fs/hfsplus/brec.c

   1 /*
   2  *  linux/fs/hfsplus/brec.c
   3  *
   4  * Copyright (C) 2001
   5  * Brad Boyer (flar@allandria.com)
   6  * (C) 2003 Ardis Technologies <roman@ardistech.com>
   7  *
   8  * Handle individual btree records
   9  */
  10
  11 #include "hfsplus_fs.h"
  12 #include "hfsplus_raw.h"
  13
  14 /* Get the length and offset of the given record in the given node */
  15 u16 hfsplus_brec_lenoff(hfsplus_bnode *node, u16 rec, u16 *off)
  16 {
  17         u16 retval[2];
  18         u16 dataoff;
  19
  20         dataoff = node->tree->node_size - (rec + 2) * 2;
  21         hfsplus_bnode_readbytes(node, retval, dataoff, 4);
  22         *off = be16_to_cpu(retval[1]);
  23         return be16_to_cpu(retval[0]) - *off;
  24 }
  25
  26 /* Get the length of the key from a keyed record */
  27 u16 hfsplus_brec_keylen(hfsplus_bnode *node, u16 rec)
  28 {
  29         u16 klsz, retval, recoff;
  30         unsigned char buf[2];
  31
  32         if ((node->kind != HFSPLUS_NODE_NDX)&&(node->kind != HFSPLUS_NODE_LEAF))
  33                 return 0;
  34
  35         klsz = (node->tree->attributes & HFSPLUS_TREE_BIGKEYS) ? 2 : 1;
  36         if ((node->kind == HFSPLUS_NODE_NDX) &&
  37            !(node->tree->attributes & HFSPLUS_TREE_VAR_NDXKEY_SIZE)) {
  38                 retval = node->tree->max_key_len;
  39         } else {
  40                 recoff = hfsplus_bnode_read_u16(node, node->tree->node_size - (rec + 1) * 2);
  41                 if (!recoff)
  42                         return 0;
  43                 hfsplus_bnode_readbytes(node, buf, recoff, klsz);
  44                 if (klsz == 1)
  45                         retval = buf[0];
  46                 else
  47                         retval = be16_to_cpu(*(u16 *)buf);
  48         }
  49         return (retval + klsz + 1) & 0xFFFE;
  50 }