src/zzip/plugin.h

   1 /*
   2  * Author:
   3  *      Guido Draheim <guidod@gmx.de>
   4  *
   5  * Copyright (c) 2002,2003 Guido Draheim
   6  *          All rights reserved
   7  *          use under the restrictions of the
   8  *          Lesser GNU General Public License
   9  *          or alternatively the restrictions
  10  *          of the Mozilla Public License 1.1
  11  *
  12  *  the interfaces for the plugin_io system
  13  *
  14  * Using the following you can provide your own file I/O functions to
  15  * e.g. read data directly from memory, provide simple
  16  * "encryption"/"decryption" of on-disk .zip-files...
  17  * Note that this currently only provides a subset of the functionality
  18  * in zziplib. It does not attempt to provide any directory functions,
  19  * but if your program 1) only uses ordinary on-disk files and you
  20  * just want this for file obfuscation, or 2) you only access your
  21  * .zip archives using zzip_open & co., this is sufficient.
  22  *
  23  * Currently the default io are the POSIX functions, except
  24  * for 'filesize' that is zziplibs own provided zzip_filesize function,
  25  * using standard POSIX fd's. You are however free to replace this with
  26  * whatever data type you need, so long as you provide implementations
  27  * for all the functions, and the data type fits an int.
  28  *
  29  * all functions receiving ext_io are able to cope with both arguments
  30  * set to zero which will let them default to a ZIP ext and posix io.
  31  */
  32 #ifndef _ZZIP_PLUGIN_H /* zzip-io.h */
  33 #define _ZZIP_PLUGIN_H 1
  34
  35 #include <zzip/zzip.h>
  36
  37 #ifdef __cplusplus
  38 extern "C" {
  39 #endif
  40
  41 /* we have renamed zzip_plugin_io.use_mmap to zzip_plugin_io.sys */
  42 #define ZZIP_PLUGIN_IO_SYS 1
  43
  44 struct zzip_plugin_io { /* use "zzip_plugin_io_handlers" in applications !! */
  45     int          (*open)(zzip_char_t* name, int flags, ...);
  46     int          (*close)(int fd);
  47     zzip_ssize_t (*read)(int fd, void* buf, zzip_size_t len);
  48     zzip_off_t   (*seeks)(int fd, zzip_off_t offset, int whence);
  49     zzip_off_t   (*filesize)(int fd);
  50     long         sys;
  51     long         type;
  52     zzip_ssize_t (*write)(int fd, _zzip_const void* buf, zzip_size_t len);
  53 };
  54
  55 typedef union _zzip_plugin_io
  56 {
  57     struct zzip_plugin_io fd;
  58     struct { void* padding[8]; } ptr;
  59 } zzip_plugin_io_handlers;
  60
  61 #define _zzip_plugin_io_handlers zzip_plugin_io_handlers
  62
  63 /* for backward compatibility, add the following to your application code:
  64  * #ifndef _zzip_plugin_io_handlers
  65  * #define _zzip_plugin_io_handlers struct zzip_plugin_io
  66  */
  67 typedef zzip_plugin_io_handlers* zzip_plugin_io_handlers_t;
  68
  69 #ifdef ZZIP_LARGEFILE_RENAME
  70 #define zzip_filesize        zzip_filesize64
  71 #define zzip_get_default_io  zzip_get_default_io64
  72 #define zzip_init_io         zzip_init_io64
  73 #endif
  74
  75 _zzip_export zzip_off_t
  76 zzip_filesize(int fd);
  77
  78 /* get the default file I/O functions.
  79  *  This functions returns a pointer to an internal static structure.
  80  */
  81 _zzip_export zzip_plugin_io_t zzip_get_default_io(void);
  82
  83 /*
  84  * Initializes a zzip_plugin_io_t to the zziplib default io.
  85  * This is useful if you only want to override e.g. the 'read' function.
  86  * all zzip functions that can receive a zzip_plugin_io_t can
  87  * handle a zero pointer in that place and default to posix io.
  88  */
  89 _zzip_export
  90 int zzip_init_io(zzip_plugin_io_handlers_t io, int flags);
  91
  92 /* zzip_init_io flags : */
  93 # define ZZIP_IO_USE_MMAP 1
  94
  95 #ifdef __cplusplus
  96 };
  97 #endif
  98
  99 #endif