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Fixed MurmurHash unaligned read.

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This commit is contained in:
Branimir Karadžić
2015-08-15 15:04:41 -07:00
parent a611d0bc87
commit 96b3b9616f
4 changed files with 69 additions and 9 deletions
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8
include/bx/allocator.h
View File

@@ -58,14 +58,6 @@ namespace bx
return un.ptr;
}
/// Check if pointer is aligned. _align must be power of two.
inline bool isPtrAligned(const void* _ptr, size_t _align = BX_CONFIG_ALLOCATOR_NATURAL_ALIGNMENT)
{
union { const void* ptr; size_t addr; } un;
un.ptr = _ptr;
return 0 == (un.addr & (_align-1) );
}
struct BX_NO_VTABLE AllocatorI
{
virtual ~AllocatorI() = 0;

8
include/bx/bx.h
View File

@@ -44,6 +44,14 @@ namespace bx
Ty tmp = _a; _a = _b; _b = tmp;
}
/// Check if pointer is aligned. _align must be power of two.
inline bool isPtrAligned(const void* _ptr, size_t _align)
{
union { const void* ptr; size_t addr; } un;
un.ptr = _ptr;
return 0 == (un.addr & (_align-1) );
}
} // namespace bx
// Annoying C++0x stuff..

58
include/bx/hash.h
View File

@@ -30,7 +30,19 @@ namespace bx
void add(const void* _data, int _len)
{
const uint8_t* data = (uint8_t*)_data;
if (BX_ENABLED(BX_PLATFORM_EMSCRIPTEN)
&& BX_UNLIKELY(!isPtrAligned(_data, 4) ) )
{
addUnaligned(_data, _len);
return;
}
addAligned(_data, _len);
}
void addAligned(const void* _data, int _len)
{
const uint8_t* data = (const uint8_t*)_data;
m_size += _len;
mixTail(data, _len);
@@ -48,6 +60,27 @@ namespace bx
mixTail(data, _len);
}
void addUnaligned(const void* _data, int _len)
{
const uint8_t* data = (const uint8_t*)_data;
m_size += _len;
mixTail(data, _len);
while(_len >= 4)
{
uint32_t kk;
readUnaligned(data, kk);
mmix(m_hash, kk);
data += 4;
_len -= 4;
}
mixTail(data, _len);
}
template<typename Ty>
void add(Ty _value)
{
@@ -67,6 +100,29 @@ namespace bx
}
private:
static void readUnaligned(const void* _data, uint32_t& _out)
{
const uint8_t* data = (const uint8_t*)_data;
if (BX_ENABLED(BX_CPU_ENDIAN_LITTLE) )
{
_out = 0
| data[0]<<24
| data[1]<<16
| data[2]<<8
| data[3]
;
}
else
{
_out = 0
| data[0]
| data[1]<<8
| data[2]<<16
| data[3]<<24
;
}
}
void mixTail(const uint8_t*& _data, int& _len)
{
while( _len && ((_len<4) || m_count) )

4
include/bx/macros.h
View File

@@ -53,6 +53,8 @@
# define BX_ALLOW_UNUSED __attribute__( (unused) )
# define BX_FORCE_INLINE __extension__ static __inline __attribute__( (__always_inline__) )
# define BX_FUNCTION __PRETTY_FUNCTION__
# define BX_LIKELY(_x) __builtin_expect(!!(_x), 1)
# define BX_UNLIKELY(_x) __builtin_expect(!!(_x), 0)
# define BX_NO_INLINE __attribute__( (noinline) )
# define BX_NO_RETURN __attribute__( (noreturn) )
# define BX_NO_VTABLE
@@ -76,6 +78,8 @@
# define BX_ALLOW_UNUSED
# define BX_FORCE_INLINE __forceinline
# define BX_FUNCTION __FUNCTION__
# define BX_LIKELY(_x) (_x)
# define BX_UNLIKELY(_x) (_x)
# define BX_NO_INLINE __declspec(noinline)
# define BX_NO_RETURN
# define BX_NO_VTABLE __declspec(novtable)