From 317c0644ccf108aa23ef3fd8358bd66c2840bfc0 Mon Sep 17 00:00:00 2001 From: Daniel Baumann Date: Sun, 14 Apr 2024 15:40:54 +0200 Subject: Adding upstream version 5:7.2.4. Signed-off-by: Daniel Baumann --- src/crcspeed.c | 282 +++++++++++++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 282 insertions(+) create mode 100644 src/crcspeed.c (limited to 'src/crcspeed.c') diff --git a/src/crcspeed.c b/src/crcspeed.c new file mode 100644 index 0000000..9682d8e --- /dev/null +++ b/src/crcspeed.c @@ -0,0 +1,282 @@ +/* + * Copyright (C) 2013 Mark Adler + * Originally by: crc64.c Version 1.4 16 Dec 2013 Mark Adler + * Modifications by Matt Stancliff : + * - removed CRC64-specific behavior + * - added generation of lookup tables by parameters + * - removed inversion of CRC input/result + * - removed automatic initialization in favor of explicit initialization + + This software is provided 'as-is', without any express or implied + warranty. In no event will the author be held liable for any damages + arising from the use of this software. + + Permission is granted to anyone to use this software for any purpose, + including commercial applications, and to alter it and redistribute it + freely, subject to the following restrictions: + + 1. The origin of this software must not be misrepresented; you must not + claim that you wrote the original software. If you use this software + in a product, an acknowledgment in the product documentation would be + appreciated but is not required. + 2. Altered source versions must be plainly marked as such, and must not be + misrepresented as being the original software. + 3. This notice may not be removed or altered from any source distribution. + + Mark Adler + madler@alumni.caltech.edu + */ + +#include "crcspeed.h" + +/* Fill in a CRC constants table. */ +void crcspeed64little_init(crcfn64 crcfn, uint64_t table[8][256]) { + uint64_t crc; + + /* generate CRCs for all single byte sequences */ + for (int n = 0; n < 256; n++) { + unsigned char v = n; + table[0][n] = crcfn(0, &v, 1); + } + + /* generate nested CRC table for future slice-by-8 lookup */ + for (int n = 0; n < 256; n++) { + crc = table[0][n]; + for (int k = 1; k < 8; k++) { + crc = table[0][crc & 0xff] ^ (crc >> 8); + table[k][n] = crc; + } + } +} + +void crcspeed16little_init(crcfn16 crcfn, uint16_t table[8][256]) { + uint16_t crc; + + /* generate CRCs for all single byte sequences */ + for (int n = 0; n < 256; n++) { + table[0][n] = crcfn(0, &n, 1); + } + + /* generate nested CRC table for future slice-by-8 lookup */ + for (int n = 0; n < 256; n++) { + crc = table[0][n]; + for (int k = 1; k < 8; k++) { + crc = table[0][(crc >> 8) & 0xff] ^ (crc << 8); + table[k][n] = crc; + } + } +} + +/* Reverse the bytes in a 64-bit word. */ +static inline uint64_t rev8(uint64_t a) { +#if defined(__GNUC__) || defined(__clang__) + return __builtin_bswap64(a); +#else + uint64_t m; + + m = UINT64_C(0xff00ff00ff00ff); + a = ((a >> 8) & m) | (a & m) << 8; + m = UINT64_C(0xffff0000ffff); + a = ((a >> 16) & m) | (a & m) << 16; + return a >> 32 | a << 32; +#endif +} + +/* This function is called once to initialize the CRC table for use on a + big-endian architecture. */ +void crcspeed64big_init(crcfn64 fn, uint64_t big_table[8][256]) { + /* Create the little endian table then reverse all the entries. */ + crcspeed64little_init(fn, big_table); + for (int k = 0; k < 8; k++) { + for (int n = 0; n < 256; n++) { + big_table[k][n] = rev8(big_table[k][n]); + } + } +} + +void crcspeed16big_init(crcfn16 fn, uint16_t big_table[8][256]) { + /* Create the little endian table then reverse all the entries. */ + crcspeed16little_init(fn, big_table); + for (int k = 0; k < 8; k++) { + for (int n = 0; n < 256; n++) { + big_table[k][n] = rev8(big_table[k][n]); + } + } +} + +/* Calculate a non-inverted CRC multiple bytes at a time on a little-endian + * architecture. If you need inverted CRC, invert *before* calling and invert + * *after* calling. + * 64 bit crc = process 8 bytes at once; + */ +uint64_t crcspeed64little(uint64_t