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| author | David Oberhollenzer <david.oberhollenzer@sigma-star.at> | 2019-08-23 01:28:25 +0200 |
|---|---|---|
| committer | David Oberhollenzer <david.oberhollenzer@sigma-star.at> | 2019-08-23 01:28:25 +0200 |
| commit | 8c8467a824c950fd1094e46a74c1f57048e5f099 (patch) | |
| tree | a2510527550ba3e15add02d86f199bac6dcf3351 | |
| parent | 8b16efb80d9a863641a0a7395204df038feeb56c (diff) | |
Add primitives for unsigned addition/multiplication with overflow
Signed-off-by: David Oberhollenzer <david.oberhollenzer@sigma-star.at>
| -rw-r--r-- | configure.ac | 5 | ||||
| -rw-r--r-- | include/util.h | 27 |
2 files changed, 32 insertions, 0 deletions
diff --git a/configure.ac b/configure.ac index 2ec9674..d6c1612 100644 --- a/configure.ac +++ b/configure.ac @@ -146,6 +146,11 @@ fi ##### additional checks ##### AX_COMPILE_CHECK_SIZEOF(time_t) +AX_COMPILE_CHECK_SIZEOF(size_t) +AX_COMPILE_CHECK_SIZEOF(short) +AX_COMPILE_CHECK_SIZEOF(int) +AX_COMPILE_CHECK_SIZEOF(long) +AX_COMPILE_CHECK_SIZEOF(long long) AC_CHECK_HEADERS([sys/xattr.h], [], []) diff --git a/include/util.h b/include/util.h index 99418f9..ae8c43c 100644 --- a/include/util.h +++ b/include/util.h @@ -11,6 +11,33 @@ #include <sys/types.h> #include <stdint.h> +#include <stddef.h> + +#if defined(__GNUC__) || defined(__clang__) +#define UI_ADD_OV __builtin_uadd_overflow +#define UL_ADD_OV __builtin_uaddl_overflow +#define ULL_ADD_OV __builtin_uaddll_overflow + +#define UI_MUL_OV __builtin_umul_overflow +#define UL_MUL_OV __builtin_umull_overflow +#define ULL_MUL_OV __builtin_umulll_overflow +#else +#error Sorry, I do not know how to trap integer overflows with this compiler +#endif + +#if SIZEOF_SIZE_T <= SIZEOF_INT +#define SZ_ADD_OV UI_ADD_OV +#define SZ_MUL_OV UI_MUL_OV +#elif SIZEOF_SIZE_T == SIZEOF_LONG +#define SZ_ADD_OV UL_ADD_OV +#define SZ_MUL_OV UL_MUL_OV +#elif SIZEOF_SIZE_T == SIZEOF_LONG_LONG +#define SZ_ADD_OV ULL_ADD_OV +#define SZ_MUL_OV ULL_MUL_OV +#else +#error Cannot determine maximum value of size_t +#endif + /* layout structure for sparse files, indicating where the actual data is */ typedef struct sparse_map_t { |