64 lines
1.4 KiB
C
64 lines
1.4 KiB
C
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/* shuf.c - Output lines in random order.
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*
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* Copyright 2023 Rob Landley <rob@landley.net>
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*
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* See https://man7.org/linux/man-pages/man1/shuf.1.html
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USE_SHUF(NEWTOY(shuf, "zen#<0", TOYFLAG_USR|TOYFLAG_BIN))
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config SHUF
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bool "shuf"
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default y
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help
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usage: shuf [-ze] [-n COUNT] [FILE...]
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Write lines of input to output in random order.
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-z Input/output lines are NUL terminated.
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-n Stop after COUNT many output lines.
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-e Echo mode: arguments are inputs to shuffle, not files to read.
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*/
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#define FOR_shuf
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#include "toys.h"
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GLOBALS(
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long n;
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char **lines;
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long count;
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)
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static void do_shuf_line(char **pline, long len)
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{
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if (!pline) return;
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if (!(TT.count&255))
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TT.lines = xrealloc(TT.lines, sizeof(void *)*(TT.count+256));
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TT.lines[TT.count++] = *pline; // TODO: repack?
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*pline = 0;
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}
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static void do_shuf(int fd, char *name)
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{
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do_lines(fd, '\n'*!FLAG(z), do_shuf_line);
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}
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void shuf_main(void)
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{
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if (FLAG(e)) {
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TT.lines = toys.optargs;
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TT.count = toys.optc;
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} else loopfiles(toys.optargs, do_shuf);
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if (!FLAG(n) || TT.n>TT.count) TT.n = TT.count;
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srandom(millitime());
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while (TT.n--) {
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long ll = random()%TT.count;
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writeall(1, TT.lines[ll], strlen(TT.lines[ll])+FLAG(z));
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if (!FLAG(e)) free(TT.lines[ll]);
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else if (!FLAG(z)) writeall(1, "\n", 1);
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TT.lines[ll] = TT.lines[--TT.count];
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}
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}
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