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b5265c813c
In some rare cases, for input data over 32 KB, lzo-rle could encode two different inputs to the same compressed representation, so that decompression is then ambiguous (i.e. data may be corrupted - although zram is not affected because it operates over 4 KB pages). This modifies the compressor without changing the decompressor or the bitstream format, such that: - there is no change to how data produced by the old compressor is decompressed - an old decompressor will correctly decode data from the updated compressor - performance and compression ratio are not affected - we avoid introducing a new bitstream format In testing over 12.8M real-world files totalling 903 GB, three files were affected by this bug. I also constructed 37M semi-random 64 KB files totalling 2.27 TB, and saw no affected files. Finally I tested over files constructed to contain each of the ~1024 possible bad input sequences; for all of these cases, updated lzo-rle worked correctly. There is no significant impact to performance or compression ratio. Signed-off-by: Dave Rodgman <dave.rodgman@arm.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Cc: Mark Rutland <mark.rutland@arm.com> Cc: Dave Rodgman <dave.rodgman@arm.com> Cc: Willy Tarreau <w@1wt.eu> Cc: Sergey Senozhatsky <sergey.senozhatsky.work@gmail.com> Cc: Markus F.X.J. Oberhumer <markus@oberhumer.com> Cc: Minchan Kim <minchan@kernel.org> Cc: Nitin Gupta <ngupta@vflare.org> Cc: Chao Yu <yuchao0@huawei.com> Cc: <stable@vger.kernel.org> Link: http://lkml.kernel.org/r/20200507100203.29785-1-dave.rodgman@arm.com Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
400 lines
9.4 KiB
C
400 lines
9.4 KiB
C
// SPDX-License-Identifier: GPL-2.0-only
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/*
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* LZO1X Compressor from LZO
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*
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* Copyright (C) 1996-2012 Markus F.X.J. Oberhumer <markus@oberhumer.com>
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*
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* The full LZO package can be found at:
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* http://www.oberhumer.com/opensource/lzo/
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*
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* Changed for Linux kernel use by:
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* Nitin Gupta <nitingupta910@gmail.com>
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* Richard Purdie <rpurdie@openedhand.com>
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*/
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#include <linux/module.h>
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#include <linux/kernel.h>
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#include <asm/unaligned.h>
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#include <linux/lzo.h>
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#include "lzodefs.h"
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static noinline size_t
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lzo1x_1_do_compress(const unsigned char *in, size_t in_len,
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unsigned char *out, size_t *out_len,
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size_t ti, void *wrkmem, signed char *state_offset,
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const unsigned char bitstream_version)
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{
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const unsigned char *ip;
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unsigned char *op;
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const unsigned char * const in_end = in + in_len;
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const unsigned char * const ip_end = in + in_len - 20;
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const unsigned char *ii;
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lzo_dict_t * const dict = (lzo_dict_t *) wrkmem;
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op = out;
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ip = in;
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ii = ip;
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ip += ti < 4 ? 4 - ti : 0;
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for (;;) {
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const unsigned char *m_pos = NULL;
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size_t t, m_len, m_off;
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u32 dv;
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u32 run_length = 0;
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literal:
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ip += 1 + ((ip - ii) >> 5);
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next:
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if (unlikely(ip >= ip_end))
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break;
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dv = get_unaligned_le32(ip);
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if (dv == 0 && bitstream_version) {
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const unsigned char *ir = ip + 4;
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const unsigned char *limit = ip_end
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< (ip + MAX_ZERO_RUN_LENGTH + 1)
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? ip_end : ip + MAX_ZERO_RUN_LENGTH + 1;
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#if defined(CONFIG_HAVE_EFFICIENT_UNALIGNED_ACCESS) && \
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defined(LZO_FAST_64BIT_MEMORY_ACCESS)
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u64 dv64;
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for (; (ir + 32) <= limit; ir += 32) {
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dv64 = get_unaligned((u64 *)ir);
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dv64 |= get_unaligned((u64 *)ir + 1);
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dv64 |= get_unaligned((u64 *)ir + 2);
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dv64 |= get_unaligned((u64 *)ir + 3);
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if (dv64)
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break;
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}
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for (; (ir + 8) <= limit; ir += 8) {
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dv64 = get_unaligned((u64 *)ir);
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if (dv64) {
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# if defined(__LITTLE_ENDIAN)
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ir += __builtin_ctzll(dv64) >> 3;
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# elif defined(__BIG_ENDIAN)
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ir += __builtin_clzll(dv64) >> 3;
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# else
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# error "missing endian definition"
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# endif
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break;
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}
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}
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#else
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while ((ir < (const unsigned char *)
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ALIGN((uintptr_t)ir, 4)) &&
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(ir < limit) && (*ir == 0))
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ir++;
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if (IS_ALIGNED((uintptr_t)ir, 4)) {
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for (; (ir + 4) <= limit; ir += 4) {
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dv = *((u32 *)ir);
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if (dv) {
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# if defined(__LITTLE_ENDIAN)
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ir += __builtin_ctz(dv) >> 3;
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# elif defined(__BIG_ENDIAN)
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ir += __builtin_clz(dv) >> 3;
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# else
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# error "missing endian definition"
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# endif
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break;
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}
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}
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}
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#endif
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while (likely(ir < limit) && unlikely(*ir == 0))
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ir++;
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run_length = ir - ip;
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if (run_length > MAX_ZERO_RUN_LENGTH)
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run_length = MAX_ZERO_RUN_LENGTH;
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} else {
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t = ((dv * 0x1824429d) >> (32 - D_BITS)) & D_MASK;
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m_pos = in + dict[t];
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dict[t] = (lzo_dict_t) (ip - in);
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if (unlikely(dv != get_unaligned_le32(m_pos)))
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goto literal;
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}
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ii -= ti;
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ti = 0;
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t = ip - ii;
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if (t != 0) {
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if (t <= 3) {
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op[*state_offset] |= t;
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COPY4(op, ii);
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op += t;
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} else if (t <= 16) {
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*op++ = (t - 3);
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COPY8(op, ii);
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COPY8(op + 8, ii + 8);
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op += t;
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} else {
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if (t <= 18) {
