diff toys/posix/split.c @ 924:b792de46d715

Implement split.
author Rob Landley <rob@landley.net>
date Sun, 16 Jun 2013 16:37:43 -0500
parents
children 0752b2d58909
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--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/toys/posix/split.c	Sun Jun 16 16:37:43 2013 -0500
@@ -0,0 +1,108 @@
+/* split.c - split a file into smaller files
+ *
+ * Copyright 2013 Rob Landley <rob@landley.net>
+ *
+ * See http://pubs.opengroup.org/onlinepubs/9699919799/utilities/split.html
+ *
+ * Standard does not cover:
+ * - should splitting an empty file produce an empty outfile? (Went with "no".)
+ * - permissions on output file
+
+USE_SPLIT(NEWTOY(split, ">2a#<1=2>9b#<1l#<1", TOYFLAG_USR|TOYFLAG_BIN))
+
+config SPLIT
+  bool "split"
+  default y
+  help
+    usage: split [-a SUFFIX_LEN] [-b BYTES] [-l LINES] [INPUT [OUTPUT]]
+
+    Copy INPUT (or stdin) data to a series of OUTPUT (or "x") files with
+    alphabetically increasing suffix (aa, ab, ac... az, ba, bb...).
+
+    -a	Suffix length (default 2)
+    -b	BYTES/file (10, 10k, 10m, 10g...)
+    -l	LINES/file (default 1000)
+*/
+
+#define FOR_split
+#include "toys.h"
+
+GLOBALS(
+  long lines;
+  long bytes;
+  long suflen;
+
+  char *outfile;
+)
+
+void do_split(int infd, char *in)
+{
+  unsigned long bytesleft, linesleft, filenum, len, pos;
+  int outfd = -1;
+  struct stat st;
+
+  // posix doesn't cover permissions on output file, so copy input (or 0777)
+  st.st_mode = 0777;
+  fstat(infd, &st);
+
+  len = pos = filenum = bytesleft = linesleft = 0;
+  for (;;) {
+    int i, j;
+
+    // Refill toybuf?
+    if (len == pos) {
+      if (!(len = xread(infd, toybuf, sizeof(toybuf)))) break;
+      pos = 0;
+    }
+
+    // Start new output file?
+    if ((TT.bytes && !bytesleft) || (TT.lines && !linesleft)) {
+      char *s = TT.outfile + strlen(TT.outfile);
+
+      j = filenum++;
+      for (i = 0; i<TT.suflen; i++) {
+        *(--s) = 'a'+(j%26);
+        j /= 26;
+      }
+      if (j) error_exit("bad suffix");
+      bytesleft = TT.bytes;
+      linesleft = TT.lines;
+      if (outfd != -1) close(outfd);
+      outfd = xcreate(TT.outfile, O_RDWR|O_CREAT|O_TRUNC, st.st_mode & 0777);
+    }
+
+    // Write next chunk of output.
+    if (TT.lines) {
+      for (i = pos; i < len; ) {
+        if (toybuf[i++] == '\n' && !--linesleft) break;
+        if (!--bytesleft) break;
+      }
+      j = i - pos;
+    } else {
+      j = len - pos;
+      if (j > bytesleft) j = bytesleft;
+      bytesleft -= j;
+    }
+    xwrite(outfd, toybuf+pos, j);
+    pos += j;
+  }
+
+  if (CFG_TOYBOX_FREE) {
+    if (outfd != -1) close(outfd);
+    if (infd) close(infd);
+    free(TT.outfile);
+  }
+  xexit();
+}
+
+void split_main(void)
+{
+  if (!TT.bytes && !TT.lines) TT.lines = 1000;
+
+  // Allocate template for output filenames
+  TT.outfile = xmsprintf("%s% *c", (toys.optc == 2) ? toys.optargs[1] : "x",
+    (int)TT.suflen, ' ');
+
+  // We only ever use one input, but this handles '-' or no input for us.
+  loopfiles(toys.optargs, do_split);
+}