diff --git a/common/src/commonMain/kotlin/net/dankito/utils/multiplatform/BigDecimal.kt b/common/src/commonMain/kotlin/net/dankito/utils/multiplatform/BigDecimal.kt
new file mode 100644
index 00000000..6e7432ad
--- /dev/null
+++ b/common/src/commonMain/kotlin/net/dankito/utils/multiplatform/BigDecimal.kt
@@ -0,0 +1,21 @@
+package net.dankito.utils.multiplatform
+
+
+expect fun Collection<BigDecimal>.sum(): BigDecimal
+
+
+expect class BigDecimal {
+
+    companion object {
+        val Zero: BigDecimal
+    }
+
+
+    constructor(decimal: String)
+
+    constructor(double: Double)
+
+
+    fun format(pattern: String): String
+
+}
\ No newline at end of file
diff --git a/common/src/commonMain/kotlin/net/dankito/utils/multiplatform/Date.kt b/common/src/commonMain/kotlin/net/dankito/utils/multiplatform/Date.kt
new file mode 100644
index 00000000..c2977776
--- /dev/null
+++ b/common/src/commonMain/kotlin/net/dankito/utils/multiplatform/Date.kt
@@ -0,0 +1,20 @@
+package net.dankito.utils.multiplatform
+
+
+fun Date.format(format: DateFormatter): String {
+    return format.format(this)
+}
+
+fun Date.format(pattern: String): String {
+    return this.format(DateFormatter(pattern))
+}
+
+
+expect class Date(millisSinceEpoch: Long) {
+
+    constructor()
+
+
+    val millisSinceEpoch: Long
+
+}
\ No newline at end of file
diff --git a/common/src/commonMain/kotlin/net/dankito/utils/multiplatform/DateFormatStyle.kt b/common/src/commonMain/kotlin/net/dankito/utils/multiplatform/DateFormatStyle.kt
new file mode 100644
index 00000000..cdc20e94
--- /dev/null
+++ b/common/src/commonMain/kotlin/net/dankito/utils/multiplatform/DateFormatStyle.kt
@@ -0,0 +1,14 @@
+package net.dankito.utils.multiplatform
+
+
+enum class DateFormatStyle {
+
+    Short,
+
+    Medium,
+
+    Long,
+
+    Full
+
+}
\ No newline at end of file
diff --git a/common/src/commonMain/kotlin/net/dankito/utils/multiplatform/DateFormatter.kt b/common/src/commonMain/kotlin/net/dankito/utils/multiplatform/DateFormatter.kt
new file mode 100644
index 00000000..48f23686
--- /dev/null
+++ b/common/src/commonMain/kotlin/net/dankito/utils/multiplatform/DateFormatter.kt
@@ -0,0 +1,13 @@
+package net.dankito.utils.multiplatform
+
+
+expect class DateFormatter constructor(pattern: String) {
+
+    constructor(dateStyle: DateFormatStyle)
+
+    constructor(dateStyle: DateFormatStyle, timeStyle: DateFormatStyle)
+
+
+    fun format(date: Date): String
+
+}
\ No newline at end of file
diff --git a/common/src/commonMain/kotlin/net/dankito/utils/multiplatform/File.kt b/common/src/commonMain/kotlin/net/dankito/utils/multiplatform/File.kt
new file mode 100644
index 00000000..02a302e4
--- /dev/null
+++ b/common/src/commonMain/kotlin/net/dankito/utils/multiplatform/File.kt
@@ -0,0 +1,19 @@
+package net.dankito.utils.multiplatform
+
+
+expect class File(path: String) {
+
+    constructor(folder: File, filename: String)
+
+
+    // have to specify it as method as property would conflict with java.io.File's getAbsolutePath
+    fun getAbsolutePath(): String
+
+    val filename: String
+
+    val fileExtension: String
+
+
+    fun mkdirs(): Boolean
+
+}
\ No newline at end of file
diff --git a/common/src/commonMain/kotlin/net/dankito/utils/multiplatform/UUID.kt b/common/src/commonMain/kotlin/net/dankito/utils/multiplatform/UUID.kt
new file mode 100644
index 00000000..8b77b083
--- /dev/null
+++ b/common/src/commonMain/kotlin/net/dankito/utils/multiplatform/UUID.kt
@@ -0,0 +1,12 @@
+package net.dankito.utils.multiplatform
+
+
+expect class UUID {
+
+    companion object {
