(ns konserve.nio-helpers

(:import [java.nio.channels Channels ReadableByteChannel]

[java.io Reader File InputStream

ByteArrayInputStream FileInputStream StringReader]

(java.util Arrays)

(java.nio ByteBuffer)))

(def

^{:doc "Type object for a Java primitive byte array."

:private true}

byte-array-type (class (make-array Byte/TYPE 0)))

(def

^{:doc "Type object for a Java primitive char array."

:private true}

char-array-type (class (make-array Character/TYPE 0)))

(defprotocol BlobToChannel

(blob->channel [input buffer-size]))

(extend-protocol BlobToChannel

InputStream

(blob->channel [input _buffer-size]

[(Channels/newChannel input)

(fn [bis buffer] (.read ^ReadableByteChannel bis ^ByteBuffer buffer))])

File

(blob->channel [input _buffer-size]

[(Channels/newChannel (FileInputStream. ^String input))

(fn [bis buffer] (.read ^ReadableByteChannel bis buffer))])

String

(blob->channel [input _buffer-size]

[(Channels/newChannel (ByteArrayInputStream. (.getBytes input)))

(fn [bis buffer] (.read ^ReadableByteChannel bis buffer))])

Reader

(blob->channel [input buffer-size]

[input

(fn [bis nio-buffer]

(let [char-array (make-array Character/TYPE buffer-size)

size (.read ^StringReader bis ^chars char-array)]

(try

(when-not (= size -1)

(let [char-array-copy (Arrays/copyOf ^chars char-array size)]

(.put ^ByteBuffer nio-buffer (.getBytes (String. char-array-copy)))))

size

(catch Exception e

(throw e)))))]))

(extend

byte-array-type

BlobToChannel

{:blob->channel (fn [input _]

[(Channels/newChannel (ByteArrayInputStream. input))

(fn [bis buffer] (.read ^ReadableByteChannel bis buffer))])})

(extend

char-array-type

BlobToChannel

{:blob->channel (fn [input _]

[(Channels/newChannel (ByteArrayInputStream. (.getBytes (String. ^chars input))))

(fn [bis buffer] (.read ^ReadableByteChannel bis buffer))])})