<?php

///////////////////////////////////////////////////////////////////////////////////////////////////
// 2009-12-22 Adapted for mPDF 4.2
///////////////////////////////////////////////////////////////////////////////////////////////////
// GIF Util - (C) 2003 Yamasoft (S/C)
// http://www.yamasoft.com
// All Rights Reserved
// This file can be freely copied, distributed, modified, updated by anyone under the only
// condition to leave the original address (Yamasoft, http://www.yamasoft.com) and this header.
///////////////////////////////////////////////////////////////////////////////////////////////////
///////////////////////////////////////////////////////////////////////////////////////////////////
// 2009-12-22 Adapted INB
// Functions calling functionname($x, $len = 0) were not working on PHP5.1.5 as pass by reference
// All edited to $len = 0; then call function.
///////////////////////////////////////////////////////////////////////////////////////////////////
///////////////////////////////////////////////////////////////////////////////////////////////////

class CGIFLZW
{

	var $MAX_LZW_BITS;

	var $Fresh, $CodeSize, $SetCodeSize, $MaxCode, $MaxCodeSize, $FirstCode, $OldCode;

	var $ClearCode, $EndCode, $Next, $Vals, $Stack, $sp, $Buf, $CurBit, $LastBit, $Done, $LastByte;

	public function __construct()
	{
		$this->MAX_LZW_BITS = 12;
		unSet($this->Next);
		unSet($this->Vals);
		unSet($this->Stack);
		unSet($this->Buf);

		$this->Next = range(0, (1 << $this->MAX_LZW_BITS) - 1);
		$this->Vals = range(0, (1 << $this->MAX_LZW_BITS) - 1);
		$this->Stack = range(0, (1 << ($this->MAX_LZW_BITS + 1)) - 1);
		$this->Buf = range(0, 279);
	}

	function deCompress($data, &$datLen)
	{
		$stLen = strlen($data);
		$datLen = 0;
		$ret = "";
		$dp = 0;  // data pointer
		// INITIALIZATION
		$this->LZWCommandInit($data, $dp);

		while (($iIndex = $this->LZWCommand($data, $dp)) >= 0) {
			$ret .= chr($iIndex);
		}

		$datLen = $dp;

		if ($iIndex != -2) {
			return false;
		}

		return $ret;
	}

	function LZWCommandInit(&$data, &$dp)
	{
		$this->SetCodeSize = ord($data[0]);
		$dp += 1;

		$this->CodeSize = $this->SetCodeSize + 1;
		$this->ClearCode = 1 << $this->SetCodeSize;
		$this->EndCode = $this->ClearCode + 1;
		$this->MaxCode = $this->ClearCode + 2;
		$this->MaxCodeSize = $this->ClearCode << 1;

		$this->GetCodeInit($data, $dp);

		$this->Fresh = 1;
		for ($i = 0; $i < $this->ClearCode; $i++) {
			$this->Next[$i] = 0;
			$this->Vals[$i] = $i;
		}

		for (; $i < (1 << $this->MAX_LZW_BITS); $i++) {
			$this->Next[$i] = 0;
			$this->Vals[$i] = 0;
		}

		$this->sp = 0;
		return 1;
	}

	function LZWCommand(&$data, &$dp)
	{
		if ($this->Fresh) {
			$this->Fresh = 0;
			do {
				$this->FirstCode = $this->GetCode($data, $dp);
				$this->OldCode = $this->FirstCode;
			} while ($this->FirstCode == $this->ClearCode);

			return $this->FirstCode;
		}

		if ($this->sp > 0) {
			$this->sp--;
			return $this->Stack[$this->sp];
		}

		while (($Code = $this->GetCode($data, $dp)) >= 0) {
			if ($Code == $this->ClearCode) {
				for ($i = 0; $i < $this->ClearCode; $i++) {
					$this->Next[$i] = 0;
					$this->Vals[$i] = $i;
				}

				for (; $i < (1 << $this->MAX_LZW_BITS); $i++) {
					$this->Next[$i] = 0;
					$this->Vals[$i] = 0;
				}

				$this->CodeSize = $this->SetCodeSize + 1;
				$this->MaxCodeSize = $this->ClearCode << 1;
				$this->MaxCode = $this->ClearCode + 2;
				$this->sp = 0;
				$this->FirstCode = $this->GetCode($data, $dp);
				$this->OldCode = $this->FirstCode;

				return $this->FirstCode;
			}

			if ($Code == $this->EndCode) {
				return -2;
			}

			$InCode = $Code;
			if ($Code >= $this->MaxCode) {
				$this->Stack[$this->sp++] = $this->FirstCode;
				$Code = $this->OldCode;
			}

			while ($Code >= $this->ClearCode) {
				$this->Stack[$this->sp++] = $this->Vals[$Code];

				if ($Code == $this->Next[$Code]) // Circular table entry, big GIF Error!
					return -1;

