On Wed, 08 Jul 2015 15:31:27 +0200, Jin, Yao wrote:
On 2015/7/8 16:57, Liam Girdwood wrote:
On Tue, 2015-07-07 at 18:19 +0200, Takashi Iwai wrote:
On Tue, 07 Jul 2015 17:54:02 +0200, Liam Girdwood wrote:
On Wed, 2015-07-01 at 18:20 +0200, Takashi Iwai wrote:
+static int get_hex_num(const char *str) +{
- char *tmp, *s = NULL;
- int i = 0;
- tmp = strdup(str);
- if (tmp == NULL)
return -ENOMEM;- s = strtok(tmp, ",");
- while (s != NULL) {
s = strtok(NULL, ",");i++;- }
- free(tmp);
- return i;
Hmm, this just counts the number of comma + 1, so you don't need to duplicate the string?
The string here is duplicated since strtok is destructive (it overwrites the delimiters with NULL) and the string is being used later on by the calling function.
Yes, but what I meant is something like below:
static int get_hex_num(const char *str) { int i = 0;
if (!*str) return 0; for (;;) { i++; str = strchr(str, ','); if (!str) return i; str++; } }
... so that it works without strdup().
But it seems that strtok() skips the starting delimiter or handles multiple delimiters as a single, so the result will become inconsistent. That is, all the following strings will give "a" and "b" via strtok(): a,b a,,b ,a,b a,b,
I guess you don't want to have an empty list element, right?
Lets ask the author :) but IMO an empty list should be skipped here.
Yao, what's your rational behind this code ?
Sorry for replying late, I just see this mail.
The get_hex_num() returns the number of hexadecimal in string.
Say the string is "0x12,0x34,0x56,0x78" or "0x12,0x34,0x56,0x78,", the get_hex_num() returns 4.
But if I use strchr, for above string, I get different number (3 or 4). That's the reason I choose the strtok().
I do this is because I think user may append the comma at the end of string.
So, is this allowed intentionally as a valid syntax? As I showed, a string like ",,,0x12,,0x34,,,,0x56,0x78,," would be handled as a valid string.
The above may look strange, but the strtok() behavior is natural if you imagine to replace "," with a space.
Takashi