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reactos/sdk/lib/ucrt/heap/align.cpp

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/***
*align.c - Aligned allocation, reallocation or freeing of memory in the heap
*
* Copyright (c) Microsoft Corporation. All rights reserved.
*
*Purpose:
* Defines the _aligned_malloc(),
* _aligned_realloc(),
* _aligned_recalloc(),
* _aligned_offset_malloc(),
* _aligned_offset_realloc(),
* _aligned_offset_recalloc(),
* _aligned_free(),
* _aligned_msize() functions.
*
*******************************************************************************/
#include <corecrt_internal.h>
#include <malloc.h>
#define IS_2_POW_N(X) ((X) != 0 && ((X) & ((X) - 1)) == 0)
#define PTR_SZ sizeof(void *)
/***
*
* |1|___6___|2|3|4|_________5__________|_6_|
*
* 1 -> Pointer to start of the block allocated by malloc.
* 2 -> Value of 1.
* 3 -> Gap used to get 1 aligned on sizeof(void *).
* 4 -> Pointer to the start of data block.
* 4+5 -> Data block.
* 6 -> Wasted memory at rear of data block.
* 6 -> Wasted memory.
*
*******************************************************************************/
static void _aligned_free_base(
_Pre_maybenull_ _Post_invalid_ void* block
);
_Check_return_ _Ret_maybenull_ _Post_writable_byte_size_(size)
static void* _aligned_malloc_base(
_In_ size_t size,
_In_ size_t alignment
);
_Check_return_
static size_t _aligned_msize_base(
_Pre_notnull_ void* block,
_In_ size_t alignment,
_In_ size_t offset
);
_Check_return_ _Ret_maybenull_ _Post_writable_byte_size_(size)
static void* _aligned_offset_malloc_base(
_In_ size_t size,
_In_ size_t alignment,
_In_ size_t offset
);
_Success_(return != 0) _Check_return_ _Ret_maybenull_ _Post_writable_byte_size_(size)
static void* _aligned_offset_realloc_base(
_Pre_maybenull_ _Post_invalid_ void* block,
_In_ size_t size,
_In_ size_t alignment,
_In_ size_t offset
);
_Success_(return != 0) _Check_return_ _Ret_maybenull_ _Post_writable_byte_size_(size * count)
static void* _aligned_offset_recalloc_base(
_Pre_maybenull_ _Post_invalid_ void* block,
_In_ size_t count,
_In_ size_t size,
_In_ size_t alignment,
_In_ size_t offset
);
_Success_(return != 0) _Check_return_ _Ret_maybenull_ _Post_writable_byte_size_(size)
static void* _aligned_realloc_base(
_Pre_maybenull_ _Post_invalid_ void* block,
_In_ size_t size,
_In_ size_t alignment
);
_Success_(return != 0) _Check_return_ _Ret_maybenull_ _Post_writable_byte_size_(size * count)
static void* _aligned_recalloc_base(
_Pre_maybenull_ _Post_invalid_ void* block,
_In_ size_t count,
_In_ size_t size,
_In_ size_t alignment
);
/***
* void *_aligned_malloc_base(size_t size, size_t alignment)
* - Get a block of aligned memory from the heap.
*
* Purpose:
* Allocate of block of aligned memory aligned on the alignment of at least
* size bytes from the heap and return a pointer to it.
*
* Entry:
* size_t size - size of block requested
* size_t alignment - alignment of memory (needs to be a power of 2)
*
* Exit:
* Success: Pointer to memory block
* Failure: Null, errno is set
*
* Exceptions:
* Input parameters are validated. Refer to the validation section of the function.
*
*******************************************************************************/
static __forceinline void* __cdecl _aligned_malloc_base(
size_t const size,
size_t const alignment
)
{
return _aligned_offset_malloc_base(size, alignment, 0);
}
/***
* void *_aligned_offset_malloc_base(size_t size, size_t alignment, int offset)
* - Get a block of memory from the heap.
