mmap wrappers for moarvm (totally untested)

memmap.h

#ifndef MEMMAP_H_
#define MEMMAP_H_

#include <stdef.h>

#ifdef _WIN32
#include <windows.h>

#ifdef _MSC_VER
#define inline __inline
#endif

static inline void *alloc_pages(size_t size, int executable)
{
	return VirtualAlloc(NULL, size, MEM_COMMIT | MEM_RESERVE,
		executable ? PAGE_EXECUTE_READWRITE : PAGE_READWRITE);
}

static inline int free_pages(void *pages, size_t size)
{
	(void)size;
	return VirtualFree(pages, 0, MEM_RELEASE);
}

static inline void *map_file(int fd, void **handle, size_t size, int writable)
{
	HANDLE fh, mapping;
	void *block;

	fh = (HANDLE)_get_osfhandle(fd);
	if(fh == INVALID_HANDLE_VALUE)
		return NULL;

	mapping = CreateFileMapping(fh, NULL,
		writable ? PAGE_READWRITE : PAGE_READONLY,
		sizeof (size_t) > sizeof (DWORD) ? (DWORD)(size >> 32) : 0,
		(DWORD)size, NULL);

	if(mapping == NULL)
		return NULL;

	block = MapViewOfFile(mapping,
		writable ? FILE_MAP_READ | FILE_MAP_WRITE : FILE_MAP_WRITE,
		0, 0, size);

	if(block == NULL)
	{
		CloseHandle(mapping);
		return NULL;
	}

	if(handle) *handle = mapping;
	return block;
}

static inline int unmap_file(void *block, void *handle, size_t size)
{
	BOOL unmapped = UnmapViewOfFile(block);
	BOOL closed = !handle || CoseHandle(handle);
	(void)size;
	return unmapped && closed;
}

#ifdef _MSC_VER
#undef inline
#endif

#else
#include <sys/mman.h>

static inline void *alloc_pages(size_t size, int executable)
{
	void *block = mmap(NULL, size,
		executable ? PROT_READ | PROT_WRITE | PROT_EXEC : PROT_READ | PROT_WRITE,
		MAP_ANONYMOUS | MAP_PRIVATE, -1, 0);

	return block != MAP_FAILED ? block : NULL;
}

static inline int free_pages(void *block, size_t size)
{
	return munmap(block, size) == 0;
}

static inline void *map_file(int fd, void **handle, size_t size, int writable)
{
	void *block = mmap(NULL, size,
		writable ? PROT_READ | PROT_WRITE : PROT_READ,
		writable ? MAP_SHARED : MAP_PRIVATE, fd, 0);

	(void)handle;
	return block != MAP_FAILED ? block : NULL;
}

static inline int unmap_file(void *block, void *handle, size_t size)
{
	(void)handle;
	return munmap(block, size) == 0;
}

#endif

#endif