对大文件做CRC32校验

今天需要做系统升级，用系统自带的mkimage工具制作升级包，生成的64字节头中有个crc32的校验值，应用中也需要对升级包做CRC32校验后，把生成的值与文件头中的校验值比较来确定是否是完整的升级包，下面是我写的测试代码：

/*
 * This file is derived from crc32.c from the zlib-1.1.3 distribution
 * by Tanqiuwei
 */

/* util_crc32.c -- compute the CRC-32 of a data stream
 * Copyright (C) 1995-1998 Mark Adler
 * For conditions of distribution and use, see copyright notice in zlib.h
 */ 
#include 
#include 
#include 
#include 
#include 
#include 
#include 
#include 
#include 
#include 
#include 
#include 
#include 
#include 
#include 
#include 
#include 

#include 
#define local static
#define ZEXPORT	/* empty */

#define cpu_to_le32(x)  (x)
#define le32_to_cpu(x)  (x)

#define tole(x)    cpu_to_le32(x)



#define uint8_t       unsigned char
#define uint16_t      unsigned short
#define uint32_t      unsigned int
#define uint64_t      unsigned long long
#define size_t        unsigned long
#define int32_t       int

/*-----------------------------------SYSTEM UPGRADE------------------------------------------*/
#define IH_MAGIC	0x27051956	/* Image Magic Number		*/
#define IH_NMLEN		32	/* Image Name Length		*/
/*
 * Legacy format image header,
 * all data in network byte order (aka natural aka bigendian).
 */
typedef struct image_header {
	uint32_t	ih_magic;	/* Image Header Magic Number	*/
	uint32_t	ih_hcrc;	/* Image Header CRC Checksum	*/
	uint32_t	ih_time;	/* Image Creation Timestamp	*/
	uint32_t	ih_size;	/* Image Data Size		*/
	uint32_t	ih_load;	/* Data	 Load  Address		*/
	uint32_t	ih_ep;		/* Entry Point Address		*/
	uint32_t	ih_dcrc;	/* Image Data CRC Checksum	*/
	uint8_t		ih_os;		/* Operating System		*/
	uint8_t		ih_arch;	/* CPU architecture		*/
	uint8_t		ih_type;	/* Image Type			*/
	uint8_t		ih_comp;	/* Compression Type		*/
	uint8_t		ih_name[IH_NMLEN];	/* Image Name		*/
} image_header_t;

#ifdef DYNAMIC_CRC_TABLE

local int crc_table_empty = 1;
local uint32_t crc_table[256];
local void make_crc_table OF((void));

/*
  Generate a table for a byte-wise 32-bit CRC calculation on the polynomial:
  x^32+x^26+x^23+x^22+x^16+x^12+x^11+x^10+x^8+x^7+x^5+x^4+x^2+x+1.

  Polynomials over GF(2) are represented in binary, one bit per coefficient,
  with the lowest powers in the most significant bit.  Then adding polynomials
  is just exclusive-or, and multiplying a polynomial by x is a right shift by
  one.  If we call the above polynomial p, and represent a byte as the
  polynomial q, also with the lowest power in the most significant bit (so the
  byte 0xb1 is the polynomial x^7+x^3+x+1), then the CRC is (q*x^32) mod p,
  where a mod b means the remainder after dividing a by b.

  This calculation is done using the shift-register method of multiplying and
  taking the remainder.  The register is initialized to zero, and for each
  incoming bit, x^32 is added mod p to the register if the bit is a one (where
  x^32 mod p is p+x^32 = x^26+...+1), and the register is multiplied mod p by
  x (which is shifting right by one and adding x^32 mod p if the bit shifted
  out is a one).  We start with the highest power (least significant bit) of
  q and repeat for all eight bits of q.

