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/*

 * wordlib.c

 * Copyright (C) 1998-2004 A.J. van Os; Released under GNU GPL

 *

 * Description:

 * Deal with the internals of a MS Word file

 */

#include "antiword.h"

static BOOL	bOldMacFile = FALSE;

/*

 * Common part of the file checking functions

 */

static BOOL

bCheckBytes(FILE *pFile, const UCHAR *aucBytes, size_t tBytes)

{

	int	iIndex, iChar;

	fail(pFile == NULL || aucBytes == NULL || tBytes == 0);

	rewind(pFile);

	for (iIndex = 0; iIndex < (int)tBytes; iIndex++) {

		iChar = getc(pFile);

		if (iChar == EOF || iChar != (int)aucBytes[iIndex]) {

			NO_DBG_HEX(iChar);

			NO_DBG_HEX(aucBytes[iIndex]);

			return FALSE;

		}

	}

	return TRUE;

} /* end of bCheckBytes */

/*

 * This function checks whether the given file is or is not a "Word for DOS"

 * document

 */

BOOL

bIsWordForDosFile(FILE *pFile, long lFilesize)

{

	static UCHAR	aucBytes[] =

		{ 0x31, 0xbe, 0x00, 0x00, 0x00, 0xab };	/* Word for DOS */

	DBG_MSG("bIsWordForDosFile");

	if (pFile == NULL || lFilesize < 0) {

		DBG_MSG("No proper file given");

		return FALSE;

	}

	if (lFilesize < 128) {

		DBG_MSG("File too small to be a Word document");

		return FALSE;

	}

	return bCheckBytes(pFile, aucBytes, elementsof(aucBytes));

} /* end of bIsWordForDosFile */

/*

 * This function checks whether the given file is or is not a file with an

 * OLE envelope (That is a document made by Word 6 or later)

 */

static BOOL

bIsWordFileWithOLE(FILE *pFile, long lFilesize)

{

	static UCHAR	aucBytes[] =

		{ 0xd0, 0xcf, 0x11, 0xe0, 0xa1, 0xb1, 0x1a, 0xe1 };

	int	iTailLen;

	if (pFile == NULL || lFilesize < 0) {

		DBG_MSG("No proper file given");

		return FALSE;

	}

	if (lFilesize < (long)BIG_BLOCK_SIZE * 3) {

		DBG_MSG("This file is too small to be a Word document");

		return FALSE;

	}

	iTailLen = (int)(lFilesize % BIG_BLOCK_SIZE);

	switch (iTailLen) {

	case 0:		/* No tail, as it should be */

		break;

	case 1:

	case 2:		/* Filesize mismatch or a buggy email program */

		if ((int)(lFilesize % 3) == iTailLen) {

			DBG_DEC(lFilesize);

			return FALSE;

		}

		/*

		 * Ignore extra bytes caused by buggy email programs.

		 * They have bugs in their base64 encoding or decoding.

		 * 3 bytes -> 4 ascii chars -> 3 bytes

		 */

		DBG_MSG("Document with extra bytes");

		break;

	default:	/* Wrong filesize for a Word document */

		DBG_DEC(lFilesize);

		DBG_DEC(iTailLen);

		return FALSE;

	}

	return bCheckBytes(pFile, aucBytes, elementsof(aucBytes));

} /* end of bIsWordFileWithOLE */

/*

 * This function checks whether the given file is or is not a RTF document

 */

BOOL

bIsRtfFile(FILE *pFile)

{

	static UCHAR	aucBytes[] =

		{ '{', '\\', 'r', 't', 'f', '1' };

	DBG_MSG("bIsRtfFile");

	return bCheckBytes(pFile, aucBytes, elementsof(aucBytes));

} /* end of bIsRtfFile */

/*

 * This function checks whether the given file is or is not a WP document

 */

BOOL

bIsWordPerfectFile(FILE *pFile)

{

	static UCHAR	aucBytes[] =

		{ 0xff, 'W', 'P', 'C' };

	DBG_MSG("bIsWordPerfectFile");

	return bCheckBytes(pFile, aucBytes, elementsof(aucBytes));

} /* end of bIsWordPerfectFile */

/*

 * This function checks whether the given file is or is not a "Win Word 1 or 2"

 * document

 */

BOOL

bIsWinWord12File(FILE *pFile, long lFilesize)

{

	static UCHAR	aucBytes[2][4] = {

		{ 0x9b, 0xa5, 0x21, 0x00 },	/* Win Word 1.x */

		{ 0xdb, 0xa5, 0x2d, 0x00 },	/* Win Word 2.0 */

	};

	int	iIndex;

	DBG_MSG("bIsWinWord12File");

	if (pFile == NULL || lFilesize < 0) {

		DBG_MSG("No proper file given");

		return FALSE;

	}

	if (lFilesize < 384) {

		DBG_MSG("This file is too small to be a Word document");

		return FALSE;

	}

	for (iIndex = 0; iIndex < (int)elementsof(aucBytes); iIndex++) {

		if (bCheckBytes(pFile,

				aucBytes[iIndex],

				elementsof(aucBytes[iIndex]))) {

			return TRUE;

		}

	}

	return FALSE;

} /* end of bIsWinWord12File */

/*

 * This function checks whether the given file is or is not a "Mac Word 4 or 5"

 * document

 */

BOOL

bIsMacWord45File(FILE *pFile)

