[linux-mm-cc] [RFC] LZO de/compression support - take 3
Nitin Gupta
nitingupta910 at gmail.com
Wed May 23 04:27:35 EDT 2007
Hi,
This contains LZO1X-1 compressor and LZO1X decompressor (safe and
standard version).
This includes changes suggested by various people - Thanks to all who
reviewed previous patches for this LZO port.
Changelog vs original LZO 2.02 code:
- Chopped down huge parts of original code that were irrelevant fot this port
- Use of standard data types
- Use memcpy() instead of COPY4 macros used in orig. code
- Various macros -> static inline functions
- Code matches general kernel style
- Various other cleanups suggested in reviews
For now, tested on x86 only.
Signed-off-by: Nitin Gupta <nitingupta910 at gmail.com>
---
diff --git a/Makefile b/Makefile
index 34210af..88053ba 100644
--- a/Makefile
+++ b/Makefile
@@ -826,11 +826,18 @@ include/config/kernel.release:
include/config/auto.conf FORCE
# Listed in dependency order
PHONY += prepare archprepare prepare0 prepare1 prepare2 prepare3
+# prepare4 does module specific things prior to compilation
+prepare4:
+ifneq ($(CONFIG_LZO1X),n)
+ $(Q)ln -sf $(srctree)/lib/lzo1x/lzo1x_decompress.c \
+ $(srctree)/lib/lzo1x/lzo1x_decompress_safe.c
+endif
+
# prepare3 is used to check if we are building in a separate output directory,
# and if so do:
# 1) Check that make has not been executed in the kernel src $(srctree)
# 2) Create the include2 directory, used for the second asm symlink
-prepare3: include/config/kernel.release
+prepare3: prepare4 include/config/kernel.release
ifneq ($(KBUILD_SRC),)
@echo ' Using $(srctree) as source for kernel'
$(Q)if [ -f $(srctree)/.config -o -d $(srctree)/include/config ]; then \
diff --git a/include/linux/lzo1x.h b/include/linux/lzo1x.h
new file mode 100755
index 0000000..7c2f633
--- /dev/null
+++ b/include/linux/lzo1x.h
@@ -0,0 +1,80 @@
+/* lzo1x.h -- public interface of the LZO1X compression algorithm
+
+ This file is part of the LZO real-time data compression library.
+
+ Copyright (C) 1996-2005 Markus Franz Xaver Johannes Oberhumer
+ All Rights Reserved.
+
+ The LZO library is free software; you can redistribute it and/or
+ modify it under the terms of the GNU General Public License,
+ version 2, as published by the Free Software Foundation.
+
+ The LZO library is distributed in the hope that it will be useful,
+ but WITHOUT ANY WARRANTY; without even the implied warranty of
+ MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+ GNU General Public License for more details.
+
+ You should have received a copy of the GNU General Public License
+ along with the LZO library; see the file COPYING.
+ If not, write to the Free Software Foundation, Inc.,
+ 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
+
+ Markus F.X.J. Oberhumer
+ <markus at oberhumer.com>
+ http://www.oberhumer.com/opensource/lzo/
+
+
+ This file is modified version of lzo1x.h found in original LZO 2.02
+ code. Some additional changes have also been made to make it work
+ in kernel space.
+
+ Nitin Gupta
+ <nitingupta910 at gmail.com>
+ */
+
+#ifndef __LZO1X_H
+#define __LZO1X_H
+
+/* LZO return codes */
+#define LZO_E_OK 0
+#define LZO_E_ERROR (-1)
+#define LZO_E_OUT_OF_MEMORY (-2) /* [not used right now] */
+#define LZO_E_NOT_COMPRESSIBLE (-3) /* [not used right now] */
+#define LZO_E_INPUT_OVERRUN (-4)
+#define LZO_E_OUTPUT_OVERRUN (-5)
+#define LZO_E_LOOKBEHIND_OVERRUN (-6)
+#define LZO_E_EOF_NOT_FOUND (-7)
+#define LZO_E_INPUT_NOT_CONSUMED (-8)
+#define LZO_E_NOT_YET_IMPLEMENTED (-9) /* [not used right now] */
+
+/* Size of temp buffer (workmem) required by lzo1x_compress */
+#define LZO1X_WORKMEM_SIZE ((size_t) (16384L * sizeof(unsigned char *)))
+
+/*
+ * This required 'workmem' of size LZO1X_WORKMEM_SIZE
+ */
+int lzo1x_compress(const unsigned char *src, size_t src_len,
+ unsigned char *dst, size_t *dst_len,
+ void *workmem);
+
+
+/*
+ * This decompressor expects valid compressed data.