  The table is simply the CRC of all possible eight bit values.  This is all
  the information needed to generate CRC's on data a byte at a time for all
  combinations of CRC register values and incoming bytes.
*/
local void make_crc_table()
{
  uint32_t c;
  int n, k;
  uLong poly;		/* polynomial exclusive-or pattern */
  /* terms of polynomial defining this crc (except x^32): */
  static const Byte p[] = {0,1,2,4,5,7,8,10,11,12,16,22,23,26};

  /* make exclusive-or pattern from polynomial (0xedb88320L) */
  poly = 0L;
  for (n = 0; n < sizeof(p)/sizeof(Byte); n++)
    poly |= 1L << (31 - p[n]);

  for (n = 0; n < 256; n++)
  {
    c = (uLong)n;
    for (k = 0; k < 8; k++)
      c = c & 1 ? poly ^ (c >> 1) : c >> 1;
    crc_table[n] = tole(c);
  }
  crc_table_empty = 0;
}
#else
/* ========================================================================
 * Table of CRC-32's of all single-byte values (made by make_crc_table)
 */

local const uint32_t crc_table[256] = {
tole(0x00000000L), tole(0x77073096L), tole(0xee0e612cL), tole(0x990951baL),
tole(0x076dc419L), tole(0x706af48fL), tole(0xe963a535L), tole(0x9e6495a3L),
tole(0x0edb8832L), tole(0x79dcb8a4L), tole(0xe0d5e91eL), tole(0x97d2d988L),
tole(0x09b64c2bL), tole(0x7eb17cbdL), tole(0xe7b82d07L), tole(0x90bf1d91L),
tole(0x1db71064L), tole(0x6ab020f2L), tole(0xf3b97148L), tole(0x84be41deL),
tole(0x1adad47dL), tole(0x6ddde4ebL), tole(0xf4d4b551L), tole(0x83d385c7L),
tole(0x136c9856L), tole(0x646ba8c0L), tole(0xfd62f97aL), tole(0x8a65c9ecL),
tole(0x14015c4fL), tole(0x63066cd9L), tole(0xfa0f3d63L), tole(0x8d080df5L),
tole(0x3b6e20c8L), tole(0x4c69105eL), tole(0xd56041e4L), tole(0xa2677172L),
tole(0x3c03e4d1L), tole(0x4b04d447L), tole(0xd20d85fdL), tole(0xa50ab56bL),
tole(0x35b5a8faL), tole(0x42b2986cL), tole(0xdbbbc9d6L), tole(0xacbcf940L),
tole(0x32d86ce3L), tole(0x45df5c75L), tole(0xdcd60dcfL), tole(0xabd13d59L),
tole(0x26d930acL), tole(0x51de003aL), tole(0xc8d75180L), tole(0xbfd06116L),
tole(0x21b4f4b5L), tole(0x56b3c423L), tole(0xcfba9599L), tole(0xb8bda50fL),
tole(0x2802b89eL), tole(0x5f058808L), tole(0xc60cd9b2L), tole(0xb10be924L),
tole(0x2f6f7c87L), tole(0x58684c11L), tole(0xc1611dabL), tole(0xb6662d3dL),
tole(0x76dc4190L), tole(0x01db7106L), tole(0x98d220bcL), tole(0xefd5102aL),
tole(0x71b18589L), tole(0x06b6b51fL), tole(0x9fbfe4a5L), tole(0xe8b8d433L),
tole(0x7807c9a2L), tole(0x0f00f934L), tole(0x9609a88eL), tole(0xe10e9818L),
tole(0x7f6a0dbbL), tole(0x086d3d2dL), tole(0x91646c97L), tole(0xe6635c01L),
tole(0x6b6b51f4L), tole(0x1c6c6162L), tole(0x856530d8L), tole(0xf262004eL),
tole(0x6c0695edL), tole(0x1b01a57bL), tole(0x8208f4c1L), tole(0xf50fc457L),
tole(0x65b0d9c6L), tole(0x12b7e950L), tole(0x8bbeb8eaL), tole(0xfcb9887cL),
tole(0x62dd1ddfL), tole(0x15da2d49L), tole(0x8cd37cf3L), tole(0xfbd44c65L),
tole(0x4db26158L), tole(0x3ab551ceL), tole(0xa3bc0074L), tole(0xd4bb30e2L),
tole(0x4adfa541L), tole(0x3dd895d7L), tole(0xa4d1c46dL), tole(0xd3d6f4fbL),
