Re: [PATCH v3 8/8] perf stat: implement --big-num grouping

From: Arnaldo Carvalho de Melo
Date: Mon Oct 08 2012 - 17:11:03 EST


Em Mon, Oct 08, 2012 at 09:43:33AM +0300, Irina Tirdea escreveu:
>
> +/* Group the digits according to the grouping rules of the current locale.
> + The interpretation of GROUPING is as in `struct lconv' from <locale.h>. */
> +static int group_number_locale(char *number, char **gnumber)
> +{
> + const char *thousands_sep = NULL, *grouping = NULL;
> + int glen, tlen, dest_alloc_size, src_size, ret = 0, cnt;

Please set ret to -ENOMEM; and...

> + char *dest_alloc_ptr, *dest_end, *src_start, *src_end;
> +

When we have else clauses, I think its better to use

#ifdef LOCALE_SUPPORT
struct lconv *lc = localeconv();
if (lc != NULL) {
thousands_sep = lc->thousands_sep;
grouping = lc->grouping;
}
#else
thousands_sep = ",";
grouping = "\x3";
#endif


> +#ifndef LOCALE_SUPPORT
> + thousands_sep = ",";
> + grouping = "\x3";
> +#else
> + struct lconv *lc = localeconv();
> + if (lc != NULL) {
> + thousands_sep = lc->thousands_sep;
> + grouping = lc->grouping;
> + }
> +#endif
> +
> + *gnumber = NULL;
> + /* No grouping */
> + if (thousands_sep == NULL || grouping == NULL ||
> + *thousands_sep == '\0' || *grouping == CHAR_MAX || *grouping <= 0) {
> + *gnumber = strdup(number);
> + if (*gnumber == NULL)
> + ret = -ENOMEM;
> + goto out;

Humm, so we bail out unconditionally? :-)

this should be:

if (*gnumber == NULL)
goto out;
> + }
> +
> + glen = *grouping++;
> + tlen = strlen(thousands_sep);
> +
> + src_size = strlen(number);
> + /* Worst case scenario we have 1-character grouping */
> + dest_alloc_size = (src_size + src_size * tlen) * sizeof(char);
> + dest_alloc_ptr = zalloc(dest_alloc_size);
> + if (dest_alloc_ptr == NULL) {
> + ret = -ENOMEM;

remove the above

> + goto out;
> + }
> + /* -1 for '\0' */
> + dest_end = dest_alloc_ptr + dest_alloc_size - 1;
> +
> + src_start = number;
> + src_end = number + src_size;
> +
> + while (src_end > src_start) {
> + *--dest_end = *--src_end;
> + if (--glen == 0 && src_end > src_start) {
> + /* A new group */
> + cnt = tlen;
> + do
> + *--dest_end = thousands_sep[--cnt];
> + while (cnt > 0);
> +
> + if (*grouping == CHAR_MAX || *grouping < 0) {
> + /* No further grouping to be done.
> + Copy the rest of the number. */
> + do
> + *--dest_end = *--src_end;
> + while (src_end > src_start);
> + break;
> + } else if (*grouping != '\0') {
> + glen = *grouping++;
> + } else {
> + /* The previous grouping repeats ad infinitum */
> + glen = grouping[-1];
> + }
> + }
> + }
> +
> + /* Make a copy with the exact needed size of the grouped number */
> + *gnumber = strdup(dest_end);
> + if (*gnumber == NULL) {
> + ret = -ENOMEM;

ditto
> + goto out_free_dest;
> + }
> +
> + /* fall through */

Why the "fall through" comment? This is a common construct and this
comment mostly applies where one would expect a break in a switch
statement :-)

Ah, here you do:

ret = 0;

Since all went well.

> +out_free_dest:
> + free(dest_alloc_ptr);
> +out:
> + return ret;
> +}
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