+ *
+ * If the compressed data gets corrupted somehow (e.g. transmission
+ * via an erroneous channel, disk errors, ...) it will probably crash
+ * your application because absolutely no additional checks are done.
+ */
+int lzo1x_decompress(const unsigned char *src, size_t src_len,
+ unsigned char *dst, size_t *dst_len);
+
+
+/*
+ * The `safe' decompressor. Somewhat slower.
+ *
+ * This decompressor will catch all compressed data violations and
+ * return an error code in this case.
+ */
+int lzo1x_decompress_safe(const unsigned char *src, size_t src_len,
+ unsigned char *dst, size_t *dst_len);
+#endif
diff --git a/lib/Kconfig b/lib/Kconfig
index 2e7ae6b..9d30b1f 100644
--- a/lib/Kconfig
+++ b/lib/Kconfig
@@ -64,6 +64,12 @@ config ZLIB_INFLATE
config ZLIB_DEFLATE
tristate
+config LZO1X
+ tristate "LZO1X Compression/Decompression"
+ help
+ Compression: LZO1X-1
+ Decompression: LZO1X
+
#
# Generic allocator support is selected if needed
#
diff --git a/lib/Makefile b/lib/Makefile
index c8c8e20..4dad99d 100644
--- a/lib/Makefile
+++ b/lib/Makefile
@@ -49,6 +49,7 @@ obj-$(CONFIG_GENERIC_ALLOCATOR) += genalloc.o
obj-$(CONFIG_ZLIB_INFLATE) += zlib_inflate/
obj-$(CONFIG_ZLIB_DEFLATE) += zlib_deflate/
obj-$(CONFIG_REED_SOLOMON) += reed_solomon/
+obj-$(CONFIG_LZO1X) += lzo1x/
obj-$(CONFIG_TEXTSEARCH) += textsearch.o
obj-$(CONFIG_TEXTSEARCH_KMP) += ts_kmp.o
diff --git a/lib/lzo1x/Makefile b/lib/lzo1x/Makefile
new file mode 100644
index 0000000..e036b42
--- /dev/null
+++ b/lib/lzo1x/Makefile
@@ -0,0 +1,11 @@
+#
+# When compiling this module out of tree, do 'make prepare_lzo'
+# before compiling as usual
+#
+obj-$(CONFIG_LZO1X) += lzo1x.o
+CFLAGS_lzo1x_decompress_safe.o += -DLZO1X_DECOMPRESS_SAFE
+lzo1x-objs := lzo1x_compress.o lzo1x_decompress.o lzo1x_decompress_safe.o
+
+prepare_lzo:
+ @ln -sf lzo1x_decompress.c lzo1x_decompress_safe.c
+
diff --git a/lib/lzo1x/lzo1x_compress.c b/lib/lzo1x/lzo1x_compress.c
new file mode 100755
index 0000000..690c082
--- /dev/null
+++ b/lib/lzo1x/lzo1x_compress.c
@@ -0,0 +1,256 @@
+/* lzo1x_compress.c -- LZO1X-1 compression
+
+ This file is part of the LZO real-time data compression library.
+
+ Copyright (C) 1996-2005 Markus Franz Xaver Johannes Oberhumer
+ All Rights Reserved.
+
+ The LZO library is free software; you can redistribute it and/or
+ modify it under the terms of the GNU General Public License,
+ version 2, as published by the Free Software Foundation.
