2
* Copyright (c) 2008 Joerg Sonnenberger
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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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* 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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* 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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* Copyright (c) 1985, 1986, 1992, 1993
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* The Regents of the University of California. All rights reserved.
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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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* 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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* 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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* 3. 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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* 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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#include "archive_platform.h"
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__FBSDID("$FreeBSD: head/lib/libarchive/archive_write_set_compression_compress.c 201111 2009-12-28 03:33:05Z kientzle $");
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#include "archive_private.h"
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#include "archive_write_private.h"
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#define HSIZE 69001 /* 95% occupancy */
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#define HSHIFT 8 /* 8 - trunc(log2(HSIZE / 65536)) */
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#define CHECK_GAP 10000 /* Ratio check interval. */
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#define MAXCODE(bits) ((1 << (bits)) - 1)
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* the next two codes should not be changed lightly, as they must not
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* lie within the contiguous general code space.
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#define FIRST 257 /* First free entry. */
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#define CLEAR 256 /* Table clear output code. */
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off_t in_count, out_count, checkpoint;
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int code_len; /* Number of bits/code. */
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int cur_maxcode; /* Maximum code, given n_bits. */
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int max_maxcode; /* Should NEVER generate this code. */
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unsigned short codetab [HSIZE];
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int first_free; /* First unused entry. */
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int cur_code, cur_fcode;
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unsigned char bit_buf;
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unsigned char *compressed;
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size_t compressed_buffer_size;
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size_t compressed_offset;
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static int archive_compressor_compress_finish(struct archive_write *);
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static int archive_compressor_compress_init(struct archive_write *);
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static int archive_compressor_compress_write(struct archive_write *,
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const void *, size_t);
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* Allocate, initialize and return a archive object.
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archive_write_set_compression_compress(struct archive *_a)
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struct archive_write *a = (struct archive_write *)_a;
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__archive_check_magic(&a->archive, ARCHIVE_WRITE_MAGIC,
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ARCHIVE_STATE_NEW, "archive_write_set_compression_compress");
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a->compressor.init = &archive_compressor_compress_init;
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a->archive.compression_code = ARCHIVE_COMPRESSION_COMPRESS;
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a->archive.compression_name = "compress";
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archive_compressor_compress_init(struct archive_write *a)
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struct private_data *state;
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a->archive.compression_code = ARCHIVE_COMPRESSION_COMPRESS;
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a->archive.compression_name = "compress";
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if (a->bytes_per_block < 4) {
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archive_set_error(&a->archive, EINVAL,
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"Can't write Compress header as single block");
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return (ARCHIVE_FATAL);
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if (a->client_opener != NULL) {
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ret = (a->client_opener)(&a->archive, a->client_data);
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if (ret != ARCHIVE_OK)
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state = (struct private_data *)malloc(sizeof(*state));
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archive_set_error(&a->archive, ENOMEM,
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"Can't allocate data for compression");
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return (ARCHIVE_FATAL);
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memset(state, 0, sizeof(*state));
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state->compressed_buffer_size = a->bytes_per_block;
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state->compressed = malloc(state->compressed_buffer_size);
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if (state->compressed == NULL) {
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archive_set_error(&a->archive, ENOMEM,
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"Can't allocate data for compression buffer");
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return (ARCHIVE_FATAL);
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a->compressor.write = archive_compressor_compress_write;
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a->compressor.finish = archive_compressor_compress_finish;
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state->max_maxcode = 0x10000; /* Should NEVER generate this code. */
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state->in_count = 0; /* Length of input. */
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state->bit_offset = 0;
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state->out_count = 3; /* Includes 3-byte header mojo. */
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state->compress_ratio = 0;
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state->checkpoint = CHECK_GAP;
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state->cur_maxcode = MAXCODE(state->code_len);
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state->first_free = FIRST;
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memset(state->hashtab, 0xff, sizeof(state->hashtab));
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/* Prime output buffer with a gzip header. */
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state->compressed[0] = 0x1f; /* Compress */
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state->compressed[1] = 0x9d;
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state->compressed[2] = 0x90; /* Block mode, 16bit max */
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state->compressed_offset = 3;
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a->compressor.data = state;
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* Output the given code.
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* code: A n_bits-bit integer. If == -1, then EOF. This assumes
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* that n_bits =< (long)wordsize - 1.
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* Outputs code to the file.
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* Chars are 8 bits long.
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* Maintain a BITS character long buffer (so that 8 codes will
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* fit in it exactly). Use the VAX insv instruction to insert each
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* code in turn. When the buffer fills up empty it and start over.
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static unsigned char rmask[9] =
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{0x00, 0x01, 0x03, 0x07, 0x0f, 0x1f, 0x3f, 0x7f, 0xff};
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output_byte(struct archive_write *a, unsigned char c)
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struct private_data *state = a->compressor.data;
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ssize_t bytes_written;
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state->compressed[state->compressed_offset++] = c;
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if (state->compressed_buffer_size == state->compressed_offset) {
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bytes_written = (a->client_writer)(&a->archive,
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state->compressed, state->compressed_buffer_size);
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if (bytes_written <= 0)
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return ARCHIVE_FATAL;
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a->archive.raw_position += bytes_written;
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state->compressed_offset = 0;
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output_code(struct archive_write *a, int ocode)
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struct private_data *state = a->compressor.data;
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int bits, ret, clear_flg, bit_offset;
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clear_flg = ocode == CLEAR;
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* Since ocode is always >= 8 bits, only need to mask the first
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bit_offset = state->bit_offset % 8;
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state->bit_buf |= (ocode << bit_offset) & 0xff;
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output_byte(a, state->bit_buf);
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bits = state->code_len - (8 - bit_offset);
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ocode >>= 8 - bit_offset;
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/* Get any 8 bit parts in the middle (<=1 for up to 16 bits). */
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output_byte(a, ocode & 0xff);
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state->bit_offset += state->code_len;
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state->bit_buf = ocode & rmask[bits];
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if (state->bit_offset == state->code_len * 8)
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state->bit_offset = 0;
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* If the next entry is going to be too big for the ocode size,
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* then increase it, if possible.