				$Code = $this->Next[$Code];
			}

			$this->FirstCode = $this->Vals[$Code];
			$this->Stack[$this->sp++] = $this->FirstCode;

			if (($Code = $this->MaxCode) < (1 << $this->MAX_LZW_BITS)) {
				$this->Next[$Code] = $this->OldCode;
				$this->Vals[$Code] = $this->FirstCode;
				$this->MaxCode++;

				if (($this->MaxCode >= $this->MaxCodeSize) && ($this->MaxCodeSize < (1 << $this->MAX_LZW_BITS))) {
					$this->MaxCodeSize *= 2;
					$this->CodeSize++;
				}
			}

			$this->OldCode = $InCode;
			if ($this->sp > 0) {
				$this->sp--;
				return $this->Stack[$this->sp];
			}
		}

		return $Code;
	}

	function GetCodeInit(&$data, &$dp)
	{
		$this->CurBit = 0;
		$this->LastBit = 0;
		$this->Done = 0;
		$this->LastByte = 2;
		return 1;
	}

	function GetCode(&$data, &$dp)
	{
		if (($this->CurBit + $this->CodeSize) >= $this->LastBit) {
			if ($this->Done) {
				if ($this->CurBit >= $this->LastBit) {
					// Ran off the end of my bits
					return 0;
				}
				return -1;
			}

			$this->Buf[0] = $this->Buf[$this->LastByte - 2];
			$this->Buf[1] = $this->Buf[$this->LastByte - 1];

			$Count = ord($data[$dp]);
			$dp += 1;

			if ($Count) {
				for ($i = 0; $i < $Count; $i++) {
					$this->Buf[2 + $i] = ord($data[$dp + $i]);
				}
				$dp += $Count;
			} else {
				$this->Done = 1;
			}

			$this->LastByte = 2 + $Count;
			$this->CurBit = ($this->CurBit - $this->LastBit) + 16;
			$this->LastBit = (2 + $Count) << 3;
		}

		$iRet = 0;
		for ($i = $this->CurBit, $j = 0; $j < $this->CodeSize; $i++, $j++) {
			$iRet |= (($this->Buf[intval($i / 8)] & (1 << ($i % 8))) != 0) << $j;
		}

		$this->CurBit += $this->CodeSize;
		return $iRet;
	}

}

class CGIFCOLORTABLE
{

	var $m_nColors;

	var $m_arColors;

	public function __construct()
	{
		unSet($this->m_nColors);
		unSet($this->m_arColors);
	}

	function load($lpData, $num)
	{
		$this->m_nColors = 0;
		$this->m_arColors = array();

		for ($i = 0; $i < $num; $i++) {
			$rgb = substr($lpData, $i * 3, 3);
			if (strlen($rgb) < 3) {
				return false;
			}

			$this->m_arColors[] = (ord($rgb[2]) << 16) + (ord($rgb[1]) << 8) + ord($rgb[0]);
			$this->m_nColors++;
		}

		return true;
	}

	function toString()
	{
		$ret = "";

		for ($i = 0; $i < $this->m_nColors; $i++) {
			$ret .=
				chr(($this->m_arColors[$i] & 0x000000FF)) . // R
				chr(($this->m_arColors[$i] & 0x0000FF00) >> 8) . // G
				chr(($this->m_arColors[$i] & 0x00FF0000) >> 16);  // B
		}

		return $ret;
	}

	function colorIndex($rgb)
	{
		$rgb = intval($rgb) & 0xFFFFFF;
		$r1 = ($rgb & 0x0000FF);
		$g1 = ($rgb & 0x00FF00) >> 8;
		$b1 = ($rgb & 0xFF0000) >> 16;
		$idx = -1;

		for ($i = 0; $i < $this->m_nColors; $i++) {
			$r2 = ($this->m_arColors[$i] & 0x000000FF);
			$g2 = ($this->m_arColors[$i] & 0x0000FF00) >> 8;
			$b2 = ($this->m_arColors[$i] & 0x00FF0000) >> 16;
			$d = abs($r2 - $r1) + abs($g2 - $g1) + abs($b2 - $b1);

			if (($idx == -1) || ($d < $dif)) {
				$idx = $i;
				$dif = $d;
			}
		}

		return $idx;
	}

}

class CGIFFILEHEADER
{

	var $m_lpVer;

	var $m_nWidth;

	var $m_nHeight;

