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Diffstat (limited to 'libbcachefs/lz4_decompress.c')
-rw-r--r--libbcachefs/lz4_decompress.c251
1 files changed, 106 insertions, 145 deletions
diff --git a/libbcachefs/lz4_decompress.c b/libbcachefs/lz4_decompress.c
index 77c9c391..9e809f97 100644
--- a/libbcachefs/lz4_decompress.c
+++ b/libbcachefs/lz4_decompress.c
@@ -43,7 +43,110 @@
#endif
#include "lz4.h"
-#include "lz4defs.h"
+
+/*
+ * Detects 64 bits mode
+ */
+#if defined(CONFIG_64BIT)
+#define LZ4_ARCH64 1
+#else
+#define LZ4_ARCH64 0
+#endif
+
+#include <asm/unaligned.h>
+#include <linux/log2.h>
+#include <linux/string.h>
+
+#define A32(_p) get_unaligned((u32 *) (_p))
+#define A16(_p) get_unaligned((u16 *) (_p))
+
+#define GET_LE16_ADVANCE(_src) \
+({ \
+ u16 _r = get_unaligned_le16(_src); \
+ (_src) += 2; \
+ _r; \
+})
+
+#define PUT_LE16_ADVANCE(_dst, _v) \
+do { \
+ put_unaligned_le16((_v), (_dst)); \
+ (_dst) += 2; \
+} while (0)
+
+#define LENGTH_LONG 15
+#define COPYLENGTH 8
+#define ML_BITS 4
+#define ML_MASK ((1U << ML_BITS) - 1)
+#define RUN_BITS (8 - ML_BITS)
+#define RUN_MASK ((1U << RUN_BITS) - 1)
+#define MEMORY_USAGE 14
+#define MINMATCH 4
+#define SKIPSTRENGTH 6
+#define LASTLITERALS 5
+#define MFLIMIT (COPYLENGTH + MINMATCH)
+#define MINLENGTH (MFLIMIT + 1)
+#define MAXD_LOG 16
+#define MAXD (1 << MAXD_LOG)
+#define MAXD_MASK (u32)(MAXD - 1)
+#define MAX_DISTANCE (MAXD - 1)
+#define HASH_LOG (MAXD_LOG - 1)
+#define HASHTABLESIZE (1 << HASH_LOG)
+#define MAX_NB_ATTEMPTS 256
+#define OPTIMAL_ML (int)((ML_MASK-1)+MINMATCH)
+#define LZ4_64KLIMIT ((1<<16) + (MFLIMIT - 1))
+
+#define __HASH_VALUE(p, bits) \
+ (((A32(p)) * 2654435761U) >> (32 - (bits)))
+
+#define HASH_VALUE(p) __HASH_VALUE(p, HASH_LOG)
+
+#define MEMCPY_ADVANCE(_dst, _src, length) \
+do { \
+ typeof(length) _length = (length); \
+ memcpy(_dst, _src, _length); \
+ _src += _length; \
+ _dst += _length; \
+} while (0)
+
+#define MEMCPY_ADVANCE_BYTES(_dst, _src, _length) \
+do { \
+ const u8 *_end = (_src) + (_length); \
+ while ((_src) < _end) \
+ *_dst++ = *_src++; \
+} while (0)
+
+#define STEPSIZE __SIZEOF_LONG__
+
+#define LZ4_COPYPACKET(_src, _dst) \
+do { \
+ MEMCPY_ADVANCE(_dst, _src, STEPSIZE); \
+ MEMCPY_ADVANCE(_dst, _src, COPYLENGTH - STEPSIZE);\
+} while (0)
+
+/*
+ * Equivalent to MEMCPY_ADVANCE - except may overrun @_dst and @_src by
+ * COPYLENGTH:
+ *
+ * Note: src and dst may overlap (with src < dst) - we must do the copy in
+ * STEPSIZE chunks for correctness
+ *
+ * Note also: length may be negative - we must not call memcpy if length is
+ * negative, but still adjust dst and src by length
+ */
+#define MEMCPY_ADVANCE_CHUNKED(_dst, _src, _length) \
+do { \
+ u8 *_end = (_dst) + (_length); \
+ while ((_dst) < _end) \
+ LZ4_COPYPACKET(_src, _dst); \
+ _src -= (_dst) - _end; \
+ _dst = _end; \
+} while (0)
+
+#define MEMCPY_ADVANCE_CHUNKED_NOFIXUP(_dst, _src, _end)\
+do { \
+ while ((_dst) < (_end)) \
+ LZ4_COPYPACKET((_src), (_dst)); \
+} while (0)
static const int dec32table[8] = {0, 3, 2, 3, 0, 0, 0, 0};
#if LZ4_ARCH64
@@ -157,124 +260,8 @@ _output_error:
return -1;
}
-static inline ssize_t get_length_safe(const u8 **ip, ssize_t length)
-{
- if (length == 15) {
- size_t len;
-
- do {
- length += (len = *(*ip)++);
- if (unlikely((ssize_t) length < 0))
- return -1;
-
- length += len;
