neels has uploaded this change for review. ( https://gerrit.osmocom.org/c/libosmocore/+/35207?usp=email )
Change subject: util: add osmo_strbuf macros to manipulate the strbuf tail ...................................................................... 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 --- M include/osmocom/core/utils.h M tests/utils/utils_test.c M tests/utils/utils_test.ok 3 files changed, 154 insertions(+), 0 deletions(-) git pull ssh://gerrit.osmocom.org:29418/libosmocore refs/changes/07/35207/1 diff --git a/include/osmocom/core/utils.h b/include/osmocom/core/utils.h index 2a3670b..d90bf6f 100644 --- a/include/osmocom/core/utils.h +++ b/include/osmocom/core/utils.h @@ -284,6 +284,10 @@ /*! Return remaining space for characters and terminating nul in the given struct osmo_strbuf. */ #define OSMO_STRBUF_REMAIN(STRBUF) ((STRBUF).buf ? (STRBUF).len - ((STRBUF).pos - (STRBUF).buf) : 0) +/*! Return number of actual characters contained in struct osmo_strbuf (without terminating nul). */ +#define OSMO_STRBUF_CHAR_COUNT(STRBUF) ((STRBUF).buf && (STRBUF).pos > (STRBUF).buf ? \ + OSMO_MIN((STRBUF).pos - (STRBUF).buf, (STRBUF).len - 1) : 0) + /*! Like OSMO_STRBUF_APPEND(), but for function signatures that return the char* buffer instead of a length. * When using this function, the final STRBUF.chars_needed may not reflect the actual number of characters needed, since * that number cannot be obtained from this kind of function signature. @@ -307,6 +311,41 @@ (STRBUF).chars_needed += _sb_l; \ } while(0) +/*! Remove up to N chars from the end of an osmo_strbuf. + * |--char-count---| - - chars_needed - - | + * |<---------drop----------| + */ +#define OSMO_STRBUF_DROP_TAIL(STRBUF, N_CHARS) do { \ + if ((STRBUF).pos > (STRBUF).buf) { \ + size_t _sb_drop_n = (STRBUF).chars_needed; \ + _sb_drop_n = OSMO_MIN(_sb_drop_n, N_CHARS); \ + (STRBUF).chars_needed -= _sb_drop_n; \ + \ + if ((STRBUF).chars_needed < OSMO_STRBUF_CHAR_COUNT(STRBUF)) { \ + (STRBUF).pos = (STRBUF).buf + (STRBUF).chars_needed; \ + *(STRBUF).pos = '\0'; \ + } \ + } \ + } while (0) + +/* Let osmo_strbuf know that N_CHARS characters (excluding nul) were written to STRBUF.pos. + * Advance STRBUF.pos and STRBUF.chars_needed by at most N_CHARS, or up to STRBUF.len - 1. + * Ensure nul termination. */ +#define OSMO_STRBUF_ADDED_TAIL(STRBUF, N_CHARS) \ + do { \ + if (!(STRBUF).pos) \ + (STRBUF).pos = (STRBUF).buf; \ + (STRBUF).chars_needed += N_CHARS; \ + size_t _sb_added = OSMO_STRBUF_REMAIN(STRBUF); \ + if (_sb_added) \ + _sb_added--; \ + _sb_added = OSMO_MIN(_sb_added, N_CHARS); \ + if (_sb_added) \ + (STRBUF).pos += _sb_added; \ + if ((STRBUF).pos < (STRBUF).buf + (STRBUF).len) \ + *(STRBUF).pos = '\0'; \ + } while (0) + bool osmo_str_startswith(const char *str, const char *startswith_str); int osmo_float_str_to_int(int64_t *val, const char *str, unsigned int precision); 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(); diff --git a/tests/utils/utils_test.ok