source: trunk/minix/commands/simple/split.c@ 11

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

#include <sys/types.h>
#include <fcntl.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.h>
#include <minix/minlib.h>

#define CHUNK_SIZE      1024

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

_PROTOTYPE(int main, (int argc, char **argv));
_PROTOTYPE(void split, (void));
_PROTOTYPE(int newfile, (void));
_PROTOTYPE(void usage, (void));
_PROTOTYPE(void quit, (void));

int 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], O_RDONLY)) < 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();
  return(0);
}

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

  fd = -1;
  while ((n = read(infile, buf, CHUNK_SIZE)) > 0) {
        base = index = buf;
        while (--n >= 0) {
                if (*index++ == '\n')
                        if (++lines % cut_line == 0) {
                                if (fd == -1) fd = newfile();
                                if (write(fd, base, (int) (index - base)) != (int) (index - base))
                                        quit();
                                base = index;
                                close(fd);
                                fd = -1;
                        }
        }
        if (index == base) continue;
        if (fd == -1) fd = newfile();
        if (write(fd, base, (int) (index - base)) != (int) (index - base))
                quit();
  }
}

int 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;
}

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

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