xdecode.c

来自「Reference Implementation of G.711 standa」· C语言 代码 · 共 1,011 行 · 第 1/3 页

    /* Search for header line */
    if (get_header(in, buf, sizeof(buf)) == NULL)
      HARAKIRI("No begin line\n", 5);

    /* Get header information: mode and name of file */
    sscanf(buf, "begin %o %s %s", &mode, dest, next_file);

    /* Check whether is last file */
    if (strcmp(next_file, this_file) == 0)
      more_to_decode = NO;

    /* Handles ~user/file format */
    if (dest[0] == '~')
    {
      if (translate_destination(dest) == NULL)
	HARAKIRI("Illegal ~user or no such user \n", 4);
    }

    /* Creates output file, only ... */
    if (first_time)
    {
      /* Set flag */
      first_time = NO;

      /* Add path as prefix, if needed */
      if (path)
      {
	char *tmp;
	tmp = (char *)calloc(sizeof(char), strlen(dest)+strlen(path)+2);
	strcpy(tmp, path);
	if (path[strlen(path)-1]!='/')
	  strcat(tmp,"/");
	strcat(tmp,dest);
	strcpy(dest,tmp);
      }

      /* Go on */
      if (strcmp(dest, ""))
      {
	if (mode_is_binary)
	{
	  if ((out = fopen(dest, WB)) == NULL)
	    KILL(dest, 3);
	  fprintf(stderr, "Output mode is BINARY\n");
	}
	else
	{
	  if ((out = fopen(dest, WT)) == NULL)
	    KILL(dest, 3);
	  fprintf(stderr, "Output mode is TEXT\n");
	}
      }
      else
	out = stdout;		/* if dest has no name, assumes stdout */

#if !defined(VMS)
      /* .. and set mode for binary file, as the original was */
      if (chmod(dest, mode))
      {
	fprintf(stderr, " -> Error changing mode of file");
	fprintf(stderr, " %s ... continuing anyway\n", dest);
      }
#endif				/* !VMS */
      fprintf(stderr, " Mounting decoded file %s from ", dest);
    }

    /* decodes the present file; report any bugs/problems */
    fprintf(stderr, "%s%c", this_file, more_to_decode ? '+' : '.');
    if ((status = decode(in, out)) != 1)
    {
      switch (status)
      {
      case 0:
	HARAKIRI("Short file\n", 7);
	break;
      case -1:
	HARAKIRI("Error reading file\n", 7);
	break;
      case 2:
	fprintf(stderr, "[*Transmission bug %d happened in file %s; %s",
		status, this_file, "Probably fixed*]");
	break;
      default:
	fprintf(stderr, "[*Unknown bug %d happened in file %s; %s",
		status, this_file, "NOT fixed*]");
	break;
      }
    }

    /* Look for end line */
    if (fgets(buf, sizeof buf, in) == NULL || strcmp(buf, "end\n"))
      HARAKIRI("No end line\n", 6);

    /* Read original CRCs */
    if ((status = fscanf(in, "%%XENCODE-CRC: %d CCITT %lx ARC %lx XMODEM %lx",
			 &version, &o_crc_c, &o_crc_a, &o_crc_x)) == 4)
    {
      bad_crc = 0;
      /* Check if incremental CRC found in file matches the calculated one */
      if (o_crc_c != crc_c)
	bad_crc += 01;
      if (o_crc_a != crc_a)
	bad_crc += 02;
      if (o_crc_x != crc_x)
	bad_crc += 04;

      if (bad_crc)
      {
	fprintf(stderr, "[*** Bad CRC %o for file %s ***]",
		bad_crc, this_file);
      }
    }
    else
      crc_present = 0;

    /* close present file */
    fclose(in);
  }

  /* Skip a line on screen */
  fprintf(stderr, "\n");

  /* Display warnings */
  if (!crc_present)
  {
    /* Warn if versions differ */
    if (version > XDECODE)
      fprintf(stderr, "%%XDECODE-WARN: x{en,de}code version numbers mismatch!\n");

    /* Warn if original CRC not present */
    fprintf(stderr, "%%XDECODE-WARN: CRC info of original file not found!\n");
  }