+
+ The LZO library is distributed in the hope that it will be useful,
+ but WITHOUT ANY WARRANTY; without even the implied warranty of
+ MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+ GNU General Public License for more details.
+
+ You should have received a copy of the GNU General Public License
+ along with the LZO library; see the file COPYING.
+ If not, write to the Free Software Foundation, Inc.,
+ 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
+
+ Markus F.X.J. Oberhumer
+ <markus at oberhumer.com>
+ http://www.oberhumer.com/opensource/lzo/
+
+
+ This file is derived from lzo1x_1.c and lzo1x_c.ch found in original
+ LZO 2.02 code. Some additional changes have also been made to make
+ it work in kernel space.
+
+ Nitin Gupta
+ <nitingupta910 at gmail.com>
+ */
+
+#include <linux/kernel.h>
+#include <linux/module.h>
+#include <linux/compiler.h>
+
+#include "lzo1x_int.h"
+
+MODULE_LICENSE("GPL");
+MODULE_DESCRIPTION("LZO1X Compression");
+
+/* compress a block of data. */
+static unsigned int
+lzo1x_compress_worker(const unsigned char *in, size_t in_len,
+ unsigned char *out, size_t *out_len,
+ void *workmem)
+{
+ const unsigned char *ip;
+ unsigned char *op;
+ const unsigned char * const in_end = in + in_len;
+ const unsigned char * const ip_end = in + in_len - M2_MAX_LEN - 5;
+ const unsigned char *ii;
+ const unsigned char ** const dict = (const unsigned char **)workmem;
+
+ op = out;
+ ip = in;
+ ii = ip;
+
+ ip += 4;
+ for (;;) {
+ const unsigned char *m_pos;
+ size_t m_off;
+ size_t m_len;
+ size_t dindex;
+
+ dindex = DINDEX1(ip);
+ m_pos = dict[dindex];
+
+ if ((m_pos < in) || (m_off = (size_t)(ip - m_pos)) <= 0
+ || m_off > M4_MAX_OFFSET)
+ goto literal;
+
+ if (m_off <= M2_MAX_OFFSET || m_pos[3] == ip[3])
+ goto try_match;
+
+ dindex = DINDEX2(dindex);
+ m_pos = dict[dindex];
+
+ if ((m_pos < in) || (m_off = (size_t)(ip - m_pos)) <= 0
+ || m_off > M4_MAX_OFFSET)
+ goto literal;
+
+ if (m_off <= M2_MAX_OFFSET || m_pos[3] == ip[3])
+ goto try_match;
+
+ goto literal;
+
+try_match:
+ if (*(const unsigned short *)m_pos ==
+ *(const unsigned short *)ip) {
+ if (likely(m_pos[2] == ip[2]))
+ goto match;
+ }
+
+ /* a literal */
+literal:
+ dict[dindex] = ip;
+ ++ip;
+ if (unlikely(ip >= ip_end))
+ break;
+ continue;
+
+ /* a match */
+match:
+ dict[dindex] = ip;
+ /* store current literal run */
+ if ((size_t)(ip - ii) > 0) {
+ size_t t = (size_t)(ip - ii);
+ if (t <= 3)
+ op[-2] |= (unsigned char)(t);
+ else if (t <= 18)
+ *op++ = (unsigned char)(t - 3);
+ else {
+ size_t tt = t - 18;
+ *op++ = 0;
+ while (tt > 255) {
+ tt -= 255;
+ *op++ = 0;
+ }
+ *op++ = (unsigned char)tt;
+ }
+ do *op++ = *ii++; while (--t > 0);
+ }
+
+ /* code the match */
+ ip += 3;
+ if (m_pos[3] != *ip++ || m_pos[4] != *ip++ ||
