Fix handling of long lines.

If we multiple long lines in succession the start index got
miscalculated and part of the latter lines discarded.

CHANGELOG

 vNEXT (in development)
 
+ * Fix handling of multiple long lines sometimes dropping part of the line
+ * Support lines with 8191 bytes of tags, as allowed by the message-tags spec
+
 v0.10.1
 
  * Added NickChangeFailed event for when nicknames are in use, banned, etc

src/main/kotlin/com/dmdirc/ktirc/io/LineBufferedSocket.kt

 
     override val receiveChannel
         get() = produce {
-            val lineBuffer = ByteArray(4096)
-            var index = 0
+            val lineBuffer = ByteArray(16384)
+            var nextByteOffset = 0
             while (!readChannel.isClosedForRead) {
-                var start = index
-                val count = readChannel.readAvailable(lineBuffer, index, lineBuffer.size - index)
-                for (i in index until index + count) {
+                var lineStart = 0
+                val bytesRead = readChannel.readAvailable(lineBuffer, nextByteOffset, lineBuffer.size - nextByteOffset)
+                for (i in nextByteOffset until nextByteOffset + bytesRead) {
                     if (lineBuffer[i] == CARRIAGE_RETURN || lineBuffer[i] == LINE_FEED) {
-                        if (start < i) {
-                            val line = lineBuffer.sliceArray(start until i)
+                        if (lineStart < i) {
+                            val line = lineBuffer.sliceArray(lineStart until i)
                             log.fine { "<<< ${String(line)}" }
                             send(line)
                         }
-                        start = i + 1
+                        lineStart = i + 1
                     }
                 }
-                lineBuffer.copyInto(lineBuffer, 0, start)
-                index = count + index - start
+                lineBuffer.copyInto(lineBuffer, 0, lineStart)
+                nextByteOffset += bytesRead - lineStart
             }
         }
 

src/test/kotlin/com/dmdirc/ktirc/io/KtorLineBufferedSocketTest.kt

         }
     }
 
+    @Test
+    fun `KtorLineBufferedSocket can receive multiple long lines of text`() = runBlocking {
+        ServerSocket(12321).use { serverSocket ->
+            val socket = KtorLineBufferedSocket(GlobalScope, "localhost", 12321)
+            val line1 = "abcdefghijklmnopqrstuvwxyz".repeat(500)
+            val line2 = "1234567890987654321[];'#,.".repeat(500)
+            val line3 = "ABCDEFGHIJKLMNOPQRSTUVWXYZ".repeat(500)
+            GlobalScope.launch {
+                serverSocket.accept().getOutputStream().write("$line1\r\n$line2\r$line3\n".toByteArray())
+            }
+
+            socket.connect()
+            val lineProducer = socket.receiveChannel
+            assertEquals(line1, String(lineProducer.receive()))
+            assertEquals(line2, String(lineProducer.receive()))
+            assertEquals(line3, String(lineProducer.receive()))
+        }
+    }
+
     @Test
     fun `KtorLineBufferedSocket can receive one line of text over multiple packets`() = runBlocking {
         ServerSocket(12321).use { serverSocket ->