[deliverable/linux.git] / fs / udf / directory.c

/*
 * directory.c
 *
 * PURPOSE
 *	Directory related functions
 *
 * COPYRIGHT
 *	This file is distributed under the terms of the GNU General Public
 *	License (GPL). Copies of the GPL can be obtained from:
 *		ftp://prep.ai.mit.edu/pub/gnu/GPL
 *	Each contributing author retains all rights to their own work.
 */

#include "udfdecl.h"
#include "udf_i.h"

#include <linux/fs.h>
#include <linux/string.h>
#include <linux/buffer_head.h>

#if 0
static uint8_t *udf_filead_read(struct inode *dir, uint8_t * tmpad,
				uint8_t ad_size, kernel_lb_addr fe_loc,
				int *pos, int *offset, struct buffer_head **bh,
				int *error)
{
	int loffset = *offset;
	int block;
	uint8_t *ad;
	int remainder;

	*error = 0;

	ad = (uint8_t *) (*bh)->b_data + *offset;
	*offset += ad_size;

	if (!ad) {
		brelse(*bh);
		*error = 1;
		return NULL;
	}

	if (*offset == dir->i_sb->s_blocksize) {
		brelse(*bh);
		block = udf_get_lb_pblock(dir->i_sb, fe_loc, ++*pos);
		if (!block)
			return NULL;
		if (!(*bh = udf_tread(dir->i_sb, block)))
			return NULL;
	} else if (*offset > dir->i_sb->s_blocksize) {
		ad = tmpad;

		remainder = dir->i_sb->s_blocksize - loffset;
		memcpy((uint8_t *) ad, (*bh)->b_data + loffset, remainder);

		brelse(*bh);
		block = udf_get_lb_pblock(dir->i_sb, fe_loc, ++*pos);
		if (!block)
			return NULL;
		if (!((*bh) = udf_tread(dir->i_sb, block)))
			return NULL;

		memcpy((uint8_t *) ad + remainder, (*bh)->b_data,
		       ad_size - remainder);
		*offset = ad_size - remainder;
	}
	return ad;
}
#endif

struct fileIdentDesc *udf_fileident_read(struct inode *dir, loff_t * nf_pos,
					 struct udf_fileident_bh *fibh,
					 struct fileIdentDesc *cfi,
					 struct extent_position *epos,
					 kernel_lb_addr * eloc, uint32_t * elen,
					 sector_t * offset)
{
	struct fileIdentDesc *fi;
	int i, num, block;
	struct buffer_head *tmp, *bha[16];

	fibh->soffset = fibh->eoffset;

	if (UDF_I_ALLOCTYPE(dir) == ICBTAG_FLAG_AD_IN_ICB) {
		fi = udf_get_fileident(UDF_I_DATA(dir) -
				       (UDF_I_EFE(dir) ?
					sizeof(struct extendedFileEntry) :
					sizeof(struct fileEntry)),
				       dir->i_sb->s_blocksize,
				       &(fibh->eoffset));

		if (!fi)
			return NULL;

		*nf_pos += ((fibh->eoffset - fibh->soffset) >> 2);

		memcpy((uint8_t *) cfi, (uint8_t *) fi,
		       sizeof(struct fileIdentDesc));

		return fi;
	}

	if (fibh->eoffset == dir->i_sb->s_blocksize) {
		int lextoffset = epos->offset;

		if (udf_next_aext(dir, epos, eloc, elen, 1) !=
		    (EXT_RECORDED_ALLOCATED >> 30))
			return NULL;

		block = udf_get_lb_pblock(dir->i_sb, *eloc, *offset);

		(*offset)++;

		if ((*offset << dir->i_sb->s_blocksize_bits) >= *elen)
			*offset = 0;
		else
			epos->offset = lextoffset;

		brelse(fibh->sbh);
		if (!(fibh->sbh = fibh->ebh = udf_tread(dir->i_sb, block)))
			return NULL;
		fibh->soffset = fibh->eoffset = 0;