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if (clear_flg || state->first_free > state->cur_maxcode) {
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* Write the whole buffer, because the input side won't
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* discover the size increase until after it has read it.
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if (state->bit_offset > 0) {
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while (state->bit_offset < state->code_len * 8) {
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ret = output_byte(a, state->bit_buf);
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if (ret != ARCHIVE_OK)
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state->bit_offset += 8;
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state->bit_offset = 0;
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state->cur_maxcode = MAXCODE(state->code_len);
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if (state->code_len == 16)
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state->cur_maxcode = state->max_maxcode;
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state->cur_maxcode = MAXCODE(state->code_len);
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output_flush(struct archive_write *a)
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struct private_data *state = a->compressor.data;
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/* At EOF, write the rest of the buffer. */
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if (state->bit_offset % 8) {
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state->code_len = (state->bit_offset % 8 + 7) / 8;
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ret = output_byte(a, state->bit_buf);
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if (ret != ARCHIVE_OK)
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* Write data to the compressed stream.
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archive_compressor_compress_write(struct archive_write *a, const void *buff,
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struct private_data *state;
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const unsigned char *bp;
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state = (struct private_data *)a->compressor.data;
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if (a->client_writer == NULL) {
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archive_set_error(&a->archive, ARCHIVE_ERRNO_PROGRAMMER,
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"No write 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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if (state->in_count == 0) {
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state->cur_code = *bp++;
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state->cur_fcode = (c << 16) + state->cur_code;
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i = ((c << HSHIFT) ^ state->cur_code); /* Xor hashing. */
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if (state->hashtab[i] == state->cur_fcode) {
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state->cur_code = state->codetab[i];
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if (state->hashtab[i] < 0) /* Empty slot. */
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/* Secondary hash (after G. Knott). */
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if (state->hashtab[i] == state->cur_fcode) {
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state->cur_code = state->codetab[i];
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if (state->hashtab[i] >= 0)
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ret = output_code(a, state->cur_code);
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if (ret != ARCHIVE_OK)
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if (state->first_free < state->max_maxcode) {
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state->codetab[i] = state->first_free++; /* code -> hashtable */
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state->hashtab[i] = state->cur_fcode;
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if (state->in_count < state->checkpoint)
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state->checkpoint = state->in_count + CHECK_GAP;
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if (state->in_count <= 0x007fffff)
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ratio = state->in_count * 256 / state->out_count;
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else if ((ratio = state->out_count / 256) == 0)
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ratio = state->in_count / ratio;
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if (ratio > state->compress_ratio)
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state->compress_ratio = ratio;
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state->compress_ratio = 0;
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memset(state->hashtab, 0xff, sizeof(state->hashtab));
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state->first_free = FIRST;
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ret = output_code(a, CLEAR);
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if (ret != ARCHIVE_OK)
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* Finish the compression...
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archive_compressor_compress_finish(struct archive_write *a)
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ssize_t block_length, target_block_length, bytes_written;
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struct private_data *state;
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state = (struct private_data *)a->compressor.data;
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if (a->client_writer == NULL) {
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archive_set_error(&a->archive, ARCHIVE_ERRNO_PROGRAMMER,
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"No write callback is registered? "
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"This is probably an internal programming error.");
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/* By default, always pad the uncompressed data. */
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if (a->pad_uncompressed) {
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while (state->in_count % a->bytes_per_block != 0) {
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tocopy = a->bytes_per_block -
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(state->in_count % a->bytes_per_block);
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if (tocopy > a->null_length)
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tocopy = a->null_length;
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ret = archive_compressor_compress_write(a, a->nulls,
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if (ret != ARCHIVE_OK)
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ret = output_code(a, state->cur_code);
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if (ret != ARCHIVE_OK)
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ret = output_flush(a);
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if (ret != ARCHIVE_OK)
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/* Optionally, pad the final compressed block. */
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block_length = state->compressed_offset;
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/* Tricky calculation to determine size of last block. */
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if (a->bytes_in_last_block <= 0)
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/* Default or Zero: pad to full block */
466
target_block_length = a->bytes_per_block;
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/* Round length to next multiple of bytes_in_last_block. */
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target_block_length = a->bytes_in_last_block *
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( (block_length + a->bytes_in_last_block - 1) /
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a->bytes_in_last_block);
472
if (target_block_length > a->bytes_per_block)
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target_block_length = a->bytes_per_block;
474
if (block_length < target_block_length) {
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memset(state->compressed + state->compressed_offset, 0,
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target_block_length - block_length);
477
block_length = target_block_length;
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/* Write the last block */
481
bytes_written = (a->client_writer)(&a->archive, a->client_data,
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state->compressed, block_length);
483
if (bytes_written <= 0)
486
a->archive.raw_position += bytes_written;
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free(state->compressed);
added
removed
libarchive/archive_write_set_compression_compress.c
