usr/src/usr.bin/split/split.c

static char *sccsid = "@(#)split.c      4.4 (Berkeley) %G%";

#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);
}