  /* Print calculated CRCs */
  fprintf(stderr, "%%XDECODE-INFO: CRCs calculated for this file are:\n");
  fprintf(stderr, "%%XDECODE-CRC:  CCITT %4X ARC %4X XMODEM %4X",
	  crc_c, crc_a, crc_x);

  /* Closes output file */
  fclose(out);

  /* And exits! */
  fprintf(stderr, "\n-> Done !\n");

#ifndef VMS
  return (0);
#endif
}
/* ........................... end of main() ........................... */



/*
  ---------------------------------------------------------------------------
  WTYPE updcrc (WTYPE icrc, unsigned char *icp, int icnt, WTYPE *crctab, 
  ~~~~~~~~~~~~  char swapped);
  
  Description:
  ~~~~~~~~~~~~
  Calculate, intelligently, the CRC-16 of a dataset incrementally given a
  buffer full at a time. The parameters on which the function relyes are:

  Parameter             CCITT   XMODEM  ARC
  ---------             ------  ------  ----
  the polynomial P	0x1021	0x1021	A001
  initial CRC value:	-1	0	0
  bit-order swap        No (0)  Yes (1) Yes (1)
  bits in CRC:          16	16	16

  Usage:
  ~~~~~~
  	newcrc = updcrc( oldcrc, bufadr, buflen, crctab, swapped)
  		   WTYPE oldcrc;
                   int buflen;
  		   char *bufadr;
                   WTYPE *crctab;
                   char swapped;

  Notes:
   Regards the data stream as an integer whose MSB is the MSB of the first
   byte recieved.  This number is 'divided' (using xor instead of subtraction)
   by the crc-polynomial P.
   XMODEM does things a little differently, essentially treating the LSB of
   the first data byte as the MSB of the integer.

  Original Author:
  ~~~~~~~~~~~~~~~~
  Mark G. Mendel, 7/86
  UUCP: ihnp4!umn-cs!hyper!mark, GEnie: mgm
  [ Original code available in comp.sources.unix volume 6 (1989) ]