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*op++ = (t - 3);
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} else {
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size_t tt = t - 18;
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*op++ = 0;
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while (unlikely(tt > 255)) {
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tt -= 255;
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*op++ = 0;
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}
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*op++ = tt;
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}
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do {
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COPY8(op, ii);
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COPY8(op + 8, ii + 8);
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op += 16;
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ii += 16;
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t -= 16;
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} while (t >= 16);
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if (t > 0) do {
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*op++ = *ii++;
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} while (--t > 0);
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}
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}
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if (unlikely(run_length)) {
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ip += run_length;
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run_length -= MIN_ZERO_RUN_LENGTH;
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put_unaligned_le32((run_length << 21) | 0xfffc18
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| (run_length & 0x7), op);
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op += 4;
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run_length = 0;
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*state_offset = -3;
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goto finished_writing_instruction;
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}
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m_len = 4;
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{
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#if defined(CONFIG_HAVE_EFFICIENT_UNALIGNED_ACCESS) && defined(LZO_USE_CTZ64)
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u64 v;
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v = get_unaligned((const u64 *) (ip + m_len)) ^
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get_unaligned((const u64 *) (m_pos + m_len));
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if (unlikely(v == 0)) {
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do {
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m_len += 8;
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v = get_unaligned((const u64 *) (ip + m_len)) ^
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get_unaligned((const u64 *) (m_pos + m_len));
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if (unlikely(ip + m_len >= ip_end))
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goto m_len_done;
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} while (v == 0);
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}
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# if defined(__LITTLE_ENDIAN)
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m_len += (unsigned) __builtin_ctzll(v) / 8;
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# elif defined(__BIG_ENDIAN)
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m_len += (unsigned) __builtin_clzll(v) / 8;
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# else
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# error "missing endian definition"
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# endif
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#elif defined(CONFIG_HAVE_EFFICIENT_UNALIGNED_ACCESS) && defined(LZO_USE_CTZ32)
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u32 v;
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v = get_unaligned((const u32 *) (ip + m_len)) ^
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get_unaligned((const u32 *) (m_pos + m_len));
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if (unlikely(v == 0)) {
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do {
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m_len += 4;
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v = get_unaligned((const u32 *) (ip + m_len)) ^
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get_unaligned((const u32 *) (m_pos + m_len));
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if (v != 0)
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break;
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m_len += 4;
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v = get_unaligned((const u32 *) (ip + m_len)) ^
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get_unaligned((const u32 *) (m_pos + m_len));
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if (unlikely(ip + m_len >= ip_end))
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goto m_len_done;
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} while (v == 0);
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}
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# if defined(__LITTLE_ENDIAN)
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m_len += (unsigned) __builtin_ctz(v) / 8;
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# elif defined(__BIG_ENDIAN)
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m_len += (unsigned) __builtin_clz(v) / 8;
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# else
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# error "missing endian definition"
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# endif
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#else
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if (unlikely(ip[m_len] == m_pos[m_len])) {
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do {
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m_len += 1;
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if (ip[m_len] != m_pos[m_len])
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break;
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m_len += 1;
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if (ip[m_len] != m_pos[m_len])
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break;
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m_len += 1;
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if (ip[m_len] != m_pos[m_len])
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break;
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m_len += 1;
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if (ip[m_len] != m_pos[m_len])
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break;
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m_len += 1;
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if (ip[m_len] != m_pos[m_len])
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break;
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m_len += 1;
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if (ip[m_len] != m_pos[m_len])
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break;
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m_len += 1;
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if (ip[m_len] != m_pos[m_len])
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break;
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m_len += 1;
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if (unlikely(ip + m_len >= ip_end))
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goto m_len_done;
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} while (ip[m_len] == m_pos[m_len]);
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}
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#endif
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}
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m_len_done:
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m_off = ip - m_pos;
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ip += m_len;
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if (m_len <= M2_MAX_LEN && m_off <= M2_MAX_OFFSET) {
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m_off -= 1;
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*op++ = (((m_len - 1) << 5) | ((m_off & 7) << 2));
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*op++ = (m_off >> 3);
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} else if (m_off <= M3_MAX_OFFSET) {
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m_off -= 1;
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if (m_len <= M3_MAX_LEN)
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*op++ = (M3_MARKER | (m_len - 2));
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else {
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m_len -= M3_MAX_LEN;
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*op++ = M3_MARKER | 0;
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while (unlikely(m_len > 255)) {
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m_len -= 255;
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*op++ = 0;
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}
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*op++ = (m_len);
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}
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*op++ = (m_off << 2);
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*op++ = (m_off >> 6);
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} else {
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m_off -= 0x4000;
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if (m_len <= M4_MAX_LEN)
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*op++ = (M4_MARKER | ((m_off >> 11) & 8)
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| (m_len - 2));
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else {
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if (unlikely(((m_off & 0x403f) == 0x403f)
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&& (m_len >= 261)
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&& (m_len <= 264))
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&& likely(bitstream_version)) {
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// Under lzo-rle, block copies
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// for 261 <= length <= 264 and
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// (distance & 0x80f3) == 0x80f3
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// can result in ambiguous
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// output. Adjust length
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// to 260 to prevent ambiguity.
