diff options
Diffstat (limited to 'time/tzset.c')
-rw-r--r-- | time/tzset.c | 81 |
1 files changed, 33 insertions, 48 deletions
diff --git a/time/tzset.c b/time/tzset.c index 9c8e5d7..d4e3037 100644 --- a/time/tzset.c +++ b/time/tzset.c @@ -88,66 +88,51 @@ static int tz_compute __P ((time_t timer, const struct tm *tm)) internal_function; static void tzset_internal __P ((int always)) internal_function; -/* Header for a list of buffers containing time zone strings. */ -struct tzstring_head +/* List of buffers containing time zone strings. */ +struct tzstring_l { - struct tzstring_head *next; - /* The buffer itself immediately follows the header. - The buffer contains zero or more (possibly overlapping) strings. - The last string is followed by 2 '\0's instead of the usual 1. */ + struct tzstring_l *next; + size_t len; /* strlen(data) - doesn't count terminating NUL! */ + char data[0]; }; -/* First in a list of buffers containing time zone strings. - All the buffers but the last are read-only. */ -static struct -{ - struct tzstring_head head; - char data[48]; -} tzstring_list; - -/* Size of the last buffer in the list, not counting its header. */ -static size_t tzstring_last_buffer_size = sizeof tzstring_list.data; +struct tzstring_l *tzstring_list; -/* Allocate a time zone string with given contents. - The string will never be moved or deallocated. - However, its contents may be shared with other such strings. */ +/* Allocate a permanent home for S. It will never be moved or deallocated, + but may share space with other strings. + Don't modify the returned string. */ char * -__tzstring (string) - const char *string; +__tzstring (const char *s) { - struct tzstring_head *h; - size_t needed; char *p; + struct tzstring_l *t, *u, *new; + size_t len = strlen(s); - /* Look through time zone string list for a duplicate of this one. */ - for (h = &tzstring_list.head; ; h = h->next) - { - for (p = (char *) (h + 1); p[0] | p[1]; ++p) - if (strcmp (p, string) == 0) + /* Walk the list and look for a match. If this string is the same + as the end of an already-allocated string, it can share space. */ + for (u = t = tzstring_list; t; u = t, t = t->next) + if (len <= t->len) + { + p = &t->data[t->len - len]; + if (strcmp (s, p) == 0) return p; - if (! h->next) - break; - } + } - /* No duplicate was found. Copy to the end of this buffer if there's room; - otherwise, append a large-enough new buffer to the list and use it. */ - ++p; - needed = strlen (string) + 2; /* Need 2 trailing '\0's after last string. */ + /* Not found; allocate a new buffer. */ + new = malloc (sizeof (struct tzstring_l) + len + 1); + if (!new) + return NULL; - if ((size_t) ((char *) (h + 1) + tzstring_last_buffer_size - p) < needed) - { - size_t buffer_size = tzstring_last_buffer_size; - while ((buffer_size *= 2) < needed) - continue; - h = malloc (sizeof *h + buffer_size); - if (h == NULL) - return NULL; - h->next = NULL; - tzstring_last_buffer_size = buffer_size; - p = (char *) (h + 1); - } + new->next = NULL; + new->len = len; + strcpy (new->data, s); + + if (u) + u->next = new; + else + tzstring_list = new; - return strncpy (p, string, needed); + return new->data; } static char *old_tz = NULL; |