#include <stdint.h>
#include <string.h>
#ifdef _WIN32
# include <memoryapi.h>
# include <sysinfoapi.h>
#else
# include <sys/mman.h>
# include <unistd.h>
#endif

#include "jit.h"

static size_t page_size = 0;


JitBuffer *
jit_buffer_new(void)
{
#ifdef _WIN32
  DWORD type;
  DWORD prot;
  SYSTEM_INFO sysinfo;

  if (page_size == 0)
    {
      GetSystemInfo(&sysinfo);
      page_size = sysinfo.dwPageSize;
    }

  type = MEM_RESERVE | MEM_COMMIT;
  prot = PAGE_READWRITE;

  return (VirtualAlloc(NULL, page_size, type, prot));
#else
  int prot;
  int flags;

  if (page_size == 0)
    {
      page_size = sysconf(_SC_PAGESIZE);
    }

  prot = PROT_READ | PROT_WRITE;
  flags = MAP_ANONYMOUS | MAP_PRIVATE;

  return (mmap(NULL, page_size, prot, flags, -1, 0));
#endif
}

void
jit_buffer_finalize(JitBuffer *buff)
{
#ifdef _WIN32
  DWORD old;

  VirtualProtect(buff, page_size, PAGE_EXECUTE_READ, &old);
#else
  mprotect(buff, page_size, PROT_READ | PROT_EXEC);
#endif
}

void
jit_buffer_add(JitBuffer *buff, int size, void *value)
{
  memcpy(buff->code + buff->count, value, size);
  buff->count += size;
}

void
jit_buffer_execute(JitBuffer *buff)
{
}

void
jit_buffer_destroy(JitBuffer *buff)
{
#ifdef _WIN32
  VirtualFree(buff, page_size, MEM_RELEASE);
#else
  munmap(buff, page_size);
#endif
}