Revision d64ea0f83bd7e676778f833c57f969a94518a28d authored by Jeff King on 13 January 2015, 01:57:37 UTC, committed by Junio C Hamano on 13 January 2015, 18:03:30 UTC
It's a common idiom to duplicate a string if it is non-NULL, or pass a literal NULL through. This is already a one-liner in C, but you do have to repeat the name of the string twice. So if there's a function call, you must write: const char *x = some_fun(...); return x ? xstrdup(x) : NULL; instead of (with this patch) just: return xstrdup_or_null(some_fun(...)); Signed-off-by: Jeff King <peff@peff.net> Signed-off-by: Junio C Hamano <gitster@pobox.com>
1 parent 1da1e07
test-mergesort.c
#include "cache.h"
#include "mergesort.h"
struct line {
char *text;
struct line *next;
};
static void *get_next(const void *a)
{
return ((const struct line *)a)->next;
}
static void set_next(void *a, void *b)
{
((struct line *)a)->next = b;
}
static int compare_strings(const void *a, const void *b)
{
const struct line *x = a, *y = b;
return strcmp(x->text, y->text);
}
int main(int argc, char **argv)
{
struct line *line, *p = NULL, *lines = NULL;
struct strbuf sb = STRBUF_INIT;
for (;;) {
if (strbuf_getwholeline(&sb, stdin, '\n'))
break;
line = xmalloc(sizeof(struct line));
line->text = strbuf_detach(&sb, NULL);
if (p) {
line->next = p->next;
p->next = line;
} else {
line->next = NULL;
lines = line;
}
p = line;
}
lines = llist_mergesort(lines, get_next, set_next, compare_strings);
while (lines) {
printf("%s", lines->text);
lines = lines->next;
}
return 0;
}
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