cleaner pointer alignment logic for autoconf-based builds

diff --git a/src/libFLAC/memory.c b/src/libFLAC/memory.c
index 2df3bfb..7c7aee9 100644 (file)
--- a/src/libFLAC/memory.c
+++ b/src/libFLAC/memory.c
@@ -45,6 +45,16 @@ void *FLAC__memory_alloc_aligned(size_t bytes, void **aligned_address)
 #ifdef FLAC__ALIGN_MALLOC_DATA
        /* align on 32-byte (256-bit) boundary */
        x = malloc(bytes+31);
+#ifdef SIZEOF_VOIDP
+#if SIZEOF_VOIDP == 4
+               /* could do  *aligned_address = x + ((unsigned) (32 - (((unsigned)x) & 31))) & 31; */
+               *aligned_address = (void*)(((unsigned)x + 31) & -32);
+#elif SIZEOF_VOIDP == 8
+               *aligned_address = (void*)(((FLAC__uint64)x + 31) & (FLAC__uint64)(-((FLAC__int64)32)));
+#else
+# error  Unsupported sizeof(void*)
+#endif
+#else
        /* there's got to be a better way to do this right for all archs */
        if(sizeof(void*) == sizeof(unsigned))
                *aligned_address = (void*)(((unsigned)x + 31) & -32);
@@ -52,6 +62,7 @@ void *FLAC__memory_alloc_aligned(size_t bytes, void **aligned_address)
                *aligned_address = (void*)(((FLAC__uint64)x + 31) & (FLAC__uint64)(-((FLAC__int64)32)));
        else
                return 0;
+#endif
 #else
        x = malloc(bytes);
        *aligned_address = x;