improvements based on other wc versions
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README.md
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README.md
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Desiderata
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# ww: count words in 50 lines of C
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- Simple: Simple operation in terms of counting spaces and \n.
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- Avoid "off by one" errors; make sure an empty file is reported as such.
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- Words as space or enter, followed by nonspace, followed by space? Make sure two spaces aren't two words?
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- Keep Linux only.
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- No flags. Only count words, not lines.
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## Desiderata
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- Simplicity: Just count words, as delimited by: spaces, tabs, newlines.
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- No flags.
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- Avoid off-by-one errors.
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- Allow piping, as well as reading files.
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- Wonder how normal utilities handle this.
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- Could use zig? => Not for now
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- Small.
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- Linux only.
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Steps:
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## Comparison with wc.
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The GNU utils version ([github](https://github.com/coreutils/coreutils/tree/master/src/wc), [savannah](http://git.savannah.gnu.org/gitweb/?p=coreutils.git;a=blob;f=src/wc.c;hb=HEAD)) is a bit over 1K lines of C. It does many things and checks many possible failure modes.
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The busybox version ([git.busybox.net](https://git.busybox.net/busybox/tree/coreutils/wc.c)) of wc is much shorter, at 257 lines, while striving to be [POSIX-compliant](https://pubs.opengroup.org/onlinepubs/9699919799/), meaning it has flags.
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The plan9port version of wc ([github](https://github.com/9fans/plan9port/blob/master/src/cmd/wc.c)) implements some sort of table method, in 352 lines. So does the [plan9](https://9p.io/sources/plan9/sys/src/cmd/wc.c) version, which is worse documented, but shorter.
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[Here](https://github.com/dspinellis/unix-history-repo/blob/Research-V7-Snapshot-Development/usr/src/cmd/wc.c) is a version of wc from UNIX V7, at 86 lines, and allowing for both word and line counts. I couldn't find a version in UNIX V6. Of all the versions, I think I understand this one best.
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## Steps:
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- [x] Look into how C utilities both read from stdin and from files.
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- [x] Program first version of the utility
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- [ ] Compare with other implementations, see how they do it, after I've read my own version
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- [ ] Compare with gnu utils,
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- Compare with musl/busybox implementations,
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- Maybe make some pull requests, if I'm doing something better?
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- [x] Compare with other implementations, see how they do it, after I've read my own version
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- [x] Compare with gnu utils.
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- [x] Compare with musl/busybox implementations,
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- ~~Maybe make some pull requests, if I'm doing something better? => doesn't seem like it~~
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- [ ] Install to ww, but check that ww is empty (installing to wc2 or smth would mean that you don't save that many keypresses vs wc -w)
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- [ ] ...
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- ~~[ ] Could use zig? => Not for now~~
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- [ ] Look specifically at how other versions
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- [ ] Distinguish between reading from stdin and reading from a file
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- If it doesn't have arguments, read from stdin.
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- [ ] Open files, read characters.
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- [ ] Write version that counts lines
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- [ ]
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5
makefile
5
makefile
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@ -15,7 +15,7 @@ OUT=ww
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DEBUG= #'-g'
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STANDARD=-std=c99
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WARNINGS=-Wall
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OPTIMIZED=-O0
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OPTIMIZED=-O3
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# OPTIMIZED=-O3 #-Ofast
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## Formatter
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@ -29,6 +29,9 @@ build: $(SRC)
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format: $(SRC)
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$(FORMATTER) $(SRC)
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install:
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cp -n $(OUT) /bin/$(OUT)
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test: $(OUT)
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/bin/echo -e "123\n45 67" | ./$(OUT)
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/bin/echo -n "" | ./ww
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4
ww.c
4
ww.c
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@ -1,7 +1,6 @@
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#include <stdio.h>
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#include <unistd.h> // read, isatty
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#include <unistd.h>
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// STDIN_FILENO
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int process_fn(int fn)
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{
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char c[1];
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@ -41,6 +40,7 @@ int main(int argc, char** argv)
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perror("Could not open file");
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return 1;
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}
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fclose(fp);
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return process_fn(fileno(fp));
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} else {
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printf("Usage: ww file.txt\n");
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