/*
   * 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>

  struct fileIdentDesc *udf_fileident_read(struct inode *dir, loff_t *nf_pos,

  					 struct udf_fileident_bh *fibh,
  					 struct fileIdentDesc *cfi,
  					 struct extent_position *epos,

  					 struct kernel_lb_addr *eloc, uint32_t *elen,

  					 sector_t *offset)

  {
  	struct fileIdentDesc *fi;
  	int i, num, block;

  	struct buffer_head *tmp, *bha[16];

  	struct udf_inode_info *iinfo = UDF_I(dir);

  
  	fibh->soffset = fibh->eoffset;

  	if (iinfo->i_alloc_type == ICBTAG_FLAG_AD_IN_ICB) {
  		fi = udf_get_fileident(iinfo->i_ext.i_data -
  				       (iinfo->i_efe ?

  					sizeof(struct extendedFileEntry) :
  					sizeof(struct fileEntry)),

  				       dir->i_sb->s_blocksize,
  				       &(fibh->eoffset));

  		if (!fi)
  			return NULL;

  		*nf_pos += fibh->eoffset - fibh->soffset;

  		memcpy((uint8_t *)cfi, (uint8_t *)fi,

  		       sizeof(struct fileIdentDesc));

  
  		return fi;
  	}

  	if (fibh->eoffset == dir->i_sb->s_blocksize) {

  		int lextoffset = epos->offset;

  		unsigned char blocksize_bits = dir->i_sb->s_blocksize_bits;

  		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 << blocksize_bits) >= *elen)

  			*offset = 0;
  		else

  			epos->offset = lextoffset;

  		brelse(fibh->sbh);

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

  			return NULL;
  		fibh->soffset = fibh->eoffset = 0;

  		if (!(*offset & ((16 >> (blocksize_bits - 9)) - 1))) {
  			i = 16 >> (blocksize_bits - 9);
  			if (i + *offset > (*elen >> blocksize_bits))
  				i = (*elen >> 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;

  	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;

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

  			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);

  			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, buffer=%p, offset=%p
  ",
  			  buffer, offset);

  		return NULL;
  	}
  
  	ptr = buffer;

  	if ((*offset > 0) && (*offset < bufsize))

  		ptr += *offset;

  	fi = (struct fileIdentDesc *)ptr;

  	if (fi->descTag.tagIdent != cpu_to_le16(TAG_IDENT_FID)) {

  		udf_debug("0x%x != TAG_IDENT_FID
  ",

  			  le16_to_cpu(fi->descTag.tagIdent));

  		udf_debug("offset: %u sizeof: %lu bufsize: %u
  ",

  			  *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;
  }

  struct short_ad *udf_get_fileshortad(uint8_t *ptr, int maxoffset, uint32_t *offset,

  			      int inc)

  {

  	struct short_ad *sa;

  	if ((!ptr) || (!offset)) {

  		pr_err("%s: invalidparms
  ", __func__);

  		return NULL;
  	}

  	if ((*offset + sizeof(struct short_ad)) > maxoffset)

  		return NULL;

  	else {

  		sa = (struct short_ad *)ptr;

  		if (sa->extLength == 0)
  			return NULL;
  	}

  
  	if (inc)

  		*offset += sizeof(struct short_ad);

  	return sa;
  }

  struct long_ad *udf_get_filelongad(uint8_t *ptr, int maxoffset, uint32_t *offset, int inc)

  {

  	struct long_ad *la;

  	if ((!ptr) || (!offset)) {

  		pr_err("%s: invalidparms
  ", __func__);

  		return NULL;
  	}

  	if ((*offset + sizeof(struct long_ad)) > maxoffset)

  		return NULL;

  	else {

  		la = (struct long_ad *)ptr;

  		if (la->extLength == 0)
  			return NULL;
  	}

  
  	if (inc)

  		*offset += sizeof(struct long_ad);

  	return la;
  }