/*
 * findtext.c
 * Copyright (C) 1998-2001 A.J. van Os; Released under GPL
 *
 * Description:
 * Find the blocks that contain the text of MS Word files
 */

#include <stdio.h>
#include <stdlib.h>
#include "antiword.h"


/*
 * bAddTextBlocks - Add the blocks to the text block list
 *
 * Returns TRUE when successful, FALSE if not
 */
BOOL
bAddTextBlocks(long lFirstOffset, long lTotalLength,
	BOOL bUsesUnicode, unsigned short usPropMod,
	long lStartBlock, const long *alBBD, size_t tBBDLen)
{
	text_block_type	tTextBlock;
	long	lTextOffset, lIndex, lToGo, lOffset;

	fail(lFirstOffset < 0);
	fail(lStartBlock < 0);
	fail(alBBD == NULL);

	NO_DBG_HEX(lFirstOffset);
	NO_DBG_DEC(lTotalLength);

	if (bUsesUnicode) {
		/* One character equals two bytes */
		NO_DBG_MSG("Uses Unicode");
		lToGo = lTotalLength * 2;
	} else {
		/* One character equals one byte */
		NO_DBG_MSG("Uses ASCII");
		lToGo = lTotalLength;
	}

	lTextOffset = lFirstOffset;
	lOffset = lFirstOffset;
	for (lIndex = lStartBlock;
	     lIndex != END_OF_CHAIN && lToGo > 0;
	     lIndex = alBBD[lIndex]) {
		if (lIndex < 0 || lIndex >= (long)tBBDLen) {
			werr(1, "The Big Block Depot is corrupt");
		}
		if (lOffset >= BIG_BLOCK_SIZE) {
			lOffset -= BIG_BLOCK_SIZE;
			continue;
		}
		tTextBlock.lFileOffset =
			(lIndex + 1) * BIG_BLOCK_SIZE + lOffset;
		tTextBlock.lTextOffset = lTextOffset;
		tTextBlock.lLength = min(BIG_BLOCK_SIZE - lOffset, lToGo);
		tTextBlock.bUsesUnicode = bUsesUnicode;
		tTextBlock.usPropMod = usPropMod;
		lOffset = 0;
		if (!bAdd2TextBlockList(&tTextBlock)) {
			DBG_HEX(tTextBlock.lFileOffset);
			DBG_HEX(tTextBlock.lTextOffset);
			DBG_DEC(tTextBlock.lLength);
			DBG_DEC(tTextBlock.bUsesUnicode);
			DBG_DEC(tTextBlock.usPropMod);
			return FALSE;
		}
		lTextOffset += tTextBlock.lLength;
		lToGo -= tTextBlock.lLength;
	}
	DBG_DEC_C(lToGo != 0, lToGo);
	return lToGo == 0;
} /* end of bAddTextBlocks */

/*
 * bGet6DocumentText - make a list of the text blocks of Word 6/7 files
 *
 * Code for "fast saved" files.
 *
 * Returns TRUE when successful, FALSE if not
 */
BOOL
bGet6DocumentText(FILE *pFile, BOOL bUsesUnicode, long lStartBlock,
	const long *alBBD, size_t tBBDLen, const unsigned char *aucHeader)
{
	unsigned char	*aucBuffer;
	long	lTextOffset, lTotLength, lBeginTextInfo;
	size_t	tTextInfoLen, tOff;
	int	iIndex, iType, iLen, iPieces;
	unsigned short	usPropMod;

	DBG_MSG("bGet6DocumentText");

	fail(pFile == NULL);
	fail(alBBD == NULL);
	fail(aucHeader == NULL);

	lBeginTextInfo = (long)ulGetLong(0x160, aucHeader);	/* fcClx */
	tTextInfoLen = (size_t)ulGetLong(0x164, aucHeader);	/* lcbClx */
	DBG_HEX(lBeginTextInfo);
	DBG_DEC(tTextInfoLen);

	aucBuffer = xmalloc(tTextInfoLen);
	if (!bReadBuffer(pFile, lStartBlock,
			alBBD, tBBDLen, BIG_BLOCK_SIZE,
			aucBuffer, lBeginTextInfo, tTextInfoLen)) {
		aucBuffer = xfree(aucBuffer);
		return FALSE;
	}
	NO_DBG_PRINT_BLOCK(aucBuffer, tTextInfoLen);

	tOff = 0;
	while (tOff < tTextInfoLen) {
		iType = (int)ucGetByte(tOff, aucBuffer);
		tOff++;
		if (iType == 0) {
			DBG_FIXME();
			tOff++;
			continue;
		}
		if (iType == 1) {
			iLen = (int)usGetWord(tOff, aucBuffer);
			vAdd2PropModList(aucBuffer + tOff);
			tOff += iLen + 2;
			continue;
		}
		if (iType != 2) {
			werr(0, "Unknown type of 'fastsaved' format");
			aucBuffer = xfree(aucBuffer);
			return FALSE;
		}
		/* Type 2 */
		iLen = (int)usGetWord(tOff, aucBuffer);
		NO_DBG_DEC(iLen);
		tOff += 4;
		iPieces = (iLen - 4) / 12;
		DBG_DEC(iPieces);
		for (iIndex = 0; iIndex < iPieces; iIndex++) {
			lTextOffset = (long)ulGetLong(
				tOff + (iPieces + 1) * 4 + iIndex * 8 + 2,
				aucBuffer);
			usPropMod = usGetWord(
				tOff + (iPieces + 1) * 4 + iIndex * 8 + 6,
				aucBuffer);
			lTotLength = (long)ulGetLong(
						tOff + (iIndex + 1) * 4,
						aucBuffer) -
					(long)ulGetLong(
						tOff + iIndex * 4,
						aucBuffer);
			NO_DBG_HEX_C(usPropMod != 0, usPropMod);
			if (!bAddTextBlocks(lTextOffset, lTotLength,
					bUsesUnicode, usPropMod,
					lStartBlock,
					alBBD, tBBDLen)) {
				aucBuffer = xfree(aucBuffer);
				return FALSE;
			}
		}
		break;
	}
	aucBuffer = xfree(aucBuffer);
	return TRUE;
} /* end of bGet6DocumentText */