- } while (len == 255);
- }
-
- return length;
-}
-
-static int lz4_uncompress_unknownoutputsize(const u8 *source, u8 *dest,
- int isize, size_t maxoutputsize)
-{
- const u8 *ip = source;
- const u8 *const iend = ip + isize;
- const u8 *ref;
- u8 *op = dest;
- u8 * const oend = op + maxoutputsize;
- u8 *cpy;
- unsigned token, offset;
- size_t length;
-
- /* Main Loop */
- while (ip < iend) {
- /* get runlength */
- token = *ip++;
- length = get_length_safe(&ip, token >> ML_BITS);
- if (unlikely((ssize_t) length < 0))
- goto _output_error;
-
- /* copy literals */
- if ((op + length > oend - COPYLENGTH) ||
- (ip + length > iend - COPYLENGTH)) {
-
- if (op + length > oend)
- goto _output_error;/* writes beyond buffer */
-
- if (ip + length != iend)
- goto _output_error;/*
- * Error: LZ4 format requires
- * to consume all input
- * at this stage
- */
- MEMCPY_ADVANCE(op, ip, length);
- break;/* Necessarily EOF, due to parsing restrictions */
- }
- MEMCPY_ADVANCE_CHUNKED(op, ip, length);
-
- /* get match offset */
- offset = GET_LE16_ADVANCE(ip);
- ref = op - offset;
-
- /* Error: offset create reference outside destination buffer */
- if (ref < (u8 * const) dest)
- goto _output_error;
-
- /* get match length */
- length = get_length_safe(&ip, token & ML_MASK);
- if (unlikely((ssize_t) length < 0))
- goto _output_error;
-
- length += MINMATCH;
-
- /* copy first STEPSIZE bytes of match: */
- if (unlikely(offset < STEPSIZE)) {
- MEMCPY_ADVANCE_BYTES(op, ref, 4);
- ref -= dec32table[offset];
-
- memcpy(op, ref, 4);
- op += STEPSIZE - 4;
- ref -= dec64table[offset];
- } else {
- MEMCPY_ADVANCE(op, ref, STEPSIZE);
- }
- length -= STEPSIZE;
-
- /* copy rest of match: */
- cpy = op + length;
- if (cpy > oend - COPYLENGTH) {
- /* Error: request to write beyond destination buffer */
- if (cpy > oend ||
- ref + COPYLENGTH > oend)
- goto _output_error;
-#if !LZ4_ARCH64
- if (op + COPYLENGTH > oend)
- goto _output_error;
-#endif
- MEMCPY_ADVANCE_CHUNKED_NOFIXUP(op, ref, oend - COPYLENGTH);
- while (op < cpy)
- *op++ = *ref++;
- op = cpy;
- /*
- * Check EOF (should never happen, since last 5 bytes
- * are supposed to be literals)
- */
- if (op == oend)
- goto _output_error;
- } else {
- MEMCPY_ADVANCE_CHUNKED(op, ref, length);
- }
- }
- /* end of decoding */
- return op - dest;
-
- /* write overflow error detected */
-_output_error:
- return -1;
-}
-
-int lz4_decompress(const unsigned char *src, size_t *src_len,
- unsigned char *dest, size_t actual_dest_len)
+int bch2_lz4_decompress(const unsigned char *src, size_t *src_len,
+ unsigned char *dest, size_t actual_dest_len)
{
int ret = -1;
int input_len = 0;
@@ -288,29 +275,3 @@ int lz4_decompress(const unsigned char *src, size_t *src_len,
exit_0:
return ret;
}
-#ifndef STATIC
-EXPORT_SYMBOL(lz4_decompress);
-#endif
-
-int lz4_decompress_unknownoutputsize(const unsigned char *src, size_t src_len,
- unsigned char *dest, size_t *dest_len)
-{
- int ret = -1;
- int out_len = 0;
-
- out_len = lz4_uncompress_unknownoutputsize(src, dest, src_len,
- *dest_len);
- if (out_len < 0)
- goto exit_0;
- *dest_len = out_len;
-
- return 0;
-exit_0:
- return ret;
-}
-#ifndef STATIC
-EXPORT_SYMBOL(lz4_decompress_unknownoutputsize);
-
-MODULE_LICENSE("Dual BSD/GPL");
-MODULE_DESCRIPTION("LZ4 Decompressor");
-#endif
generated by cgit v1.2.3 (git 2.46.0) at 2025-08-02 04:24:10 +0000