*
* Purpose:
* Allocate a block of memory which is shifted by offset from alignment of
* at least size bytes from the heap and return a pointer to it.
*
* Entry:
* size_t size - size of block of memory
* size_t alignment - alignment of memory (needs to be a power of 2)
* size_t offset - offset of memory from the alignment
*
* Exit:
* Success: Pointer to memory block
* Failure: Null, errno is set
*
* Exceptions:
* Input parameters are validated. Refer to the validation section of the function.
*
*******************************************************************************/
static __forceinline void* __cdecl _aligned_offset_malloc_base(
size_t size,
size_t align,
size_t offset
)
{
uintptr_t ptr, retptr, gap;
size_t nonuser_size,block_size;
/* validation section */
_VALIDATE_RETURN(IS_2_POW_N(align), EINVAL, nullptr);
_VALIDATE_RETURN(offset == 0 || offset < size, EINVAL, nullptr);
align = (align > PTR_SZ ? align : PTR_SZ) -1;
/* gap = number of bytes needed to round up offset to align with PTR_SZ*/
gap = (0 - offset)&(PTR_SZ -1);
nonuser_size = PTR_SZ +gap +align;
block_size = nonuser_size + size;
_VALIDATE_RETURN_NOEXC(size <= block_size, ENOMEM, nullptr)
if ( (ptr =(uintptr_t)malloc(block_size)) == (uintptr_t)nullptr)
return nullptr;
retptr =((ptr +nonuser_size+offset)&~align)- offset;
((uintptr_t *)(retptr - gap))[-1] = ptr;
return (void *)retptr;
}
/***
*
* void *_aligned_realloc_base(void * memblock, size_t size, size_t alignment)
* - Reallocate a block of aligned memory from the heap.
*
* Purpose:
* Reallocates of block of aligned memory aligned on the alignment of at
* least size bytes from the heap and return a pointer to it. Size can be
* either greater or less than the original size of the block.
* The reallocation may result in moving the block as well as changing the
* size.
*
* Entry:
* void *memblock - pointer to block in the heap previously allocated by
* call to _aligned_malloc(), _aligned_offset_malloc(),
* _aligned_realloc() or _aligned_offset_realloc().
* size_t size - size of block requested
* size_t alignment - alignment of memory
*
* Exit:
* Success: Pointer to re-allocated memory block
* Failure: Null, errno is set
*
* Exceptions:
* Input parameters are validated. Refer to the validation section of the function.
*
*******************************************************************************/
static __forceinline void* __cdecl _aligned_realloc_base(
void* const block,
size_t const size,
size_t const alignment
)
{
return _aligned_offset_realloc_base(block, size, alignment, 0);
}
/***
*
* void *_aligned_recalloc_base(void * memblock, size_t count, size_t size, size_t alignment)
* - Reallocate a block of aligned memory from the heap.
*
* Purpose:
* Reallocates of block of aligned memory aligned on the alignment of at
* least size bytes from the heap and return a pointer to it. Size can be
* either greater or less than the original size of the block.
* The reallocation may result in moving the block as well as changing the
* size.
*
* Entry:
* void *memblock - pointer to block in the heap previously allocated by
* call to _aligned_malloc(), _aligned_offset_malloc(),
* _aligned_realloc() or _aligned_offset_realloc().
* size_t count - count of items
* size_t size - size of item
* size_t alignment - alignment of memory
*
* Exit:
* Success: Pointer to re-allocated memory block
* Failure: Null, errno is set
*
* Exceptions:
* Input parameters are validated. Refer to the validation section of the function.
*
*******************************************************************************/
static __forceinline void* __cdecl _aligned_recalloc_base(
void* const block,
size_t const count,
size_t const size,
size_t const alignment
)
{
return _aligned_offset_recalloc_base(block, count, size, alignment, 0);
}
/***
*
* void *_aligned_offset_realloc_base (void * memblock, size_t size,
* size_t alignment, int offset)
* - Reallocate a block of memory from the heap.
