From f8719f5ae5acdc31d3794ddfea8ac963359de41e Mon Sep 17 00:00:00 2001
From: Mark Adler <madler@alumni.caltech.edu>
Date: Tue, 11 Dec 2018 01:11:38 -0800
Subject: Speed up software CRC-32 computation by a factor of 1.5 to 3.
Use the interleaved method of Kadatch and Jenkins in order to make
use of pipelined instructions through multiple ALUs in a single
core. This also speeds up and simplifies the combination of CRCs,
and updates the functions to pre-calculate and use an operator for
CRC combination.
---
zlib.h | 22 ++++++++++------------
1 file changed, 10 insertions(+), 12 deletions(-)
(limited to 'zlib.h')
diff --git a/zlib.h b/zlib.h
index 14d87a2..d33db13 100644
--- a/zlib.h
+++ b/zlib.h
@@ -1724,7 +1724,7 @@ ZEXTERN uLong ZEXPORT adler32_combine OF((uLong adler1, uLong adler2,
negative, the result has no meaning or utility.
*/
-ZEXTERN uLong ZEXPORT crc32 OF((uLong crc, const Bytef *buf, uInt len));
+ZEXTERN uLong ZEXPORT crc32 OF((uLong crc, const Bytef *buf, uInt len));
/*
Update a running CRC-32 with the bytes buf[0..len-1] and return the
updated CRC-32. If buf is Z_NULL, this function returns the required
@@ -1758,19 +1758,17 @@ ZEXTERN uLong ZEXPORT crc32_combine OF((uLong crc1, uLong crc2, z_off_t len2));
*/
/*
-ZEXTERN void ZEXPORT crc32_combine_gen OF((z_crc_t op[32], z_off_t len2));
+ZEXTERN uLong ZEXPORT crc32_combine_gen OF((z_off_t len2));
- Generate the operator op corresponding to length len2, to be used with
- crc32_combine_op(). op must have room for 32 z_crc_t values. (32 is the
- number of bits in the CRC.)
+ Return the operator corresponding to length len2, to be used with
+ crc32_combine_op().
*/
-ZEXTERN uLong ZEXPORT crc32_combine_op OF((uLong crc1, uLong crc2,
- const z_crc_t *op));
+ZEXTERN uLong ZEXPORT crc32_combine_op OF((uLong crc1, uLong crc2, uLong op));
/*
Give the same result as crc32_combine(), using op in place of len2. op is
is generated from len2 by crc32_combine_gen(). This will be faster than
- crc32_combine() if the generated op is used many times.
+ crc32_combine() if the generated op is used more than once.
*/
@@ -1860,7 +1858,7 @@ ZEXTERN int ZEXPORT gzgetc_ OF((gzFile file)); /* backward compatibility */
ZEXTERN z_off64_t ZEXPORT gzoffset64 OF((gzFile));
ZEXTERN uLong ZEXPORT adler32_combine64 OF((uLong, uLong, z_off64_t));
ZEXTERN uLong ZEXPORT crc32_combine64 OF((uLong, uLong, z_off64_t));
- ZEXTERN void ZEXPORT crc32_combine_gen64 OF((z_crc_t *op, z_off64_t));
+ ZEXTERN uLong ZEXPORT crc32_combine_gen64 OF((z_off64_t));
#endif
#if !defined(ZLIB_INTERNAL) && defined(Z_WANT64)
@@ -1888,7 +1886,7 @@ ZEXTERN int ZEXPORT gzgetc_ OF((gzFile file)); /* backward compatibility */
ZEXTERN z_off_t ZEXPORT gzoffset64 OF((gzFile));
ZEXTERN uLong ZEXPORT adler32_combine64 OF((uLong, uLong, z_off_t));
ZEXTERN uLong ZEXPORT crc32_combine64 OF((uLong, uLong, z_off_t));
- ZEXTERN void ZEXPORT crc32_combine_gen64 OF((z_crc_t *op, z_off_t));
+ ZEXTERN uLong ZEXPORT crc32_combine_gen64 OF((z_off_t));
# endif
#else
ZEXTERN gzFile ZEXPORT gzopen OF((const char *, const char *));
@@ -1897,14 +1895,14 @@ ZEXTERN int ZEXPORT gzgetc_ OF((gzFile file)); /* backward compatibility */
ZEXTERN z_off_t ZEXPORT gzoffset OF((gzFile));
ZEXTERN uLong ZEXPORT adler32_combine OF((uLong, uLong, z_off_t));
ZEXTERN uLong ZEXPORT crc32_combine OF((uLong, uLong, z_off_t));
- ZEXTERN void ZEXPORT crc32_combine_gen OF((z_crc_t *op, z_off_t));
+ ZEXTERN uLong ZEXPORT crc32_combine_gen OF((z_off_t));
#endif
#else /* Z_SOLO */
ZEXTERN uLong ZEXPORT adler32_combine OF((uLong, uLong, z_off_t));
ZEXTERN uLong ZEXPORT crc32_combine OF((uLong, uLong, z_off_t));
- ZEXTERN void ZEXPORT crc32_combine_gen OF((z_crc_t *op, z_off_t));
+ ZEXTERN uLong ZEXPORT crc32_combine_gen OF((z_off_t));
#endif /* !Z_SOLO */
--
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