f501dbec5f
increases performance when extracting a single entry from a large
uncompressed archive, especially on slow devices such as USB hard
drives.
Requires a number of changes:
* New archive_read_open2() supports a 'skip' client function
* Old archive_read_open() is implemented as a wrapper now, to
continue supporting the old API/ABI.
* _read_open_fd and _read_open_file sprout new 'skip' functions.
* compression layer gets a new 'skip' operation.
* compression_none passes skip requests through to client.
* compression_{gzip,bzip2,compress} simply ignore skip requests.
Thanks to: Benjamin Lutz, who designed and implemented the whole thing.
I'm just committing it. ;-)
TODO: Need to update the documentation a little bit.
247 lines
8.8 KiB
C
247 lines
8.8 KiB
C
/*-
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* Copyright (c) 2003-2004 Tim Kientzle
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* All rights reserved.
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*
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* Redistribution and use in source and binary forms, with or without
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* modification, are permitted provided that the following conditions
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* are met:
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* 1. Redistributions of source code must retain the above copyright
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* notice, this list of conditions and the following disclaimer
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* in this position and unchanged.
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* 2. Redistributions in binary form must reproduce the above copyright
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* notice, this list of conditions and the following disclaimer in the
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* documentation and/or other materials provided with the distribution.
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*
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* THIS SOFTWARE IS PROVIDED BY THE AUTHOR(S) ``AS IS'' AND ANY EXPRESS OR
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* IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
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* OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
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* IN NO EVENT SHALL THE AUTHOR(S) BE LIABLE FOR ANY DIRECT, INDIRECT,
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* INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
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* NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
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* DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
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* THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
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* (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
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* THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
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*
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* $FreeBSD$
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*/
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#ifndef ARCHIVE_PRIVATE_H_INCLUDED
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#define ARCHIVE_PRIVATE_H_INCLUDED
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#include "archive.h"
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#include "archive_string.h"
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#define ARCHIVE_WRITE_MAGIC (0xb0c5c0deU)
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#define ARCHIVE_READ_MAGIC (0xdeb0c5U)
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struct archive {
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/*
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* The magic/state values are used to sanity-check the
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* client's usage. If an API function is called at a
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* rediculous time, or the client passes us an invalid
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* pointer, these values allow me to catch that.
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*/
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unsigned magic;
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unsigned state;
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struct archive_entry *entry;
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uid_t user_uid; /* UID of current user. */
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/* Dev/ino of the archive being read/written. */
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dev_t skip_file_dev;
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ino_t skip_file_ino;
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/* Utility: Pointer to a block of nulls. */
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const unsigned char *nulls;
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size_t null_length;
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/*
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* Used by archive_read_data() to track blocks and copy
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* data to client buffers, filling gaps with zero bytes.
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*/
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const char *read_data_block;
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off_t read_data_offset;
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off_t read_data_output_offset;
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size_t read_data_remaining;
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/* Callbacks to open/read/write/close archive stream. */
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archive_open_callback *client_opener;
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archive_read_callback *client_reader;
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archive_skip_callback *client_skipper;
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archive_write_callback *client_writer;
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archive_close_callback *client_closer;
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void *client_data;
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/*
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* Blocking information. Note that bytes_in_last_block is
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* misleadingly named; I should find a better name. These
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* control the final output from all compressors, including
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* compression_none.
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*/
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int bytes_per_block;
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int bytes_in_last_block;
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/*
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* These control whether data within a gzip/bzip2 compressed
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* stream gets padded or not. If pad_uncompressed is set,
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* the data will be padded to a full block before being
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* compressed. The pad_uncompressed_byte determines the value
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* that will be used for padding. Note that these have no
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* effect on compression "none."
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*/
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int pad_uncompressed;
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int pad_uncompressed_byte; /* TODO: Support this. */
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/* Position in UNCOMPRESSED data stream. */
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off_t file_position;
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/* Position in COMPRESSED data stream. */
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off_t raw_position;
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/* File offset of beginning of most recently-read header. */
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off_t header_position;
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/*
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* Detection functions for decompression: bid functions are
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* given a block of data from the beginning of the stream and
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* can bid on whether or not they support the data stream.
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* General guideline: bid the number of bits that you actually
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* test, e.g., 16 if you test a 2-byte magic value. The
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* highest bidder will have their init function invoked, which
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* can set up pointers to specific handlers.
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*
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* On write, the client just invokes an archive_write_set function
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* which sets up the data here directly.