*
* Purpose:
* Reallocates a block of memory which is shifted by offset from
* alignment of at least size bytes from the heap and return a pointer
* to it. Size can be either greater or less than the original size of the
* block.
*
* Entry:
* void *memblock - pointer to block in the heap previously allocated by
* call to _aligned_malloc(), _aligned_offset_malloc(),
* _aligned_realloc() or _aligned_offset_realloc().
* size_t size - size of block of memory
* size_t alignment - alignment of memory
* size_t offset - offset of memory from the alignment
*
* Exit:
* Success: Pointer to re-allocated memory block
* Failure: Null, errno is set
*
* Exceptions:
* Input parameters are validated. Refer to the validation section of the function.
*
*******************************************************************************/
static __forceinline void* __cdecl _aligned_offset_realloc_base(
void* block,
size_t size,
size_t align,
size_t offset
)
{
uintptr_t ptr, retptr, gap, stptr, diff;
uintptr_t movsz, reqsz;
int bFree = 0;
/* special cases */
if (block == nullptr)
{
return _aligned_offset_malloc_base(size, align, offset);
}
if (size == 0)
{
_aligned_free_base(block);
return nullptr;
}
/* validation section */
_VALIDATE_RETURN(IS_2_POW_N(align), EINVAL, nullptr);
_VALIDATE_RETURN(offset == 0 || offset < size, EINVAL, nullptr);
stptr = (uintptr_t)block;
/* ptr points to the pointer to starting of the memory block */
stptr = (stptr & ~(PTR_SZ -1)) - PTR_SZ;
/* ptr is the pointer to the start of memory block*/
stptr = *((uintptr_t *)stptr);
align = (align > PTR_SZ ? align : PTR_SZ) -1;
/* gap = number of bytes needed to round up offset to align with PTR_SZ*/
gap = (0 -offset)&(PTR_SZ -1);
diff = (uintptr_t)block - stptr;
/* Mov size is min of the size of data available and sizw requested.
*/
#pragma warning(push)
#pragma warning(disable: 22018) // Silence prefast about overflow/underflow
movsz = _msize_base((void *)stptr) - ((uintptr_t)block - stptr);
#pragma warning(pop)
movsz = movsz > size ? size : movsz;
reqsz = PTR_SZ + gap + align + size;
_VALIDATE_RETURN_NOEXC(size <= reqsz, ENOMEM, nullptr);
/* First check if we can expand(reducing or expanding using expand) data
* safely, ie no data is lost. eg, reducing alignment and keeping size
* same might result in loss of data at the tail of data block while
* expanding.
*
* If no, use malloc to allocate the new data and move data.
*
* If yes, expand and then check if we need to move the data.
*/
if ((stptr +align +PTR_SZ +gap)<(uintptr_t)block)
{
if ((ptr = (uintptr_t)malloc(reqsz)) == (uintptr_t) nullptr)
return nullptr;
bFree = 1;
}
else
{
/* we need to save errno, which can be modified by _expand */
errno_t save_errno = errno;
if ((ptr = (uintptr_t)_expand((void *)stptr, reqsz)) == (uintptr_t)nullptr)
{
errno = save_errno;
if ((ptr = (uintptr_t)malloc(reqsz)) == (uintptr_t) nullptr)
return nullptr;
bFree = 1;
}
else
stptr = ptr;
}
if ( ptr == ((uintptr_t)block - diff)
&& !( ((size_t)block + gap +offset) & ~(align) ))
{
return block;
}
retptr =((ptr +PTR_SZ +gap +align +offset)&~align)- offset;
memmove((void *)retptr, (void *)(stptr + diff), movsz);
if ( bFree)
free ((void *)stptr);
((uintptr_t *)(retptr - gap))[-1] = ptr;
return (void *)retptr;
}
/***
*
* size_t _aligned_msize_base(void *memblock, size_t align, size_t offset)
*
* Purpose:
* Computes the size of an aligned block.
