commit 253fea84cf9504a733db6979e2fc140a8c702615 Author: Nick Mathewson <nickm@torproject.org> Date: Thu Jan 10 13:56:22 2019 -0500 Add a smartlist_grow() function to expand a smartlist Tests included. --- src/lib/smartlist_core/smartlist_core.c | 24 +++++++++++++ src/lib/smartlist_core/smartlist_core.h | 1 + src/test/test_containers.c | 61 +++++++++++++++++++++++++++++++++ 3 files changed, 86 insertions(+) diff --git a/src/lib/smartlist_core/smartlist_core.c b/src/lib/smartlist_core/smartlist_core.c index 8364a8180..d6b86e1e3 100644 --- a/src/lib/smartlist_core/smartlist_core.c +++ b/src/lib/smartlist_core/smartlist_core.c @@ -88,6 +88,30 @@ smartlist_ensure_capacity(smartlist_t *sl, size_t size) #undef MAX_CAPACITY } +/** Expand <b>sl</b> so that its length is at least <b>new_size</b>, + * filling in previously unused entries with NULL> + * + * Do nothing if <b>sl</b> already had at least <b>new_size</b> elements. + */ +void +smartlist_grow(smartlist_t *sl, size_t new_size) +{ + smartlist_ensure_capacity(sl, new_size); + + if (new_size > (size_t)sl->num_used) { + /* This memset() should be a no-op: everything else in the smartlist code + * tries to make sure that unused entries are always NULL. Still, that is + * meant as a safety mechanism, so let's clear the memory here. + */ + memset(sl->list + sl->num_used, 0, + sizeof(void *) * (new_size - sl->num_used)); + + /* This cast is safe, since we already asserted that we were below + * MAX_CAPACITY in smartlist_ensure_capacity(). */ + sl->num_used = (int)new_size; + } +} + /** Append element to the end of the list. */ void smartlist_add(smartlist_t *sl, void *element) diff --git a/src/lib/smartlist_core/smartlist_core.h b/src/lib/smartlist_core/smartlist_core.h index 974fb0175..7d7b7f07c 100644 --- a/src/lib/smartlist_core/smartlist_core.h +++ b/src/lib/smartlist_core/smartlist_core.h @@ -43,6 +43,7 @@ void smartlist_clear(smartlist_t *sl); void smartlist_add(smartlist_t *sl, void *element); void smartlist_add_all(smartlist_t *sl, const smartlist_t *s2); void smartlist_add_strdup(struct smartlist_t *sl, const char *string); +void smartlist_grow(smartlist_t *sl, size_t new_size); void smartlist_remove(smartlist_t *sl, const void *element); void smartlist_remove_keeporder(smartlist_t *sl, const void *element); diff --git a/src/test/test_containers.c b/src/test/test_containers.c index ad0edf4aa..4ca9542dc 100644 --- a/src/test/test_containers.c +++ b/src/test/test_containers.c @@ -606,6 +606,66 @@ test_container_smartlist_ints_eq(void *arg) smartlist_free(sl2); } +static void +test_container_smartlist_grow(void *arg) +{ + (void)arg; + smartlist_t *sl = smartlist_new(); + int i; + const char *s[] = { "first", "2nd", "3rd" }; + + /* case 1: starting from empty. */ + smartlist_grow(sl, 10); + tt_int_op(10, OP_EQ, smartlist_len(sl)); + for (i = 0; i < 10; ++i) { + tt_ptr_op(smartlist_get(sl, i), OP_EQ, NULL); + } + + /* case 2: starting with a few elements, probably not reallocating. */ + smartlist_free(sl); + sl = smartlist_new(); + smartlist_add(sl, (char*)s[0]); + smartlist_add(sl, (char*)s[1]); + smartlist_add(sl, (char*)s[2]); + smartlist_grow(sl, 5); + tt_int_op(5, OP_EQ, smartlist_len(sl)); + for (i = 0; i < 3; ++i) { + tt_ptr_op(smartlist_get(sl, i), OP_EQ, s[i]); + } + tt_ptr_op(smartlist_get(sl, 3), OP_EQ, NULL); + tt_ptr_op(smartlist_get(sl, 4), OP_EQ, NULL); + + /* case 3: starting with a few elements, but reallocating. */ + smartlist_free(sl); + sl = smartlist_new(); + smartlist_add(sl, (char*)s[0]); + smartlist_add(sl, (char*)s[1]); + smartlist_add(sl, (char*)s[2]); + smartlist_grow(sl, 100); + tt_int_op(100, OP_EQ, smartlist_len(sl)); + for (i = 0; i < 3; ++i) { + tt_ptr_op(smartlist_get(sl, i), OP_EQ, s[i]); + } + for (i = 3; i < 100; ++i) { + tt_ptr_op(smartlist_get(sl, i), OP_EQ, NULL); + } + + /* case 4: shrinking doesn't happen. */ + smartlist_free(sl); + sl = smartlist_new(); + smartlist_add(sl, (char*)s[0]); + smartlist_add(sl, (char*)s[1]); + smartlist_add(sl, (char*)s[2]); + smartlist_grow(sl, 1); + tt_int_op(3, OP_EQ, smartlist_len(sl)); + for (i = 0; i < 3; ++i) { + tt_ptr_op(smartlist_get(sl, i), OP_EQ, s[i]); + } + + done: + smartlist_free(sl); +} + /** Run unit tests for bitarray code */ static void test_container_bitarray(void *arg) @@ -1312,6 +1372,7 @@ struct testcase_t container_tests[] = { CONTAINER_LEGACY(smartlist_pos), CONTAINER(smartlist_remove, 0), CONTAINER(smartlist_ints_eq, 0), + CONTAINER(smartlist_grow, 0), CONTAINER_LEGACY(bitarray), CONTAINER_LEGACY(digestset), CONTAINER_LEGACY(strmap),