+
+        fun random(): String
+
+    }
+
+}
\ No newline at end of file
diff --git a/common/src/commonMain/kotlin/net/dankito/utils/multiplatform/log/ConsoleLogger.kt b/common/src/commonMain/kotlin/net/dankito/utils/multiplatform/log/ConsoleLogger.kt
index 654242fd..fc6b9997 100644
--- a/common/src/commonMain/kotlin/net/dankito/utils/multiplatform/log/ConsoleLogger.kt
+++ b/common/src/commonMain/kotlin/net/dankito/utils/multiplatform/log/ConsoleLogger.kt
@@ -1,17 +1,18 @@
 package net.dankito.utils.multiplatform.log
 
-import com.soywiz.klock.DateTime
+import net.dankito.utils.multiplatform.Date
+import net.dankito.utils.multiplatform.DateFormatter
 
 
 open class ConsoleLogger(name: String) : LoggerBase(name) {
 
     companion object {
-        private val DateFormat = com.soywiz.klock.DateFormat.invoke("HH:mm:ss.SSS")
+        private val DateFormatter = DateFormatter("HH:mm:ss.SSS")
     }
 
 
     override fun log(level: LogLevel, message: String) {
-        println("${DateTime.nowLocal().toString(DateFormat)} $level $name - $message")
+        println("${DateFormatter.format(Date())} $level $name - $message")
     }
 
 }
\ No newline at end of file
diff --git a/common/src/iosMain/kotlin/net/dankito/utils/multiplatform/BigDecimal.kt b/common/src/iosMain/kotlin/net/dankito/utils/multiplatform/BigDecimal.kt
new file mode 100644
index 00000000..b33f34d8
--- /dev/null
+++ b/common/src/iosMain/kotlin/net/dankito/utils/multiplatform/BigDecimal.kt
@@ -0,0 +1,51 @@
+package net.dankito.utils.multiplatform
+
+import platform.Foundation.NSCoder
+import platform.Foundation.NSDecimalNumber
+import platform.Foundation.NSNumberFormatter
+import platform.Foundation.NSOrderedSame
+
+
+fun NSDecimalNumber.toBigDecimal(): BigDecimal {
+    return BigDecimal(this.stringValue) // TODO: find a better way than double string conversion
+}
+
+actual fun Collection<BigDecimal>.sum(): BigDecimal {
+    return this.fold(NSDecimalNumber.zero) { acc, e -> acc.decimalNumberByAdding(e) }.toBigDecimal()
+}
+
+
+actual class BigDecimal actual constructor(decimal: String) : NSDecimalNumber(NSCoder()) {
+
+    actual companion object {
+        actual val Zero = BigDecimal("0") // TODO: is this correct?
+    }
+
+
+    actual constructor(double: Double) : this(NSDecimalNumber(double).stringValue)
+
+
+    init {
+        super.decimalNumberByAdding(NSDecimalNumber(decimal))
+    }
+
+
+    actual fun format(pattern: String): String {
+        val formatter = NSNumberFormatter()
+
+        formatter.positiveFormat = pattern
+        formatter.negativeFormat = pattern
+
+        return formatter.stringFromNumber(this) ?: ""
+    }
+
+
+    override fun isEqual(`object`: Any?): Boolean {
+        if (`object` is BigDecimal) {
+            return this.compare(`object`) == NSOrderedSame
+        }
+
+        return super.equals(`object`)
+    }
+
+}
\ No newline at end of file
diff --git a/common/src/iosMain/kotlin/net/dankito/utils/multiplatform/Date.kt b/common/src/iosMain/kotlin/net/dankito/utils/multiplatform/Date.kt
new file mode 100644
index 00000000..41810fd9
--- /dev/null
+++ b/common/src/iosMain/kotlin/net/dankito/utils/multiplatform/Date.kt
@@ -0,0 +1,25 @@
+package net.dankito.utils.multiplatform
+
+import platform.Foundation.*
+
+
+fun NSTimeInterval.toMillis(): Long {
+    return this.toLong() * 1000
+}
+
+
+actual class Date actual constructor(millisSinceEpoch: Long)
+    : NSDate(timeIntervalSinceReferenceDate = ((millisSinceEpoch - DiffBetweenEpochTimeAndReferenceDate) / 1000).toDouble()) { // TODO: does this work?