  History:
  ~~~~~~~~
  xx.Jul.86 v1.0  Release by the author [posted to c.s.misc in 1989]
  01.Sep.93 v1.0a Adapted by Simao <[e-mail]> to be used in the
 		  x{en,de}code.c.

  ---------------------------------------------------------------------------
*/

/* Table for CCITT CRCs */
static WTYPE    crctab_ccitt[1 << B] = {
  0x0, 0x1021, 0x2042, 0x3063, 0x4084, 0x50a5, 0x60c6, 0x70e7,
  0x8108, 0x9129, 0xa14a, 0xb16b, 0xc18c, 0xd1ad, 0xe1ce, 0xf1ef,
  0x1231, 0x210, 0x3273, 0x2252, 0x52b5, 0x4294, 0x72f7, 0x62d6,
  0x9339, 0x8318, 0xb37b, 0xa35a, 0xd3bd, 0xc39c, 0xf3ff, 0xe3de,
  0x2462, 0x3443, 0x420, 0x1401, 0x64e6, 0x74c7, 0x44a4, 0x5485,
  0xa56a, 0xb54b, 0x8528, 0x9509, 0xe5ee, 0xf5cf, 0xc5ac, 0xd58d,
  0x3653, 0x2672, 0x1611, 0x630, 0x76d7, 0x66f6, 0x5695, 0x46b4,
  0xb75b, 0xa77a, 0x9719, 0x8738, 0xf7df, 0xe7fe, 0xd79d, 0xc7bc,
  0x48c4, 0x58e5, 0x6886, 0x78a7, 0x840, 0x1861, 0x2802, 0x3823,
  0xc9cc, 0xd9ed, 0xe98e, 0xf9af, 0x8948, 0x9969, 0xa90a, 0xb92b,
  0x5af5, 0x4ad4, 0x7ab7, 0x6a96, 0x1a71, 0xa50, 0x3a33, 0x2a12,
  0xdbfd, 0xcbdc, 0xfbbf, 0xeb9e, 0x9b79, 0x8b58, 0xbb3b, 0xab1a,
  0x6ca6, 0x7c87, 0x4ce4, 0x5cc5, 0x2c22, 0x3c03, 0xc60, 0x1c41,
  0xedae, 0xfd8f, 0xcdec, 0xddcd, 0xad2a, 0xbd0b, 0x8d68, 0x9d49,
  0x7e97, 0x6eb6, 0x5ed5, 0x4ef4, 0x3e13, 0x2e32, 0x1e51, 0xe70,
  0xff9f, 0xefbe, 0xdfdd, 0xcffc, 0xbf1b, 0xaf3a, 0x9f59, 0x8f78,
  0x9188, 0x81a9, 0xb1ca, 0xa1eb, 0xd10c, 0xc12d, 0xf14e, 0xe16f,
  0x1080, 0xa1, 0x30c2, 0x20e3, 0x5004, 0x4025, 0x7046, 0x6067,
  0x83b9, 0x9398, 0xa3fb, 0xb3da, 0xc33d, 0xd31c, 0xe37f, 0xf35e,
  0x2b1, 0x1290, 0x22f3, 0x32d2, 0x4235, 0x5214, 0x6277, 0x7256,
  0xb5ea, 0xa5cb, 0x95a8, 0x8589, 0xf56e, 0xe54f, 0xd52c, 0xc50d,
  0x34e2, 0x24c3, 0x14a0, 0x481, 0x7466, 0x6447, 0x5424, 0x4405,
  0xa7db, 0xb7fa, 0x8799, 0x97b8, 0xe75f, 0xf77e, 0xc71d, 0xd73c,
  0x26d3, 0x36f2, 0x691, 0x16b0, 0x6657, 0x7676, 0x4615, 0x5634,
  0xd94c, 0xc96d, 0xf90e, 0xe92f, 0x99c8, 0x89e9, 0xb98a, 0xa9ab,
  0x5844, 0x4865, 0x7806, 0x6827, 0x18c0, 0x8e1, 0x3882, 0x28a3,
  0xcb7d, 0xdb5c, 0xeb3f, 0xfb1e, 0x8bf9, 0x9bd8, 0xabbb, 0xbb9a,
  0x4a75, 0x5a54, 0x6a37, 0x7a16, 0xaf1, 0x1ad0, 0x2ab3, 0x3a92,
  0xfd2e, 0xed0f, 0xdd6c, 0xcd4d, 0xbdaa, 0xad8b, 0x9de8, 0x8dc9,
  0x7c26, 0x6c07, 0x5c64, 0x4c45, 0x3ca2, 0x2c83, 0x1ce0, 0xcc1,
  0xef1f, 0xff3e, 0xcf5d, 0xdf7c, 0xaf9b, 0xbfba, 0x8fd9, 0x9ff8,
  0x6e17, 0x7e36, 0x4e55, 0x5e74, 0x2e93, 0x3eb2, 0xed1, 0x1ef0,
