Add read-only support for .Z compressed archives.
This commit is contained in:
Tim Kientzle
parent
2e31e339d1
commit
72271236bb
471
lib/libarchive/archive_read_support_compression_compress.c
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471
lib/libarchive/archive_read_support_compression_compress.c
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@ -0,0 +1,471 @@
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/*-
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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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/*
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* This code borrows heavily from "compress" source code, which is
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* protected by the following copyright. (Clause 3 dropped by request
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* of the Regents.)
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*/
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/*-
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* Copyright (c) 1985, 1986, 1992, 1993
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* The Regents of the University of California. All rights reserved.
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*
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* This code is derived from software contributed to Berkeley by
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* Diomidis Spinellis and James A. Woods, derived from original
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* work by Spencer Thomas and Joseph Orost.
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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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* 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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* 4. Neither the name of the University nor the names of its contributors
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* may be used to endorse or promote products derived from this software
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* without specific prior written permission.
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*
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* THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
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* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
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* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
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* ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
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* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
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* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
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* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
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* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
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* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
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* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
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* SUCH DAMAGE.
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*/
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#include "archive_platform.h"
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__FBSDID("$FreeBSD$");
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#include <err.h>
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#include <errno.h>
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#include <stdlib.h>
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#include <string.h>
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#include <unistd.h>
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#include "archive.h"
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#include "archive_private.h"
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/*
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* Because LZW decompression is pretty simple, I've just implemented
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* the whole decompressor here (cribbing from "compress" source code,
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* of course), rather than relying on an external library. I have
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* made an effort to clarify and simplify the algorithm, so the
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* names and structure here don't exactly match those used by compress.
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*/
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struct private_data {
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/* Input variables. */
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const unsigned char *next_in;
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size_t avail_in;
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int bit_buffer;
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int bits_avail;
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size_t bytes_in_section;
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/* Output variables. */
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size_t uncompressed_buffer_size;
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void *uncompressed_buffer;
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unsigned char *read_next; /* Data for client. */
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unsigned char *next_out; /* Where to write new data. */
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size_t avail_out; /* Space at end of buffer. */
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/* Decompression status variables. */
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int use_reset_code;
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int end_of_stream; /* EOF status. */
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int maxcode; /* Largest code. */
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int maxcode_bits; /* Length of largest code. */
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int section_end_code; /* When to increase bits. */
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int bits; /* Current code length. */
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int oldcode; /* Previous code. */
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int finbyte; /* Last byte of prev code. */
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/* Dictionary. */
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int free_ent; /* Next dictionary entry. */
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unsigned char suffix[65536];
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uint16_t prefix[65536];
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/*
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* Scratch area for expanding dictionary entries. Note:
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* "worst" case here comes from compressing /dev/zero: the
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* last code in the dictionary will code a sequence of
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* 65536-256 zero bytes. Thus, we need stack space to expand
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* a 65280-byte dictionary entry. (Of course, 32640:1
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* compression could also be considered the "best" case. ;-)
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*/
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unsigned char *stackp;
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unsigned char stack[65300];
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};
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static int bid(const void *, size_t);
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static int finish(struct archive *);
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static int init(struct archive *, const void *, size_t);
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static ssize_t read_ahead(struct archive *, const void **, size_t);
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static ssize_t read_consume(struct archive *, size_t);
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static int getbits(struct archive *, struct private_data *, int n);
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static int next_code(struct archive *a, struct private_data *state);
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int
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archive_read_support_compression_compress(struct archive *a)
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{
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return (__archive_read_register_compression(a, bid, init));
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}
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/*
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* Test whether we can handle this data.
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*
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* This logic returns zero if any part of the signature fails. It
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* also tries to Do The Right Thing if a very short buffer prevents us
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* from verifying as much as we would like.
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*/
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static int
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bid(const void *buff, size_t len)
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{
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const unsigned char *buffer;
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int bits_checked;
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if (len < 1)
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return (0);
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buffer = buff;
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bits_checked = 0;
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if (buffer[0] != 037) /* Verify first ID byte. */
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return (0);
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bits_checked += 8;
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if (len < 2)
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return (bits_checked);
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if (buffer[1] != 0235) /* Verify second ID byte. */
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return (0);
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bits_checked += 8;
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if (len < 3)
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return (bits_checked);
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/*
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* TODO: Verify more.