+
+    companion object {
+        val DiffBetweenEpochTimeAndReferenceDate = (NSDate.timeIntervalSinceReferenceDate - NSTimeIntervalSince1970).toMillis()
+    }
+
+
+    actual constructor() : this(NSDate().timeIntervalSince1970.toMillis())
+
+
+    actual val millisSinceEpoch: Long
+        get() = timeIntervalSince1970.toMillis()
+
+}
\ No newline at end of file
diff --git a/common/src/iosMain/kotlin/net/dankito/utils/multiplatform/DateFormatter.kt b/common/src/iosMain/kotlin/net/dankito/utils/multiplatform/DateFormatter.kt
new file mode 100644
index 00000000..251431f9
--- /dev/null
+++ b/common/src/iosMain/kotlin/net/dankito/utils/multiplatform/DateFormatter.kt
@@ -0,0 +1,40 @@
+package net.dankito.utils.multiplatform
+
+import platform.Foundation.*
+
+
+fun DateFormatStyle.convert(): ULong {
+    return when (this) {
+        DateFormatStyle.Short -> NSDateFormatterShortStyle
+        DateFormatStyle.Medium -> NSDateFormatterMediumStyle
+        DateFormatStyle.Long -> NSDateFormatterLongStyle
+        DateFormatStyle.Full -> NSDateFormatterFullStyle
+    }
+}
+
+
+
+actual class DateFormatter actual constructor(val pattern: String): NSDateFormatter() {
+
+    actual constructor(dateStyle: DateFormatStyle) : this(NSDateFormatter().apply {
+        this.dateStyle = dateStyle.convert()
+    }.dateFormat) // TODO: does this work?
+
+    actual constructor(dateStyle: DateFormatStyle, timeStyle: DateFormatStyle) : this(NSDateFormatter().apply {
+        this.dateStyle = dateStyle.convert()
+        this.timeStyle = timeStyle.convert()
+    }.dateFormat) // TODO: does this work?
+
+
+    init {
+        this.dateFormat = pattern
+
+        this.timeZone = NSTimeZone.localTimeZone // TODO: needed?
+    }
+
+
+    actual fun format(date: Date): String {
+        return stringFromDate(date)
+    }
+
+}
\ No newline at end of file
diff --git a/common/src/iosMain/kotlin/net/dankito/utils/multiplatform/File.kt b/common/src/iosMain/kotlin/net/dankito/utils/multiplatform/File.kt
new file mode 100644
index 00000000..4c9c8b43
--- /dev/null
+++ b/common/src/iosMain/kotlin/net/dankito/utils/multiplatform/File.kt
@@ -0,0 +1,29 @@
+package net.dankito.utils.multiplatform
+
+import platform.Foundation.NSFileManager
+import platform.Foundation.NSURL
+import platform.Foundation.lastPathComponent
+
+
+actual class File actual constructor(path: String) : NSURL(fileURLWithPath = path) {
+
+    actual constructor(folder: File, filename: String)
+            : this(NSURL(string = filename, relativeToURL = folder).absoluteString ?: "") // TODO: or use 'fileURLWithPath'?
