fsck_hfs/dfalib/BTreeScanner.h

   1 /*
   2  * Copyright (c) 1996-2002 Apple Computer, Inc. All rights reserved.
   3  *
   4  * @APPLE_LICENSE_HEADER_START@
   5  *
   6  * This file contains Original Code and/or Modifications of Original Code
   7  * as defined in and that are subject to the Apple Public Source License
   8  * Version 2.0 (the 'License'). You may not use this file except in
   9  * compliance with the License. Please obtain a copy of the License at
  10  * http://www.opensource.apple.com/apsl/ and read it before using this
  11  * file.
  12  *
  13  * The Original Code and all software distributed under the License are
  14  * distributed on an 'AS IS' basis, WITHOUT WARRANTY OF ANY KIND, EITHER
  15  * EXPRESS OR IMPLIED, AND APPLE HEREBY DISCLAIMS ALL SUCH WARRANTIES,
  16  * INCLUDING WITHOUT LIMITATION, ANY WARRANTIES OF MERCHANTABILITY,
  17  * FITNESS FOR A PARTICULAR PURPOSE, QUIET ENJOYMENT OR NON-INFRINGEMENT.
  18  * Please see the License for the specific language governing rights and
  19  * limitations under the License.
  20  *
  21  * @APPLE_LICENSE_HEADER_END@
  22  *
  23  *      @(#)BTreeScanner.h
  24  */
  25
  26 #ifndef _BTREESCANNER_H_
  27 #define _BTREESCANNER_H_
  28
  29 #include "BTreePrivate.h"
  30
  31 // btree node scanner buffer size.  Joe Sokol suggests 128K as a max (2002 WWDC)
  32 enum { kCatScanBufferSize = (128 * 1024) };
  33
  34
  35 /*
  36         BTScanState - This structure is used to keep track of the current state
  37         of a BTree scan.  It contains both the dynamic state information (like
  38         the current node number and record number) and information that is static
  39         for the duration of a scan (such as buffer pointers).
  40
  41         NOTE: recordNum may equal or exceed the number of records in the node
  42         number nodeNum.  If so, then the next attempt to get a record will move
  43         to a new node number.
  44 */
  45 struct BTScanState
  46 {
  47         //      The following fields are set up once at initialization time.
  48         //      They are not changed during a scan.
  49         u_int32_t                       bufferSize;
  50         void *                          bufferPtr;
  51         BTreeControlBlock *     btcb;
  52
  53         //      The following fields are the dynamic state of the current scan.
  54         u_int32_t                       nodeNum;                        // zero is first node
  55         u_int32_t                       recordNum;                      // zero is first record
  56         BTNodeDescriptor *      currentNodePtr;         // points to current node within buffer
  57         int32_t                         nodesLeftInBuffer;      // number of valid nodes still in the buffer
  58         int64_t                         recordsFound;           // number of leaf records seen so far
  59 };
  60 typedef struct BTScanState BTScanState;
  61
  62
  63 /* *********************** PROTOTYPES *********************** */
  64
  65 int     BTScanInitialize(       const SFCB *    btreeFile,
  66                                                         BTScanState     *       scanState     );
  67
  68 int BTScanNextRecord(   BTScanState *   scanState,
  69                                                 void * *                key,
  70                                                 void * *                data,
  71                                                 u_int32_t *             dataSize  );
  72
  73 int     BTScanTerminate(        BTScanState *   scanState       );
  74
  75 #endif /* !_BTREESCANNER_H_ */