commands/split/split.c

   1 /* split - split a file                 Author: Michiel Huisjes */
   2
   3 #include <sys/types.h>
   4 #include <fcntl.h>
   5 #include <stdlib.h>
   6 #include <string.h>
   7 #include <unistd.h>
   8 #include <minix/minlib.h>
   9
  10 #define CHUNK_SIZE      1024
  11
  12 int cut_line = 1000;
  13 int infile;
  14 char out_file[100];
  15 char *suffix;
  16
  17 int main(int argc, char **argv);
  18 void split(void);
  19 int newfile(void);
  20 void usage(void);
  21 void quit(void);
  22
  23 int main(argc, argv)
  24 int argc;
  25 char **argv;
  26 {
  27   unsigned short i;
  28
  29   out_file[0] = 'x';
  30   infile = -1;
  31
  32   if (argc > 4) usage();
  33   for (i = 1; i < argc; i++) {
  34         if (argv[i][0] == '-') {
  35                 if (argv[i][1] >= '0' && argv[i][1] <= '9'
  36                     && cut_line == 1000)
  37                         cut_line = atoi(argv[i]);
  38                 else if (argv[i][1] == '\0' && infile == -1)
  39                         infile = 0;
  40                 else
  41                         usage();
  42         } else if (infile == -1) {
  43                 if ((infile = open(argv[i], O_RDONLY)) < 0) {
  44                         std_err("Cannot open input file.\n");
  45                         exit(1);
  46                 }
  47         } else
  48                 strcpy(out_file, argv[i]);
  49   }
  50   if (infile == -1) infile = 0;
  51   strcat(out_file, "aa");
  52   for (suffix = out_file; *suffix; suffix++);
  53   suffix--;
  54
  55 /* Appendix now points to last `a' of "aa". We have to decrement it by one */
  56   *suffix = 'a' - 1;
  57   split();
  58   return(0);
  59 }
  60
  61 void split()
  62 {
  63   char buf[CHUNK_SIZE];
  64   register char *index, *base;
  65   register int n;
  66   int fd;
  67   long lines = 0L;
  68
  69   fd = -1;
  70   while ((n = read(infile, buf, CHUNK_SIZE)) > 0) {
  71         base = index = buf;
  72         while (--n >= 0) {
  73                 if (*index++ == '\n')
  74                         if (++lines % cut_line == 0) {
  75                                 if (fd == -1) fd = newfile();
  76                                 if (write(fd, base, (int) (index - base)) != (int) (index - base))
  77                                         quit();
  78                                 base = index;
  79                                 close(fd);
  80                                 fd = -1;
  81                         }
  82         }
  83         if (index == base) continue;
  84         if (fd == -1) fd = newfile();
  85         if (write(fd, base, (int) (index - base)) != (int) (index - base))
  86                 quit();
  87   }
  88 }
  89
  90 int newfile()
  91 {
  92   int fd;
  93
  94   if (++*suffix > 'z') {        /* Increment letter */
  95         *suffix = 'a';          /* Reset last letter */
  96         ++*(suffix - 1);        /* Previous letter must be incremented */
  97         /* E.g. was `filename.az' */
  98         /* Now `filename.ba' */
  99   }
 100   if ((fd = creat(out_file, 0644)) < 0) {
 101         std_err("Cannot create new file.\n");
 102         exit(2);
 103   }
 104   return fd;
 105 }
 106
 107 void usage()
 108 {
 109   std_err("Usage: split [-n] [file [name]].\n");
 110   exit(1);
 111 }
 112
 113 void quit()
 114 {
 115   std_err("split: write error\n");
 116   exit(1);
 117 }