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  • /*
     *  Copyright (C) 2009 Gabor Juhos <juhosg@openwrt.org>
     *
     *  This program is free software; you can redistribute it and/or modify it
     *  under the terms of the GNU General Public License version 2 as published
     *  by the Free Software Foundation.
     *
     */
    
    #include <stdio.h>
    #include <stdlib.h>
    #include <stdint.h>
    #include <string.h>
    #include <unistd.h>     /* for unlink() */
    #include <libgen.h>
    #include <getopt.h>     /* for getopt() */
    #include <stdarg.h>
    #include <errno.h>
    #include <sys/stat.h>
    
    #if (__BYTE_ORDER == __LITTLE_ENDIAN)
    #  define HOST_TO_LE16(x)	(x)
    #  define HOST_TO_LE32(x)	(x)
    #  define LE16_TO_HOST(x)	(x)
    #  define LE32_TO_HOST(x)	(x)
    #else
    #  define HOST_TO_LE16(x)	bswap_16(x)
    #  define HOST_TO_LE32(x)	bswap_32(x)
    #  define LE16_TO_HOST(x)	bswap_16(x)
    #  define LE32_TO_HOST(x)	bswap_32(x)
    #endif
    
    uint32_t crc32buf(char *buf, size_t len);
    
    /*
     * Globals
     */
    static char *ifname;
    static char *progname;
    static char *ofname;
    
    /*
     * Message macros
     */
    #define ERR(fmt, ...) do { \
    	fflush(0); \
    	fprintf(stderr, "[%s] *** error: " fmt "\n", \
    			progname, ## __VA_ARGS__ ); \
    } while (0)
    
    #define ERRS(fmt, ...) do { \
    	int save = errno; \
    	fflush(0); \
    
    	fprintf(stderr, "[%s] *** error: " fmt ": %s\n", \
    
    			progname, ## __VA_ARGS__, strerror(save)); \
    } while (0)
    
    void usage(int status)
    {
    	FILE *stream = (status != EXIT_SUCCESS) ? stderr : stdout;
    	struct board_info *board;
    
    	fprintf(stream, "Usage: %s [OPTIONS...]\n", progname);
    	fprintf(stream,
    "\n"
    "Options:\n"
    "  -i <file>       read input from the file <file>\n"
    "  -o <file>       write output to the file <file>\n"
    "  -h              show this screen\n"
    	);
    
    	exit(status);
    }
    
    int main(int argc, char *argv[])
    {
    	int res = EXIT_FAILURE;
    	int buflen;
    	int err;
    	struct stat st;
    	char *buf;
    	uint32_t *hdr;
    	uint32_t crc;
    
    	FILE *outfile, *infile;
    
    	progname = basename(argv[0]);
    
    	while ( 1 ) {
    		int c;
    
    		c = getopt(argc, argv, "i:o:h");
    		if (c == -1)
    			break;
    
    		switch (c) {
    		case 'i':
    			ifname = optarg;
    			break;
    		case 'o':
    			ofname = optarg;
    			break;
    		case 'h':
    			usage(EXIT_SUCCESS);
    			break;
    		default:
    			usage(EXIT_FAILURE);
    			break;
    		}
    	}
    
    	if (ifname == NULL) {
    		ERR("no input file specified");
    		goto err;
    	}
    
    	if (ofname == NULL) {
    		ERR("no output file specified");
    		goto err;
    	}
    
    	err = stat(ifname, &st);
    	if (err){
    		ERRS("stat failed on %s", ifname);
    		goto err;
    	}
    
    	buflen = st.st_size;
    	buf = malloc(buflen);
    	if (!buf) {
    		ERR("no memory for buffer\n");
    		goto err;
    	}
    
    	infile = fopen(ifname, "r");
    	if (infile == NULL) {
    		ERRS("could not open \"%s\" for reading", ifname);
    		goto err_free;
    	}
    
    	errno = 0;
    	fread(buf, buflen, 1, infile);
    	if (errno != 0) {
    		ERRS("unable to read from file %s", ifname);
    		goto err_close_in;
    	}
    
    	crc = crc32buf(buf, buflen);
    	hdr = (uint32_t *)buf;
    	*hdr = HOST_TO_LE32(crc);
    
    	outfile = fopen(ofname, "w");
    	if (outfile == NULL) {
    		ERRS("could not open \"%s\" for writing", ofname);
    		goto err_close_in;
    	}
    
    	errno = 0;
    	fwrite(buf, buflen, 1, outfile);
    	if (errno) {
    		ERRS("unable to write to file %s", ofname);
    		goto err_close_out;
    	}
    
    	res = EXIT_SUCCESS;
    
     out_flush:
    	fflush(outfile);
    
     err_close_out:
    	fclose(outfile);
    	if (res != EXIT_SUCCESS) {
    		unlink(ofname);
    	}
    
     err_close_in:
    	fclose(infile);
    
     err_free:
    	free(buf);
    
     err:
    	return res;
    }
    
    /**********************************************************************/
    /* The following was grabbed and tweaked from the old snippets collection
     * of public domain C code. */
    
