/*
	Adobe Systems Incorporated(r) Source Code License Agreement
	Copyright(c) 2005 Adobe Systems Incorporated. All rights reserved.
	
	Please read this Source Code License Agreement carefully before using
	the source code.
	
	Adobe Systems Incorporated grants to you a perpetual, worldwide, non-exclusive, 
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	distribute this source code and such derivative works in source or 
	object code form without any attribution requirements.  
	
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	derived from the source code without prior written permission.
	
	You agree to indemnify, hold harmless and defend Adobe Systems Incorporated from and
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	fees that arise or result from your use or distribution of the source 
	code.
	
	THIS SOURCE CODE IS PROVIDED "AS IS" AND "WITH ALL FAULTS", WITHOUT 
	ANY TECHNICAL SUPPORT OR ANY EXPRESSED OR IMPLIED WARRANTIES, INCLUDING,
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	FOR A PARTICULAR PURPOSE ARE DISCLAIMED.  ALSO, THERE IS NO WARRANTY OF 
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*/
package com.adobe.images
{
	import flash.geom.*;
	import flash.display.*;
	import flash.utils.*;
	
	/**
	 * Class that converts BitmapData into a valid JPEG
	 */		
	public class JPGEncoder
	{

		// Static table initialization
	
		private var ZigZag:Array = [
			 0, 1, 5, 6,14,15,27,28,
			 2, 4, 7,13,16,26,29,42,
			 3, 8,12,17,25,30,41,43,
			 9,11,18,24,31,40,44,53,
			10,19,23,32,39,45,52,54,
			20,22,33,38,46,51,55,60,
			21,34,37,47,50,56,59,61,
			35,36,48,49,57,58,62,63
		];
	
		private var YTable:Array = new Array(64);
		private var UVTable:Array = new Array(64);
		private var fdtbl_Y:Array = new Array(64);
		private var fdtbl_UV:Array = new Array(64);
	
		private function initQuantTables(sf:int):void
		{
			var i:int;
			var t:Number;
			var YQT:Array = [
				16, 11, 10, 16, 24, 40, 51, 61,
				12, 12, 14, 19, 26, 58, 60, 55,
				14, 13, 16, 24, 40, 57, 69, 56,
				14, 17, 22, 29, 51, 87, 80, 62,
				18, 22, 37, 56, 68,109,103, 77,
				24, 35, 55, 64, 81,104,113, 92,
				49, 64, 78, 87,103,121,120,101,
				72, 92, 95, 98,112,100,103, 99
			];
			for (i = 0; i < 64; i++) {
				t = Math.floor((YQT[i]*sf+50)/100);
				if (t < 1) {
					t = 1;
				} else if (t > 255) {
					t = 255;
				}
				YTable[ZigZag[i]] = t;
			}
			var UVQT:Array = [
				17, 18, 24, 47, 99, 99, 99, 99,
				18, 21, 26, 66, 99, 99, 99, 99,
				24, 26, 56, 99, 99, 99, 99, 99,
				47, 66, 99, 99, 99, 99, 99, 99,
				99, 99, 99, 99, 99, 99, 99, 99,
				99, 99, 99, 99, 99, 99, 99, 99,
				99, 99, 99, 99, 99, 99, 99, 99,
				99, 99, 99, 99, 99, 99, 99, 99
			];
			for (i = 0; i < 64; i++) {
				t = Math.floor((UVQT[i]*sf+50)/100);
				if (t < 1) {
					t = 1;
				} else if (t > 255) {
					t = 255;
				}
				UVTable[ZigZag[i]] = t;
			}
			var aasf:Array = [
				1.0, 1.387039845, 1.306562965, 1.175875602,
				1.0, 0.785694958, 0.541196100, 0.275899379
			];
			i = 0;
			for (var row:int = 0; row < 8; row++)
			{
				for (var col:int = 0; col < 8; col++)
				{
					fdtbl_Y[i]  = (1.0 / (YTable [ZigZag[i]] * aasf[row] * aasf[col] * 8.0));
					fdtbl_UV[i] = (1.0 / (UVTable[ZigZag[i]] * aasf[row] * aasf[col] * 8.0));
					i++;
				}
			}
		}
	
		private var YDC_HT:Array;
		private var UVDC_HT:Array;
		private var YAC_HT:Array;
		private var UVAC_HT:Array;
	
		private function computeHuffmanTbl(nrcodes:Array, std_table:Array):Array
		{
			var codevalue:int = 0;
			var pos_in_table:int = 0;
			var HT:Array = new Array();
			for (var k:int=1; k<=16; k++) {
				for (var j:int=1; j<=nrcodes[k]; j++) {
					HT[std_table[pos_in_table]] = new BitString();
					HT[std_table[pos_in_table]].val = codevalue;
					HT[std_table[pos_in_table]].len = k;
					pos_in_table++;
					codevalue++;
				}
				codevalue*=2;
			}
			return HT;
		}
	