tole(0x4369e96aL), tole(0x346ed9fcL), tole(0xad678846L), tole(0xda60b8d0L),
tole(0x44042d73L), tole(0x33031de5L), tole(0xaa0a4c5fL), tole(0xdd0d7cc9L),
tole(0x5005713cL), tole(0x270241aaL), tole(0xbe0b1010L), tole(0xc90c2086L),
tole(0x5768b525L), tole(0x206f85b3L), tole(0xb966d409L), tole(0xce61e49fL),
tole(0x5edef90eL), tole(0x29d9c998L), tole(0xb0d09822L), tole(0xc7d7a8b4L),
tole(0x59b33d17L), tole(0x2eb40d81L), tole(0xb7bd5c3bL), tole(0xc0ba6cadL),
tole(0xedb88320L), tole(0x9abfb3b6L), tole(0x03b6e20cL), tole(0x74b1d29aL),
tole(0xead54739L), tole(0x9dd277afL), tole(0x04db2615L), tole(0x73dc1683L),
tole(0xe3630b12L), tole(0x94643b84L), tole(0x0d6d6a3eL), tole(0x7a6a5aa8L),
tole(0xe40ecf0bL), tole(0x9309ff9dL), tole(0x0a00ae27L), tole(0x7d079eb1L),
tole(0xf00f9344L), tole(0x8708a3d2L), tole(0x1e01f268L), tole(0x6906c2feL),
tole(0xf762575dL), tole(0x806567cbL), tole(0x196c3671L), tole(0x6e6b06e7L),
tole(0xfed41b76L), tole(0x89d32be0L), tole(0x10da7a5aL), tole(0x67dd4accL),
tole(0xf9b9df6fL), tole(0x8ebeeff9L), tole(0x17b7be43L), tole(0x60b08ed5L),
tole(0xd6d6a3e8L), tole(0xa1d1937eL), tole(0x38d8c2c4L), tole(0x4fdff252L),
tole(0xd1bb67f1L), tole(0xa6bc5767L), tole(0x3fb506ddL), tole(0x48b2364bL),
tole(0xd80d2bdaL), tole(0xaf0a1b4cL), tole(0x36034af6L), tole(0x41047a60L),
tole(0xdf60efc3L), tole(0xa867df55L), tole(0x316e8eefL), tole(0x4669be79L),
tole(0xcb61b38cL), tole(0xbc66831aL), tole(0x256fd2a0L), tole(0x5268e236L),
tole(0xcc0c7795L), tole(0xbb0b4703L), tole(0x220216b9L), tole(0x5505262fL),
tole(0xc5ba3bbeL), tole(0xb2bd0b28L), tole(0x2bb45a92L), tole(0x5cb36a04L),
tole(0xc2d7ffa7L), tole(0xb5d0cf31L), tole(0x2cd99e8bL), tole(0x5bdeae1dL),
tole(0x9b64c2b0L), tole(0xec63f226L), tole(0x756aa39cL), tole(0x026d930aL),
tole(0x9c0906a9L), tole(0xeb0e363fL), tole(0x72076785L), tole(0x05005713L),
tole(0x95bf4a82L), tole(0xe2b87a14L), tole(0x7bb12baeL), tole(0x0cb61b38L),
tole(0x92d28e9bL), tole(0xe5d5be0dL), tole(0x7cdcefb7L), tole(0x0bdbdf21L),
tole(0x86d3d2d4L), tole(0xf1d4e242L), tole(0x68ddb3f8L), tole(0x1fda836eL),
tole(0x81be16cdL), tole(0xf6b9265bL), tole(0x6fb077e1L), tole(0x18b74777L),
tole(0x88085ae6L), tole(0xff0f6a70L), tole(0x66063bcaL), tole(0x11010b5cL),
tole(0x8f659effL), tole(0xf862ae69L), tole(0x616bffd3L), tole(0x166ccf45L),
tole(0xa00ae278L), tole(0xd70dd2eeL), tole(0x4e048354L), tole(0x3903b3c2L),
tole(0xa7672661L), tole(0xd06016f7L), tole(0x4969474dL), tole(0x3e6e77dbL),
tole(0xaed16a4aL), tole(0xd9d65adcL), tole(0x40df0b66L), tole(0x37d83bf0L),
tole(0xa9bcae53L), tole(0xdebb9ec5L), tole(0x47b2cf7fL), tole(0x30b5ffe9L),
tole(0xbdbdf21cL), tole(0xcabac28aL), tole(0x53b39330L), tole(0x24b4a3a6L),
tole(0xbad03605L), tole(0xcdd70693L), tole(0x54de5729L), tole(0x23d967bfL),
tole(0xb3667a2eL), tole(0xc4614ab8L), tole(0x5d681b02L), tole(0x2a6f2b94L),
tole(0xb40bbe37L), tole(0xc30c8ea1L), tole(0x5a05df1bL), tole(0x2d02ef8dL)
};
#endif