    /**********************************************************************\
    |* Demonstration program to compute the 32-bit CRC used as the frame  *|
    |* check sequence in ADCCP (ANSI X3.66, also known as FIPS PUB 71     *|
    |* and FED-STD-1003, the U.S. versions of CCITT's X.25 link-level     *|
    |* protocol).  The 32-bit FCS was added via the Federal Register,     *|
    |* 1 June 1982, p.23798.  I presume but don't know for certain that   *|
    |* this polynomial is or will be included in CCITT V.41, which        *|
    |* defines the 16-bit CRC (often called CRC-CCITT) polynomial.  FIPS  *|
    |* PUB 78 says that the 32-bit FCS reduces otherwise undetected       *|
    |* errors by a factor of 10^-5 over 16-bit FCS.                       *|
    \**********************************************************************/
    
    /* Copyright (C) 1986 Gary S. Brown.  You may use this program, or
       code or tables extracted from it, as desired without restriction.*/
    
    /* First, the polynomial itself and its table of feedback terms.  The  */
    /* polynomial is                                                       */
    /* 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+X^0 */
    /* Note that we take it "backwards" and put the highest-order term in  */
    /* the lowest-order bit.  The X^32 term is "implied"; the LSB is the   */
    /* X^31 term, etc.  The X^0 term (usually shown as "+1") results in    */
    /* the MSB being 1.                                                    */
    
    /* Note that the usual hardware shift register implementation, which   */
    /* is what we're using (we're merely optimizing it by doing eight-bit  */
    /* chunks at a time) shifts bits into the lowest-order term.  In our   */
    /* implementation, that means shifting towards the right.  Why do we   */
    /* do it this way?  Because the calculated CRC must be transmitted in  */
    /* order from highest-order term to lowest-order term.  UARTs transmit */
    /* characters in order from LSB to MSB.  By storing the CRC this way,  */
    /* we hand it to the UART in the order low-byte to high-byte; the UART */
    /* sends each low-bit to hight-bit; and the result is transmission bit */
    /* by bit from highest- to lowest-order term without requiring any bit */
    /* shuffling on our part.  Reception works similarly.                  */
    
    /* The feedback terms table consists of 256, 32-bit entries.  Notes:   */
    /*                                                                     */
    /*  1. The table can be generated at runtime if desired; code to do so */
    /*     is shown later.  It might not be obvious, but the feedback      */
    /*     terms simply represent the results of eight shift/xor opera-    */
    /*     tions for all combinations of data and CRC register values.     */
    /*                                                                     */
    /*  2. The CRC accumulation logic is the same for all CRC polynomials, */
    /*     be they sixteen or thirty-two bits wide.  You simply choose the */
    /*     appropriate table.  Alternatively, because the table can be     */
    /*     generated at runtime, you can start by generating the table for */
    /*     the polynomial in question and use exactly the same "updcrc",   */
    /*     if your application needn't simultaneously handle two CRC       */
    /*     polynomials.  (Note, however, that XMODEM is strange.)          */
    /*                                                                     */
    /*  3. For 16-bit CRCs, the table entries need be only 16 bits wide;   */
    /*     of course, 32-bit entries work OK if the high 16 bits are zero. */
    /*                                                                     */
    /*  4. The values must be right-shifted by eight bits by the "updcrc"  */
    /*     logic; the shift must be unsigned (bring in zeroes).  On some   */
    /*     hardware you could probably optimize the shift in assembler by  */
    /*     using byte-swap instructions.                                   */
    
