Add number to string conversion with the specified radix.

#KT-8286

libraries/stdlib/src/kotlin/text/ParsePrimitivesJVM.kt

@@ -5,6 +5,34 @@
 
 package kotlin.text
 
+/**
+ * Returns a string representation of this [Byte] value in the specified [radix].
+ */
+@SinceKotlin("1.1")
+@kotlin.internal.InlineOnly
+public inline fun Byte.toString(radix: Int): String = this.toInt().toString(radix)
+
+/**
+ * Returns a string representation of this [Short] value in the specified [radix].
+ */
+@SinceKotlin("1.1")
+@kotlin.internal.InlineOnly
+public inline fun Short.toString(radix: Int): String = this.toInt().toString(radix)
+
+/**
+ * Returns a string representation of this [Int] value in the specified [radix].
+ */
+@SinceKotlin("1.1")
+@kotlin.internal.InlineOnly
+// TODO: use checkRadix(radix) when PublishedApi is available
+public inline fun Int.toString(radix: Int): String = java.lang.Integer.toString(this, radix)
+
+/**
+ * Returns a string representation of this [Long] value in the specified [radix].
+ */
+@SinceKotlin("1.1")
+@kotlin.internal.InlineOnly
+public inline fun Long.toString(radix: Int): String = java.lang.Long.toString(this, radix)
 
 /**
  * Returns `true` if the contents of this string is equal to the word "true", ignoring case, and `false` otherwise.
@@ -25,6 +53,7 @@ public inline fun String.toByte(): Byte = java.lang.Byte.parseByte(this)
  */
 @SinceKotlin("1.1")
 @kotlin.internal.InlineOnly
+// TODO: use checkRadix(radix) when PublishedApi is available
 public inline fun String.toByte(radix: Int): Byte = java.lang.Byte.parseByte(this, radix)
 
 
@@ -295,8 +324,11 @@ private inline fun <T> screenFloatValue(str: String, parse: (String) -> T): T? {
 }
 
 internal fun digitOf(char: Char, radix: Int): Int = Character.digit(char.toInt(), radix)
-internal fun checkRadix(radix: Int) {
+
+// TODO: @PublishedApi
+internal fun checkRadix(radix: Int): Int {
     if(radix !in Character.MIN_RADIX..Character.MAX_RADIX) {
         throw IllegalArgumentException("radix $radix was not in valid range ${Character.MIN_RADIX..Character.MAX_RADIX}")
     }
+    return radix
 }

libraries/stdlib/test/text/ParsePrimitivesJVMTest.kt

@@ -155,6 +155,40 @@ class ParsePrimitivesJVMTest {
             assertFailsOrNull("007 not a number")
         }
     }
+
+    @Test fun byteToStringWithRadix() {
+        assertEquals("7a", 0x7a.toByte().toString(16))
+        assertEquals("-80", Byte.MIN_VALUE.toString(radix = 16))
+        assertEquals("3v", Byte.MAX_VALUE.toString(radix = 32))
+        assertEquals("-40", Byte.MIN_VALUE.toString(radix = 32))
+        // TODO: IllegalArgumentException on incorrect radix
+    }
+
+    @Test fun shortToStringWithRadix() {
+        assertEquals("7FFF", 0x7FFF.toShort().toString(radix = 16).toUpperCase())
+        assertEquals("-8000", (-0x8000).toShort().toString(radix = 16))
+        assertEquals("-sfs", (-29180).toShort().toString(radix = 32))
+
+        // TODO: IllegalArgumentException on incorrect radix
+    }
+
+    @Test fun intToStringWithRadix() {
+        assertEquals("-ff", (-255).toString(radix = 16))
+        assertEquals("1100110", 102.toString(radix = 2))
+        assertEquals("kona", 411787.toString(radix = 27))
+        // TODO: IllegalArgumentException on incorrect radix
+
+    }
+
+    @Test fun longToStringWithRadix() {
+        assertEquals("7f11223344556677", 0x7F11223344556677.toString(radix = 16))
+        assertEquals("hazelnut", 1356099454469L.toString(radix = 36))
+        assertEquals("-8000000000000000", Long.MIN_VALUE.toString(radix = 16))
+
+        // TODO: IllegalArgumentException on incorrect radix
+//        assertFailsWith<IllegalArgumentException>("Expected to fail with radix 37") { 37.toString(radix = 37) }
+//        assertFailsWith<IllegalArgumentException>("Expected to fail with radix 1") { 1.toString(radix = 1) }
+    }
 }
 
 
@@ -181,7 +215,7 @@ private class ConversionContext<T: Any>(val convertOrFail: (String) -> T,
 
     fun assertFailsOrNull(input: String) {
         assertFailsWith<NumberFormatException>("Expected to fail on input \"$input\"") { convertOrFail(input) }
-        assertNull (convertOrNull(input), message = "On input \"$input\"")
+        assertNull(convertOrNull(input), message = "On input \"$input\"")
     }
 }
 
@@ -196,7 +230,7 @@ private class ConversionWithRadixContext<T: Any>(val convertOrFail: String.(Int)
         assertFailsWith<NumberFormatException>("Expected to fail on input \"$input\" with radix $radix",
                                                { input.convertOrFail(radix) })
 
-        assertNull (input.convertOrNull(radix), message = "On input \"$input\" with radix $radix")
+        assertNull(input.convertOrNull(radix), message = "On input \"$input\" with radix $radix")
     }
 }