*
* Entry:
* void * memblock - pointer to the aligned block of memory
*
* Exceptions:
* None. If memblock == nullptr 0 is returned.
*
*******************************************************************************/
static __forceinline size_t __cdecl _aligned_msize_base(
void* block,
size_t align,
size_t offset
)
{
size_t header_size = 0; /* Size of the header block */
size_t footer_size = 0; /* Size of the footer block */
size_t total_size = 0; /* total size of the allocated block */
size_t user_size = 0; /* size of the user block*/
uintptr_t gap = 0; /* keep the alignment of the data block */
/* after the sizeof(void*) aligned pointer */
/* to the beginning of the allocated block */
uintptr_t ptr = 0; /* computes the beginning of the allocated block */
_VALIDATE_RETURN(block != nullptr, EINVAL, static_cast<size_t>(-1));
/* HEADER SIZE + FOOTER SIZE = GAP + ALIGN + SIZE OF A POINTER*/
/* HEADER SIZE + USER SIZE + FOOTER SIZE = TOTAL SIZE */
ptr = (uintptr_t)block; /* ptr points to the start of the aligned memory block */
ptr = (ptr & ~(PTR_SZ - 1)) - PTR_SZ; /* ptr is one position behind memblock */
/* the value in ptr is the start of the real allocated block */
ptr = *((uintptr_t *)ptr); /* after dereference ptr points to the beginning of the allocated block */
total_size = _msize_base((void*)ptr);
header_size = (uintptr_t) block - ptr;
gap = (0 - offset) & (PTR_SZ - 1);
/* Alignment cannot be less than sizeof(void*) */
align = (align > PTR_SZ ? align : PTR_SZ) -1;
footer_size = gap + align + PTR_SZ - header_size;
user_size = total_size - header_size - footer_size;
return user_size;
}
/***
*
* void *_aligned_offset_recalloc_base (void * memblock, size_t size, size_t count, size_t alignment, int offset)
* - Reallocate a block of memory from the heap.
*
* Purpose:
* Reallocates a block of memory which is shifted by offset from
* alignment of at least size bytes from the heap and return a pointer
* to it. Size can be either greater or less than the original size of the
* block.
*
* Entry:
* void *memblock - pointer to block in the heap previously allocated by
* call to _aligned_malloc(), _aligned_offset_malloc(),
* _aligned_realloc() or _aligned_offset_realloc().
* size_t count - count of items
* size_t size - size of items
* size_t alignment - alignment of memory
* size_t offset - offset of memory from the alignment
*
* Exit:
* Success: Pointer to re-allocated memory block
* Failure: Null, errno is set
*
* Exceptions:
* Input parameters are validated. Refer to the validation section of the function.
*
*******************************************************************************/
static __forceinline void* __cdecl _aligned_offset_recalloc_base(
void* block,
size_t count,
size_t size,
size_t align,
size_t offset
)
{
size_t user_size = 0; /* wanted size, passed to aligned realoc */
size_t start_fill = 0; /* location where aligned recalloc starts to fill with 0 */
/* filling must start from the end of the previous user block */
void * retptr = nullptr; /* result of aligned recalloc*/
/* ensure that (size * num) does not overflow */
if (count > 0)
{
_VALIDATE_RETURN_NOEXC((_HEAP_MAXREQ / count) >= size, ENOMEM, nullptr);
}
user_size = size * count;
if (block != nullptr)
{
start_fill = _aligned_msize_base(block, align, offset);
}
retptr = _aligned_offset_realloc_base(block, user_size, align, offset);
if (retptr != nullptr)
{
if (start_fill < user_size)
{
memset ((char*)retptr + start_fill, 0, user_size - start_fill);
}
}
return retptr;
}
/***
*
* void *_aligned_free_base(void *memblock)
* - Free the memory which was allocated using _aligned_malloc or
* _aligned_offset_memory
*
* Purpose:
* Frees the aligned memory block which was allocated using _aligned_malloc.