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*/
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return (bits_checked);
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}
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/*
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* Setup the callbacks.
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*/
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static int
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init(struct archive *a, const void *buff, size_t n)
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{
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struct private_data *state;
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int code;
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a->compression_code = ARCHIVE_COMPRESSION_COMPRESS;
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a->compression_name = "compress (.Z)";
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a->compression_read_ahead = read_ahead;
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a->compression_read_consume = read_consume;
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a->compression_finish = finish;
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state = malloc(sizeof(*state));
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if (state == NULL) {
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archive_set_error(a, ENOMEM,
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"Can't allocate data for %s decompression",
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a->compression_name);
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return (ARCHIVE_FATAL);
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}
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memset(state, 0, sizeof(*state));
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state->uncompressed_buffer_size = 64 * 1024;
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state->uncompressed_buffer = malloc(state->uncompressed_buffer_size);
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if (state->uncompressed_buffer == NULL) {
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archive_set_error(a, ENOMEM,
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"Can't allocate %s decompression buffers",
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a->compression_name);
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goto fatal;
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}
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state->next_in = buff;
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state->avail_in = n;
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state->read_next = state->next_out = state->uncompressed_buffer;
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state->avail_out = state->uncompressed_buffer_size;
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code = getbits(a, state, 8);
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if (code != 037)
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goto fatal;
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code = getbits(a, state, 8);
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if (code != 0235)
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goto fatal;
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code = getbits(a, state, 8);
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state->maxcode_bits = code & 0x1f;
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state->maxcode = (1 << state->maxcode_bits);
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state->use_reset_code = code & 0x80;
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/* Initialize decompressor. */
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state->free_ent = 256;
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state->stackp = state->stack;
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if (state->use_reset_code)
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state->free_ent++;
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state->bits = 9;
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state->section_end_code = (1<<state->bits) - 1;
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state->oldcode = -1;
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for (code = 255; code >= 0; code--) {
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state->prefix[code] = 0;
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state->suffix[code] = code;
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}
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next_code(a, state);
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a->compression_data = state;
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return (ARCHIVE_OK);
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fatal:
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finish(a);
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return (ARCHIVE_FATAL);
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}
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/*
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* Return a block of data from the decompression buffer. Decompress more
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* as necessary.
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*/
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static ssize_t
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read_ahead(struct archive *a, const void **p, size_t min)
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{
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struct private_data *state;
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int read_avail, was_avail, ret;
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state = a->compression_data;
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was_avail = -1;
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if (!a->client_reader) {
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archive_set_error(a, ARCHIVE_ERRNO_PROGRAMMER,
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"No read callback is registered? "
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"This is probably an internal programming error.");
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return (ARCHIVE_FATAL);
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}
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read_avail = state->next_out - state->read_next;
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if (read_avail < (int)min && state->end_of_stream) {
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if (state->end_of_stream == ARCHIVE_EOF)
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return (0);
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else
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return (-1);
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}
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if (read_avail < (int)min) {
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memmove(state->uncompressed_buffer, state->read_next,
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read_avail);
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state->read_next = state->uncompressed_buffer;
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state->next_out = state->read_next + read_avail;
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state->avail_out
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= state->uncompressed_buffer_size - read_avail;
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while (read_avail < (int)state->uncompressed_buffer_size
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&& !state->end_of_stream) {
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if (state->stackp > state->stack) {
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*state->next_out++ = *--state->stackp;
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state->avail_out--;
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read_avail++;
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} else {
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ret = next_code(a, state);
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if (ret)
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state->end_of_stream = ret;
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}
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}
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}
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*p = state->read_next;
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return (read_avail);
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}
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/*
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* Mark a previously-returned block of data as read.
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*/
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static ssize_t
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read_consume(struct archive *a, size_t n)
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{
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struct private_data *state;
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state = a->compression_data;
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a->file_position += n;
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state->read_next += n;
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if (state->read_next > state->next_out)
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errx(1, "Internal error: Request to consume too many "
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"bytes from %s decompressor.\n",
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a->compression_name);
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return (n);
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}
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/*
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* Clean up the decompressor.
