diff options
| author | David Herrmann <dh.herrmann@gmail.com> | 2014-09-22 12:05:16 +0200 |
|---|---|---|
| committer | David Herrmann <dh.herrmann@gmail.com> | 2014-09-22 14:27:02 +0200 |
| commit | 95d78c7e7c81a6b788f28c33ef2cafd87471a0d7 (patch) | |
| tree | 165ff83c1a3c42ca003e15d1211062254dd830c8 /src | |
| parent | eee846339d2f76f568c62b3725bf75bcee728115 (diff) | |
util: add alloca_align()
The alloca_align() helper is the alloca() equivalent of posix_memalign().
As there is no such function provided by glibc, we simply account for
additional memory and return a pointer offset into the allocated memory to
grant the alignment.
Furthermore, alloca0_align() is added, which simply clears the allocated
memory.
Diffstat (limited to 'src')
| -rw-r--r-- | src/shared/util.h | 16 | ||||
| -rw-r--r-- | src/test/test-util.c | 14 |
2 files changed, 30 insertions, 0 deletions
diff --git a/src/shared/util.h b/src/shared/util.h index 08d556fc92..a1d5657237 100644 --- a/src/shared/util.h +++ b/src/shared/util.h @@ -852,6 +852,22 @@ int unlink_noerrno(const char *path); (void *) memset(_new_, 0, _len_); \ }) +#define alloca_align(size, align) \ + ({ \ + void *_ptr_; \ + size_t _mask_ = (align) - 1; \ + _ptr_ = alloca((size) + _mask_); \ + (void*)(((uintptr_t)_ptr_ + _mask_) & ~_mask_); \ + }) + +#define alloca0_align(size, align) \ + ({ \ + void *_new_; \ + size_t _size_ = (size); \ + _new_ = alloca_align(_size_, (align)); \ + (void*)memset(_new_, 0, _size_); \ + }) + #define strappenda(a, ...) \ ({ \ int _len = strlen(a); \ diff --git a/src/test/test-util.c b/src/test/test-util.c index f8e42f3a55..1311184815 100644 --- a/src/test/test-util.c +++ b/src/test/test-util.c @@ -131,6 +131,19 @@ static void test_container_of(void) { v1) == &myval); } +static void test_alloca(void) { + static const uint8_t zero[997] = { }; + char *t; + + t = alloca_align(17, 512); + assert_se(!((uintptr_t)t & 0xff)); + memzero(t, 17); + + t = alloca0_align(997, 1024); + assert_se(!((uintptr_t)t & 0x1ff)); + assert_se(!memcmp(t, zero, 997)); +} + static void test_first_word(void) { assert_se(first_word("Hello", "")); assert_se(first_word("Hello", "Hello")); @@ -1272,6 +1285,7 @@ int main(int argc, char *argv[]) { test_align_power2(); test_max(); test_container_of(); + test_alloca(); test_first_word(); test_close_many(); test_parse_boolean(); |