		private var std_dc_luminance_nrcodes:Array = [0,0,1,5,1,1,1,1,1,1,0,0,0,0,0,0,0];
		private var std_dc_luminance_values:Array = [0,1,2,3,4,5,6,7,8,9,10,11];
		private var std_ac_luminance_nrcodes:Array = [0,0,2,1,3,3,2,4,3,5,5,4,4,0,0,1,0x7d];
		private var std_ac_luminance_values:Array = [
			0x01,0x02,0x03,0x00,0x04,0x11,0x05,0x12,
			0x21,0x31,0x41,0x06,0x13,0x51,0x61,0x07,
			0x22,0x71,0x14,0x32,0x81,0x91,0xa1,0x08,
			0x23,0x42,0xb1,0xc1,0x15,0x52,0xd1,0xf0,
			0x24,0x33,0x62,0x72,0x82,0x09,0x0a,0x16,
			0x17,0x18,0x19,0x1a,0x25,0x26,0x27,0x28,
			0x29,0x2a,0x34,0x35,0x36,0x37,0x38,0x39,
			0x3a,0x43,0x44,0x45,0x46,0x47,0x48,0x49,
			0x4a,0x53,0x54,0x55,0x56,0x57,0x58,0x59,
			0x5a,0x63,0x64,0x65,0x66,0x67,0x68,0x69,
			0x6a,0x73,0x74,0x75,0x76,0x77,0x78,0x79,
			0x7a,0x83,0x84,0x85,0x86,0x87,0x88,0x89,
			0x8a,0x92,0x93,0x94,0x95,0x96,0x97,0x98,
			0x99,0x9a,0xa2,0xa3,0xa4,0xa5,0xa6,0xa7,
			0xa8,0xa9,0xaa,0xb2,0xb3,0xb4,0xb5,0xb6,
			0xb7,0xb8,0xb9,0xba,0xc2,0xc3,0xc4,0xc5,
			0xc6,0xc7,0xc8,0xc9,0xca,0xd2,0xd3,0xd4,
			0xd5,0xd6,0xd7,0xd8,0xd9,0xda,0xe1,0xe2,
			0xe3,0xe4,0xe5,0xe6,0xe7,0xe8,0xe9,0xea,
			0xf1,0xf2,0xf3,0xf4,0xf5,0xf6,0xf7,0xf8,
			0xf9,0xfa
		];
	
		private var std_dc_chrominance_nrcodes:Array = [0,0,3,1,1,1,1,1,1,1,1,1,0,0,0,0,0];
		private var std_dc_chrominance_values:Array = [0,1,2,3,4,5,6,7,8,9,10,11];
		private var std_ac_chrominance_nrcodes:Array = [0,0,2,1,2,4,4,3,4,7,5,4,4,0,1,2,0x77];
		private var std_ac_chrominance_values:Array = [
			0x00,0x01,0x02,0x03,0x11,0x04,0x05,0x21,
			0x31,0x06,0x12,0x41,0x51,0x07,0x61,0x71,
			0x13,0x22,0x32,0x81,0x08,0x14,0x42,0x91,
			0xa1,0xb1,0xc1,0x09,0x23,0x33,0x52,0xf0,
			0x15,0x62,0x72,0xd1,0x0a,0x16,0x24,0x34,
			0xe1,0x25,0xf1,0x17,0x18,0x19,0x1a,0x26,
			0x27,0x28,0x29,0x2a,0x35,0x36,0x37,0x38,
			0x39,0x3a,0x43,0x44,0x45,0x46,0x47,0x48,
			0x49,0x4a,0x53,0x54,0x55,0x56,0x57,0x58,
			0x59,0x5a,0x63,0x64,0x65,0x66,0x67,0x68,
			0x69,0x6a,0x73,0x74,0x75,0x76,0x77,0x78,
			0x79,0x7a,0x82,0x83,0x84,0x85,0x86,0x87,
			0x88,0x89,0x8a,0x92,0x93,0x94,0x95,0x96,
			0x97,0x98,0x99,0x9a,0xa2,0xa3,0xa4,0xa5,
			0xa6,0xa7,0xa8,0xa9,0xaa,0xb2,0xb3,0xb4,
			0xb5,0xb6,0xb7,0xb8,0xb9,0xba,0xc2,0xc3,
			0xc4,0xc5,0xc6,0xc7,0xc8,0xc9,0xca,0xd2,
			0xd3,0xd4,0xd5,0xd6,0xd7,0xd8,0xd9,0xda,
			0xe2,0xe3,0xe4,0xe5,0xe6,0xe7,0xe8,0xe9,
			0xea,0xf2,0xf3,0xf4,0xf5,0xf6,0xf7,0xf8,
			0xf9,0xfa
		];
	