+ m_pos[5] != *ip++ || m_pos[6] != *ip++ ||
+ m_pos[7] != *ip++ || m_pos[8] != *ip++) {
+ --ip;
+ m_len = (size_t)(ip - ii);
+
+ if (m_off <= M2_MAX_OFFSET) {
+ m_off -= 1;
+ *op++ = (unsigned char)(((m_len - 1) << 5) |
+ ((m_off & 7) << 2));
+ *op++ = (unsigned char)(m_off >> 3);
+ }
+ else if (m_off <= M3_MAX_OFFSET) {
+ m_off -= 1;
+ *op++ = (unsigned char)(M3_MARKER |
+ (m_len - 2));
+ goto m3_m4_offset;
+ } else {
+ m_off -= 0x4000;
+ *op++ = (unsigned char)(M4_MARKER |
+ ((m_off & 0x4000) >> 11) |
+ (m_len - 2));
+ goto m3_m4_offset;
+ }
+ } else {
+ const unsigned char *end = in_end;
+ const unsigned char *m = m_pos + M2_MAX_LEN + 1;
+ while (ip < end && *m == *ip)
+ m++, ip++;
+ m_len = (size_t)(ip - ii);
+
+ if (m_off <= M3_MAX_OFFSET) {
+ m_off -= 1;
+ if (m_len <= 33)
+ *op++ = (unsigned char)(M3_MARKER |
+ (m_len - 2));
+ else {
+ m_len -= 33;
+ *op++ = M3_MARKER | 0;
+ goto m3_m4_len;
+ }
+ } else {
+ m_off -= 0x4000;
+ if (m_len <= M4_MAX_LEN)
+ *op++ = (unsigned char)(M4_MARKER |
+ ((m_off & 0x4000) >> 11) |
+ (m_len - 2));
+ else {
+ m_len -= M4_MAX_LEN;
+ *op++ = (unsigned char)(M4_MARKER |
+ ((m_off & 0x4000) >> 11));
+m3_m4_len:
+ while (m_len > 255) {
+ m_len -= 255;
+ *op++ = 0;
+ }
+ *op++ = (unsigned char)(m_len);
+ }
+ }
+
+m3_m4_offset:
+ *op++ = (unsigned char)((m_off & 63) << 2);
+ *op++ = (unsigned char)(m_off >> 6);
+ }
+
+ ii = ip;
+ if (unlikely(ip >= ip_end))
+ break;
+ }
+
+ *out_len = (size_t)(op - out);
+ return (size_t)(in_end - ii);
+}
+
+
+/*
+ * This requires buffer (workmem) of size LZO1X_WORKMEM_SIZE
+ * (exported by lzo1x.h).
+ */
+int
+lzo1x_compress(const unsigned char *in, size_t in_len,
+ unsigned char *out, size_t *out_len,
+ void *workmem)
+{
+ unsigned char *op = out;
+ size_t t;
+
+ if (!workmem)
+ return -EINVAL;
+
+ if (unlikely(in_len <= M2_MAX_LEN + 5))
+ t = in_len;
+ else {
+ t = lzo1x_compress_worker(in, in_len, op, out_len, workmem);
+ op += *out_len;
+ }
+
+ if (t > 0) {
+ const unsigned char *ii = in + in_len - t;
+
+ if (op == out && t <= 238)
+ *op++ = (unsigned char)(17 + t);
+ else if (t <= 3)
+ op[-2] |= (unsigned char)(t);
+ else if (t <= 18)
+ *op++ = (unsigned char)(t - 3);
+ else {
+ size_t tt = t - 18;
+ *op++ = 0;
+ while (tt > 255) {
+ tt -= 255;
+ *op++ = 0;
+ }
+ *op++ = (unsigned char)tt;
+ }
+ memcpy(op, ii, t);
+ op += t;
+ ii += t;
+ }
+ *op++ = M4_MARKER | 1;
+ *op++ = 0;
+ *op++ = 0;
+
+ *out_len = (size_t)(op - out);
+ return 0;
+}
+
+EXPORT_SYMBOL(lzo1x_compress);
diff --git a/lib/lzo1x/lzo1x_decompress.c b/lib/lzo1x/lzo1x_decompress.c
new file mode 100755
index 0000000..09fa1ca
--- /dev/null
+++ b/lib/lzo1x/lzo1x_decompress.c
@@ -0,0 +1,224 @@
+/* lzo1x_decompress.c -- LZO1X decompression
+
+ This file is part of the LZO real-time data compression library.