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*/
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static int
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finish(struct archive *a)
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{
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struct private_data *state;
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int ret;
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state = a->compression_data;
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ret = ARCHIVE_OK;
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free(state->uncompressed_buffer);
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free(state);
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a->compression_data = NULL;
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if (a->client_closer != NULL)
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(a->client_closer)(a, a->client_data);
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return (ret);
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}
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/*
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* Process the next code and fill the stack with the expansion
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* of the code. Returns TRUE if we hit the end of the data.
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*/
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static int
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next_code(struct archive *a, struct private_data *state)
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{
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int code, newcode;
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static int debug_buff[1024];
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static unsigned debug_index;
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code = newcode = getbits(a, state, state->bits);
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if (code < 0)
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return (code);
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debug_buff[debug_index++] = code;
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if (debug_index >= sizeof(debug_buff)/sizeof(debug_buff[0]))
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debug_index = 0;
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/* If it's a reset code, reset the dictionary. */
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if ((code == 256) && state->use_reset_code) {
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/*
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* The original 'compress' implementation blocked its
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* I/O in a manner that resulted in junk bytes being
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* inserted after every reset. The next section skips
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* this junk. (Yes, the number of *bytes* to skip is
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* a function of the current *bit* length.)
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*/
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int skip_bytes = state->bits -
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(state->bytes_in_section % state->bits);
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skip_bytes %= state->bits;
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state->bits_avail = 0; /* Discard rest of this byte. */
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while (skip_bytes-- > 0) {
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code = getbits(a, state, 8);
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if (code < 0)
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return (code);
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}
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/* Now, actually do the reset. */
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state->bytes_in_section = 0;
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state->bits = 9;
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state->section_end_code = (1 << state->bits) - 1;
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state->free_ent = 257;
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state->oldcode = -1;
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return (next_code(a, state));
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}
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if (code > state->free_ent)
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/* XXX invalid code? This is fatal. XXX */
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return (1);
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/* Special case for KwKwK string. */
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if (code >= state->free_ent) {
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*state->stackp++ = state->finbyte;
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code = state->oldcode;
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}
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/* Generate output characters in reverse order. */
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while (code >= 256) {
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*state->stackp++ = state->suffix[code];
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code = state->prefix[code];
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}
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*state->stackp++ = state->finbyte = code;
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/* Generate the new entry. */
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code = state->free_ent;
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if (code < state->maxcode && state->oldcode >= 0) {
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state->prefix[code] = state->oldcode;
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state->suffix[code] = state->finbyte;
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++state->free_ent;
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}
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if (state->free_ent > state->section_end_code) {
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state->bits++;
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state->bytes_in_section = 0;
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if (state->bits == state->maxcode_bits)
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state->section_end_code = state->maxcode;
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else
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state->section_end_code = (1 << state->bits) - 1;
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}
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/* Remember previous code. */
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state->oldcode = newcode;
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return (0);
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}
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/*
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* Return next 'n' bits from stream.
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*
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* -1 indicates end of available data.
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*/
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static int
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getbits(struct archive *a, struct private_data *state, int n)
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{
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int code, ret;
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static const int mask[] = {
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0x00, 0x01, 0x03, 0x07, 0x0f, 0x1f, 0x3f, 0x7f, 0xff,
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0x1ff, 0x3ff, 0x7ff, 0xfff, 0x1fff, 0x3fff, 0x7fff, 0xffff
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};
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while (state->bits_avail < n) {
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if (state->avail_in <= 0) {
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ret = (a->client_reader)(a, a->client_data,
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(const void **)&state->next_in);
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if (ret < 0)
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return (ARCHIVE_FATAL);
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if (ret == 0)
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return (ARCHIVE_EOF);
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a->raw_position += ret;
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state->avail_in = ret;
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}
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state->bit_buffer |= *state->next_in++ << state->bits_avail;
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state->avail_in--;
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state->bits_avail += 8;
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state->bytes_in_section++;
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}
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code = state->bit_buffer;
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state->bit_buffer >>= n;
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state->bits_avail -= n;
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return (code & mask[n]);
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}
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