#include "malunal/config.h"

#if MALUNAL_PLATFORM_WIN32
#include <stdlib.h>
#include <memoryapi.h>
#include "malunal/allocator.h"


static
malunal_size_t
g_platform_page_size = 0;

malunal_size_t
platform_page_size() {
  if (g_platform_page_size != 0)
    return g_platform_page_size;

  SYSTEM_INFO si;
  GetSystemInfo(&si);
  g_platform_page_size = si.dwPageSize;
  return g_platform_page_size;
}

static
error_t
win32_allocator_acquire(
  allocator_mptr_t allocator,
  malunal_size_t   size,
  malunal_mptr_t*  out
) {
  MALUNAL_UNUSED(allocator);

  const malunal_int32_t memops  = MEM_COMMIT | MEM_RESERVE;
  const malunal_int32_t pageops = PAGE_READWRITE;

  malunal_mptr_t addr = VirtualAlloc(NULL_ADDRESS, size, memops, pageops);
  if (addr == NULL_ADDRESS)
    return (error_t) {
      .domain = &ERROR_DOMAIN_ALLOCATOR_T,
      .code   = ALLOCATOR_ERROR_OUT_OF_MEMORY
    };

  *out = addr;
  return NO_ERROR;
}

static
error_t
win32_allocator_release(
  allocator_mptr_t allocator,
  malunal_mptr_t   address,
  malunal_size_t   size
) {
  MALUNAL_UNUSED(allocator);
  VirtualFree(address, size, MEM_RELEASE);
  return NO_ERROR;
}

static const
allocator_vtable_t win32_alllocator_vtable = {
  .acquire = (allocator_acquire_pfn_t)&win32_allocator_acquire,
  .dispose = (allocator_dispose_pfn_t)&win32_allocator_release
};

static const
allocator_t win32_allocator_instance = {
  .vtable = &win32_alllocator_vtable
};

allocator_mptr_t
win32_allocator() {
  return &win32_allocator_instance;
}
#endif /* MALUNAL_PLATFORM_WIN32 */