+
+
+    actual fun getAbsolutePath(): String {
+        return absoluteString ?: absoluteURL?.absoluteString ?: path ?: ""
+    }
+
+    actual val filename: String
+        get() = lastPathComponent ?: ""
+
+    actual val fileExtension: String
+        get() = filename.substringAfterLast('.', "")
+
+
+    actual fun mkdirs(): Boolean {
+        return NSFileManager.defaultManager.createDirectoryAtURL(this, true, null, null)
+    }
+
+}
\ No newline at end of file
diff --git a/common/src/iosMain/kotlin/net/dankito/utils/multiplatform/UUID.kt b/common/src/iosMain/kotlin/net/dankito/utils/multiplatform/UUID.kt
new file mode 100644
index 00000000..0f46238e
--- /dev/null
+++ b/common/src/iosMain/kotlin/net/dankito/utils/multiplatform/UUID.kt
@@ -0,0 +1,16 @@
+package net.dankito.utils.multiplatform
+
+import platform.Foundation.NSUUID
+
+
+actual class UUID {
+
+    actual companion object {
+
+        actual fun random(): String {
+            return NSUUID().UUIDString
+        }
+
+    }
+
+}
\ No newline at end of file
diff --git a/common/src/jvmMain/kotlin/net/dankito/utils/multiplatform/BigDecimal.kt b/common/src/jvmMain/kotlin/net/dankito/utils/multiplatform/BigDecimal.kt
new file mode 100644
index 00000000..b4468d4e
--- /dev/null
+++ b/common/src/jvmMain/kotlin/net/dankito/utils/multiplatform/BigDecimal.kt
@@ -0,0 +1,54 @@
+package net.dankito.utils.multiplatform
+
+
+fun java.math.BigDecimal.toBigDecimal(): BigDecimal {
+    return BigDecimal(this.toPlainString()) // TODO: find a better way than double string conversion
+}
+
+actual fun Collection<BigDecimal>.sum(): BigDecimal {
+    return this.fold(java.math.BigDecimal.ZERO) { acc, e -> (acc + e) }.toBigDecimal()
+}
+
+
+actual class BigDecimal actual constructor(decimal: String) : java.math.BigDecimal(decimal) {
+
+    actual companion object {
+        actual val Zero =
+            BigDecimal("0") // TODO: is this correct?
+    }
+
+
+    internal constructor() : this("0") // for object deserializers
+
+    actual constructor(double: Double) : this(java.math.BigDecimal.valueOf(double).toPlainString()) // for object deserializers
+
+
+    actual fun format(pattern: String): String {
+        return String.format(pattern, this)
+    }
+
+
+    override fun equals(other: Any?): Boolean {
+        if (other is BigDecimal) {
+            return this.compareTo(other) == 0
+        }
+
+        return super.equals(other)
+    }
+
+
+    /*      TODO: where are these methods coming from?      */
+
+    override fun toByte(): Byte {
+        return 0 // will never be called; where is this method coming from?
+    }
+
+    override fun toChar(): Char {
+        return 0.toChar() // will never be called; where is this method coming from?
+    }
+
+    override fun toShort(): Short {
+        return 0 // will never be called; where is this method coming from?
+    }
+
+}
\ No newline at end of file
diff --git a/common/src/jvmMain/kotlin/net/dankito/utils/multiplatform/Date.kt b/common/src/jvmMain/kotlin/net/dankito/utils/multiplatform/Date.kt
new file mode 100644
index 00000000..09416b05
--- /dev/null
+++ b/common/src/jvmMain/kotlin/net/dankito/utils/multiplatform/Date.kt
@@ -0,0 +1,12 @@
+package net.dankito.utils.multiplatform
+
+
+actual class Date actual constructor(millisSinceEpoch: Long) : java.util.Date(millisSinceEpoch) {
+
+    actual constructor() : this(System.currentTimeMillis())
+
+
+    actual val millisSinceEpoch: Long
+        get() = time
+
+}
\ No newline at end of file
diff --git a/common/src/jvmMain/kotlin/net/dankito/utils/multiplatform/DateFormatter.kt b/common/src/jvmMain/kotlin/net/dankito/utils/multiplatform/DateFormatter.kt
new file mode 100644
index 00000000..0985663a
--- /dev/null
+++ b/common/src/jvmMain/kotlin/net/dankito/utils/multiplatform/DateFormatter.kt
@@ -0,0 +1,30 @@
+package net.dankito.utils.multiplatform
+
+import java.text.DateFormat
+import java.text.SimpleDateFormat
+
+
+fun DateFormatStyle.convert(): Int {
