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| |
| #include "qplatformdefs.h" |
| |
| #include <stdlib.h> |
| #include <string.h> |
| |
| /* |
| Define the container allocation functions in a separate file, so that our |
| users can easily override them. |
| */ |
| |
| QT_BEGIN_NAMESPACE |
| |
| #if !QT_DEPRECATED_SINCE(5, 0) |
| // Make sure they're defined to be exported |
| Q_CORE_EXPORT void *qMalloc(size_t size) Q_ALLOC_SIZE(1); |
| Q_CORE_EXPORT void qFree(void *ptr); |
| Q_CORE_EXPORT void *qRealloc(void *ptr, size_t size) Q_ALLOC_SIZE(2); |
| #endif |
| |
| |
| void *qMalloc(size_t size) |
| { |
| return ::malloc(size); |
| } |
| |
| void qFree(void *ptr) |
| { |
| ::free(ptr); |
| } |
| |
| void *qRealloc(void *ptr, size_t size) |
| { |
| return ::realloc(ptr, size); |
| } |
| |
| void *qMallocAligned(size_t size, size_t alignment) |
| { |
| return qReallocAligned(nullptr, size, 0, alignment); |
| } |
| |
| void *qReallocAligned(void *oldptr, size_t newsize, size_t oldsize, size_t alignment) |
| { |
| // fake an aligned allocation |
| void *actualptr = oldptr ? static_cast<void **>(oldptr)[-1] : nullptr; |
| if (alignment <= sizeof(void*)) { |
| // special, fast case |
| void **newptr = static_cast<void **>(realloc(actualptr, newsize + sizeof(void*))); |
| if (!newptr) |
| return nullptr; |
| if (newptr == actualptr) { |
| // realloc succeeded without reallocating |
| return oldptr; |
| } |
| |
| *newptr = newptr; |
| return newptr + 1; |
| } |
| |
| // malloc returns pointers aligned at least at sizeof(size_t) boundaries |
| // but usually more (8- or 16-byte boundaries). |
| // So we overallocate by alignment-sizeof(size_t) bytes, so we're guaranteed to find a |
| // somewhere within the first alignment-sizeof(size_t) that is properly aligned. |
| |
| // However, we need to store the actual pointer, so we need to allocate actually size + |
| // alignment anyway. |
| |
| void *real = realloc(actualptr, newsize + alignment); |
| if (!real) |
| return nullptr; |
| |
| quintptr faked = reinterpret_cast<quintptr>(real) + alignment; |
| faked &= ~(alignment - 1); |
| void **faked_ptr = reinterpret_cast<void **>(faked); |
| |
| if (oldptr) { |
| qptrdiff oldoffset = static_cast<char *>(oldptr) - static_cast<char *>(actualptr); |
| qptrdiff newoffset = reinterpret_cast<char *>(faked_ptr) - static_cast<char *>(real); |
| if (oldoffset != newoffset) |
| memmove(faked_ptr, static_cast<char *>(real) + oldoffset, qMin(oldsize, newsize)); |
| } |
| |
| // now save the value of the real pointer at faked-sizeof(void*) |
| // by construction, alignment > sizeof(void*) and is a power of 2, so |
| // faked-sizeof(void*) is properly aligned for a pointer |
| faked_ptr[-1] = real; |
| |
| return faked_ptr; |
| } |
| |
| void qFreeAligned(void *ptr) |
| { |
| if (!ptr) |
| return; |
| void **ptr2 = static_cast<void **>(ptr); |
| free(ptr2[-1]); |
| } |
| |
| QT_END_NAMESPACE |
| |