contrib/libarchive-2.0/libarchive/archive_read_private.h

   1 /*-
   2  * Copyright (c) 2003-2007 Tim Kientzle
   3  * All rights reserved.
   4  *
   5  * Redistribution and use in source and binary forms, with or without
   6  * modification, are permitted provided that the following conditions
   7  * are met:
   8  * 1. Redistributions of source code must retain the above copyright
   9  *    notice, this list of conditions and the following disclaimer.
  10  * 2. Redistributions in binary form must reproduce the above copyright
  11  *    notice, this list of conditions and the following disclaimer in the
  12  *    documentation and/or other materials provided with the distribution.
  13  *
  14  * THIS SOFTWARE IS PROVIDED BY THE AUTHOR(S) ``AS IS'' AND ANY EXPRESS OR
  15  * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
  16  * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
  17  * IN NO EVENT SHALL THE AUTHOR(S) BE LIABLE FOR ANY DIRECT, INDIRECT,
  18  * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
  19  * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
  20  * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
  21  * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
  22  * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
  23  * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
  24  *
  25  * $FreeBSD: src/lib/libarchive/archive_read_private.h,v 1.2 2007/04/02 00:11:54 kientzle Exp $
  26  */
  27
  28 #ifndef ARCHIVE_READ_PRIVATE_H_INCLUDED
  29 #define ARCHIVE_READ_PRIVATE_H_INCLUDED
  30
  31 #include "archive.h"
  32 #include "archive_string.h"
  33 #include "archive_private.h"
  34
  35 struct archive_read {
  36         struct archive  archive;
  37
  38         struct archive_entry    *entry;
  39
  40         /* Dev/ino of the archive being read/written. */
  41         dev_t             skip_file_dev;
  42         ino_t             skip_file_ino;
  43
  44         /* Utility:  Pointer to a block of nulls. */
  45         const unsigned char     *nulls;
  46         size_t                   null_length;
  47
  48         /*
  49          * Used by archive_read_data() to track blocks and copy
  50          * data to client buffers, filling gaps with zero bytes.
  51          */
  52         const char       *read_data_block;
  53         off_t             read_data_offset;
  54         off_t             read_data_output_offset;
  55         size_t            read_data_remaining;
  56
  57         /* Callbacks to open/read/write/close archive stream. */
  58         archive_open_callback   *client_opener;
  59         archive_read_callback   *client_reader;
  60         archive_skip_callback   *client_skipper;
  61         archive_write_callback  *client_writer;
  62         archive_close_callback  *client_closer;
  63         void                    *client_data;
  64
  65         /*
  66          * Blocking information.  Note that bytes_in_last_block is
  67          * misleadingly named; I should find a better name.  These
  68          * control the final output from all compressors, including
  69          * compression_none.
  70          */
  71         int               bytes_per_block;
  72         int               bytes_in_last_block;
  73
  74         /*
  75          * These control whether data within a gzip/bzip2 compressed
  76          * stream gets padded or not.  If pad_uncompressed is set,
  77          * the data will be padded to a full block before being
  78          * compressed.  The pad_uncompressed_byte determines the value
  79          * that will be used for padding.  Note that these have no
  80          * effect on compression "none."
  81          */
  82         int               pad_uncompressed;
  83         int               pad_uncompressed_byte; /* TODO: Support this. */
  84
  85         /* File offset of beginning of most recently-read header. */
  86         off_t             header_position;
  87
  88         /*
  89          * Detection functions for decompression: bid functions are
  90          * given a block of data from the beginning of the stream and
  91          * can bid on whether or not they support the data stream.
  92          * General guideline: bid the number of bits that you actually
  93          * test, e.g., 16 if you test a 2-byte magic value.  The
  94          * highest bidder will have their init function invoked, which
  95          * can set up pointers to specific handlers.
  96          */
  97         struct {
  98                 int     (*bid)(const void *buff, size_t);
  99                 int     (*init)(struct archive_read *, const void *buff, size_t);
 100         }       decompressors[4];
 101         /* Read/write data stream (with compression). */
 102         void     *compression_data;             /* Data for (de)compressor. */
 103         int     (*compression_finish)(struct archive_read *);
 104
 105         /*
 106          * Read uses a peek/consume I/O model: the decompression code
 107          * returns a pointer to the requested block and advances the
 108          * file position only when requested by a consume call.  This
 109          * reduces copying and also simplifies look-ahead for format
 110          * detection.
 111          */
 112         ssize_t (*compression_read_ahead)(struct archive_read *,
 113                     const void **, size_t request);
 114         ssize_t (*compression_read_consume)(struct archive_read *, size_t);
 115         off_t (*compression_skip)(struct archive_read *, off_t);
 116
 117         /*
 118          * Format detection is mostly the same as compression
 119          * detection, with two significant differences: The bidders
 120          * use the read_ahead calls above to examine the stream rather
 121          * than having the supervisor hand them a block of data to
 122          * examine, and the auction is repeated for every header.
 123          * Winning bidders should set the archive_format and
 124          * archive_format_name appropriately.  Bid routines should
 125          * check archive_format and decline to bid if the format of
 126          * the last header was incompatible.
 127          *
 128          * Again, write support is considerably simpler because there's
 129          * no need for an auction.
 130          */
 131
 132         struct archive_format_descriptor {
 133                 int     (*bid)(struct archive_read *);
 134                 int     (*read_header)(struct archive_read *, struct archive_entry *);
 135                 int     (*read_data)(struct archive_read *, const void **, size_t *, off_t *);
 136                 int     (*read_data_skip)(struct archive_read *);
 137                 int     (*cleanup)(struct archive_read *);
 138                 void     *format_data;  /* Format-specific data for readers. */
 139         }       formats[8];
 140         struct archive_format_descriptor        *format; /* Active format. */
 141
 142         /*
 143          * Storage for format-specific data.  Note that there can be
 144          * multiple format readers active at one time, so we need to
 145          * allow for multiple format readers to have their data
 146          * available.  The pformat_data slot here is the solution: on
 147          * read, it is guaranteed to always point to a void* variable
 148          * that the format can use.
 149          */
 150         void    **pformat_data;         /* Pointer to current format_data. */
 151         void     *format_data;          /* Used by writers. */
 152
 153         /*
 154          * Pointers to format-specific functions for writing.  They're
 155          * initialized by archive_write_set_format_XXX() calls.
 156          */
 157         int     (*format_init)(struct archive *); /* Only used on write. */
 158         int     (*format_finish)(struct archive *);
 159         int     (*format_finish_entry)(struct archive *);
 160         int     (*format_write_header)(struct archive *,
 161                     struct archive_entry *);
 162         ssize_t (*format_write_data)(struct archive *,
 163                     const void *buff, size_t);
 164
 165         /*
 166          * Various information needed by archive_extract.
 167          */
 168         struct extract           *extract;
 169         int                     (*cleanup_archive_extract)(struct archive_read *);
 170 };
 171
 172 int     __archive_read_register_format(struct archive_read *a,
 173             void *format_data,
 174             int (*bid)(struct archive_read *),
 175             int (*read_header)(struct archive_read *, struct archive_entry *),
 176             int (*read_data)(struct archive_read *, const void **, size_t *, off_t *),
 177             int (*read_data_skip)(struct archive_read *),
 178             int (*cleanup)(struct archive_read *));
 179
 180 int     __archive_read_register_compression(struct archive_read *a,
 181             int (*bid)(const void *, size_t),
 182             int (*init)(struct archive_read *, const void *, size_t));
 183
 184 #endif