summaryrefslogtreecommitdiff
path: root/wallet/src/main/java/net/taler/wallet/Amount.kt
diff options
context:
space:
mode:
Diffstat (limited to 'wallet/src/main/java/net/taler/wallet/Amount.kt')
-rw-r--r--wallet/src/main/java/net/taler/wallet/Amount.kt141
1 files changed, 141 insertions, 0 deletions
diff --git a/wallet/src/main/java/net/taler/wallet/Amount.kt b/wallet/src/main/java/net/taler/wallet/Amount.kt
new file mode 100644
index 00000000..a19e9bc4
--- /dev/null
+++ b/wallet/src/main/java/net/taler/wallet/Amount.kt
@@ -0,0 +1,141 @@
+/*
+ * 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 <http://www.gnu.org/licenses/>
+ */
+
+@file:Suppress("EXPERIMENTAL_API_USAGE", "EXPERIMENTAL_UNSIGNED_LITERALS")
+
+package net.taler.wallet
+
+import com.fasterxml.jackson.core.JsonParser
+import com.fasterxml.jackson.databind.DeserializationContext
+import com.fasterxml.jackson.databind.annotation.JsonDeserialize
+import com.fasterxml.jackson.databind.deser.std.StdDeserializer
+import org.json.JSONObject
+import kotlin.math.round
+
+private const val FRACTIONAL_BASE = 1e8
+
+@JsonDeserialize(using = AmountDeserializer::class)
+data class Amount(val currency: String, val amount: String) {
+ fun isZero(): Boolean {
+ return amount.toDouble() == 0.0
+ }
+
+ companion object {
+ fun fromJson(jsonAmount: JSONObject): Amount {
+ val amountCurrency = jsonAmount.getString("currency")
+ val amountValue = jsonAmount.getString("value")
+ val amountFraction = jsonAmount.getString("fraction")
+ val amountIntValue = Integer.parseInt(amountValue)
+ val amountIntFraction = Integer.parseInt(amountFraction)
+ return Amount(
+ amountCurrency,
+ (amountIntValue + amountIntFraction / FRACTIONAL_BASE).toString()
+ )
+ }
+
+ fun fromString(strAmount: String): Amount {
+ val components = strAmount.split(":")
+ return Amount(components[0], components[1])
+ }
+ }
+
+ override fun toString(): String {
+ return String.format("%.2f $currency", amount.toDouble())
+ }
+}
+
+class AmountDeserializer : StdDeserializer<Amount>(Amount::class.java) {
+ override fun deserialize(p: JsonParser, ctxt: DeserializationContext): Amount {
+ val node = p.codec.readValue(p, String::class.java)
+ return Amount.fromString(node)
+ }
+}
+
+class ParsedAmount(
+ /**
+ * name of the currency using either a three-character ISO 4217 currency code,
+ * or a regional currency identifier starting with a "*" followed by at most 10 characters.
+ * ISO 4217 exponents in the name are not supported,
+ * although the "fraction" is corresponds to an ISO 4217 exponent of 6.
+ */
+ val currency: String,
+
+ /**
+ * unsigned 32 bit value in the currency,
+ * note that "1" here would correspond to 1 EUR or 1 USD, depending on currency, not 1 cent.
+ */
+ val value: UInt,
+
+ /**
+ * unsigned 32 bit fractional value to be added to value
+ * representing an additional currency fraction,
+ * in units of one millionth (1e-6) of the base currency value.
+ * For example, a fraction of 500,000 would correspond to 50 cents.
+ */
+ val fraction: Double
+) {
+ companion object {
+ fun parseAmount(str: String): ParsedAmount {
+ val split = str.split(":")
+ check(split.size == 2)
+ val currency = split[0]
+ val valueSplit = split[1].split(".")
+ val value = valueSplit[0].toUInt()
+ val fraction: Double = if (valueSplit.size > 1) {
+ round("0.${valueSplit[1]}".toDouble() * FRACTIONAL_BASE)
+ } else 0.0
+ return ParsedAmount(currency, value, fraction)
+ }
+ }
+
+ operator fun minus(other: ParsedAmount): ParsedAmount {
+ check(currency == other.currency) { "Can only subtract from same currency" }
+ var resultValue = value
+ var resultFraction = fraction
+ if (resultFraction < other.fraction) {
+ if (resultValue < 1u) {
+ return ParsedAmount(currency, 0u, 0.0)
+ }
+ resultValue--
+ resultFraction += FRACTIONAL_BASE
+ }
+ check(resultFraction >= other.fraction)
+ resultFraction -= other.fraction
+ if (resultValue < other.value) {
+ return ParsedAmount(currency, 0u, 0.0)
+ }
+ resultValue -= other.value
+ return ParsedAmount(currency, resultValue, resultFraction)
+ }
+
+ fun isZero(): Boolean {
+ return value == 0u && fraction == 0.0
+ }
+
+ @Suppress("unused")
+ fun toJSONString(): String {
+ return "$currency:${getValueString()}"
+ }
+
+ override fun toString(): String {
+ return "${getValueString()} $currency"
+ }
+
+ private fun getValueString(): String {
+ return "$value${(fraction / FRACTIONAL_BASE).toString().substring(1)}"
+ }
+
+}