		if (!
		    (*offset & ((16 >> (dir->i_sb->s_blocksize_bits - 9)) - 1)))
		{
			i = 16 >> (dir->i_sb->s_blocksize_bits - 9);
			if (i + *offset >
			    (*elen >> dir->i_sb->s_blocksize_bits))
				i = (*elen >> dir->i_sb->s_blocksize_bits) -
				    *offset;
			for (num = 0; i > 0; i--) {
				block =
				    udf_get_lb_pblock(dir->i_sb, *eloc,
						      *offset + i);
				tmp = udf_tgetblk(dir->i_sb, block);
				if (tmp && !buffer_uptodate(tmp)
				    && !buffer_locked(tmp))
					bha[num++] = tmp;
				else
					brelse(tmp);
			}
			if (num) {
				ll_rw_block(READA, num, bha);
				for (i = 0; i < num; i++)
					brelse(bha[i]);
			}
		}
	} else if (fibh->sbh != fibh->ebh) {
		brelse(fibh->sbh);
		fibh->sbh = fibh->ebh;
	}

	fi = udf_get_fileident(fibh->sbh->b_data, dir->i_sb->s_blocksize,
			       &(fibh->eoffset));

	if (!fi)
		return NULL;

	*nf_pos += ((fibh->eoffset - fibh->soffset) >> 2);

	if (fibh->eoffset <= dir->i_sb->s_blocksize) {
		memcpy((uint8_t *) cfi, (uint8_t *) fi,
		       sizeof(struct fileIdentDesc));
	} else if (fibh->eoffset > dir->i_sb->s_blocksize) {
		int lextoffset = epos->offset;

		if (udf_next_aext(dir, epos, eloc, elen, 1) !=
		    (EXT_RECORDED_ALLOCATED >> 30))
			return NULL;

		block = udf_get_lb_pblock(dir->i_sb, *eloc, *offset);

		(*offset)++;

		if ((*offset << dir->i_sb->s_blocksize_bits) >= *elen)
			*offset = 0;
		else
			epos->offset = lextoffset;

		fibh->soffset -= dir->i_sb->s_blocksize;
		fibh->eoffset -= dir->i_sb->s_blocksize;

		if (!(fibh->ebh = udf_tread(dir->i_sb, block)))
			return NULL;

		if (sizeof(struct fileIdentDesc) > -fibh->soffset) {
			int fi_len;

			memcpy((uint8_t *) cfi, (uint8_t *) fi, -fibh->soffset);
			memcpy((uint8_t *) cfi - fibh->soffset,
			       fibh->ebh->b_data,
			       sizeof(struct fileIdentDesc) + fibh->soffset);

			fi_len =
			    (sizeof(struct fileIdentDesc) +
			     cfi->lengthFileIdent +
			     le16_to_cpu(cfi->lengthOfImpUse) + 3) & ~3;

			*nf_pos +=
			    ((fi_len - (fibh->eoffset - fibh->soffset)) >> 2);
			fibh->eoffset = fibh->soffset + fi_len;
		} else {
			memcpy((uint8_t *) cfi, (uint8_t *) fi,
			       sizeof(struct fileIdentDesc));
		}
	}
	return fi;
}

struct fileIdentDesc *udf_get_fileident(void *buffer, int bufsize, int *offset)
{
	struct fileIdentDesc *fi;
	int lengthThisIdent;
	uint8_t *ptr;
	int padlen;

	if ((!buffer) || (!offset)) {
		udf_debug("invalidparms\n, buffer=%p, offset=%p\n", buffer,
			  offset);
		return NULL;
	}

	ptr = buffer;

	if ((*offset > 0) && (*offset < bufsize)) {
		ptr += *offset;
	}
	fi = (struct fileIdentDesc *)ptr;
	if (le16_to_cpu(fi->descTag.tagIdent) != TAG_IDENT_FID) {
		udf_debug("0x%x != TAG_IDENT_FID\n",
			  le16_to_cpu(fi->descTag.tagIdent));
		udf_debug("offset: %u sizeof: %lu bufsize: %u\n",
			  *offset, (unsigned long)sizeof(struct fileIdentDesc),
			  bufsize);
		return NULL;
	}
	if ((*offset + sizeof(struct fileIdentDesc)) > bufsize) {
		lengthThisIdent = sizeof(struct fileIdentDesc);
	} else
		lengthThisIdent = sizeof(struct fileIdentDesc) +
		    fi->lengthFileIdent + le16_to_cpu(fi->lengthOfImpUse);