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ip -= m_len - 260;
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m_len = 260;
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}
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m_len -= M4_MAX_LEN;
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*op++ = (M4_MARKER | ((m_off >> 11) & 8));
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while (unlikely(m_len > 255)) {
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m_len -= 255;
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*op++ = 0;
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}
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*op++ = (m_len);
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}
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*op++ = (m_off << 2);
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*op++ = (m_off >> 6);
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}
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*state_offset = -2;
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finished_writing_instruction:
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ii = ip;
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goto next;
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}
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*out_len = op - out;
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return in_end - (ii - ti);
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}
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int lzogeneric1x_1_compress(const unsigned char *in, size_t in_len,
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unsigned char *out, size_t *out_len,
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void *wrkmem, const unsigned char bitstream_version)
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{
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const unsigned char *ip = in;
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unsigned char *op = out;
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unsigned char *data_start;
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size_t l = in_len;
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size_t t = 0;
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signed char state_offset = -2;
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unsigned int m4_max_offset;
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// LZO v0 will never write 17 as first byte (except for zero-length
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// input), so this is used to version the bitstream
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if (bitstream_version > 0) {
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*op++ = 17;
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*op++ = bitstream_version;
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m4_max_offset = M4_MAX_OFFSET_V1;
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} else {
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m4_max_offset = M4_MAX_OFFSET_V0;
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}
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data_start = op;
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while (l > 20) {
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size_t ll = l <= (m4_max_offset + 1) ? l : (m4_max_offset + 1);
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uintptr_t ll_end = (uintptr_t) ip + ll;
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if ((ll_end + ((t + ll) >> 5)) <= ll_end)
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break;
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BUILD_BUG_ON(D_SIZE * sizeof(lzo_dict_t) > LZO1X_1_MEM_COMPRESS);
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memset(wrkmem, 0, D_SIZE * sizeof(lzo_dict_t));
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t = lzo1x_1_do_compress(ip, ll, op, out_len, t, wrkmem,
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&state_offset, bitstream_version);
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ip += ll;
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op += *out_len;
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l -= ll;
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}
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t += l;
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if (t > 0) {
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const unsigned char *ii = in + in_len - t;
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if (op == data_start && t <= 238) {
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*op++ = (17 + t);
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} else if (t <= 3) {
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op[state_offset] |= t;
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} else if (t <= 18) {
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*op++ = (t - 3);
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} else {
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size_t tt = t - 18;
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*op++ = 0;
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while (tt > 255) {
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tt -= 255;
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*op++ = 0;
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}
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*op++ = tt;
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}
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if (t >= 16) do {
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COPY8(op, ii);
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COPY8(op + 8, ii + 8);
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op += 16;
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ii += 16;
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t -= 16;
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} while (t >= 16);
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if (t > 0) do {
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*op++ = *ii++;
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} while (--t > 0);
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}
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*op++ = M4_MARKER | 1;
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*op++ = 0;
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*op++ = 0;
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*out_len = op - out;
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return LZO_E_OK;
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}
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int lzo1x_1_compress(const unsigned char *in, size_t in_len,
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unsigned char *out, size_t *out_len,
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void *wrkmem)
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{
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return lzogeneric1x_1_compress(in, in_len, out, out_len, wrkmem, 0);
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}
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int lzorle1x_1_compress(const unsigned char *in, size_t in_len,
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unsigned char *out, size_t *out_len,
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void *wrkmem)
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{
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return lzogeneric1x_1_compress(in, in_len, out, out_len,
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wrkmem, LZO_VERSION);
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}
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EXPORT_SYMBOL_GPL(lzo1x_1_compress);
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EXPORT_SYMBOL_GPL(lzorle1x_1_compress);
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MODULE_LICENSE("GPL");
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MODULE_DESCRIPTION("LZO1X-1 Compressor");
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