+    return when (this) {
+        DateFormatStyle.Short -> DateFormat.SHORT
+        DateFormatStyle.Medium -> DateFormat.MEDIUM
+        DateFormatStyle.Long -> DateFormat.LONG
+        DateFormatStyle.Full -> DateFormat.FULL
+    }
+}
+
+
+actual class DateFormatter actual constructor(val pattern: String): SimpleDateFormat(pattern) {
+
+    actual constructor(dateStyle: DateFormatStyle)
+            : this((DateFormat.getDateInstance(dateStyle.convert()) as? SimpleDateFormat)?.toPattern() ?: "")
+
+    actual constructor(dateStyle: DateFormatStyle, timeStyle: DateFormatStyle)
+            : this((DateFormat.getDateTimeInstance(dateStyle.convert(), timeStyle.convert()) as? SimpleDateFormat)?.toPattern() ?: "")
+
+
+    actual fun format(date: Date): String {
+        return super.format(date)
+    }
+
+}
\ No newline at end of file
diff --git a/common/src/jvmMain/kotlin/net/dankito/utils/multiplatform/Extensions.kt b/common/src/jvmMain/kotlin/net/dankito/utils/multiplatform/Extensions.kt
new file mode 100644
index 00000000..f1a30fbd
--- /dev/null
+++ b/common/src/jvmMain/kotlin/net/dankito/utils/multiplatform/Extensions.kt
@@ -0,0 +1,6 @@
+package net.dankito.utils.multiplatform
+
+
+fun java.util.Date.toDate(): Date {
+    return Date(this.time)
+}
\ No newline at end of file
diff --git a/common/src/jvmMain/kotlin/net/dankito/utils/multiplatform/File.kt b/common/src/jvmMain/kotlin/net/dankito/utils/multiplatform/File.kt
new file mode 100644
index 00000000..e6fd6b1f
--- /dev/null
+++ b/common/src/jvmMain/kotlin/net/dankito/utils/multiplatform/File.kt
@@ -0,0 +1,35 @@
+package net.dankito.utils.multiplatform
+
+import java.io.File
+
+
+fun File.toFile(): net.dankito.utils.multiplatform.File {
+    return net.dankito.utils.multiplatform.File(this.absolutePath)
+}
+
+
+actual class File actual constructor(path: String) : File(path) {
+
+    actual constructor(folder: net.dankito.utils.multiplatform.File, filename: String)
+            : this(File(folder, filename).absolutePath)
+
+
+    internal constructor() : this("") // for object deserializers
+
+
+    actual override fun getAbsolutePath(): String {
+        return super.getAbsolutePath()
+    }
+
+    actual val filename: String
+        get() = super.getName()
+
+    actual val fileExtension: String
+        get() = this.extension
+
+
+    actual override fun mkdirs(): Boolean {
+        return super.mkdirs()
+    }
+
+}
\ No newline at end of file
diff --git a/common/src/jvmMain/kotlin/net/dankito/utils/multiplatform/UUID.kt b/common/src/jvmMain/kotlin/net/dankito/utils/multiplatform/UUID.kt
new file mode 100644
index 00000000..9de050ae
--- /dev/null
+++ b/common/src/jvmMain/kotlin/net/dankito/utils/multiplatform/UUID.kt
@@ -0,0 +1,16 @@
+package net.dankito.utils.multiplatform
+
+import java.util.UUID
+
+
+actual class UUID {
+
+    actual companion object {
+
+        actual fun random(): String {
+            return UUID.randomUUID().toString()
+        }
+
+    }
+
+}
\ No newline at end of file
diff --git a/common/src/jvmMain/kotlin/net/dankito/utils/multiplatform/log/DefaultLoggerFactory.kt b/common/src/jvmMain/kotlin/net/dankito/utils/multiplatform/log/DefaultLoggerFactory.kt
new file mode 100644
index 00000000..a32e4901
--- /dev/null
+++ b/common/src/jvmMain/kotlin/net/dankito/utils/multiplatform/log/DefaultLoggerFactory.kt
@@ -0,0 +1,24 @@
+package net.dankito.utils.multiplatform.log
+
+
+actual class DefaultLoggerFactory {
+
+    actual fun createDefaultLoggerFactory(): ILoggerFactory {
+        if (isClassAvailable("org.slf4j.Logger")) {
+            return Slf4jLoggerFactory()
+        }
+
+        return LogToConsoleLoggerFactory()
+    }
+
+    private fun isClassAvailable(qualifiedClassName: String): Boolean {
+        try {
+            Class.forName(qualifiedClassName)
+
+            return true
+        } catch (ignored: Exception) { }
+
+        return false
+    }
+
+}
\ No newline at end of file