	/* we need to figure padding, too! */
	padlen = lengthThisIdent % UDF_NAME_PAD;
	if (padlen)
		lengthThisIdent += (UDF_NAME_PAD - padlen);
	*offset = *offset + lengthThisIdent;

	return fi;
}

#if 0
static extent_ad *udf_get_fileextent(void *buffer, int bufsize, int *offset)
{
	extent_ad *ext;
	struct fileEntry *fe;
	uint8_t *ptr;

	if ((!buffer) || (!offset)) {
		printk(KERN_ERR "udf: udf_get_fileextent() invalidparms\n");
		return NULL;
	}

	fe = (struct fileEntry *)buffer;

	if (le16_to_cpu(fe->descTag.tagIdent) != TAG_IDENT_FE) {
		udf_debug("0x%x != TAG_IDENT_FE\n",
			  le16_to_cpu(fe->descTag.tagIdent));
		return NULL;
	}

	ptr =
	    (uint8_t *) (fe->extendedAttr) +
	    le32_to_cpu(fe->lengthExtendedAttr);

	if ((*offset > 0) && (*offset < le32_to_cpu(fe->lengthAllocDescs))) {
		ptr += *offset;
	}

	ext = (extent_ad *) ptr;

	*offset = *offset + sizeof(extent_ad);
	return ext;
}
#endif

short_ad *udf_get_fileshortad(uint8_t * ptr, int maxoffset, int *offset,
			      int inc)
{
	short_ad *sa;

	if ((!ptr) || (!offset)) {
		printk(KERN_ERR "udf: udf_get_fileshortad() invalidparms\n");
		return NULL;
	}

	if ((*offset < 0) || ((*offset + sizeof(short_ad)) > maxoffset))
		return NULL;
	else if ((sa = (short_ad *) ptr)->extLength == 0)
		return NULL;

	if (inc)
		*offset += sizeof(short_ad);
	return sa;
}

long_ad *udf_get_filelongad(uint8_t * ptr, int maxoffset, int *offset, int inc)
{
	long_ad *la;

	if ((!ptr) || (!offset)) {
		printk(KERN_ERR "udf: udf_get_filelongad() invalidparms\n");
		return NULL;
	}

	if ((*offset < 0) || ((*offset + sizeof(long_ad)) > maxoffset))
		return NULL;
	else if ((la = (long_ad *) ptr)->extLength == 0)
		return NULL;

