coreutils/split.c

   1 /* vi: set sw=4 ts=4: */
   2 /*
   3  * split - split a file into pieces
   4  * Copyright (c) 2007 Bernhard Reutner-Fischer
   5  *
   6  * Licensed under GPLv2 or later, see file LICENSE in this source tree.
   7  */
   8 //config:config SPLIT
   9 //config:       bool "split (5 kb)"
  10 //config:       default y
  11 //config:       help
  12 //config:       Split a file into pieces.
  13 //config:
  14 //config:config FEATURE_SPLIT_FANCY
  15 //config:       bool "Fancy extensions"
  16 //config:       default y
  17 //config:       depends on SPLIT
  18 //config:       help
  19 //config:       Add support for features not required by SUSv3.
  20 //config:       Supports additional suffixes 'b' for 512 bytes,
  21 //config:       'g' for 1GiB for the -b option.
  22
  23 //applet:IF_SPLIT(APPLET(split, BB_DIR_USR_BIN, BB_SUID_DROP))
  24
  25 //kbuild:lib-$(CONFIG_SPLIT) += split.o
  26
  27 /* BB_AUDIT: SUSv3 compliant
  28  * SUSv3 requirements:
  29  * http://www.opengroup.org/onlinepubs/009695399/utilities/split.html
  30  */
  31
  32 //usage:#define split_trivial_usage
  33 //usage:       "[OPTIONS] [INPUT [PREFIX]]"
  34 //usage:#define split_full_usage "\n\n"
  35 //usage:       "        -b N[k|m]       Split by N (kilo|mega)bytes"
  36 //usage:     "\n        -l N            Split by N lines"
  37 //usage:     "\n        -a N            Use N letters as suffix"
  38 //usage:
  39 //usage:#define split_example_usage
  40 //usage:       "$ split TODO foo\n"
  41 //usage:       "$ cat TODO | split -a 2 -l 2 TODO_\n"
  42
  43 #include "libbb.h"
  44 #include "common_bufsiz.h"
  45
  46 #if ENABLE_FEATURE_SPLIT_FANCY
  47 static const struct suffix_mult split_suffixes[] = {
  48         { "b", 512 },
  49         { "k", 1024 },
  50         { "m", 1024*1024 },
  51         { "g", 1024*1024*1024 },
  52         { "", 0 }
  53 };
  54 #endif
  55
  56 /* Increment the suffix part of the filename.
  57  * Returns NULL if we are out of filenames.
  58  */
  59 static char *next_file(char *old, unsigned suffix_len)
  60 {
  61         size_t end = strlen(old);
  62         unsigned i = 1;
  63         char *curr;
  64
  65         while (1) {
  66                 curr = old + end - i;
  67                 if (*curr < 'z') {
  68                         *curr += 1;
  69                         break;
  70                 }
  71                 i++;
  72                 if (i > suffix_len) {
  73                         return NULL;
  74                 }
  75                 *curr = 'a';
  76         }
  77
  78         return old;
  79 }
  80
  81 #define read_buffer bb_common_bufsiz1
  82 enum { READ_BUFFER_SIZE = COMMON_BUFSIZE - 1 };
  83
  84 #define SPLIT_OPT_l (1<<0)
  85 #define SPLIT_OPT_b (1<<1)
  86 #define SPLIT_OPT_a (1<<2)
  87
  88 int split_main(int argc, char **argv) MAIN_EXTERNALLY_VISIBLE;
  89 int split_main(int argc UNUSED_PARAM, char **argv)
  90 {
  91         unsigned suffix_len = 2;
  92         char *pfx;
  93         char *count_p;
  94         const char *sfx;
  95         off_t cnt = 1000;
  96         off_t remaining = 0;
  97         unsigned opt;
  98         ssize_t bytes_read, to_write;
  99         char *src;
 100
 101         setup_common_bufsiz();
 102
 103         opt = getopt32(argv, "^"
 104                         "l:b:a:+" /* -a N */
 105                         "\0" "?2"/*max 2 args*/,
 106                         &count_p, &count_p, &suffix_len
 107         );
 108
 109         if (opt & SPLIT_OPT_l)
 110                 cnt = XATOOFF(count_p);
 111         if (opt & SPLIT_OPT_b) // FIXME: also needs XATOOFF
 112                 cnt = xatoull_sfx(count_p,
 113                                 IF_FEATURE_SPLIT_FANCY(split_suffixes)
 114                                 IF_NOT_FEATURE_SPLIT_FANCY(km_suffixes)
 115                 );
 116         sfx = "x";
 117
 118         argv += optind;
 119         if (argv[0]) {
 120                 int fd;
 121                 if (argv[1])
 122                         sfx = argv[1];
 123                 fd = xopen_stdin(argv[0]);
 124                 xmove_fd(fd, STDIN_FILENO);
 125         } else {
 126                 argv[0] = (char *) bb_msg_standard_input;
 127         }
 128
 129         if (NAME_MAX < strlen(sfx) + suffix_len)
 130                 bb_error_msg_and_die("suffix too long");
 131
 132         {
 133                 char *char_p = xzalloc(suffix_len + 1);
 134                 memset(char_p, 'a', suffix_len);
 135                 pfx = xasprintf("%s%s", sfx, char_p);
 136                 if (ENABLE_FEATURE_CLEAN_UP)
 137                         free(char_p);
 138         }
 139
 140         while (1) {
 141                 bytes_read = safe_read(STDIN_FILENO, read_buffer, READ_BUFFER_SIZE);
 142                 if (!bytes_read)
 143                         break;
 144                 if (bytes_read < 0)
 145                         bb_simple_perror_msg_and_die(argv[0]);
 146                 src = read_buffer;
 147                 do {
 148                         if (!remaining) {
 149                                 if (!pfx)
 150                                         bb_error_msg_and_die("suffixes exhausted");
 151                                 xmove_fd(xopen(pfx, O_WRONLY | O_CREAT | O_TRUNC), 1);
 152                                 pfx = next_file(pfx, suffix_len);
 153                                 remaining = cnt;
 154                         }
 155
 156                         if (opt & SPLIT_OPT_b) {
 157                                 /* split by bytes */
 158                                 to_write = (bytes_read < remaining) ? bytes_read : remaining;
 159                                 remaining -= to_write;
 160                         } else {
 161                                 /* split by lines */
 162                                 /* can be sped up by using _memrchr_
 163                                  * and writing many lines at once... */
 164                                 char *end = memchr(src, '\n', bytes_read);
 165                                 if (end) {
 166                                         --remaining;
 167                                         to_write = end - src + 1;
 168                                 } else {
 169                                         to_write = bytes_read;
 170                                 }
 171                         }
 172
 173                         xwrite(STDOUT_FILENO, src, to_write);
 174                         bytes_read -= to_write;
 175                         src += to_write;
 176                 } while (bytes_read);
 177         }
 178         return EXIT_SUCCESS;
 179 }