+
+ Copyright (C) 1996-2005 Markus Franz Xaver Johannes Oberhumer
+ All Rights Reserved.
+
+ The LZO library is free software; you can redistribute it and/or
+ modify it under the terms of the GNU General Public License,
+ version 2, as published by the Free Software Foundation.
+
+ The LZO library is distributed in the hope that it will be useful,
+ but WITHOUT ANY WARRANTY; without even the implied warranty of
+ MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+ GNU General Public License for more details.
+
+ You should have received a copy of the GNU General Public License
+ along with the LZO library; see the file COPYING.
+ If not, write to the Free Software Foundation, Inc.,
+ 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
+
+ Markus F.X.J. Oberhumer
+ <markus at oberhumer.com>
+ http://www.oberhumer.com/opensource/lzo/
+
+
+ This file is derived from lzo1x_d1.c and lzo1x_d.ch found in original
+ LZO 2.02 code. Some additional changes have also been made to make
+ it work in kernel space.
+
+ Nitin Gupta
+ <nitingupta910 at gmail.com>
+ */
+
+#include <linux/kernel.h>
+#include <linux/module.h>
+#include <asm/byteorder.h>
+#include <linux/lzo1x.h>
+
+#include "lzo1x_int.h"
+
+MODULE_LICENSE("GPL");
+MODULE_DESCRIPTION("LZO1X Decompression");
+
+int
+lzo1x_decompress(const unsigned char *in, size_t in_len,
+ unsigned char *out, size_t *out_len)
+{
+ size_t t;
+ unsigned char *op = out;
+ const unsigned char *ip = in, *m_pos;
+ const unsigned char * const ip_end = in + in_len;
+#if defined(HAVE_ANY_OP)
+ unsigned char * const op_end = out + *out_len;
+#endif
+ *out_len = 0;
+
+ if (*ip > 17) {
+ t = *ip++ - 17;
+ if (t < 4)
+ goto match_next;
+ NEED_OP(t);
+ NEED_IP(t + 1);
+ memcpy(op, ip, t);
+ op += t;
+ ip += t;
+ goto first_literal_run;
+ }
+
+ while (TEST_IP) {
+ t = *ip++;
+ if (t >= 16)
+ goto match;
+ /* a literal run */
+ if (t == 0) {
+ NEED_IP(1);
+ while (*ip == 0) {
+ t += 255;
+ ip++;
+ NEED_IP(1);
+ }
+ t += 15 + *ip++;
+ }
+ /* copy literals */
+ NEED_OP(t + 3);
+ NEED_IP(t + 4);
+ memcpy(op, ip, t + 3);
+ op += t + 3;
+ ip += t + 3;
+
+first_literal_run:
+ t = *ip++;
+ if (t >= 16)
+ goto match;
+ m_pos = op - (1 + M2_MAX_OFFSET);
+ m_pos -= t >> 2;
+ m_pos -= *ip++ << 2;
+ TEST_LB(m_pos);
+ NEED_OP(3);
+ *op++ = *m_pos++;
+ *op++ = *m_pos++;
+ *op++ = *m_pos;
+ goto match_done;
+
+ /* handle matches */
+ do {
+match:
+ if (t >= 64) { /* a M2 match */
+ m_pos = op - 1;
+ m_pos -= (t >> 2) & 7;
+ m_pos -= *ip++ << 3;
+ t = (t >> 5) - 1;
+ TEST_LB(m_pos);
+ NEED_OP(t + 3 - 1);
+ goto copy_match;
+ } else if (t >= 32) { /* a M3 match */
+ t &= 31;
+ if (t == 0) {
+ NEED_IP(1);
+ while (*ip == 0) {
+ t += 255;
+ ip++;
+ NEED_IP(1);
+ }