	var $m_bGlobalClr;

	var $m_nColorRes;

	var $m_bSorted;

	var $m_nTableSize;

	var $m_nBgColor;

	var $m_nPixelRatio;

	var $m_colorTable;

	public function __construct()
	{
		unSet($this->m_lpVer);
		unSet($this->m_nWidth);
		unSet($this->m_nHeight);
		unSet($this->m_bGlobalClr);
		unSet($this->m_nColorRes);
		unSet($this->m_bSorted);
		unSet($this->m_nTableSize);
		unSet($this->m_nBgColor);
		unSet($this->m_nPixelRatio);
		unSet($this->m_colorTable);
	}

	function load($lpData, &$hdrLen)
	{
		$hdrLen = 0;

		$this->m_lpVer = substr($lpData, 0, 6);
		if (($this->m_lpVer <> "GIF87a") && ($this->m_lpVer <> "GIF89a")) {
			return false;
		}

		$this->m_nWidth = $this->w2i(substr($lpData, 6, 2));
		$this->m_nHeight = $this->w2i(substr($lpData, 8, 2));
		if (!$this->m_nWidth || !$this->m_nHeight) {
			return false;
		}

		$b = ord(substr($lpData, 10, 1));
		$this->m_bGlobalClr = ($b & 0x80) ? true : false;
		$this->m_nColorRes = ($b & 0x70) >> 4;
		$this->m_bSorted = ($b & 0x08) ? true : false;
		$this->m_nTableSize = 2 << ($b & 0x07);
		$this->m_nBgColor = ord(substr($lpData, 11, 1));
		$this->m_nPixelRatio = ord(substr($lpData, 12, 1));
		$hdrLen = 13;

		if ($this->m_bGlobalClr) {
			$this->m_colorTable = new CGIFCOLORTABLE();
			if (!$this->m_colorTable->load(substr($lpData, $hdrLen), $this->m_nTableSize)) {
				return false;
			}
			$hdrLen += 3 * $this->m_nTableSize;
		}

		return true;
	}

	function w2i($str)
	{
		return ord(substr($str, 0, 1)) + (ord(substr($str, 1, 1)) << 8);
	}

}

class CGIFIMAGEHEADER
{

	var $m_nLeft;

	var $m_nTop;

	var $m_nWidth;

	var $m_nHeight;

	var $m_bLocalClr;

	var $m_bInterlace;

	var $m_bSorted;

	var $m_nTableSize;

	var $m_colorTable;

	public function __construct()
	{
		unSet($this->m_nLeft);
		unSet($this->m_nTop);
		unSet($this->m_nWidth);
		unSet($this->m_nHeight);
		unSet($this->m_bLocalClr);
		unSet($this->m_bInterlace);
		unSet($this->m_bSorted);
		unSet($this->m_nTableSize);
		unSet($this->m_colorTable);
	}

	function load($lpData, &$hdrLen)
	{
		$hdrLen = 0;

		$this->m_nLeft = $this->w2i(substr($lpData, 0, 2));
		$this->m_nTop = $this->w2i(substr($lpData, 2, 2));
		$this->m_nWidth = $this->w2i(substr($lpData, 4, 2));
		$this->m_nHeight = $this->w2i(substr($lpData, 6, 2));

		if (!$this->m_nWidth || !$this->m_nHeight) {
			return false;
		}

		$b = ord($lpData{8});
		$this->m_bLocalClr = ($b & 0x80) ? true : false;
		$this->m_bInterlace = ($b & 0x40) ? true : false;
		$this->m_bSorted = ($b & 0x20) ? true : false;
		$this->m_nTableSize = 2 << ($b & 0x07);
		$hdrLen = 9;

		if ($this->m_bLocalClr) {
			$this->m_colorTable = new CGIFCOLORTABLE();
			if (!$this->m_colorTable->load(substr($lpData, $hdrLen), $this->m_nTableSize)) {
				return false;
			}
			$hdrLen += 3 * $this->m_nTableSize;
		}

		return true;
	}

	function w2i($str)
	{
		return ord(substr($str, 0, 1)) + (ord(substr($str, 1, 1)) << 8);
	}

