/src/zziplib/zzip/__mmap.h

  1#ifndef __ZZIP_INTERNAL_MMAP_H
  2#define __ZZIP_INTERNAL_MMAP_H
  3#include <zzip/types.h>
  4
  5/*
  6 * DO NOT USE THIS CODE.
  7 *
  8 * It is an internal header file for zziplib that carries some inline
  9 * functions (or just static members) and a few defines, simply to be
 10 * able to reuse these across - and have everything in a specific place.
 11 *
 12 * Copyright (c) 2002,2003 Guido Draheim
 13 *          All rights reserved,
 14 *          use under the restrictions of the 
 15 *          Lesser GNU General Public License
 16 *          or alternatively the restrictions 
 17 *          of the Mozilla Public License 1.1
 18 */
 19
 20#ifdef _USE_MMAP
 21#if    defined ZZIP_HAVE_SYS_MMAN_H
 22#include <sys/mman.h>
 23#define USE_POSIX_MMAP 1
 24#elif defined ZZIP_HAVE_WINBASE_H || defined WIN32
 25#include <windows.h>
 26#define USE_WIN32_MMAP 1
 27#else
 28#undef _USE_MMAP
 29#endif
 30#endif
 31
 32/* -------------- specify MMAP function imports --------------------------- */
 33
 34#if     defined  USE_POSIX_MMAP
 35#define USE_MMAP 1
 36
 37#define _zzip_mmap(user, fd, offs, len) \
 38              mmap (0, len, PROT_READ, MAP_SHARED, fd, offs)
 39#define _zzip_munmap(user, ptr, len) \
 40              munmap (ptr, len)
 41#define _zzip_getpagesize(user) getpagesize()
 42
 43#ifndef MAP_FAILED /* hpux10.20 does not have it */
 44#define MAP_FAILED ((void*)(-1))
 45#endif
 46
 47#elif   defined USE_WIN32_MMAP
 48#define USE_MMAP 1
 49#ifndef MAP_FAILED
 50#define MAP_FAILED 0
 51#endif
 52/* we (ab)use the "*user" variable to store the FileMapping handle */
 53                 /* which assumes (sizeof(long) == sizeof(HANDLE)) */
 54
 55static size_t win32_getpagesize (void)
 56{ 
 57    SYSTEM_INFO si; GetSystemInfo (&si); 
 58    return si.dwAllocationGranularity; 
 59}
 60static void*  win32_mmap (long* user, int fd, zzip_off_t offs, size_t len)
 61{
 62    if (! user || *user != 1) /* || offs % getpagesize() */
 63	return 0;
 64  {
 65    HANDLE hFile = (HANDLE)_get_osfhandle(fd);
 66    if (hFile)
 67	*user = (int) CreateFileMapping (hFile, 0, PAGE_READONLY, 0, 0, NULL);
 68    if (*user)
 69    {
 70	char* p = 0;
 71	p = MapViewOfFile(*(HANDLE*)user, FILE_MAP_READ, 0, offs, len);
 72	if (p) return p + offs;
 73	CloseHandle (*(HANDLE*)user); *user = 1;
 74    } 
 75    return MAP_FAILED;
 76  }
 77}
 78static void win32_munmap (long* user, char* fd_map, size_t len)
 79{
 80    UnmapViewOfFile (fd_map);
 81    CloseHandle (*(HANDLE*)user); *user = 1;
 82}
 83
 84#define _zzip_mmap(user, fd, offs, len) \
 85        win32_mmap ((long*) &(user), fd, offs, len)
 86#define _zzip_munmap(user, ptr, len) \
 87        win32_munmap ((long*) &(user), ptr, len)
 88#define _zzip_getpagesize(user) win32_getpagesize()
 89
 90#else   /* disable */
 91#define USE_MMAP 0
 92/* USE_MAP is intentional: we expect the compiler to do some "code removal"
 93 * on any source code enclosed in if (USE_MMAP) {...}   i.e. the unreachable
 94 * branch of an if (0) {....} is not emitted to the final object binary. */
 95
 96#ifndef MAP_FAILED
 97#define MAP_FAILED  0
 98#endif
 99
100#define _zzip_mmap(user, fd, offs, len) (MAP_FAILED)
101#define _zzip_munmap(user, ptr, len) {}
102#define _zzip_getpagesize(user) 1
103
104#endif /* USE_MMAP defines */
105
106
107#endif