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 lines;
32  long bytes;
33  long suflen;
34
35  char *outfile;
36)
37
38static void do_split(int infd, char *in)
39{
40  unsigned long bytesleft, linesleft, filenum, len, pos;
41  int outfd = -1;
42  struct stat st;
43
44  // posix doesn't cover permissions on output file, so copy input (or 0777)
45  st.st_mode = 0777;
46  fstat(infd, &st);
47
48  len = pos = filenum = bytesleft = linesleft = 0;
49  for (;;) {
50    int i, j;
51
52    // Refill toybuf?
53    if (len == pos) {
54      if (!(len = xread(infd, toybuf, sizeof(toybuf)))) break;
55      pos = 0;
56    }
57
58    // Start new output file?
59    if ((TT.bytes && !bytesleft) || (TT.lines && !linesleft)) {
60      char *s = TT.outfile + strlen(TT.outfile);
61
62      j = filenum++;
63      for (i = 0; i<TT.suflen; i++) {
64        *(--s) = 'a'+(j%26);
65        j /= 26;
66      }
67      if (j) error_exit("bad suffix");
68      bytesleft = TT.bytes;
69      linesleft = TT.lines;
70      if (outfd != -1) close(outfd);
71      outfd = xcreate(TT.outfile, O_RDWR|O_CREAT|O_TRUNC, st.st_mode & 0777);
72    }
73
74    // Write next chunk of output.
75    if (TT.lines) {
76      for (i = pos; i < len; ) {
77        if (toybuf[i++] == '\n' && !--linesleft) break;
78        if (!--bytesleft) break;
79      }
80      j = i - pos;
81    } else {
82      j = len - pos;
83      if (j > bytesleft) j = bytesleft;
84      bytesleft -= j;
85    }
86    xwrite(outfd, toybuf+pos, j);
87    pos += j;
88  }
89
90  if (CFG_TOYBOX_FREE) {
91    if (outfd != -1) close(outfd);
92    if (infd) close(infd);
93    free(TT.outfile);
94  }
95  xexit();
96}
97
98void split_main(void)
99{
100  if (!TT.bytes && !TT.lines) TT.lines = 1000;
101
102  // Allocate template for output filenames
103  TT.outfile = xmprintf("%s%*c", (toys.optc == 2) ? toys.optargs[1] : "x",
104    (int)TT.suflen, ' ');
105
106  // We only ever use one input, but this handles '-' or no input for us.
107  loopfiles(toys.optargs, do_split);
108}
109