	if (inc)
		*offset += sizeof(long_ad);
	return la;
}
Commit	Line	Data
1da177e4 LT	1	/*
	2	* directory.c
	3	*
	4	* PURPOSE
	5	* Directory related functions
	6	*
1da177e4 LT	7	* COPYRIGHT
	8	* This file is distributed under the terms of the GNU General Public
	9	* License (GPL). Copies of the GPL can be obtained from:
	10	* ftp://prep.ai.mit.edu/pub/gnu/GPL
	11	* Each contributing author retains all rights to their own work.
	12	*/
	13
	14	#include "udfdecl.h"
	15	#include "udf_i.h"
	16
	17	#include <linux/fs.h>
	18	#include <linux/string.h>
	19	#include <linux/buffer_head.h>
	20
	21	#if 0
cb00ea35 CG	22	static uint8_t udf_filead_read(struct inode dir, uint8_t * tmpad,
	23	uint8_t ad_size, kernel_lb_addr fe_loc,
	24	int pos, int offset, struct buffer_head **bh,
	25	int *error)
1da177e4 LT	26	{
	27	int loffset = *offset;
	28	int block;
	29	uint8_t *ad;
	30	int remainder;
	31
	32	*error = 0;
	33
cb00ea35	34	ad = (uint8_t ) (bh)->b_data + *offset;
1da177e4 LT	35	*offset += ad_size;
1da177e4 LT	36
cb00ea35	37	if (!ad) {
3bf25cb4	38	brelse(*bh);
1da177e4 LT	39	*error = 1;
	40	return NULL;
	41	}
	42
cb00ea35	43	if (*offset == dir->i_sb->s_blocksize) {
3bf25cb4	44	brelse(*bh);
1da177e4 LT	45	block = udf_get_lb_pblock(dir->i_sb, fe_loc, ++*pos);
	46	if (!block)
	47	return NULL;
	48	if (!(*bh = udf_tread(dir->i_sb, block)))
	49	return NULL;
cb00ea35	50	} else if (*offset > dir->i_sb->s_blocksize) {
1da177e4 LT	51	ad = tmpad;
	52
	53	remainder = dir->i_sb->s_blocksize - loffset;
cb00ea35	54	memcpy((uint8_t ) ad, (bh)->b_data + loffset, remainder);
1da177e4	55
3bf25cb4	56	brelse(*bh);
1da177e4 LT	57	block = udf_get_lb_pblock(dir->i_sb, fe_loc, ++*pos);
	58	if (!block)
	59	return NULL;
	60	if (!((*bh) = udf_tread(dir->i_sb, block)))
	61	return NULL;
	62
cb00ea35 CG	63	memcpy((uint8_t ) ad + remainder, (bh)->b_data,
cb00ea35 CG	64	ad_size - remainder);
1da177e4 LT	65	*offset = ad_size - remainder;
	66	}
	67	return ad;
	68	}
	69	#endif
	70
cb00ea35 CG	71	struct fileIdentDesc udf_fileident_read(struct inode dir, loff_t * nf_pos,
	72	struct udf_fileident_bh *fibh,
	73	struct fileIdentDesc *cfi,
	74	struct extent_position *epos,
	75	kernel_lb_addr * eloc, uint32_t * elen,
	76	sector_t * offset)
1da177e4 LT	77	{
	78	struct fileIdentDesc *fi;
	79	int i, num, block;
cb00ea35	80	struct buffer_head tmp, bha[16];
1da177e4 LT	81
	82	fibh->soffset = fibh->eoffset;
	83
cb00ea35	84	if (UDF_I_ALLOCTYPE(dir) == ICBTAG_FLAG_AD_IN_ICB) {
1da177e4	85	fi = udf_get_fileident(UDF_I_DATA(dir) -
cb00ea35 CG	86	(UDF_I_EFE(dir) ?
	87	sizeof(struct extendedFileEntry) :
	88	sizeof(struct fileEntry)),
	89	dir->i_sb->s_blocksize,
	90	&(fibh->eoffset));
1da177e4 LT	91
	92	if (!fi)
	93	return NULL;
	94
	95	*nf_pos += ((fibh->eoffset - fibh->soffset) >> 2);
	96
cb00ea35 CG	97	memcpy((uint8_t ) cfi, (uint8_t ) fi,
cb00ea35 CG	98	sizeof(struct fileIdentDesc));
1da177e4 LT	99
	100	return fi;
	101	}
	102
cb00ea35	103	if (fibh->eoffset == dir->i_sb->s_blocksize) {
ff116fc8	104	int lextoffset = epos->offset;
1da177e4	105
ff116fc8	106	if (udf_next_aext(dir, epos, eloc, elen, 1) !=
cb00ea35	107	(EXT_RECORDED_ALLOCATED >> 30))
1da177e4	108	return NULL;
1da177e4 LT	109
	110	block = udf_get_lb_pblock(dir->i_sb, eloc, offset);
	111
cb00ea35	112	(*offset)++;
1da177e4 LT	113
	114	if ((offset << dir->i_sb->s_blocksize_bits) >= elen)
