String { + return "$amountStr $currency" + } + + override fun compareTo(other: Amount): Int { + check(currency == other.currency) { "Can only compare amounts with the same currency" } + when { + value == other.value -> { + if (fraction < other.fraction) return -1 + if (fraction > other.fraction) return 1 + return 0 + } + value < other.value -> return -1 + else -> return 1 + } + } + +} + +@Serializer(forClass = Amount::class) +object KotlinXAmountSerializer: KSerializer { + override fun serialize(encoder: Encoder, value: Amount) { + encoder.encodeString(value.toJSONString()) + } + + override fun deserialize(decoder: Decoder): Amount { + return Amount.fromJSONString(decoder.decodeString()) + } +} diff --git a/taler-kotlin-common/src/commonMain/kotlin/net/taler/common/Time.kt b/taler-kotlin-common/src/commonMain/kotlin/net/taler/common/Time.kt new file mode 100644 index 0000000..962e004 --- /dev/null +++ b/taler-kotlin-common/src/commonMain/kotlin/net/taler/common/Time.kt @@ -0,0 +1,81 @@ +/* + * This file is part of GNU Taler + * (C) 2020 Taler Systems S.A. + * + * GNU Taler is free software; you can redistribute it and/or modify it under the + * terms of the GNU General Public License as published by the Free Software + * Foundation; either version 3, or (at your option) any later version. + * + * GNU Taler is distributed in the hope that it will be useful, but WITHOUT ANY + * WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR + * A PARTICULAR PURPOSE. See the GNU General Public License for more details. + * + * You should have received a copy of the GNU General Public License along with + * GNU Taler; see the file COPYING. If not, see + */ + +package net.taler.common + +import kotlinx.serialization.SerialName +import kotlinx.serialization.Serializable +import net.taler.common.Duration.Companion.FOREVER +import kotlin.math.max + +expect fun nowMillis(): Long + +@Serializable +data class Timestamp( + @SerialName("t_ms") + val ms: Long +) : Comparable { + + companion object { + const val NEVER: Long = -1 // TODO or UINT64_MAX? + fun now(): Timestamp = Timestamp(nowMillis()) + } + + /** + * Returns a copy of this [Timestamp] rounded to seconds. + */ + fun truncateSeconds(): Timestamp { + if (ms == NEVER) return Timestamp(ms) + return Timestamp((ms / 1000L) * 1000L) + } + + operator fun minus(other: Timestamp): Duration = when { + ms == NEVER -> Duration(FOREVER) + other.ms == NEVER -> throw Error("Invalid argument for timestamp comparision") + ms < other.ms -> Duration(0) + else -> Duration(ms - other.ms) + } + + operator fun minus(other: Duration): Timestamp = when { + ms == NEVER -> this + other.ms == FOREVER -> Timestamp(0) + else -> Timestamp(max(0, ms - other.ms)) + } + + override fun compareTo(other: Timestamp): Int { + return if (ms == NEVER) { + if (other.ms == NEVER) 0 + else 1 + } else { + if (other.ms == NEVER) -1 + else ms.compareTo(other.ms) + } + } + +} + +@Serializable +data class Duration( + /** + * Duration in milliseconds. + */ + @SerialName("d_ms") + val ms: Long +) { + companion object { + const val FOREVER: Long = -1 // TODO or UINT64_MAX? + } +} diff --git a/taler-kotlin-common/src/commonMain/kotlin/net/taler/common/Version.kt b/taler-kotlin-common/src/commonMain/kotlin/net/taler/common/Version.kt new file mode 100644 index 0000000..8774115 --- /dev/null +++ b/taler-kotlin-common/src/commonMain/kotlin/net/taler/common/Version.kt @@ -0,0 +1,70 @@ +/* + * This file is part of GNU Taler + * (C) 2020 Taler Systems S.A. + * + * GNU Taler is free software; you can redistribute it and/or modify it under the + * terms of the GNU General Public License as published by the Free Software + * Foundation; either version 3, or (at your option) any later version. + * + * GNU Taler is distributed in the hope that it will be useful, but WITHOUT ANY + * WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR + * A PARTICULAR PURPOSE. See the GNU General Public License for more details. + * + * You should have received a copy of the GNU General Public License along with + * GNU Taler; see the file COPYING. If not, see + */ + +package net.taler.common + +import kotlin.math.sign + +/** + * Semantic versioning, but libtool-style. + * See https://www.gnu.org/software/libtool/manual/html_node/Libtool-versioning.html + */ +data class Version( + val current: Int, + val revision: Int, + val age: Int +) { + companion object { + fun parse(v: String): Version? { + val elements = v.split(":") + if (elements.size != 3) return null + val (currentStr, revisionStr, ageStr) = elements + val current = currentStr.toIntOrNull() + val revision = revisionStr.toIntOrNull() + val age = ageStr.toIntOrNull() + if (current == null || revision == null || age == null) return null + return Version(current, revision, age) + } + } + + /** + * Compare two libtool-style versions. + * + * Returns a [VersionMatchResult] or null if the given version was null. + */ + fun compare(other: Version?): VersionMatchResult? { + if (other == null) return null + val compatible = current - age <= other.current && + current >= other.current - other.age + val currentCmp = sign((current - other.current).toDouble()).toInt() + return VersionMatchResult(compatible, currentCmp) + } + + /** + * Result of comparing two libtool versions. + */ + data class VersionMatchResult( + /** + * Is the first version compatible with the second? + */ + val compatible: Boolean, + /** + * Is the first version older (-1), newer (+1) or identical (0)? + */ + val currentCmp: Int + ) + +} -- cgit v1.2.3