+ t += 31 + *ip++;
+ }
+ m_pos = op - 1 - (cpu_to_le16(
+ *(const unsigned short *)ip) >> 2);
+ ip += 2;
+ } else if (t >= 16) { /* a M4 match */
+ m_pos = op;
+ m_pos -= (t & 8) << 11;
+ t &= 7;
+ if (t == 0) {
+ NEED_IP(1);
+ while (*ip == 0) {
+ t += 255;
+ ip++;
+ NEED_IP(1);
+ }
+ t += 7 + *ip++;
+ }
+ m_pos -= cpu_to_le16(
+ *(const unsigned short *)ip) >> 2;
+ ip += 2;
+ if (m_pos == op)
+ goto eof_found;
+ m_pos -= 0x4000;
+ } else { /* a M1 match */
+ m_pos = op - 1;
+ m_pos -= t >> 2;
+ m_pos -= *ip++ << 2;
+ TEST_LB(m_pos);
+ NEED_OP(2);
+ *op++ = *m_pos++;
+ *op++ = *m_pos;
+ goto match_done;
+ }
+
+ /* copy match */
+ TEST_LB(m_pos);
+ NEED_OP(t + 3 - 1);
+
+copy_match:
+ if (op - m_pos >= BITS_PER_LONG / BITS_PER_BYTE) {
+ memcpy(op, m_pos, t + 2);
+ op += t + 2;
+ m_pos += t + 2;
+ } else {
+ *op = *m_pos;
+ *++op = *++m_pos;
+ do
+ *++op = *++m_pos;
+ while (--t > 0);
+ op++;
+ m_pos++;
+ }
+
+match_done:
+ t = ip[-2] & 3;
+ if (t == 0)
+ break;
+
+ /* copy literals */
+match_next:
+ NEED_OP(t);
+ NEED_IP(t+1);
+ *op++ = *ip++;
+ if (t > 1) {
+ *op++ = *ip++;
+ if (t > 2)
+ *op++ = *ip++;
+ }
+ t = *ip++;
+ } while (TEST_IP);
+ }
+
+#if defined(HAVE_TEST_IP)
+ /* no EOF code was found */
+ *out_len = (size_t)(op - out);
+ return LZO_E_EOF_NOT_FOUND;
+#endif
+
+eof_found:
+ *out_len = (size_t)(op - out);
+ return (ip == ip_end ? LZO_E_OK :
+ (ip < ip_end ? LZO_E_INPUT_NOT_CONSUMED : LZO_E_INPUT_OVERRUN));
+
+#if defined(LZO1X_DECOMPRESS_SAFE)
+input_overrun:
+ *out_len = (size_t)(op - out);
+ return LZO_E_INPUT_OVERRUN;
+
+output_overrun:
+ *out_len = (size_t)(op - out);
+ return LZO_E_OUTPUT_OVERRUN;
+
+lookbehind_overrun:
+ *out_len = (size_t)(op - out);
+ return LZO_E_LOOKBEHIND_OVERRUN;
+#endif
+}
+
+EXPORT_SYMBOL(lzo1x_decompress);
diff --git a/lib/lzo1x/lzo1x_int.h b/lib/lzo1x/lzo1x_int.h
new file mode 100755
index 0000000..69e6d9b
--- /dev/null
+++ b/lib/lzo1x/lzo1x_int.h
@@ -0,0 +1,122 @@
+/* lzo1x_int.h -- to be used internally by LZO de/compression algorithms
+
+ This file is part of the LZO real-time data compression library.
+
+ Copyright (C) 1996-2005 Markus Franz Xaver Johannes Oberhumer
+ All Rights Reserved.
+
+ The LZO library is free software; you can redistribute it and/or
+ modify it under the terms of the GNU General Public License,
+ version 2, as published by the Free Software Foundation.
+
+ The LZO library is distributed in the hope that it will be useful,
+ but WITHOUT ANY WARRANTY; without even the implied warranty of
+ MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+ GNU General Public License for more details.
+
+ You should have received a copy of the GNU General Public License
+ along with the LZO library; see the file COPYING.