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*/
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int compression_code; /* Currently active compression. */
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const char *compression_name;
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struct {
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int (*bid)(const void *buff, size_t);
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int (*init)(struct archive *, const void *buff, size_t);
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} decompressors[4];
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/* Read/write data stream (with compression). */
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void *compression_data; /* Data for (de)compressor. */
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int (*compression_init)(struct archive *); /* Initialize. */
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int (*compression_finish)(struct archive *);
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int (*compression_write)(struct archive *, const void *, size_t);
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/*
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* Read uses a peek/consume I/O model: the decompression code
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* returns a pointer to the requested block and advances the
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* file position only when requested by a consume call. This
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* reduces copying and also simplifies look-ahead for format
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* detection.
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*/
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ssize_t (*compression_read_ahead)(struct archive *,
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const void **, size_t request);
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ssize_t (*compression_read_consume)(struct archive *, size_t);
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ssize_t (*compression_skip)(struct archive *, size_t);
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/*
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* Format detection is mostly the same as compression
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* detection, with two significant differences: The bidders
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* use the read_ahead calls above to examine the stream rather
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* than having the supervisor hand them a block of data to
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* examine, and the auction is repeated for every header.
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* Winning bidders should set the archive_format and
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* archive_format_name appropriately. Bid routines should
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* check archive_format and decline to bid if the format of
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* the last header was incompatible.
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*
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* Again, write support is considerably simpler because there's
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* no need for an auction.
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*/
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int archive_format;
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const char *archive_format_name;
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struct archive_format_descriptor {
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int (*bid)(struct archive *);
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int (*read_header)(struct archive *, struct archive_entry *);
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int (*read_data)(struct archive *, const void **, size_t *, off_t *);
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int (*read_data_skip)(struct archive *);
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int (*cleanup)(struct archive *);
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void *format_data; /* Format-specific data for readers. */
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} formats[8];
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struct archive_format_descriptor *format; /* Active format. */
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/*
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* Storage for format-specific data. Note that there can be
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* multiple format readers active at one time, so we need to
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* allow for multiple format readers to have their data
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* available. The pformat_data slot here is the solution: on
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* read, it is gauranteed to always point to a void* variable
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* that the format can use.
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*/
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void **pformat_data; /* Pointer to current format_data. */
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void *format_data; /* Used by writers. */
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/*
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* Pointers to format-specific functions for writing. They're
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* initialized by archive_write_set_format_XXX() calls.
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*/
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int (*format_init)(struct archive *); /* Only used on write. */
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int (*format_finish)(struct archive *);
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int (*format_finish_entry)(struct archive *);
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int (*format_write_header)(struct archive *,
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struct archive_entry *);
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int (*format_write_data)(struct archive *,
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const void *buff, size_t);
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/*
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* Various information needed by archive_extract.
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*/
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struct extract *extract;
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void (*extract_progress)(void *);
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void *extract_progress_user_data;
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void (*cleanup_archive_extract)(struct archive *);
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int archive_error_number;
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const char *error;
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struct archive_string error_string;
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};
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#define ARCHIVE_STATE_ANY 0xFFFFU
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#define ARCHIVE_STATE_NEW 1U
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#define ARCHIVE_STATE_HEADER 2U
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#define ARCHIVE_STATE_DATA 4U
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#define ARCHIVE_STATE_EOF 8U
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#define ARCHIVE_STATE_CLOSED 0x10U
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#define ARCHIVE_STATE_FATAL 0x8000U
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/* Check magic value and state; exit if it isn't valid. */
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void __archive_check_magic(struct archive *, unsigned magic,
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unsigned state, const char *func);
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int __archive_read_register_format(struct archive *a,
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void *format_data,
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int (*bid)(struct archive *),
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int (*read_header)(struct archive *, struct archive_entry *),
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int (*read_data)(struct archive *, const void **, size_t *, off_t *),
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int (*read_data_skip)(struct archive *),
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int (*cleanup)(struct archive *));
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int __archive_read_register_compression(struct archive *a,
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int (*bid)(const void *, size_t),
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int (*init)(struct archive *, const void *, size_t));
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void __archive_errx(int retvalue, const char *msg);
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#define err_combine(a,b) ((a) < (b) ? (a) : (b))
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/*
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* Utility function to format a USTAR header into a buffer. If
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* "strict" is set, this tries to create the absolutely most portable
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* version of a ustar header. If "strict" is set to 0, then it will
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* relax certain requirements.
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*
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* Generally, format-specific declarations don't belong in this
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* header; this is a rare example of a function that is shared by
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* two very similar formats (ustar and pax).
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*/
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int
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__archive_write_format_header_ustar(struct archive *, char buff[512],
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struct archive_entry *, int tartype, int strict);
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#endif
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