		private function initHuffmanTbl():void
		{
			YDC_HT = computeHuffmanTbl(std_dc_luminance_nrcodes,std_dc_luminance_values);
			UVDC_HT = computeHuffmanTbl(std_dc_chrominance_nrcodes,std_dc_chrominance_values);
			YAC_HT = computeHuffmanTbl(std_ac_luminance_nrcodes,std_ac_luminance_values);
			UVAC_HT = computeHuffmanTbl(std_ac_chrominance_nrcodes,std_ac_chrominance_values);
		}
	
		private var bitcode:Array = new Array(65535);
		private var category:Array = new Array(65535);
	
		private function initCategoryNumber():void
		{
			var nrlower:int = 1;
			var nrupper:int = 2;
			var nr:int;
			for (var cat:int=1; cat<=15; cat++) {
				//Positive numbers
				for (nr=nrlower; nr<nrupper; nr++) {
					category[32767+nr] = cat;
					bitcode[32767+nr] = new BitString();
					bitcode[32767+nr].len = cat;
					bitcode[32767+nr].val = nr;
				}
				//Negative numbers
				for (nr=-(nrupper-1); nr<=-nrlower; nr++) {
					category[32767+nr] = cat;
					bitcode[32767+nr] = new BitString();
					bitcode[32767+nr].len = cat;
					bitcode[32767+nr].val = nrupper-1+nr;
				}
				nrlower <<= 1;
				nrupper <<= 1;
			}
		}
	
		// IO functions
	
		private var byteout:ByteArray;
		private var bytenew:int = 0;
		private var bytepos:int = 7;
	
		private function writeBits(bs:BitString):void
		{
			var value:int = bs.val;
			var posval:int = bs.len-1;
			while ( posval >= 0 ) {
				if (value & uint(1 << posval) ) {
					bytenew |= uint(1 << bytepos);
				}
				posval--;
				bytepos--;
				if (bytepos < 0) {
					if (bytenew == 0xFF) {
						writeByte(0xFF);
						writeByte(0);
					}
					else {
						writeByte(bytenew);
					}
					bytepos=7;
					bytenew=0;
				}
			}
		}
	
		private function writeByte(value:int):void
		{
			byteout.writeByte(value);
		}
	
		private function writeWord(value:int):void
		{
			writeByte((value>>8)&0xFF);
			writeByte((value   )&0xFF);
		}
	
		// DCT & quantization core
	
		private function fDCTQuant(data:Array, fdtbl:Array):Array
		{
			var tmp0:Number, tmp1:Number, tmp2:Number, tmp3:Number, tmp4:Number, tmp5:Number, tmp6:Number, tmp7:Number;
			var tmp10:Number, tmp11:Number, tmp12:Number, tmp13:Number;
			var z1:Number, z2:Number, z3:Number, z4:Number, z5:Number, z11:Number, z13:Number;
			var i:int;
			/* Pass 1: process rows. */
			var dataOff:int=0;
			for (i=0; i<8; i++) {
				tmp0 = data[dataOff+0] + data[dataOff+7];
				tmp7 = data[dataOff+0] - data[dataOff+7];
				tmp1 = data[dataOff+1] + data[dataOff+6];
				tmp6 = data[dataOff+1] - data[dataOff+6];
				tmp2 = data[dataOff+2] + data[dataOff+5];
				tmp5 = data[dataOff+2] - data[dataOff+5];
				tmp3 = data[dataOff+3] + data[dataOff+4];
				tmp4 = data[dataOff+3] - data[dataOff+4];
	
				/* Even part */
				tmp10 = tmp0 + tmp3;	/* phase 2 */
				tmp13 = tmp0 - tmp3;
				tmp11 = tmp1 + tmp2;
				tmp12 = tmp1 - tmp2;
	
				data[dataOff+0] = tmp10 + tmp11; /* phase 3 */
				data[dataOff+4] = tmp10 - tmp11;
	
				z1 = (tmp12 + tmp13) * 0.707106781; /* c4 */
				data[dataOff+2] = tmp13 + z1; /* phase 5 */
				data[dataOff+6] = tmp13 - z1;
	
				/* Odd part */
				tmp10 = tmp4 + tmp5; /* phase 2 */
				tmp11 = tmp5 + tmp6;
				tmp12 = tmp6 + tmp7;
	
				/* The rotator is modified from fig 4-8 to avoid extra negations. */
				z5 = (tmp10 - tmp12) * 0.382683433; /* c6 */
				z2 = 0.541196100 * tmp10 + z5; /* c2-c6 */
				z4 = 1.306562965 * tmp12 + z5; /* c2+c6 */
				z3 = tmp11 * 0.707106781; /* c4 */
	
				z11 = tmp7 + z3;	/* phase 5 */
				z13 = tmp7 - z3;
	
				data[dataOff+5] = z13 + z2;	/* phase 6 */
				data[dataOff+3] = z13 - z2;
				data[dataOff+1] = z11 + z4;