Add xxh32 library which could be used by following xattr bloom filter feature.
Signed-off-by: Jingbo Xu <[email protected]> --- include/erofs/xxhash.h | 35 +++++++++++++++++ lib/Makefile.am | 3 +- lib/xxhash.c | 85 ++++++++++++++++++++++++++++++++++++++++++ 3 files changed, 122 insertions(+), 1 deletion(-) create mode 100644 include/erofs/xxhash.h create mode 100644 lib/xxhash.c diff --git a/include/erofs/xxhash.h b/include/erofs/xxhash.h new file mode 100644 index 0000000..fd9384e --- /dev/null +++ b/include/erofs/xxhash.h @@ -0,0 +1,35 @@ +/* SPDX-License-Identifier: GPL-2.0 */ +#ifndef __EROFS_XXHASH_H +#define __EROFS_XXHASH_H + +#ifdef __cplusplus +extern "C" +{ +#endif + +#include "defs.h" + +/* + * Copied from + * https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git + * xxHash - Extremely Fast Hash algorithm + */ + +/** + * xxh32() - calculate the 32-bit hash of the input with a given seed. + * + * @input: The data to hash. + * @length: The length of the data to hash. + * @seed: The seed can be used to alter the result predictably. + * + * Speed on Core 2 Duo @ 3 GHz (single thread, SMHasher benchmark) : 5.4 GB/s + * + * Return: The 32-bit hash of the data. + */ +uint32_t xxh32(const void *input, size_t length, uint32_t seed); + +#ifdef __cplusplus +} +#endif + +#endif diff --git a/lib/Makefile.am b/lib/Makefile.am index faa7311..a049af6 100644 --- a/lib/Makefile.am +++ b/lib/Makefile.am @@ -23,13 +23,14 @@ noinst_HEADERS = $(top_srcdir)/include/erofs_fs.h \ $(top_srcdir)/include/erofs/xattr.h \ $(top_srcdir)/include/erofs/compress_hints.h \ $(top_srcdir)/include/erofs/fragments.h \ + $(top_srcdir)/include/erofs/xxhash.h \ $(top_srcdir)/lib/liberofs_private.h noinst_HEADERS += compressor.h liberofs_la_SOURCES = config.c io.c cache.c super.c inode.c xattr.c exclude.c \ namei.c data.c compress.c compressor.c zmap.c decompress.c \ compress_hints.c hashmap.c sha256.c blobchunk.c dir.c \ - fragments.c rb_tree.c dedupe.c + fragments.c rb_tree.c dedupe.c xxhash.c liberofs_la_CFLAGS = -Wall -I$(top_srcdir)/include if ENABLE_LZ4 diff --git a/lib/xxhash.c b/lib/xxhash.c new file mode 100644 index 0000000..e5f511c --- /dev/null +++ b/lib/xxhash.c @@ -0,0 +1,85 @@ +// SPDX-License-Identifier: GPL-2.0 +/* + * Copied from + * https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git + * xxHash - Extremely Fast Hash algorithm + */ +#include "erofs/xxhash.h" + +/*-************************************* + * Macros + **************************************/ +#define xxh_rotl32(x, r) ((x << r) | (x >> (32 - r))) + +/*-************************************* + * Constants + **************************************/ +static const uint32_t PRIME32_1 = 2654435761U; +static const uint32_t PRIME32_2 = 2246822519U; +static const uint32_t PRIME32_3 = 3266489917U; +static const uint32_t PRIME32_4 = 668265263U; +static const uint32_t PRIME32_5 = 374761393U; + +/*-*************************** + * Simple Hash Functions + ****************************/ +static uint32_t xxh32_round(uint32_t seed, const uint32_t input) +{ + seed += input * PRIME32_2; + seed = xxh_rotl32(seed, 13); + seed *= PRIME32_1; + return seed; +} + +uint32_t xxh32(const void *input, const size_t len, const uint32_t seed) +{ + const uint8_t *p = (const uint8_t *)input; + const uint8_t *b_end = p + len; + uint32_t h32; + + if (len >= 16) { + const uint8_t *const limit = b_end - 16; + uint32_t v1 = seed + PRIME32_1 + PRIME32_2; + uint32_t v2 = seed + PRIME32_2; + uint32_t v3 = seed + 0; + uint32_t v4 = seed - PRIME32_1; + + do { + v1 = xxh32_round(v1, get_unaligned_le32(p)); + p += 4; + v2 = xxh32_round(v2, get_unaligned_le32(p)); + p += 4; + v3 = xxh32_round(v3, get_unaligned_le32(p)); + p += 4; + v4 = xxh32_round(v4, get_unaligned_le32(p)); + p += 4; + } while (p <= limit); + + h32 = xxh_rotl32(v1, 1) + xxh_rotl32(v2, 7) + + xxh_rotl32(v3, 12) + xxh_rotl32(v4, 18); + } else { + h32 = seed + PRIME32_5; + } + + h32 += (uint32_t)len; + + while (p + 4 <= b_end) { + h32 += get_unaligned_le32(p) * PRIME32_3; + h32 = xxh_rotl32(h32, 17) * PRIME32_4; + p += 4; + } + + while (p < b_end) { + h32 += (*p) * PRIME32_5; + h32 = xxh_rotl32(h32, 11) * PRIME32_1; + p++; + } + + h32 ^= h32 >> 15; + h32 *= PRIME32_2; + h32 ^= h32 >> 13; + h32 *= PRIME32_3; + h32 ^= h32 >> 16; + + return h32; +} -- 2.19.1.6.gb485710b