/* ========================================================================= */
# if __BYTE_ORDER == __LITTLE_ENDIAN
#  define DO_CRC(x) crc = tab[(crc ^ (x)) & 255] ^ (crc >> 8)
# else
#  define DO_CRC(x) crc = tab[((crc >> 24) ^ (x)) & 255] ^ (crc << 8)
# endif

/* ========================================================================= */

/* No ones complement version. JFFS2 (and other things ?)
 * don't use ones compliment in their CRC calculations.
 */
uint32_t ZEXPORT crc32_no_comp(uint32_t crc, const unsigned char *buf, size_t len)
{
    const uint32_t *tab = crc_table;
    const uint32_t *b =(const uint32_t *)buf;
    size_t rem_len;
#ifdef DYNAMIC_CRC_TABLE
    if (crc_table_empty)
      make_crc_table();
#endif
    crc = cpu_to_le32(crc);
    /* Align it */
    if (((long)b) & 3 && len) {
	 uint8_t *p = (uint8_t *)b;
	 do {
	      DO_CRC(*p++);
	 } while ((--len) && ((long)p)&3);
	 b = (uint32_t *)p;
    }

    rem_len = len & 3;
    len = len >> 2;
    for (--b; len; --len) {
	 /* load data 32 bits wide, xor data 32 bits wide. */
	 crc ^= *++b; /* use pre increment for speed */
	 DO_CRC(0);
	 DO_CRC(0);
	 DO_CRC(0);
	 DO_CRC(0);
    }
    len = rem_len;
    /* And the last few bytes */
    if (len) {
	 uint8_t *p = (uint8_t *)(b + 1) - 1;
	 do {
	      DO_CRC(*++p); /* use pre increment for speed */
	 } while (--len);
    }

    return le32_to_cpu(crc);
}
#undef DO_CRC

uint32_t util_crc32 (uint32_t crc, const unsigned char *p, size_t len)
{
     return crc32_no_comp(crc ^ 0xffffffffL, p, len) ^ 0xffffffffL;
}

int CheckImageFileCRC32(const char * LocalFile,  uint32_t *crc32_val)
{
	const char *filename = NULL;
	int  val = 0;
	struct stat filestat;
	image_header_t hdr;
	unsigned long checksum;
	int fil_fd = -1;

	if (LocalFile == NULL)
	{
		return -1;
	}
	filename = LocalFile;
	printf("filename<%s>\n", filename);
	
	/* get some info about the file we want to copy */
	fil_fd = open (filename,O_RDONLY);
	if (fstat (fil_fd,&filestat) < 0)
	{
		printf ("Err: While trying to get the file status of %s failed!\n",filename);
		return -1;
	}
	
	/* read the update file header from filename */
	memset(&hdr, 0, sizeof(image_header_t));
	val = read (fil_fd, &hdr, sizeof(image_header_t));
	if (val <= 0)
	{
		return -1;
	}
	printf("ih_name<%s>, ih_size<%d> ,st_size<%d>\n", hdr.ih_name, (size_t)ntohl(hdr.ih_size), (size_t)filestat.st_size);

	/*映射升级文件到内存*/
	void * start = mmap(NULL, filestat.st_size, PROT_READ, MAP_PRIVATE, fil_fd, 0);
	if (start == MAP_FAILED)
	{
		return -1;
	}
	
	/* check the data CRC */
	checksum = ntohl(hdr.ih_dcrc);	
	*crc32_val = util_crc32(0, (unsigned char const *)(start + sizeof(hdr)), ntohl(hdr.ih_size));
	if (*crc32_val != checksum) 
	{
		printf("Image %s bad data checksum, CrcVal<%lx>, checksum<%lx>\n", filename, *crc32_val, checksum);
		return -1;
	}
	printf("Image %s bad data checksum, CrcVal<%lx>, checksum<%lx>\n", filename, *crc32_val, checksum);

	return 0;
}

main(int argc, char **argv)
{
	int result=-1; 
	uint32_t crc32 = 0;
	char filename[256] = {0};
	
	if(argc >= 2)
	{
		sscanf(argv[1], "%s", filename);
	}

	result = CheckImageFileCRC32(filename,  &crc32);
	printf("========result<%d>, crc32<%x>\n", result, crc32);
	
}