b/tests/utils/utils_test.ok index 3f453e9..6f5d46b 100644 --- a/tests/utils/utils_test.ok +++ b/tests/utils/utils_test.ok @@ -470,6 +470,60 @@ more: 0001011100101010000 (need=19) 10: 000101110 (need=9) +strbuf_test_tail_for_buflen(64) +1: "banananana\n" sb.chars_needed=11 sb.pos=&sb.buf[11] +2: "bananana" sb.chars_needed=8 sb.pos=&sb.buf[8] +3: "bananana\n" sb.chars_needed=9 sb.pos=&sb.buf[9] +4: "banana" sb.chars_needed=6 sb.pos=&sb.buf[6] +5: "banana\n" sb.chars_needed=7 sb.pos=&sb.buf[7] +6: "banana" sb.chars_needed=6 sb.pos=&sb.buf[6] +7: "bananabread\n" sb.chars_needed=12 sb.pos=&sb.buf[12] + +strbuf_test_tail_for_buflen(32) +1: "banananana\n" sb.chars_needed=11 sb.pos=&sb.buf[11] +2: "bananana" sb.chars_needed=8 sb.pos=&sb.buf[8] +3: "bananana\n" sb.chars_needed=9 sb.pos=&sb.buf[9] +4: "banana" sb.chars_needed=6 sb.pos=&sb.buf[6] +5: "banana\n" sb.chars_needed=7 sb.pos=&sb.buf[7] +6: "banana" sb.chars_needed=6 sb.pos=&sb.buf[6] +7: "bananabread\n" sb.chars_needed=12 sb.pos=&sb.buf[12] + +strbuf_test_tail_for_buflen(16) +1: "banananana\n" sb.chars_needed=11 sb.pos=&sb.buf[11] +2: "bananana" sb.chars_needed=8 sb.pos=&sb.buf[8] +3: "bananana\n" sb.chars_needed=9 sb.pos=&sb.buf[9] +4: "banana" sb.chars_needed=6 sb.pos=&sb.buf[6] +5: "banana\n" sb.chars_needed=7 sb.pos=&sb.buf[7] +6: "banana" sb.chars_needed=6 sb.pos=&sb.buf[6] +7: "bananabread\n" sb.chars_needed=12 sb.pos=&sb.buf[12] + +strbuf_test_tail_for_buflen(8) +1: "bananan" sb.chars_needed=11 sb.pos=&sb.buf[8] +2: "bananan" sb.chars_needed=8 sb.pos=&sb.buf[8] +3: "bananan" sb.chars_needed=9 sb.pos=&sb.buf[8] +4: "banana" sb.chars_needed=6 sb.pos=&sb.buf[6] +5: "banana\n" sb.chars_needed=7 sb.pos=&sb.buf[7] +6: "banana" sb.chars_needed=6 sb.pos=&sb.buf[6] +7: "bananab" sb.chars_needed=12 sb.pos=&sb.buf[7] + +strbuf_test_tail_for_buflen(4) +1: "ban" sb.chars_needed=11 sb.pos=&sb.buf[4] +2: "ban" sb.chars_needed=8 sb.pos=&sb.buf[4] +3: "ban" sb.chars_needed=9 sb.pos=&sb.buf[4] +4: "ban" sb.chars_needed=6 sb.pos=&sb.buf[4] +5: "ban" sb.chars_needed=7 sb.pos=&sb.buf[4] +6: "ban" sb.chars_needed=6 sb.pos=&sb.buf[4] +7: "ban" sb.chars_needed=12 sb.pos=&sb.buf[4] + +strbuf_test_tail_for_buflen(1) +1: "" sb.chars_needed=11 sb.pos=&sb.buf[1] +2: "" sb.chars_needed=8 sb.pos=&sb.buf[1] +3: "" sb.chars_needed=9 sb.pos=&sb.buf[1] +4: "" sb.chars_needed=6 sb.pos=&sb.buf[1] +5: "" sb.chars_needed=7 sb.pos=&sb.buf[1] +6: "" sb.chars_needed=6 sb.pos=&sb.buf[1] +7: "" sb.chars_needed=12 sb.pos=&sb.buf[1] + startswith_test() osmo_str_startswith(NULL, NULL) == true osmo_str_startswith("", NULL) == true -- To view, visit https://gerrit.osmocom.org/c/libosmocore/+/35207?usp=email To unsubscribe, or for help writing mail filters, visit https://gerrit.osmocom.org/settings Gerrit-Project: libosmocore Gerrit-Branch: master Gerrit-Change-Id: I997707c328eab3ffa00a78fdb9a0a2cbe18404b4 Gerrit-Change-Number: 35207 Gerrit-PatchSet: 1 Gerrit-Owner: neels <nhofm...@sysmocom.de> Gerrit-MessageType: newchange