    static const uint32_t crc_32_tab[] = { /* CRC polynomial 0xedb88320 */
    0x00000000, 0x77073096, 0xee0e612c, 0x990951ba, 0x076dc419, 0x706af48f,
    0xe963a535, 0x9e6495a3, 0x0edb8832, 0x79dcb8a4, 0xe0d5e91e, 0x97d2d988,
    0x09b64c2b, 0x7eb17cbd, 0xe7b82d07, 0x90bf1d91, 0x1db71064, 0x6ab020f2,
    0xf3b97148, 0x84be41de, 0x1adad47d, 0x6ddde4eb, 0xf4d4b551, 0x83d385c7,
    0x136c9856, 0x646ba8c0, 0xfd62f97a, 0x8a65c9ec, 0x14015c4f, 0x63066cd9,
    0xfa0f3d63, 0x8d080df5, 0x3b6e20c8, 0x4c69105e, 0xd56041e4, 0xa2677172,
    0x3c03e4d1, 0x4b04d447, 0xd20d85fd, 0xa50ab56b, 0x35b5a8fa, 0x42b2986c,
    0xdbbbc9d6, 0xacbcf940, 0x32d86ce3, 0x45df5c75, 0xdcd60dcf, 0xabd13d59,
    0x26d930ac, 0x51de003a, 0xc8d75180, 0xbfd06116, 0x21b4f4b5, 0x56b3c423,
    0xcfba9599, 0xb8bda50f, 0x2802b89e, 0x5f058808, 0xc60cd9b2, 0xb10be924,
    0x2f6f7c87, 0x58684c11, 0xc1611dab, 0xb6662d3d, 0x76dc4190, 0x01db7106,
    0x98d220bc, 0xefd5102a, 0x71b18589, 0x06b6b51f, 0x9fbfe4a5, 0xe8b8d433,
    0x7807c9a2, 0x0f00f934, 0x9609a88e, 0xe10e9818, 0x7f6a0dbb, 0x086d3d2d,
    0x91646c97, 0xe6635c01, 0x6b6b51f4, 0x1c6c6162, 0x856530d8, 0xf262004e,
    0x6c0695ed, 0x1b01a57b, 0x8208f4c1, 0xf50fc457, 0x65b0d9c6, 0x12b7e950,
    0x8bbeb8ea, 0xfcb9887c, 0x62dd1ddf, 0x15da2d49, 0x8cd37cf3, 0xfbd44c65,
    0x4db26158, 0x3ab551ce, 0xa3bc0074, 0xd4bb30e2, 0x4adfa541, 0x3dd895d7,
    0xa4d1c46d, 0xd3d6f4fb, 0x4369e96a, 0x346ed9fc, 0xad678846, 0xda60b8d0,
    0x44042d73, 0x33031de5, 0xaa0a4c5f, 0xdd0d7cc9, 0x5005713c, 0x270241aa,
    0xbe0b1010, 0xc90c2086, 0x5768b525, 0x206f85b3, 0xb966d409, 0xce61e49f,
    0x5edef90e, 0x29d9c998, 0xb0d09822, 0xc7d7a8b4, 0x59b33d17, 0x2eb40d81,
    0xb7bd5c3b, 0xc0ba6cad, 0xedb88320, 0x9abfb3b6, 0x03b6e20c, 0x74b1d29a,
    0xead54739, 0x9dd277af, 0x04db2615, 0x73dc1683, 0xe3630b12, 0x94643b84,
    0x0d6d6a3e, 0x7a6a5aa8, 0xe40ecf0b, 0x9309ff9d, 0x0a00ae27, 0x7d079eb1,
    0xf00f9344, 0x8708a3d2, 0x1e01f268, 0x6906c2fe, 0xf762575d, 0x806567cb,
    0x196c3671, 0x6e6b06e7, 0xfed41b76, 0x89d32be0, 0x10da7a5a, 0x67dd4acc,
    0xf9b9df6f, 0x8ebeeff9, 0x17b7be43, 0x60b08ed5, 0xd6d6a3e8, 0xa1d1937e,
    0x38d8c2c4, 0x4fdff252, 0xd1bb67f1, 0xa6bc5767, 0x3fb506dd, 0x48b2364b,
    0xd80d2bda, 0xaf0a1b4c, 0x36034af6, 0x41047a60, 0xdf60efc3, 0xa867df55,
    0x316e8eef, 0x4669be79, 0xcb61b38c, 0xbc66831a, 0x256fd2a0, 0x5268e236,
    0xcc0c7795, 0xbb0b4703, 0x220216b9, 0x5505262f, 0xc5ba3bbe, 0xb2bd0b28,
    0x2bb45a92, 0x5cb36a04, 0xc2d7ffa7, 0xb5d0cf31, 0x2cd99e8b, 0x5bdeae1d,
    0x9b64c2b0, 0xec63f226, 0x756aa39c, 0x026d930a, 0x9c0906a9, 0xeb0e363f,
    0x72076785, 0x05005713, 0x95bf4a82, 0xe2b87a14, 0x7bb12bae, 0x0cb61b38,
    0x92d28e9b, 0xe5d5be0d, 0x7cdcefb7, 0x0bdbdf21, 0x86d3d2d4, 0xf1d4e242,
    0x68ddb3f8, 0x1fda836e, 0x81be16cd, 0xf6b9265b, 0x6fb077e1, 0x18b74777,
    0x88085ae6, 0xff0f6a70, 0x66063bca, 0x11010b5c, 0x8f659eff, 0xf862ae69,
    0x616bffd3, 0x166ccf45, 0xa00ae278, 0xd70dd2ee, 0x4e048354, 0x3903b3c2,
    0xa7672661, 0xd06016f7, 0x4969474d, 0x3e6e77db, 0xaed16a4a, 0xd9d65adc,
    0x40df0b66, 0x37d83bf0, 0xa9bcae53, 0xdebb9ec5, 0x47b2cf7f, 0x30b5ffe9,
    0xbdbdf21c, 0xcabac28a, 0x53b39330, 0x24b4a3a6, 0xbad03605, 0xcdd70693,
    0x54de5729, 0x23d967bf, 0xb3667a2e, 0xc4614ab8, 0x5d681b02, 0x2a6f2b94,
    0xb40bbe37, 0xc30c8ea1, 0x5a05df1b, 0x2d02ef8d
    };
    
    #define UPDC32(octet,crc) (crc_32_tab[((crc) ^ (octet)) & 0xff] ^ ((crc) >> 8))
    
    uint32_t crc32buf(char *buf, size_t len)
    {
          uint32_t crc;
    
          crc = 0xFFFFFFFF;
    
          for ( ; len; --len, ++buf)
          {
                crc = UPDC32(*buf, crc);
          }
    
          return crc ^ 0xFFFFFFFF;
    }