util: add osmo_strbuf macros to manipulate the strbuf tail
Upcoming patch adopts osmo_strbuf in logging.c, which sometimes needs to
steal and re-add trailing newline characters, and also needs to let
ctime_r() write to the buffer before updating the osmo_strbuf state.
Related: OS#6284
Related: Ib577a5e0d7450ce93ff21f37ba3262704cbf4752
Change-Id: I997707c328eab3ffa00a78fdb9a0a2cbe18404b4
diff --git a/tests/utils/utils_test.c b/tests/utils/utils_test.c
index 0b7bfe4..bdeedb5 100644
--- a/tests/utils/utils_test.c
+++ b/tests/utils/utils_test.c
@@ -31,6 +31,7 @@
#include <errno.h>
#include <limits.h>
#include <inttypes.h>
+#include <string.h>
static void hexdump_test(void)
{
@@ -1306,6 +1307,50 @@
printf("%zu: %s (need=%zu)\n", sb.len, buf, sb.chars_needed);
}
+void strbuf_test_tail_for_buflen(size_t buflen)
+{
+ char buf[buflen];
+ struct osmo_strbuf sb = { .buf = buf, .len = buflen };
+ printf("\n%s(%zu)\n", __func__, buflen);
+
+#define SHOW(N) \
+ printf(#N ": %s sb.chars_needed=%zu sb.pos=&sb.buf[%d]\n", \
+ osmo_quote_str(buf, -1), sb.chars_needed, (int)(sb.pos - sb.buf))
+
+ /* shorten in steps using OSMO_STRBUF_DROP_TAIL(), removing and re-adding a trailing newline. */
+ OSMO_STRBUF_PRINTF(sb, "banananana\n");
+ SHOW(1);
+ OSMO_STRBUF_DROP_TAIL(sb, 3);
+ SHOW(2);
+ OSMO_STRBUF_PRINTF(sb, "\n");
+ SHOW(3);
+ OSMO_STRBUF_DROP_TAIL(sb, 3);
+ SHOW(4);
+ OSMO_STRBUF_PRINTF(sb, "\n");
+ SHOW(5);
+
+ /* drop trailing newline */
+ OSMO_STRBUF_DROP_TAIL(sb, 1);
+ SHOW(6);
+
+ /* test writing something to the end and letting OSMO_STRBUF_ADDED_TAIL() know later */
+ int n = OSMO_MIN(6, OSMO_STRBUF_REMAIN(sb));
+ if (n)
+ memcpy(sb.pos, "bread\n", n);
+ OSMO_STRBUF_ADDED_TAIL(sb, 6);
+ SHOW(7);
+}
+
+void strbuf_test_tail(void)
+{
+ strbuf_test_tail_for_buflen(64);
+ strbuf_test_tail_for_buflen(32);
+ strbuf_test_tail_for_buflen(16);
+ strbuf_test_tail_for_buflen(8);
+ strbuf_test_tail_for_buflen(4);
+ strbuf_test_tail_for_buflen(1);
+}
+
static void startswith_test_str(const char *str, const char *startswith_str, bool expect_rc)
{
bool rc = osmo_str_startswith(str, startswith_str);
@@ -2152,6 +2197,7 @@
osmo_str_tolowupper_test();
strbuf_test();
strbuf_test_nolen();
+ strbuf_test_tail();
startswith_test();
name_c_impl_test();
osmo_print_n_test();