Minix1.1/usr/src/commands/split.c

/* split - split a file		Author: Michiel Huisjes */

#include "blocksize.h"

int cut_line = 1000;
int infile;
char out_file[100];
char *suffix;

main(argc, argv)
int argc;
char **argv;
{
  unsigned short i;

  out_file[0] = 'x';
  infile = -1;

  if (argc > 4)
  	usage();
  for (i = 1; i < argc; i++) {
  	if (argv[i][0] == '-') {
  		if (argv[i][1] >= '0' && argv[i][1] <= '9'
  						    && cut_line == 1000)
  			cut_line = atoi(argv[i]);
  		else if (argv[i][1] == '\0' && infile == -1)
  			infile = 0;
  		else
  			usage();
  	}
  	else if (infile == -1) {
  		if ((infile = open(argv[i], 0)) < 0) {
  			std_err("Cannot open input file.\n");
  			exit (1);
  		}
  	}
  	else
  		strcpy(out_file, argv[i]);
  }
  if (infile == -1)
  	infile = 0;
  strcat(out_file, "aa");
  for (suffix = out_file; *suffix; suffix++)
  	;
  suffix--;
/* Appendix now points to last `a' of "aa". We have to decrement it by one */
  *suffix = 'a' - 1;
  split();
  exit(0);
}

split()
{
  char buf[BLOCK_SIZE];
  register char *index, *base;
  register int n;
  int fd;
  long lines = 0L;

  fd = newfile();
  while ((n = read(infile, buf, BLOCK_SIZE)) > 0) {
  	base = index = buf;
  	while (--n >= 0) {
  		if (*index++ == '\n')
  			if (++lines % cut_line == 0)  {
  				if (write(fd, base, index-base) != index-base)
					quit();
  				base = index;
  				close(fd);
  				fd = newfile();
  			}
  	}
  	if (write(fd, base, index - base) != index - base) quit();
  }
}

newfile()
{
  int fd;

  if (++*suffix > 'z') {	/* Increment letter */
  	*suffix = 'a';	/* Reset last letter */
  	++*(suffix - 1);	/* Previous letter must be incremented*/
  				/* E.g. was `filename.az' */
  				/* Now `filename.ba' */
  }
  if ((fd = creat(out_file, 0644)) < 0) {
  	std_err("Cannot create new file.\n");
  	exit(2);
  }
  return fd;
}

usage ()
{
  std_err("Usage: split [-n] [file [name]].\n");
  exit(1);
}

quit()
{
  std_err("split: write error\n");
  exit(1);
}