*
* Entry:
* void * memblock - pointer to the block of memory
*
* Exceptions:
* None. If memblock == nullptr we simply return without doing anything.
*
*******************************************************************************/
static __forceinline void __cdecl _aligned_free_base(void* const block)
{
uintptr_t ptr;
if (block == nullptr)
return;
ptr = (uintptr_t)block;
/* ptr points to the pointer to starting of the memory block */
ptr = (ptr & ~(PTR_SZ -1)) - PTR_SZ;
/* ptr is the pointer to the start of memory block*/
ptr = *((uintptr_t*)ptr);
free((void *)ptr);
}
// These functions are patchable and therefore must be marked noinline.
// Their *_base implementations are marked __forceinline in order to
// ensure each export is separated from each other and that there is
// enough space in each export to host a patch.
extern "C" __declspec(noinline) void __cdecl _aligned_free(void* const block)
{
#ifdef _DEBUG
_aligned_free_dbg(block);
#else
_aligned_free_base(block);
#endif
}
extern "C" __declspec(noinline) _CRTRESTRICT void* __cdecl _aligned_malloc(
size_t const size,
size_t const alignment
)
{
#ifdef _DEBUG
return _aligned_offset_malloc_dbg(size, alignment, 0, nullptr, 0);
#else
return _aligned_malloc_base(size, alignment);
#endif
}
extern "C" __declspec(noinline) size_t __cdecl _aligned_msize(
void* const block,
size_t const alignment,
size_t const offset)
{
#ifdef _DEBUG
return _aligned_msize_dbg(block, alignment, offset);
#else
return _aligned_msize_base(block, alignment, offset);
#endif
}
extern "C" __declspec(noinline) _CRTRESTRICT void* __cdecl _aligned_offset_malloc(
size_t const size,
size_t const alignment,
size_t const offset
)
{
#ifdef _DEBUG
return _aligned_offset_malloc_dbg(size, alignment, offset, nullptr, 0);
#else
return _aligned_offset_malloc_base(size, alignment, offset);
#endif
}
extern "C" __declspec(noinline) _CRTRESTRICT void* __cdecl _aligned_offset_realloc(
void* const block,
size_t const size,
size_t const alignment,
size_t const offset
)
{
#ifdef _DEBUG
return _aligned_offset_realloc_dbg(block, size, alignment, offset, nullptr, 0);
#else
return _aligned_offset_realloc_base(block, size, alignment, offset);
#endif
}
extern "C" __declspec(noinline) _CRTRESTRICT void* __cdecl _aligned_offset_recalloc(
void* const block,
size_t const count,
size_t const size,
size_t const alignment,
size_t const offset
)
{
#ifdef _DEBUG
return _aligned_offset_recalloc_dbg(block, count, size, alignment, offset, nullptr, 0);
#else
return _aligned_offset_recalloc_base(block, count, size, alignment, offset);
#endif
}
extern "C" __declspec(noinline) _CRTRESTRICT void* __cdecl _aligned_realloc(
void* const block,
size_t const size,
size_t const alignment
)
{
#ifdef _DEBUG
return _aligned_offset_realloc_dbg(block, size, alignment, 0, nullptr, 0);
#else
return _aligned_realloc_base(block, size, alignment);
#endif
}
extern "C" __declspec(noinline) _CRTRESTRICT void* __cdecl _aligned_recalloc(
void* const block,
size_t const count,
size_t const size,
size_t const alignment
)
{
#ifdef _DEBUG
return _aligned_offset_recalloc_dbg(block, count, size, alignment, 0, nullptr, 0);
#else
return _aligned_recalloc_base(block, count, size, alignment);
#endif
}
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