static char *sccsid = "@(#)split.c	4.4 (Berkeley) 05/18/87";

#include <sys/param.h>
#include <sys/file.h>
#include <stdio.h>
#include <ctype.h>

#define DEFLINE	1000			/* default num lines per file */
#define ERR	-1			/* general error */
#define ERREXIT	0			/* error exit */
#define NO	0			/* no/false */
#define OK	0			/* okay exit */
#define YES	1			/* yes/true */

static long	bytecnt,		/* byte count to split on */
		numlines;		/* lines in each file */
static int	ifd = ERR,		/* input file descriptor */
		ofd = ERR;		/* output file descriptor */
static short	file_open;		/* if a file open */
static char	bfr[MAXBSIZE],		/* I/O buffer */
		fname[MAXPATHLEN];	/* file name */

main(argc,argv)
int	argc;
char	**argv;
{
	register int	cnt;		/* general counter */
	long	atol();
	char	*strcpy();

	for (cnt = 1;cnt < argc;++cnt) {
		if (argv[cnt][0] == '-')
			switch(argv[cnt][1]) {
				case 0:		/* stdin by request */
					if (ifd != ERR)
						usage();
					ifd = 0;
					break;
				case 'b':	/* byte count split */
					if (numlines)
						usage();
					if (!argv[cnt][2])
						bytecnt = atol(argv[++cnt]);
					else
						bytecnt = atol(argv[cnt] + 2);
					if (bytecnt <= 0) {
						fputs("split: byte count must be greater than zero.\n",stderr);
						usage();
					}
					break;
				default:
					if (!isdigit(argv[cnt][1]) || bytecnt)
						usage();
					if ((numlines = atol(argv[cnt] + 1)) <= 0) {
						fputs("split: line count must be greater than zero.\n",stderr);
						usage();
					}
					break;
			}
		else if (ifd == ERR) {		/* input file */
			if ((ifd = open(argv[cnt],O_RDONLY,0)) < 0) {
				perror(argv[cnt]);
				exit(ERREXIT);
			}
		}
		else if (!*fname)		/* output file prefix */
			strcpy(fname,argv[cnt]);
		else
			usage();
	}
	if (ifd == ERR)				/* stdin by default */
		ifd = 0;
	if (bytecnt)
		split1();
	if (!numlines)
		numlines = DEFLINE;
	split2();
}

/*
 * split1 --
 *	split by bytes
 */
static
split1()
{
	register long	bcnt;		/* byte counter */
	register int	dist,		/* buffer offset */
			len;		/* read length */
	register char	*C;		/* tmp pointer into buffer */

	for (bcnt = 0;;)
		switch(len = read(ifd,bfr,MAXBSIZE)) {
			case 0:
				exit(OK);
			case ERR:
				perror("read");
				exit(ERREXIT);
			default:
				if (!file_open) {
					newfile();
					file_open = YES;
				}
				if (bcnt + len >= bytecnt) {
					dist = bytecnt - bcnt;
					write(ofd,bfr,dist);
					len -= dist;
					for (C = bfr + dist;len >= bytecnt;len -= bytecnt,C += bytecnt) {
						newfile();
						write(ofd,C,(int)bytecnt);
					}
					if (len) {
						newfile();
						write(ofd,C,len);
					}
					else
						file_open = NO;
					bcnt = len;
				}
				else {
					bcnt += len;
					write(ofd,bfr,len);
				}
		}
}

/*
 * split2 --
 *	split by lines
 */
static
split2()
{
	register char	*Ce,			/* start/end pointers */
			*Cs;
	register long	lcnt;			/* line counter */
	register int	len;			/* read length */

	for (lcnt = 0;;)
		switch(len = read(ifd,bfr,MAXBSIZE)) {
			case 0:
				exit(0);
			case ERR:
				perror("read");
				break;
			default:
				if (!file_open) {
					newfile();
					file_open = YES;
				}
				for (Cs = Ce = bfr;len--;Ce++)
					if (*Ce == '\n' && ++lcnt == numlines) {
						write(ofd,Cs,(int)(Ce - Cs) + 1);
						lcnt = 0;
						Cs = Ce + 1;
						if (len)
							newfile();
						else
							file_open = NO;
					}
				if (Cs < Ce)
					write(ofd,Cs,(int)(Ce - Cs));
		}
}

/*
 * newfile --
 *	open a new file
 */
static
newfile()
{
	static long	fnum;		/* file name counter */
	static short	defname;	/* using default name, "x" */
	static char	*fpnt;		/* output file name pointer */

	if (ofd == ERR) {
		if (fname[0]) {
			fpnt = fname + strlen(fname);
			defname = NO;
		}
		else {
			fname[0] = 'x';
			fpnt = fname + 1;
			defname = YES;
		}
		ofd = fileno(stdout);
	}
	/*
	 * hack to increase max files; original code just wandered through
	 * magic characters.  Maximum files is 3 * 26 * 26 == 2028
	 */
#define MAXFILES	676
	if (fnum == MAXFILES) {
		if (!defname || fname[0] == 'z') {
			fputs("split: too many files.\n",stderr);
			exit(ERREXIT);
		}
		++fname[0];
		fnum = 0;
	}
	fpnt[0] = fnum / 26 + 'a';
	fpnt[1] = fnum % 26 + 'a';
	++fnum;
	if (!freopen(fname,"w",stdout)) {
		fprintf(stderr,"split: unable to write to %s.\n",fname);
		exit(ERR);
	}
}

/*
 * usage --
 *	print usage message and die
 */
static
usage()
{
	fputs("usage: split [-] [-#] [-b byte_count] [file [prefix]]\n",stderr);
	exit(ERREXIT);
}