};

/* Table for xmodem CRCs */
static WTYPE    crctab_xmodem[1 << B] = {
  0x0, 0x17ce, 0xfdf, 0x1811, 0x1fbe, 0x870, 0x1061, 0x7af,
  0x1f3f, 0x8f1, 0x10e0, 0x72e, 0x81, 0x174f, 0xf5e, 0x1890,
  0x1e3d, 0x9f3, 0x11e2, 0x62c, 0x183, 0x164d, 0xe5c, 0x1992,
  0x102, 0x16cc, 0xedd, 0x1913, 0x1ebc, 0x972, 0x1163, 0x6ad,
  0x1c39, 0xbf7, 0x13e6, 0x428, 0x387, 0x1449, 0xc58, 0x1b96,
  0x306, 0x14c8, 0xcd9, 0x1b17, 0x1cb8, 0xb76, 0x1367, 0x4a9,
  0x204, 0x15ca, 0xddb, 0x1a15, 0x1dba, 0xa74, 0x1265, 0x5ab,
  0x1d3b, 0xaf5, 0x12e4, 0x52a, 0x285, 0x154b, 0xd5a, 0x1a94,
  0x1831, 0xfff, 0x17ee, 0x20, 0x78f, 0x1041, 0x850, 0x1f9e,
  0x70e, 0x10c0, 0x8d1, 0x1f1f, 0x18b0, 0xf7e, 0x176f, 0xa1,
  0x60c, 0x11c2, 0x9d3, 0x1e1d, 0x19b2, 0xe7c, 0x166d, 0x1a3,
  0x1933, 0xefd, 0x16ec, 0x122, 0x68d, 0x1143, 0x952, 0x1e9c,
  0x408, 0x13c6, 0xbd7, 0x1c19, 0x1bb6, 0xc78, 0x1469, 0x3a7,
  0x1b37, 0xcf9, 0x14e8, 0x326, 0x489, 0x1347, 0xb56, 0x1c98,
  0x1a35, 0xdfb, 0x15ea, 0x224, 0x58b, 0x1245, 0xa54, 0x1d9a,
  0x50a, 0x12c4, 0xad5, 0x1d1b, 0x1ab4, 0xd7a, 0x156b, 0x2a5,
  0x1021, 0x7ef, 0x1ffe, 0x830, 0xf9f, 0x1851, 0x40, 0x178e,
  0xf1e, 0x18d0, 0xc1, 0x170f, 0x10a0, 0x76e, 0x1f7f, 0x8b1,
  0xe1c, 0x19d2, 0x1c3, 0x160d, 0x11a2, 0x66c, 0x1e7d, 0x9b3,
  0x1123, 0x6ed, 0x1efc, 0x932, 0xe9d, 0x1953, 0x142, 0x168c,
  0xc18, 0x1bd6, 0x3c7, 0x1409, 0x13a6, 0x468, 0x1c79, 0xbb7,
  0x1327, 0x4e9, 0x1cf8, 0xb36, 0xc99, 0x1b57, 0x346, 0x1488,
  0x1225, 0x5eb, 0x1dfa, 0xa34, 0xd9b, 0x1a55, 0x244, 0x158a,
  0xd1a, 0x1ad4, 0x2c5, 0x150b, 0x12a4, 0x56a, 0x1d7b, 0xab5,
  0x810, 0x1fde, 0x7cf, 0x1001, 0x17ae, 0x60, 0x1871, 0xfbf,
  0x172f, 0xe1, 0x18f0, 0xf3e, 0x891, 0x1f5f, 0x74e, 0x1080,
  0x162d, 0x1e3, 0x19f2, 0xe3c, 0x993, 0x1e5d, 0x64c, 0x1182,
  0x912, 0x1edc, 0x6cd, 0x1103, 0x16ac, 0x162, 0x1973, 0xebd,
  0x1429, 0x3e7, 0x1bf6, 0xc38, 0xb97, 0x1c59, 0x448, 0x1386,
  0xb16, 0x1cd8, 0x4c9, 0x1307, 0x14a8, 0x366, 0x1b77, 0xcb9,
  0xa14, 0x1dda, 0x5cb, 0x1205, 0x15aa, 0x264, 0x1a75, 0xdbb,
  0x152b, 0x2e5, 0x1af4, 0xd3a, 0xa95, 0x1d5b, 0x54a, 0x1284,
};

/* Table for ARC CRCs */
static WTYPE    crctab_arc[1 << B] = {
  0x0, 0xc0c1, 0xc181, 0x140, 0xc301, 0x3c0, 0x280, 0xc241,
  0xc601, 0x6c0, 0x780, 0xc741, 0x500, 0xc5c1, 0xc481, 0x440,
  0xcc01, 0xcc0, 0xd80, 0xcd41, 0xf00, 0xcfc1, 0xce81, 0xe40,
  0xa00, 0xcac1, 0xcb81, 0xb40, 0xc901, 0x9c0, 0x880, 0xc841,
  0xd801, 0x18c0, 0x1980, 0xd941, 0x1b00, 0xdbc1, 0xda81, 0x1a40,