{

	static UCHAR	aucBytes[2][6] = {

		{ 0xfe, 0x37, 0x00, 0x1c, 0x00, 0x00 },	/* Mac Word 4 */

		{ 0xfe, 0x37, 0x00, 0x23, 0x00, 0x00 },	/* Mac Word 5 */

	};

	int	iIndex;

	DBG_MSG("bIsMacWord45File");

	for (iIndex = 0; iIndex < (int)elementsof(aucBytes); iIndex++) {

		if (bCheckBytes(pFile,

				aucBytes[iIndex],

				elementsof(aucBytes[iIndex]))) {

			return TRUE;

		}

	}

	return FALSE;

} /* end of bIsMacWord45File */

/*

 * iGuessVersionNumber - guess the Word version number from first few bytes

 *

 * Returns the guessed version number or -1 when no guess it possible

 */

int

iGuessVersionNumber(FILE *pFile, long lFilesize)

{

	if(bIsWordForDosFile(pFile, lFilesize)) {

		return 0;

	}

	if (bIsWinWord12File(pFile, lFilesize)) {

		return 2;

	}

	if (bIsMacWord45File(pFile)) {

		return 5;

	}

	if (bIsWordFileWithOLE(pFile, lFilesize)) {

		return 6;

	}

	return -1;

} /* end of iGuessVersionNumber */

/*

 * iGetVersionNumber - get the Word version number from the header

 *

 * Returns the version number or -1 when unknown

 */

int

iGetVersionNumber(const UCHAR *aucHeader)

{

	USHORT	usFib, usChse;

	usFib = usGetWord(0x02, aucHeader);

	if (usFib >= 0x1000) {

		/* To big: must be MacWord using Big Endian */

		DBG_HEX(usFib);

		usFib = usGetWordBE(0x02, aucHeader);

	}

	DBG_DEC(usFib);

	bOldMacFile = FALSE;

	switch (usFib) {

	case   0:

		DBG_MSG("Word for DOS");

		return 0;

	case  28:

		DBG_MSG("Word 4 for Macintosh");

		bOldMacFile = TRUE;

		return 4;

	case  33:

		DBG_MSG("Word 1.x for Windows");

		return 1;

	case  35:

		DBG_MSG("Word 5 for Macintosh");

		bOldMacFile = TRUE;

		return 5;

	case  45:

		DBG_MSG("Word 2 for Windows");

		return 2;

	case 101:

	case 102:

		DBG_MSG("Word 6 for Windows");

		return 6;

	case 103:

	case 104:

		usChse = usGetWord(0x14, aucHeader);

		DBG_DEC(usChse);

		switch (usChse) {

		case 0:

			DBG_MSG("Word 7 for Win95");

			return 7;

		case 256:

			DBG_MSG("Word 6 for Macintosh");

			bOldMacFile = TRUE;

			return 6;

		default:

			DBG_FIXME();

			if ((int)ucGetByte(0x05, aucHeader) == 0xe0) {

				DBG_MSG("Word 7 for Win95");

				return 7;

			}

			DBG_MSG("Word 6 for Macintosh");

			bOldMacFile = TRUE;

			return 6;

		}

	default:

		usChse = usGetWord(0x14, aucHeader);

		DBG_DEC(usChse);

		if (usFib < 192) {

			/* Unknown or unsupported version of Word */

			DBG_DEC(usFib);

			return -1;

		}

		DBG_MSG_C(usChse != 256, "Word97 for Win95/98/NT");

		DBG_MSG_C(usChse == 256, "Word98 for Macintosh");

		return 8;

	}

} /* end of iGetVersionNumber */

/*

 * TRUE if the current file was made by Word version 6 or older on an

 * Apple Macintosh, otherwise FALSE.

 * This function hides the methode of how to find out from the rest of the

 * program.

 */

BOOL

bIsOldMacFile(void)

{

	return bOldMacFile;

} /* end of bIsOldMacFile */

/*

 * iInitDocument - initialize a document

 *

 * Returns the version of Word that made the document or -1

 */

int

iInitDocument(FILE *pFile, long lFilesize)

{

	int	iGuess, iWordVersion;

	iGuess = iGuessVersionNumber(pFile, lFilesize);

	switch (iGuess) {

	case 0:

		iWordVersion = iInitDocumentDOS(pFile, lFilesize);

		break;

	case 2:

		iWordVersion = iInitDocumentWIN(pFile, lFilesize);

		break;

	case 5:

		iWordVersion = iInitDocumentMAC(pFile, lFilesize);

		break;

	case 6:

		iWordVersion = iInitDocumentOLE(pFile, lFilesize);

		break;

	default:

		DBG_DEC(iGuess);

		iWordVersion = -1;

		break;

	}

	return iWordVersion;

} /* end of iInitDocument */

/*

 * vFreeDocument - free a document by free-ing its parts

 */

void

vFreeDocument(void)

{

	DBG_MSG("vFreeDocument");

	/* Free the memory */

	vDestroyTextBlockList();

	vDestroyDataBlockList();

	vDestroyListInfoList();

	vDestroyRowInfoList();

	vDestroyStyleInfoList();

	vDestroyFontInfoList();

	vDestroyStylesheetList();

	vDestroyPictInfoList();

	vDestroyDocumentInfoList();

	vDestroySectionInfoList();

	vDestroyHdrFtrInfoList();

	vDestroyPropModList();

	vDestroyNotesInfoLists();

	vDestroyFontTable();

	vDestroySummaryInfo();

} /* end of vFreeDocument */