[PATCH] commands: add 'findstr' to get string from file
Christoph Fritz
chf.fritz at googlemail.com
Tue May 20 13:29:20 PDT 2014
Hi Alexander
On Tue, 2014-05-20 at 20:08 +0200, Alexander Aring wrote:
> On Tue, May 20, 2014 at 07:27:55PM +0200, Christoph Fritz wrote:
> > +config CMD_FINDSTR
> > + tristate
> > + default n
> not needed.
Ok
> > + while ((opt = getopt(argc, argv, "o:l:t:")) > 0) {
> > + switch (opt) {
> > + case 'o':
> > + offset = simple_strtoul(optarg, NULL, 0);
> > + break;
> > + case 'l':
> > + len = simple_strtoul(optarg, NULL, 0);
> > + break;
> > + case 't':
> > + t = optarg;
> > + break;
> > + }
>
> switch case without default branch can occur compiler warnings.
>
> You should return COMMAND_ERROR_USAGE in the default branch if non valid
> parameter is given.
Ok
> > + fd = open(argv[optind+1], O_RDONLY);
> > + if (fd < 0)
> > + return COMMAND_ERROR_USAGE;
> > +
> > + while (1) {
> > + r = read(fd, mem_rw_buf, RW_BUF_SIZE);
> > + if (r < 0) {
> > + ret = -EIO;
> > + goto out;
> > + }
> > + if (!r)
> > + break;
> > +
> > + v_idx = 0;
> > +
> > + while (r) {
> > + if (v[v_idx] == s[s_idx])
> > + s_idx++;
> > + else
> > + s_idx = 0;
> > +
> > + idx++;
> > + v_idx++;
> > +
> > + if (s_idx == strlen(s)) { /* found */
> > + loff_t sz;
> > + loff_t hit = idx - strlen(s);
> > +
> > + if (lseek(fd, hit + offset, SEEK_SET) < 0) {
> > + ret = -EIO;
> > + goto out;
> > + }
> > +
> > + if (!len)
> > + len = strlen(s);
> > + sz = min_t(loff_t, len, RW_BUF_SIZE - 1);
> > + r = read(fd, mem_rw_buf, sz);
> > + if (r != sz) {
> > + ret = -EIO;
> > + goto out;
> > + }
> > +
> > + v[sz] = '\0';
> > +
> > + if (t)
> > + setenv(t, v);
> > + else
> > + printf("%s\n", v);
> > +
> > + ret = 0;
> > + goto out;
> > + }
> > + r--;
> > + }
>
> Why not use read_file and the awesome string function strstr and then
> write the file back.
read_file() reads the whole file which can get pretty slow over an i2c
link accessing an eeprom which mostly holds the configuration-string at
the beginning.
Why would I want to write the file back?
Thanks
-- Christoph
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