	115	*offset = 0;
	116	else
ff116fc8	117	epos->offset = lextoffset;
1da177e4	118
3bf25cb4	119	brelse(fibh->sbh);
1da177e4 LT	120	if (!(fibh->sbh = fibh->ebh = udf_tread(dir->i_sb, block)))
	121	return NULL;
	122	fibh->soffset = fibh->eoffset = 0;
	123
cb00ea35 CG	124	if (!
cb00ea35 CG	125	(*offset & ((16 >> (dir->i_sb->s_blocksize_bits - 9)) - 1)))
1da177e4 LT	126	{
1da177e4 LT	127	i = 16 >> (dir->i_sb->s_blocksize_bits - 9);
cb00ea35 CG	128	if (i + *offset >
	129	(*elen >> dir->i_sb->s_blocksize_bits))
	130	i = (*elen >> dir->i_sb->s_blocksize_bits) -
	131	*offset;
	132	for (num = 0; i > 0; i--) {
	133	block =
	134	udf_get_lb_pblock(dir->i_sb, *eloc,
	135	*offset + i);
1da177e4	136	tmp = udf_tgetblk(dir->i_sb, block);
cb00ea35 CG	137	if (tmp && !buffer_uptodate(tmp)
cb00ea35 CG	138	&& !buffer_locked(tmp))
1da177e4 LT	139	bha[num++] = tmp;
	140	else
	141	brelse(tmp);
	142	}
cb00ea35	143	if (num) {
1da177e4	144	ll_rw_block(READA, num, bha);
cb00ea35	145	for (i = 0; i < num; i++)
1da177e4 LT	146	brelse(bha[i]);
	147	}
	148	}
cb00ea35	149	} else if (fibh->sbh != fibh->ebh) {
3bf25cb4	150	brelse(fibh->sbh);
1da177e4 LT	151	fibh->sbh = fibh->ebh;
	152	}
	153
	154	fi = udf_get_fileident(fibh->sbh->b_data, dir->i_sb->s_blocksize,
cb00ea35	155	&(fibh->eoffset));
1da177e4 LT	156
	157	if (!fi)
	158	return NULL;
	159
	160	*nf_pos += ((fibh->eoffset - fibh->soffset) >> 2);
	161
cb00ea35 CG	162	if (fibh->eoffset <= dir->i_sb->s_blocksize) {
	163	memcpy((uint8_t ) cfi, (uint8_t ) fi,
	164	sizeof(struct fileIdentDesc));
	165	} else if (fibh->eoffset > dir->i_sb->s_blocksize) {
ff116fc8	166	int lextoffset = epos->offset;
1da177e4	167
ff116fc8	168	if (udf_next_aext(dir, epos, eloc, elen, 1) !=
cb00ea35	169	(EXT_RECORDED_ALLOCATED >> 30))
1da177e4	170	return NULL;
1da177e4 LT	171
	172	block = udf_get_lb_pblock(dir->i_sb, eloc, offset);
	173
cb00ea35	174	(*offset)++;
1da177e4 LT	175
	176	if ((offset << dir->i_sb->s_blocksize_bits) >= elen)
	177	*offset = 0;
	178	else
ff116fc8	179	epos->offset = lextoffset;
1da177e4 LT	180
	181	fibh->soffset -= dir->i_sb->s_blocksize;
	182	fibh->eoffset -= dir->i_sb->s_blocksize;
	183
	184	if (!(fibh->ebh = udf_tread(dir->i_sb, block)))
	185	return NULL;
	186
cb00ea35	187	if (sizeof(struct fileIdentDesc) > -fibh->soffset) {
1da177e4 LT	188	int fi_len;
1da177e4 LT	189
cb00ea35 CG	190	memcpy((uint8_t ) cfi, (uint8_t ) fi, -fibh->soffset);
	191	memcpy((uint8_t *) cfi - fibh->soffset,
	192	fibh->ebh->b_data,
	193	sizeof(struct fileIdentDesc) + fibh->soffset);
1da177e4	194
cb00ea35 CG	195	fi_len =
	196	(sizeof(struct fileIdentDesc) +
	197	cfi->lengthFileIdent +
	198	le16_to_cpu(cfi->lengthOfImpUse) + 3) & ~3;
1da177e4	199
cb00ea35 CG	200	*nf_pos +=
cb00ea35 CG	201	((fi_len - (fibh->eoffset - fibh->soffset)) >> 2);
1da177e4	202	fibh->eoffset = fibh->soffset + fi_len;
cb00ea35 CG	203	} else {
	204	memcpy((uint8_t ) cfi, (uint8_t ) fi,
	205	sizeof(struct fileIdentDesc));
1da177e4 LT	206	}
	207	}
	208	return fi;
	209	}
	210
cb00ea35	211	struct fileIdentDesc udf_get_fileident(void buffer, int bufsize, int *offset)
1da177e4 LT	212	{
	213	struct fileIdentDesc *fi;
	214	int lengthThisIdent;
cb00ea35	215	uint8_t *ptr;
1da177e4 LT	216	int padlen;
1da177e4 LT	217
cb00ea35 CG	218	if ((!buffer) \|\| (!offset)) {
