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      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 typedef struct sparse_header {
     18   __le32	magic;		/* 0xed26ff3a */
     19   __le16	major_version;	/* (0x1) - reject images with higher major versions */
     20   __le16	minor_version;	/* (0x0) - allow images with higer minor versions */
     21   __le16	file_hdr_sz;	/* 28 bytes for first revision of the file format */
     22   __le16	chunk_hdr_sz;	/* 12 bytes for first revision of the file format */
     23   __le32	blk_sz;		/* block size in bytes, must be a multiple of 4 (4096) */
     24   __le32	total_blks;	/* total blocks in the non-sparse output image */
     25   __le32	total_chunks;	/* total chunks in the sparse input image */
     26   __le32	image_checksum; /* CRC32 checksum of the original data, counting "don't care" */
     27 				/* as 0. Standard 802.3 polynomial, use a Public Domain */
     28 				/* table implementation */
     29 } sparse_header_t;
     30 
     31 #define SPARSE_HEADER_MAGIC	0xed26ff3a
     32 
     33 #define CHUNK_TYPE_RAW		0xCAC1
     34 #define CHUNK_TYPE_FILL		0xCAC2
     35 #define CHUNK_TYPE_DONT_CARE	0xCAC3
     36 #define CHUNK_TYPE_CRC32    0xCAC4
     37 
     38 typedef struct chunk_header {
     39   __le16	chunk_type;	/* 0xCAC1 -> raw; 0xCAC2 -> fill; 0xCAC3 -> don't care */
     40   __le16	reserved1;
     41   __le32	chunk_sz;	/* in blocks in output image */
     42   __le32	total_sz;	/* in bytes of chunk input file including chunk header and data */
     43 } chunk_header_t;
     44 
     45 /* Following a Raw or Fill or CRC32 chunk is data.
     46  *  For a Raw chunk, it's the data in chunk_sz * blk_sz.
     47  *  For a Fill chunk, it's 4 bytes of the fill data.
     48  *  For a CRC32 chunk, it's 4 bytes of CRC32
     49  */
     50 
     51