}

class CGIFIMAGE
{

	var $m_disp;

	var $m_bUser;

	var $m_bTrans;

	var $m_nDelay;

	var $m_nTrans;

	var $m_lpComm;

	var $m_gih;

	var $m_data;

	var $m_lzw;

	public function __construct()
	{
		unSet($this->m_disp);
		unSet($this->m_bUser);
		unSet($this->m_bTrans);
		unSet($this->m_nDelay);
		unSet($this->m_nTrans);
		unSet($this->m_lpComm);
		unSet($this->m_data);
		$this->m_gih = new CGIFIMAGEHEADER();
		$this->m_lzw = new CGIFLZW();
	}

	function load($data, &$datLen)
	{
		$datLen = 0;

		while (true) {
			$b = ord($data[0]);
			$data = substr($data, 1);
			$datLen++;

			switch ($b) {
				case 0x21: // Extension
					$len = 0;
					if (!$this->skipExt($data, $len)) {
						return false;
					}
					$datLen += $len;
					break;

				case 0x2C: // Image
					// LOAD HEADER & COLOR TABLE
					$len = 0;
					if (!$this->m_gih->load($data, $len)) {
						return false;
					}
					$data = substr($data, $len);
					$datLen += $len;

					// ALLOC BUFFER
					$len = 0;

					if (!($this->m_data = $this->m_lzw->deCompress($data, $len))) {
						return false;
					}

					$data = substr($data, $len);
					$datLen += $len;

					if ($this->m_gih->m_bInterlace) {
						$this->deInterlace();
					}

					return true;

				case 0x3B: // EOF
				default:
					return false;
			}
		}
		return false;
	}

	function skipExt(&$data, &$extLen)
	{
		$extLen = 0;

		$b = ord($data[0]);
		$data = substr($data, 1);
		$extLen++;

		switch ($b) {
			case 0xF9: // Graphic Control
				$b = ord($data[1]);
				$this->m_disp = ($b & 0x1C) >> 2;
				$this->m_bUser = ($b & 0x02) ? true : false;
				$this->m_bTrans = ($b & 0x01) ? true : false;
				$this->m_nDelay = $this->w2i(substr($data, 2, 2));
				$this->m_nTrans = ord($data[4]);
				break;

			case 0xFE: // Comment
				$this->m_lpComm = substr($data, 1, ord($data[0]));
				break;

			case 0x01: // Plain text
				break;

			case 0xFF: // Application
				break;
		}

		// SKIP DEFAULT AS DEFS MAY CHANGE
		$b = ord($data[0]);
		$data = substr($data, 1);
		$extLen++;
		while ($b > 0) {
			$data = substr($data, $b);
			$extLen += $b;
			$b = ord($data[0]);
			$data = substr($data, 1);
			$extLen++;
		}
		return true;
	}

	function w2i($str)
	{
		return ord(substr($str, 0, 1)) + (ord(substr($str, 1, 1)) << 8);
	}

	function deInterlace()
	{
		$data = $this->m_data;

		for ($i = 0; $i < 4; $i++) {
			switch ($i) {
				case 0:
					$s = 8;
					$y = 0;
					break;

				case 1:
					$s = 8;
					$y = 4;
					break;

				case 2:
					$s = 4;
					$y = 2;
					break;

				case 3:
					$s = 2;
					$y = 1;
					break;
			}

			for (; $y < $this->m_gih->m_nHeight; $y += $s) {
				$lne = substr($this->m_data, 0, $this->m_gih->m_nWidth);
				$this->m_data = substr($this->m_data, $this->m_gih->m_nWidth);

				$data = substr($data, 0, $y * $this->m_gih->m_nWidth) .
					$lne .
					substr($data, ($y + 1) * $this->m_gih->m_nWidth);
			}
		}

		$this->m_data = $data;
	}

}

class CGIF
{

	var $m_gfh;

	var $m_lpData;

	var $m_img;

	var $m_bLoaded;

	public function __construct()
	{
		$this->m_gfh = new CGIFFILEHEADER();
		$this->m_img = new CGIFIMAGE();
		$this->m_lpData = "";
		$this->m_bLoaded = false;
	}

	function ClearData()
	{
		$this->m_lpData = '';
		unSet($this->m_img->m_data);
		unSet($this->m_img->m_lzw->Next);
		unSet($this->m_img->m_lzw->Vals);
		unSet($this->m_img->m_lzw->Stack);
		unSet($this->m_img->m_lzw->Buf);
	}

	function loadFile(&$data, $iIndex)
	{
		if ($iIndex < 0) {
			return false;
		}
		$this->m_lpData = $data;

		// GET FILE HEADER
		$len = 0;
		if (!$this->m_gfh->load($this->m_lpData, $len)) {
			return false;
		}

		$this->m_lpData = substr($this->m_lpData, $len);

		do {
			$imgLen = 0;
			if (!$this->m_img->load($this->m_lpData, $imgLen)) {
				return false;
			}
			$this->m_lpData = substr($this->m_lpData, $imgLen);
		} while ($iIndex-- > 0);

		$this->m_bLoaded = true;
		return true;
	}

}