	219	udf_debug("invalidparms\n, buffer=%p, offset=%p\n", buffer,
	220	offset);
1da177e4 LT	221	return NULL;
	222	}
	223
	224	ptr = buffer;
	225
cb00ea35	226	if ((offset > 0) && (offset < bufsize)) {
1da177e4 LT	227	ptr += *offset;
1da177e4 LT	228	}
cb00ea35 CG	229	fi = (struct fileIdentDesc *)ptr;
cb00ea35 CG	230	if (le16_to_cpu(fi->descTag.tagIdent) != TAG_IDENT_FID) {
1da177e4	231	udf_debug("0x%x != TAG_IDENT_FID\n",
cb00ea35	232	le16_to_cpu(fi->descTag.tagIdent));
1da177e4	233	udf_debug("offset: %u sizeof: %lu bufsize: %u\n",
cb00ea35 CG	234	*offset, (unsigned long)sizeof(struct fileIdentDesc),
cb00ea35 CG	235	bufsize);
1da177e4 LT	236	return NULL;
1da177e4 LT	237	}
cb00ea35	238	if ((*offset + sizeof(struct fileIdentDesc)) > bufsize) {
1da177e4	239	lengthThisIdent = sizeof(struct fileIdentDesc);
cb00ea35	240	} else
1da177e4	241	lengthThisIdent = sizeof(struct fileIdentDesc) +
cb00ea35	242	fi->lengthFileIdent + le16_to_cpu(fi->lengthOfImpUse);
1da177e4 LT	243
	244	/* we need to figure padding, too! */
	245	padlen = lengthThisIdent % UDF_NAME_PAD;
	246	if (padlen)
	247	lengthThisIdent += (UDF_NAME_PAD - padlen);
	248	offset = offset + lengthThisIdent;
	249
	250	return fi;
	251	}
	252
	253	#if 0
cb00ea35	254	static extent_ad udf_get_fileextent(void buffer, int bufsize, int *offset)
1da177e4	255	{
cb00ea35	256	extent_ad *ext;
1da177e4	257	struct fileEntry *fe;
cb00ea35	258	uint8_t *ptr;
1da177e4	259
cb00ea35	260	if ((!buffer) \|\| (!offset)) {
1da177e4 LT	261	printk(KERN_ERR "udf: udf_get_fileextent() invalidparms\n");
	262	return NULL;
	263	}
	264
	265	fe = (struct fileEntry *)buffer;
	266
cb00ea35	267	if (le16_to_cpu(fe->descTag.tagIdent) != TAG_IDENT_FE) {
1da177e4	268	udf_debug("0x%x != TAG_IDENT_FE\n",
cb00ea35	269	le16_to_cpu(fe->descTag.tagIdent));
1da177e4 LT	270	return NULL;
	271	}
	272
cb00ea35 CG	273	ptr =
	274	(uint8_t *) (fe->extendedAttr) +
	275	le32_to_cpu(fe->lengthExtendedAttr);
1da177e4	276
cb00ea35	277	if ((offset > 0) && (offset < le32_to_cpu(fe->lengthAllocDescs))) {
1da177e4 LT	278	ptr += *offset;
	279	}
	280
cb00ea35	281	ext = (extent_ad *) ptr;
1da177e4 LT	282
	283	offset = offset + sizeof(extent_ad);
	284	return ext;
	285	}
	286	#endif
	287
cb00ea35 CG	288	short_ad udf_get_fileshortad(uint8_t ptr, int maxoffset, int *offset,
cb00ea35 CG	289	int inc)
1da177e4 LT	290	{
	291	short_ad *sa;
	292
cb00ea35	293	if ((!ptr) \|\| (!offset)) {
1da177e4 LT	294	printk(KERN_ERR "udf: udf_get_fileshortad() invalidparms\n");
	295	return NULL;
	296	}
	297
cb00ea35	298	if ((offset < 0) \|\| ((offset + sizeof(short_ad)) > maxoffset))
1da177e4	299	return NULL;
cb00ea35	300	else if ((sa = (short_ad *) ptr)->extLength == 0)
1da177e4 LT	301	return NULL;
	302
	303	if (inc)
	304	*offset += sizeof(short_ad);
	305	return sa;
	306	}
	307
cb00ea35	308	long_ad udf_get_filelongad(uint8_t ptr, int maxoffset, int *offset, int inc)
1da177e4 LT	309	{
	310	long_ad *la;
	311
cb00ea35	312	if ((!ptr) \|\| (!offset)) {
1da177e4 LT	313	printk(KERN_ERR "udf: udf_get_filelongad() invalidparms\n");
	314	return NULL;
	315	}
	316
cb00ea35	317	if ((offset < 0) \|\| ((offset + sizeof(long_ad)) > maxoffset))
1da177e4	318	return NULL;
cb00ea35	319	else if ((la = (long_ad *) ptr)->extLength == 0)
1da177e4 LT	320	return NULL;
	321
	322	if (inc)
	323	*offset += sizeof(long_ad);
	324	return la;
	325	}