+ If not, write to the Free Software Foundation, Inc.,
+ 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
+
+ Markus F.X.J. Oberhumer
+ <markus at oberhumer.com>
+ http://www.oberhumer.com/opensource/lzo/
+
+
+ This file was derived from several header files found in original
+ LZO 2.02 code. Some additional changes have also been made to make
+ it work in kernel space.
+
+ Nitin Gupta
+ <nitingupta910 at gmail.com>
+ */
+
+#ifndef __LZO1X_INT_H
+#define __LZO1X_INT_H
+
+#include <linux/types.h>
+
+#define D_BITS 14
+#define D_SIZE (1u << D_BITS)
+#define D_MASK (D_SIZE - 1)
+#define D_HIGH ((D_MASK >> 1) + 1)
+
+static inline size_t DX2(const unsigned char *p, size_t s1, size_t s2)
+{
+ return (((((size_t)(p[2]) << s2) ^ p[1]) << s1) ^ p[0]);
+}
+
+static inline size_t DX3(const unsigned char *p, size_t s1, size_t
s2, size_t s3)
+{
+ return (DX2(p + 1, s2, s3) << s1) ^ p[0];
+}
+
+static inline size_t DINDEX1(const unsigned char *p)
+{
+ return ((size_t)(0x21 * DX3(p, 5, 5, 6)) >> 5) & D_MASK;
+}
+
+static inline size_t DINDEX2(size_t d)
+{
+ return (d & (D_MASK & 0x7ff)) ^ (D_HIGH | 0x1f);
+}
+
+/* LZO1X Specific constants */
+#define M1_MAX_OFFSET 0x0400
+#define M2_MAX_OFFSET 0x0800
+#define M3_MAX_OFFSET 0x4000
+#define M4_MAX_OFFSET 0xbfff
+
+#define M1_MIN_LEN 2
+#define M1_MAX_LEN 2
+#define M2_MIN_LEN 3
+#define M2_MAX_LEN 8
+#define M3_MIN_LEN 3
+#define M3_MAX_LEN 33
+#define M4_MIN_LEN 3
+#define M4_MAX_LEN 9
+
+#define M1_MARKER 0
+#define M2_MARKER 64
+#define M3_MARKER 32
+#define M4_MARKER 16
+
+/* LZO return codes */
+#define LZO_E_OK 0
+#define LZO_E_ERROR (-1)
+#define LZO_E_OUT_OF_MEMORY (-2) /* [not used right now] */
+#define LZO_E_NOT_COMPRESSIBLE (-3) /* [not used right now] */
+#define LZO_E_INPUT_OVERRUN (-4)
+#define LZO_E_OUTPUT_OVERRUN (-5)
+#define LZO_E_LOOKBEHIND_OVERRUN (-6)
+#define LZO_E_EOF_NOT_FOUND (-7)
+#define LZO_E_INPUT_NOT_CONSUMED (-8)
+#define LZO_E_NOT_YET_IMPLEMENTED (-9) /* [not used right now] */
+
+/* Macros for 'safe' decompression */
+#ifdef LZO1X_DECOMPRESS_SAFE
+
+#define lzo1x_decompress lzo1x_decompress_safe
+#define TEST_IP (ip < ip_end)
+#define NEED_IP(x) \
+ if ((size_t)(ip_end - ip) < (size_t)(x)) goto input_overrun
+#define NEED_OP(x) \
+ if ((size_t)(op_end - op) < (size_t)(x)) goto output_overrun
+#define TEST_LB(m_pos) \
+ if (m_pos < out || m_pos >= op) goto lookbehind_overrun
+#define HAVE_TEST_IP
+#define HAVE_ANY_OP
+
+#else /* !LZO1X_DECOMPRESS_SAFE */
+
+#define TEST_IP 1
+#define TEST_LB(x) ((void) 0)
+#define NEED_IP(x) ((void) 0)
+#define NEED_OP(x) ((void) 0)
+#undef HAVE_TEST_IP
+#undef HAVE_ANY_OP
+
+#endif /* LZO1X_DECOMPRESS_SAFE */
+
+#endif
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