/*
 * Copyright (C)2005-2019 Haxe Foundation
 *
 * Permission is hereby granted, free of charge, to any person obtaining a
 * copy of this software and associated documentation files (the "Software"),
 * to deal in the Software without restriction, including without limitation
 * the rights to use, copy, modify, merge, publish, distribute, sublicense,
 * and/or sell copies of the Software, and to permit persons to whom the
 * Software is furnished to do so, subject to the following conditions:
 *
 * The above copyright notice and this permission notice shall be included in
 * all copies or substantial portions of the Software.
 *
 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
 * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
 * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
 * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER
 * DEALINGS IN THE SOFTWARE.
 */

package haxe.io;

class BytesInput extends Input {
	var b:#if js js.lib.Uint8Array #elseif hl hl.Bytes #else BytesData #end;
	#if !flash
	var pos:Int;
	var len:Int;
	var totlen:Int;
	#end

	/** The current position in the stream in bytes. */
	public var position(get, set):Int;

	/** The length of the stream in bytes. */
	public var length(get, never):Int;

	public function new(b:Bytes, ?pos:Int, ?len:Int) {
		if (pos == null)
			pos = 0;
		if (len == null)
			len = b.length - pos;
		if (pos < 0 || len < 0 || pos + len > b.length)
			throw Error.OutsideBounds;
		#if flash
		var ba = b.getData();
		ba.position = pos;
		if (len != ba.bytesAvailable) {
			// truncate
			this.b = new flash.utils.ByteArray();
			ba.readBytes(this.b, 0, len);
		} else
			this.b = ba;
		this.b.endian = flash.utils.Endian.LITTLE_ENDIAN;
		#else
		this.b = #if (js || hl) @:privateAccess b.b #else b.getData() #end;
		this.pos = pos;
		this.len = len;
		this.totlen = len;
		#end
		#if python
		bigEndian = false;
		#end
	}

	inline function get_position():Int {
		#if flash
		return b.position;
		#else
		return pos;
		#end
	}

	inline function get_length():Int {
		#if flash
		return b.length;
		#else
		return totlen;
		#end
	}

	function set_position(p:Int):Int {
		if (p < 0)
			p = 0;
		else if (p > length)
			p = length;
		#if flash
		return b.position = p;
		#else
		len = totlen - p;
		return pos = p;
		#end
	}

	public override function readByte():Int {
		#if flash
		return try b.readUnsignedByte() catch (e:Dynamic) throw new Eof();
		#else
		if (this.len == 0)
			throw new Eof();
		len--;
		#if neko
		return untyped __dollar__sget(b, pos++);
		#elseif cpp
		return untyped b[pos++];
		#elseif java
		return untyped b[pos++] & 0xFF;
		#elseif python // dodge https://github.com/HaxeFoundation/haxe/issues/5080
		var b = b[pos];
		pos++;
		return b;
		#else
		return b[pos++];
		#end
		#end
	}

	public override function readBytes(buf:Bytes, pos:Int, len:Int):Int {
		#if !neko
		if (pos < 0 || len < 0 || pos + len > buf.length)
			throw Error.OutsideBounds;
		#end
		#if flash
		var avail:Int = b.bytesAvailable;
		if (len > avail && avail > 0)
			len = avail;
		try
			b.readBytes(buf.getData(), pos, len)
		catch (e:Dynamic)
			throw new Eof();
		#elseif java
		var avail:Int = this.len;
		if (len > avail)
			len = avail;
		if (len == 0)
			throw new Eof();
		java.lang.System.arraycopy(this.b, this.pos, buf.getData(), pos, len);
		this.pos += len;
		this.len -= len;
		#elseif cs
		var avail:Int = this.len;
		if (len > avail)
			len = avail;
		if (len == 0)
			throw new Eof();
		cs.system.Array.Copy(this.b, this.pos, buf.getData(), pos, len);
		this.pos += len;
		this.len -= len;
		#else
		if (this.len == 0 && len > 0)
			throw new Eof();
		if (this.len < len)
			len = this.len;
		#if neko
		try
			untyped __dollar__sblit(buf.getData(), pos, b, this.pos, len)
		catch (e:Dynamic)
			throw Error.OutsideBounds;
		#elseif hl
		@:privateAccess buf.b.blit(pos, b, this.pos, len);
		#else
		var b1 = b;
		var b2 = #if js @:privateAccess buf.b #else buf.getData() #end;
		for (i in 0...len)
			b2[pos + i] = b1[this.pos + i];
		#end
		this.pos += len;
		this.len -= len;
		#end
		return len;
	}

	#if flash
	@:dox(hide)
	override function set_bigEndian(e) {
		bigEndian = e;
		b.endian = e ? flash.utils.Endian.BIG_ENDIAN : flash.utils.Endian.LITTLE_ENDIAN;
		return e;
	}

	@:dox(hide)
	override function readFloat() {
		return try b.readFloat() catch (e:Dynamic) throw new Eof();
	}

	@:dox(hide)
	override function readDouble() {
		return try b.readDouble() catch (e:Dynamic) throw new Eof();
	}

	@:dox(hide)
	override function readInt8() {
		return try b.readByte() catch (e:Dynamic) throw new Eof();
	}

	@:dox(hide)
	override function readInt16() {
		return try b.readShort() catch (e:Dynamic) throw new Eof();
	}

	@:dox(hide)
	override function readUInt16():Int {
		return try b.readUnsignedShort() catch (e:Dynamic) throw new Eof();
	}

	@:dox(hide)
	override function readInt32():Int {
		return try b.readInt() catch (e:Dynamic) throw new Eof();
	}

	@:dox(hide)
	override function readString(len:Int, ?encoding:Encoding) {
		return try encoding == RawNative ? b.readMultiByte(len, "unicode") : b.readUTFBytes(len) catch (e:Dynamic) throw new Eof();
	}
	#end
}