/*  BCODE: bcode encoder version 1.03-kr by Craig Bruce 05-Oct-93
**
**  CRC-32 code based on "File Verification Using CRC" by Mark R. Nelson in
**  Dr. Dobb's Journal, May 1992, pp. 64-67.  Note that CRC-32 values ARE the
**  same as in ZMODEM and PKZIP.
**
**  v1.00-kr: original release, of course, in K&R C.
**  v1.01-kr: fixed some bad print formats.
**  v1.02-kr: fixed some more bad print formats.
**  v1.03-kr: changed the encoding format to use 72 chars/line, rather than 76.
*/

#include <stdio.h>
#include <string.h>

#define VERSION		"1.03-kr"
#define MAX_CHUNK	54
#define MAX_LINE	80
#define MAX_FILENAME	85

typedef unsigned char BYTE;
typedef unsigned long ULONG;
typedef int BOOL;
#define TRUE	1
#define FALSE	0

void	main();
void	EncodeFile();
BOOL	EncodeSeg();
ULONG	EncodeLine();
int	ReadChunk();

char	base64Char[64] = {
	'A','B','C','D','E','F','G','H','I','J','K','L','M','N','O','P',
	'Q','R','S','T','U','V','W','X','Y','Z','a','b','c','d','e','f',
	'g','h','i','j','k','l','m','n','o','p','q','r','s','t','u','v',
	'w','x','y','z','0','1','2','3','4','5','6','7','8','9','+','/'
};

char   *progname;
BOOL	verbose;

ULONG crcTable[256] = {
    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
};

/****************************************************************************/
void main( argc, argv )
	int	argc;
	char   *argv[];
{
	FILE   *fin;
	int	i;
	ULONG	maxlines;
	BOOL	filenameUsed;
	char   *alias;

	progname = argv[0];
	filenameUsed = FALSE;
	verbose = FALSE;
	alias = "stdin";
	maxlines = 0;

	i = 1;
	while (i<argc) {
		if (argv[i][0] == '-') {
			switch (argv[i][1]) {
			case 'l':
				maxlines = atoi( argv[i+1] );
				i++;
				break;
			case 'a':
				alias = argv[i+1];
				i++;
				break;
			case 'v':
				verbose = TRUE;
				fprintf(stderr, "bcode: version %s\n",VERSION);
				break;
			default:
				fprintf(stderr,
"usage: %s [-l max_line_count] [-v] [[filename][-a encoding_alias]] ...\n",
					progname);
				exit( 1 );
				break;
			}
		} else {
			filenameUsed = TRUE;
			if (verbose) {
				fprintf(stderr, "%s: bcoding file \"%s\"\n",
					progname, argv[i]);
			}
			if( (fin = fopen(argv[i], "rb")) == NULL) {
				fprintf(stderr, "%s: error opening \"%s\"\n",
					progname, argv[i]);
			} else {
				if (i+2<argc && argv[i+1][0]=='-'
				  && argv[i+1][1]=='a') {
					EncodeFile( fin, argv[i], argv[i+2],
						maxlines );
					i += 2;
				} else {
					EncodeFile( fin, argv[i], argv[i],
						maxlines );
				}
				fclose( fin );
			}
		}
		i++;
	}
	if (!filenameUsed) {
		if (verbose) {
			fprintf(stderr, "%s: encoding from standard input\n",
				progname);
		}
		EncodeFile( stdin, "stdin", alias, maxlines );
	}
}

/****************************************************************************/
void EncodeFile( fin, filename, alias, maxlines )
	FILE   *fin;
	char   *filename;
	char   *alias;
	int	maxlines;
{
	FILE   *fout;
	ULONG	segnum;
	BOOL	moreSegs;
	char	outname[MAX_FILENAME];

	for( segnum = 1; ; segnum++ ) {
		if (maxlines>0) {
			sprintf(outname, "%s.b%02lu", filename, segnum);
			if (verbose) {
				fprintf(stderr,
					"%s: outputting to file \"%s\"\n",
					progname, outname);
			}
			fout = fopen(outname, "w");
			if (fout == NULL) {
				fprintf(stderr,
				   "%s: error opening \"%s\" for writing\n",
				   progname, outname);
				return;
			}
		} else {
			fout = stdout;
		}
		moreSegs = EncodeSeg(alias, segnum, maxlines, fin, fout);
		if (!moreSegs) break;
		if (maxlines>0) {
			fclose( fout );
		}
	}
}

/****************************************************************************/
BOOL EncodeSeg( filename, segnum, maxlines, fin, fout )
	char   *filename;
	ULONG	segnum;
	ULONG	maxlines;
	FILE   *fin;
	FILE   *fout;
{
	ULONG	segcrc, seglen, len;
	ULONG	linenum;
	char   *ends;

	fprintf(fout,"--bcode-begin %lu %s\n", segnum, filename);

	seglen = 0;
	segcrc = 0xFFFFFFFF;
	linenum = 1;
	while (!maxlines || linenum<=maxlines) {
		len = EncodeLine( fin, fout, &segcrc );
		seglen += len;
		if (len <= 0) break;
		linenum++;
	}
	segcrc ^= 0xFFFFFFFF;

	if (linenum>maxlines && maxlines) {
		ends = "continued";
	} else {
		ends = "end";
	}
	fprintf(fout, "--bcode-%s %lu %lu %08lx\n", ends,segnum,seglen,segcrc);
	return( len );
}

/****************************************************************************/
ULONG EncodeLine( fin, fout, totalCrc )
	FILE   *fin;
	FILE   *fout;
	ULONG  *totalCrc;
{
	register int	b0,b1,b2;
	register ULONG	crc;
	register int	bufpos, len, linepos;
	BYTE		buf[MAX_CHUNK+3];
	BYTE		line[MAX_LINE];

	crc = *totalCrc;
	len = ReadChunk( fin, buf );
	if (len > 0) {
		buf[len] = 0;
		buf[len+1] = 0;
		buf[len+2] = 0;

		/* convert line */
		for (bufpos = 0, linepos = 0; bufpos < len; bufpos+=3,
		linepos+=4) {
			b0 = buf[bufpos];
			b1 = buf[bufpos+1];
			b2 = buf[bufpos+2];
			line[linepos  ] = base64Char[ b0 >> 2 ];
			line[linepos+1] = base64Char[ (b0&0x03)<<4 |
								(b1&0xF0)>>4 ];
			line[linepos+2] = base64Char[ (b1&0x0F)<<2 |
								(b2&0xC0)>>6 ];
			line[linepos+3] = base64Char[ b2 & 0x3F ];
		}

		/* fix non-integral-length (last) line */
		switch( len%3 ) {
			case 1:	line[linepos-2] = '='; /* fall though */
			case 2:	line[linepos-1] = '='; /* fall though */
			case 0:	break;
		}
		line[linepos] = '\n';
		line[linepos+1] = '\0';
		fputs(line,fout);

		/* take crc of line data */
		for( bufpos=0; bufpos < len; bufpos++ ) {
			crc = ((crc>>8) & 0x00FFFFFF)
				^ crcTable[ (crc^buf[bufpos]) & 0xFF];
		}
	}
	*totalCrc = crc;
	return( len );
}

/****************************************************************************/
int ReadChunk( fin, buf )
	FILE *fin;
	BYTE *buf;
{
	int	rem, readLen;

	rem = MAX_CHUNK;
	while( rem>0 && (readLen=fread( buf, sizeof(char), rem, fin)) > 0) {
		buf += readLen;
		rem -= readLen;
	}
	return( MAX_CHUNK - rem );
}