/*
 * bGet8DocumentText - make a list of the text blocks of Word 8/97 files
 *
 * Returns TRUE when successful, FALSE if not
 */
BOOL
bGet8DocumentText(FILE *pFile, const pps_info_type *pPPS,
	const long *alBBD, size_t tBBDLen, const long *alSBD, size_t tSBDLen,
	const unsigned char *aucHeader)
{
	const long	*alBlockDepot;
	unsigned char	*aucBuffer;
	long	lTextOffset, lTotLength, lBeginTextInfo, lLen;
	long	lTableStartBlock, lTableSize, lIndex, lPieces;
	size_t	tTextInfoLen, tBlockDepotLen, tBlockSize, tOff;
	int	iType, iLen;
	BOOL	bUsesUnicode;
	unsigned short	usDocStatus, usPropMod;

	DBG_MSG("bGet8DocumentText");

	fail(pFile == NULL || pPPS == NULL);
	fail(alBBD == NULL || alSBD == NULL);
	fail(aucHeader == NULL);

  	lBeginTextInfo = (long)ulGetLong(0x1a2, aucHeader);	/* fcClx */
	tTextInfoLen = (size_t)ulGetLong(0x1a6, aucHeader);	/* lcbClx */
	DBG_HEX(lBeginTextInfo);
	DBG_DEC(tTextInfoLen);

	/* Use 0Table or 1Table? */
	usDocStatus = usGetWord(0x0a, aucHeader);
	if (usDocStatus & BIT(9)) {
		lTableStartBlock = pPPS->t1Table.lSb;
		lTableSize = pPPS->t1Table.lSize;
	} else {
		lTableStartBlock = pPPS->t0Table.lSb;
		lTableSize = pPPS->t0Table.lSize;
	}
	DBG_DEC(lTableStartBlock);
	if (lTableStartBlock < 0) {
		DBG_DEC(lTableStartBlock);
		return FALSE;
	}
	DBG_HEX(lTableSize);
	if (lTableSize < MIN_SIZE_FOR_BBD_USE) {
	  	/* Use the Small Block Depot */
		alBlockDepot = alSBD;
		tBlockDepotLen = tSBDLen;
		tBlockSize = SMALL_BLOCK_SIZE;
	} else {
	  	/* Use the Big Block Depot */
		alBlockDepot = alBBD;
		tBlockDepotLen = tBBDLen;
		tBlockSize = BIG_BLOCK_SIZE;
	}
	aucBuffer = xmalloc(tTextInfoLen);
	if (!bReadBuffer(pFile, lTableStartBlock,
			alBlockDepot, tBlockDepotLen, tBlockSize,
			aucBuffer, lBeginTextInfo, tTextInfoLen)) {
		aucBuffer = xfree(aucBuffer);
		return FALSE;
	}
	NO_DBG_PRINT_BLOCK(aucBuffer, tTextInfoLen);

	tOff = 0;
	while (tOff < tTextInfoLen) {
		iType = (int)ucGetByte(tOff, aucBuffer);
		tOff++;
		if (iType == 0) {
			DBG_FIXME();
			tOff++;
			continue;
		}
		if (iType == 1) {
			iLen = (int)usGetWord(tOff, aucBuffer);
			vAdd2PropModList(aucBuffer + tOff);
			tOff += iLen + 2;
			continue;
		}
		if (iType != 2) {
			werr(0, "Unknown type of 'fastsaved' format");
			aucBuffer = xfree(aucBuffer);
			return FALSE;
		}
		/* Type 2 */
		lLen = (long)ulGetLong(tOff, aucBuffer);
		NO_DBG_DEC(lLen);
		tOff += 4;
		lPieces = (lLen - 4) / 12;
		DBG_DEC(lPieces);
		for (lIndex = 0; lIndex < lPieces; lIndex++) {
			lTextOffset = (long)ulGetLong(
				tOff + (lPieces + 1) * 4 + lIndex * 8 + 2,
				aucBuffer);
			usPropMod = usGetWord(
				tOff + (lPieces + 1) * 4 + lIndex * 8 + 6,
				aucBuffer);
			lTotLength = (long)ulGetLong(
						tOff + (lIndex + 1) * 4,
						aucBuffer) -
					(long)ulGetLong(
						tOff + lIndex * 4,
						aucBuffer);
			if ((lTextOffset & BIT(30)) == 0) {
				bUsesUnicode = TRUE;
			} else {
				bUsesUnicode = FALSE;
				lTextOffset &= ~BIT(30);
				lTextOffset /= 2;
			}
			DBG_HEX_C(usPropMod != 0, usPropMod);
			if (!bAddTextBlocks(lTextOffset, lTotLength,
					bUsesUnicode, usPropMod,
					pPPS->tWordDocument.lSb,
					alBBD, tBBDLen)) {
				aucBuffer = xfree(aucBuffer);
				return FALSE;
			}
		}
		break;
	}
	aucBuffer = xfree(aucBuffer);
	return TRUE;
} /* end of bGet8DocumentText */