libsparse/sparse_format.h

   1 /*
   2  * Copyright (C) 2010 The Android Open Source Project
   3  *
   4  * Licensed under the Apache License, Version 2.0 (the "License");
   5  * you may not use this file except in compliance with the License.
   6  * You may obtain a copy of the License at
   7  *
   8  *      http://www.apache.org/licenses/LICENSE-2.0
   9  *
  10  * Unless required by applicable law or agreed to in writing, software
  11  * distributed under the License is distributed on an "AS IS" BASIS,
  12  * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
  13  * See the License for the specific language governing permissions and
  14  * limitations under the License.
  15  */
  16
  17 #ifndef _LIBSPARSE_SPARSE_FORMAT_H_
  18 #define _LIBSPARSE_SPARSE_FORMAT_H_
  19 #include "sparse_defs.h"
  20
  21 typedef struct sparse_header {
  22   __le32        magic;          /* 0xed26ff3a */
  23   __le16        major_version;  /* (0x1) - reject images with higher major versions */
  24   __le16        minor_version;  /* (0x0) - allow images with higer minor versions */
  25   __le16        file_hdr_sz;    /* 28 bytes for first revision of the file format */
  26   __le16        chunk_hdr_sz;   /* 12 bytes for first revision of the file format */
  27   __le32        blk_sz;         /* block size in bytes, must be a multiple of 4 (4096) */
  28   __le32        total_blks;     /* total blocks in the non-sparse output image */
  29   __le32        total_chunks;   /* total chunks in the sparse input image */
  30   __le32        image_checksum; /* CRC32 checksum of the original data, counting "don't care" */
  31                                 /* as 0. Standard 802.3 polynomial, use a Public Domain */
  32                                 /* table implementation */
  33 } sparse_header_t;
  34
  35 #define SPARSE_HEADER_MAGIC     0xed26ff3a
  36
  37 #define CHUNK_TYPE_RAW          0xCAC1
  38 #define CHUNK_TYPE_FILL         0xCAC2
  39 #define CHUNK_TYPE_DONT_CARE    0xCAC3
  40 #define CHUNK_TYPE_CRC32    0xCAC4
  41
  42 typedef struct chunk_header {
  43   __le16        chunk_type;     /* 0xCAC1 -> raw; 0xCAC2 -> fill; 0xCAC3 -> don't care */
  44   __le16        reserved1;
  45   __le32        chunk_sz;       /* in blocks in output image */
  46   __le32        total_sz;       /* in bytes of chunk input file including chunk header and data */
  47 } chunk_header_t;
  48
  49 /* Following a Raw or Fill or CRC32 chunk is data.
  50  *  For a Raw chunk, it's the data in chunk_sz * blk_sz.
  51  *  For a Fill chunk, it's 4 bytes of the fill data.
  52  *  For a CRC32 chunk, it's 4 bytes of CRC32
  53  */
  54
  55 #endif