common/almalloc.cpp

   1
   2 #include "config.h"
   3
   4 #include "almalloc.h"
   5
   6 #include <cassert>
   7 #include <cstddef>
   8 #include <cstdlib>
   9 #include <cstring>
  10 #include <memory>
  11 #ifdef HAVE_MALLOC_H
  12 #include <malloc.h>
  13 #endif
  14
  15
  16 void *al_malloc(size_t alignment, size_t size)
  17 {
  18     assert((alignment & (alignment-1)) == 0);
  19     alignment = std::max(alignment, alignof(std::max_align_t));
  20
  21 #if defined(HAVE_STD_ALIGNED_ALLOC)
  22     size = (size+(alignment-1))&~(alignment-1);
  23     return std::aligned_alloc(alignment, size);
  24 #elif defined(HAVE_POSIX_MEMALIGN)
  25     void *ret{};
  26     if(posix_memalign(&ret, alignment, size) == 0)
  27         return ret;
  28     return nullptr;
  29 #elif defined(HAVE__ALIGNED_MALLOC)
  30     return _aligned_malloc(size, alignment);
  31 #else
  32     size_t total_size{size + alignment-1 + sizeof(void*)};
  33     void *base{std::malloc(total_size)};
  34     if(base != nullptr)
  35     {
  36         void *aligned_ptr{static_cast<char*>(base) + sizeof(void*)};
  37         total_size -= sizeof(void*);
  38
  39         std::align(alignment, size, aligned_ptr, total_size);
  40         *(static_cast<void**>(aligned_ptr)-1) = base;
  41         base = aligned_ptr;
  42     }
  43     return base;
  44 #endif
  45 }
  46
  47 void *al_calloc(size_t alignment, size_t size)
  48 {
  49     void *ret{al_malloc(alignment, size)};
  50     if(ret) std::memset(ret, 0, size);
  51     return ret;
  52 }
  53
  54 void al_free(void *ptr) noexcept
  55 {
  56 #if defined(HAVE_STD_ALIGNED_ALLOC) || defined(HAVE_POSIX_MEMALIGN)
  57     std::free(ptr);
  58 #elif defined(HAVE__ALIGNED_MALLOC)
  59     _aligned_free(ptr);
  60 #else
  61     if(ptr != nullptr)
  62         std::free(*(static_cast<void**>(ptr) - 1));
  63 #endif
  64 }