  0x1e00, 0xdec1, 0xdf81, 0x1f40, 0xdd01, 0x1dc0, 0x1c80, 0xdc41,
  0x1400, 0xd4c1, 0xd581, 0x1540, 0xd701, 0x17c0, 0x1680, 0xd641,
  0xd201, 0x12c0, 0x1380, 0xd341, 0x1100, 0xd1c1, 0xd081, 0x1040,
  0xf001, 0x30c0, 0x3180, 0xf141, 0x3300, 0xf3c1, 0xf281, 0x3240,
  0x3600, 0xf6c1, 0xf781, 0x3740, 0xf501, 0x35c0, 0x3480, 0xf441,
  0x3c00, 0xfcc1, 0xfd81, 0x3d40, 0xff01, 0x3fc0, 0x3e80, 0xfe41,
  0xfa01, 0x3ac0, 0x3b80, 0xfb41, 0x3900, 0xf9c1, 0xf881, 0x3840,
  0x2800, 0xe8c1, 0xe981, 0x2940, 0xeb01, 0x2bc0, 0x2a80, 0xea41,
  0xee01, 0x2ec0, 0x2f80, 0xef41, 0x2d00, 0xedc1, 0xec81, 0x2c40,
  0xe401, 0x24c0, 0x2580, 0xe541, 0x2700, 0xe7c1, 0xe681, 0x2640,
  0x2200, 0xe2c1, 0xe381, 0x2340, 0xe101, 0x21c0, 0x2080, 0xe041,
  0xa001, 0x60c0, 0x6180, 0xa141, 0x6300, 0xa3c1, 0xa281, 0x6240,
  0x6600, 0xa6c1, 0xa781, 0x6740, 0xa501, 0x65c0, 0x6480, 0xa441,
  0x6c00, 0xacc1, 0xad81, 0x6d40, 0xaf01, 0x6fc0, 0x6e80, 0xae41,
  0xaa01, 0x6ac0, 0x6b80, 0xab41, 0x6900, 0xa9c1, 0xa881, 0x6840,
  0x7800, 0xb8c1, 0xb981, 0x7940, 0xbb01, 0x7bc0, 0x7a80, 0xba41,
  0xbe01, 0x7ec0, 0x7f80, 0xbf41, 0x7d00, 0xbdc1, 0xbc81, 0x7c40,
  0xb401, 0x74c0, 0x7580, 0xb541, 0x7700, 0xb7c1, 0xb681, 0x7640,
  0x7200, 0xb2c1, 0xb381, 0x7340, 0xb101, 0x71c0, 0x7080, 0xb041,
  0x5000, 0x90c1, 0x9181, 0x5140, 0x9301, 0x53c0, 0x5280, 0x9241,
  0x9601, 0x56c0, 0x5780, 0x9741, 0x5500, 0x95c1, 0x9481, 0x5440,
  0x9c01, 0x5cc0, 0x5d80, 0x9d41, 0x5f00, 0x9fc1, 0x9e81, 0x5e40,
  0x5a00, 0x9ac1, 0x9b81, 0x5b40, 0x9901, 0x59c0, 0x5880, 0x9841,
  0x8801, 0x48c0, 0x4980, 0x8941, 0x4b00, 0x8bc1, 0x8a81, 0x4a40,
  0x4e00, 0x8ec1, 0x8f81, 0x4f40, 0x8d01, 0x4dc0, 0x4c80, 0x8c41,
  0x4400, 0x84c1, 0x8581, 0x4540, 0x8701, 0x47c0, 0x4680, 0x8641,
  0x8201, 0x42c0, 0x4380, 0x8341, 0x4100, 0x81c1, 0x8081, 0x4040,
};

/* -------------- Begin of function updcrc() ---------------------- */
WTYPE
updcrc(icrc, icp, icnt, crctab, swapped)
  WTYPE           icrc, *crctab;
  unsigned char  *icp;
  int             icnt;
  char            swapped;
{
  register WTYPE  crc = icrc;
  register unsigned char *cp = icp;
  register int    cnt = icnt;

  if (swapped)
    while (cnt--)
    {
      crc = (crc >> B) ^ crctab[(crc & ((1 << B) - 1)) ^ *cp++];
    }
  else
    while (cnt--)
    {
      crc = (crc << B) ^ crctab[(crc >> (W - B)) ^ *cp++];
    }

  return (crc);
}
/* .......................... End of updcrc() ............................ */


/*