LXR toybox/toys/posix/split.c

   1/* split.c - split a file into smaller files
   2 *
   3 * Copyright 2013 Rob Landley <rob@landley.net>
   4 *
   5 * See http://pubs.opengroup.org/onlinepubs/9699919799/utilities/split.html
   6 *
   7 * Standard does not cover:
   8 * - should splitting an empty file produce an empty outfile? (Went with "no".)
   9 * - permissions on output file
  10
  11USE_SPLIT(NEWTOY(split, ">2a#<1=2>9b#<1l#<1[!bl]", TOYFLAG_USR|TOYFLAG_BIN))
  12
  13config SPLIT
  14  bool "split"
  15  default y
  16  help
  17    usage: split [-a SUFFIX_LEN] [-b BYTES] [-l LINES] [INPUT [OUTPUT]]
  18
  19    Copy INPUT (or stdin) data to a series of OUTPUT (or "x") files with
  20    alphabetically increasing suffix (aa, ab, ac... az, ba, bb...).
  21
  22    -a  Suffix length (default 2)
  23    -b  BYTES/file (10, 10k, 10m, 10g...)
  24    -l  LINES/file (default 1000)
  25*/
  26
  27#define FOR_split
  28#include "toys.h"
  29
  30GLOBALS(
  31  long l, b, a;
  32
  33  char *outfile;
  34)
  35
  36static void do_split(int infd, char *in)
  37{
  38  unsigned long bytesleft, linesleft, filenum, len, pos;
  39  int outfd = -1;
  40  struct stat st;
  41
  42  // posix doesn't cover permissions on output file, so copy input (or 0777)
  43  st.st_mode = 0777;
  44  fstat(infd, &st);
  45
  46  len = pos = filenum = bytesleft = linesleft = 0;
  47  for (;;) {
  48    int i, j;
  49
  50    // Refill toybuf?
  51    if (len == pos) {
  52      if (!(len = xread(infd, toybuf, sizeof(toybuf)))) break;
  53      pos = 0;
  54    }
  55
  56    // Start new output file?
  57    if ((TT.b && !bytesleft) || (TT.l && !linesleft)) {
  58      char *s = TT.outfile + strlen(TT.outfile);
  59
  60      j = filenum++;
  61      for (i = 0; i<TT.a; i++) {
  62        *(--s) = 'a'+(j%26);
  63        j /= 26;
  64      }
  65      if (j) error_exit("bad suffix");
  66      bytesleft = TT.b;
  67      linesleft = TT.l;
  68      if (outfd != -1) close(outfd);
  69      outfd = xcreate(TT.outfile, O_RDWR|O_CREAT|O_TRUNC, st.st_mode & 0777);
  70    }
  71
  72    // Write next chunk of output.
  73    if (TT.l) {
  74      for (i = pos; i < len; ) {
  75        if (toybuf[i++] == '\n' && !--linesleft) break;
  76        if (!--bytesleft) break;
  77      }
  78      j = i - pos;
  79    } else {
  80      j = len - pos;
  81      if (j > bytesleft) j = bytesleft;
  82      bytesleft -= j;
  83    }
  84    xwrite(outfd, toybuf+pos, j);
  85    pos += j;
  86  }
  87
  88  if (CFG_TOYBOX_FREE) {
  89    if (outfd != -1) close(outfd);
  90    if (infd) close(infd);
  91    free(TT.outfile);
  92  }
  93  xexit();
  94}
  95
  96void split_main(void)
  97{
  98  if (!TT.b && !TT.l) TT.l = 1000;
  99
 100  // Allocate template for output filenames
 101  TT.outfile = xmprintf("%s%*c", (toys.optc == 2) ? toys.optargs[1] : "x",
 102    (int)TT.a, ' ');
 103
 104  // We only ever use one input, but this handles '-' or no input for us.
 105  loopfiles(toys.optargs, do_split);
 106}
 107