Re: [dev] [PATCH][RFC] Add a basic version of tr

From: sin <sin_AT_2f30.org>
Date: Wed, 15 Jan 2014 11:24:06 +0000

On Mon, Jan 13, 2014 at 11:19:49AM -0800, Silvan Jegen wrote:
> I have rewritten "tr" to use mmap and the wchar.h functions. It seems
> to be quite slow but as far as I can tell it works reasonably well (at
> least when using a UTF-8 locale). Comments/review and testing welcome
> (I am relatively new to C so beware)!

Thanks for your patch!

> If you think adding this version of "tr" to sbase makes sense I can
> prepare a man page that points out all the shortcomings (e. g. no
> character classes) of this implementation.

Yes, we will need the manpages for merging this in.
> +void
> +handle_escapes(char *s)

We try to avoid underscores when naming things.

> +void
> +parse_mapping(char *set1, char *set2, wchar_t *mappings)
> +{
> + char *s;
> + wchar_t runeleft;
> + wchar_t runeright;
> + int leftbytes;
> + int rightbytes;
> + size_t n = 0;
> + size_t lset2;
> +
> + if(set2) {
> + lset2 = strnlen(set2, 255 * sizeof(wchar_t));
> + } else {
> + set2 = (char*) &set1[0];

Here you use `(char*)' but further down you use `(const char *)'.

> + lset2 = 0;
> + }
> +
> + s = set1;
> + while(*s) {
> + if(*s == '\\') {
> + handle_escapes(++s);
> + }
> +
> + leftbytes = mbtowc(&runeleft, (const char *) s, 4);
> + if(*(set2 + n))

set2[n]. Maybe it is worth checking specifically against != '\0'. It
is a good idea to use `if (p) { ... }' or `if (!p) { ... }' only when
p is a pointer.

> +int
> +main(int argc, char *argv[])
> +{
> + wchar_t *mappings;
> + char *buf = NULL;
> + size_t size = 0;
> + void (*mapfunc) (const wchar_t*, char*);
> +
> + setlocale(LC_ALL, "");
> +
> + mappings = (wchar_t *) mmap(NULL, 0x110000 * sizeof(wchar_t), PROT_READ|PROT_WRITE, MAP_ANONYMOUS|MAP_PRIVATE, -1, 0);

Break this line into two lines.

> +
> + ARGBEGIN {
> + default:
> + usage();
> + } ARGEND;
> +
> + if(!argc)

argc != 0.

> + if (ferror(stdin)) {
> + eprintf("<stdin>: read error:");
> + return EXIT_FAILURE;

No need for return EXIT_FAILURE.
Received on Wed Jan 15 2014 - 12:24:06 CET