little_table[8][256], uint64_t crc, + void *buf, size_t len) { + unsigned char *next = buf; + + /* process individual bytes until we reach an 8-byte aligned pointer */ + while (len && ((uintptr_t)next & 7) != 0) { + crc = little_table[0][(crc ^ *next++) & 0xff] ^ (crc >> 8); + len--; + } + + /* fast middle processing, 8 bytes (aligned!) per loop */ + while (len >= 8) { + crc ^= *(uint64_t *)next; + crc = little_table[7][crc & 0xff] ^ + little_table[6][(crc >> 8) & 0xff] ^ + little_table[5][(crc >> 16) & 0xff] ^ + little_table[4][(crc >> 24) & 0xff] ^ + little_table[3][(crc >> 32) & 0xff] ^ + little_table[2][(crc >> 40) & 0xff] ^ + little_table[1][(crc >> 48) & 0xff] ^ + little_table[0][crc >> 56]; + next += 8; + len -= 8; + } + + /* process remaining bytes (can't be larger than 8) */ + while (len) { + crc = little_table[0][(crc ^ *next++) & 0xff] ^ (crc >> 8); + len--; + } + + return crc; +} + +uint16_t crcspeed16little(uint16_t little_table[8][256], uint16_t crc, + void *buf, size_t len) { + unsigned char *next = buf; + + /* process individual bytes until we reach an 8-byte aligned pointer */ + while (len && ((uintptr_t)next & 7) != 0) { + crc = little_table[0][((crc >> 8) ^ *next++) & 0xff] ^ (crc << 8); + len--; + } + + /* fast middle processing, 8 bytes (aligned!) per loop */ + while (len >= 8) { + uint64_t n = *(uint64_t *)next; + crc = little_table[7][(n & 0xff) ^ ((crc >> 8) & 0xff)] ^ + little_table[6][((n >> 8) & 0xff) ^ (crc & 0xff)] ^ + little_table[5][(n >> 16) & 0xff] ^ + little_table[4][(n >> 24) & 0xff] ^ + little_table[3][(n >> 32) & 0xff] ^ + little_table[2][(n >> 40) & 0xff] ^ + little_table[1][(n >> 48) & 0xff] ^ + little_table[0][n >> 56]; + next += 8; + len -= 8; + } + + /* process remaining bytes (can't be larger than 8) */ + while (len) { + crc = little_table[0][((crc >> 8) ^ *next++) & 0xff] ^ (crc << 8); + len--; + } + + return crc; +} + +/* Calculate a non-inverted CRC eight bytes at a time on a big-endian + * architecture. + */ +uint64_t crcspeed64big(uint64_t big_table[8][256], uint64_t crc, void *buf, + size_t len) { + unsigned char *next = buf; + + crc = rev8(crc); + while (len && ((uintptr_t)next & 7) != 0) { + crc = big_table[0][(crc >> 56) ^ *next++] ^ (crc << 8); + len--; + } + + while (len >= 8) { + crc ^= *(uint64_t *)next; + crc = big_table[0][crc & 0xff] ^ + big_table[1][(crc >> 8) & 0xff] ^ + big_table[2][(crc >> 16) & 0xff] ^ + big_table[3][(crc >> 24) & 0xff] ^ + big_table[4][(crc >> 32) & 0xff] ^ + big_table[5][(crc >> 40) & 0xff] ^ + big_table[6][(crc >> 48) & 0xff] ^ + big_table[7][crc >> 56]; + next += 8; + len -= 8; + } + + while (len) { + crc = big_table[0][(crc >> 56) ^ *next++] ^ (crc << 8); + len--; + } + + return rev8(crc); +} + +/* WARNING: Completely untested on big endian architecture. Possibly broken. */ +uint16_t crcspeed16big(uint16_t big_table[8][256], uint16_t crc_in, void *buf, + size_t len) { + unsigned char *next = buf; + uint64_t crc = crc_in; + + crc = rev8(crc); + while (len && ((uintptr_t)next & 7) != 0) { + crc = big_table[0][((crc >> (56 - 8)) ^ *next++) & 0xff] ^ (crc >> 8); + len--; + } + + while (len >= 8) { + uint64_t n = *(uint64_t *)next; + crc = big_table[0][(n & 0xff) ^ ((crc >> (56 - 8)) & 0xff)] ^ + big_table[1][((n >> 8) & 0xff) ^ (crc & 0xff)] ^ + big_table[2][(n >> 16) & 0xff] ^ + big_table[3][(n >> 24) & 0xff] ^ + big_table[4][(n >> 32) & 0xff] ^ + big_table[5][(n >> 40) & 0xff] ^ + big_table[6][(n >> 48) & 0xff] ^ + big_table[7][n >> 56]; + next += 8; + len -= 8; + } + + while (len) { + crc = big_table[0][((crc >> (56 - 8)) ^ *next++) & 0xff] ^ (crc >> 8); + len--; + } + + return rev8(crc); +} + +/* Return the CRC of buf[0..len-1] with initial crc, processing eight bytes + at a time using passed-in lookup table. + This selects one of two routines depending on the endianness of + the architecture. */ +uint64_t crcspeed64native(uint64_t table[8][256], uint64_t crc, void *buf, + size_t len) { + uint64_t n = 1; + + return *(char *)&n ? crcspeed64little(table, crc, buf, len) + : crcspeed64big(table, crc, buf, len); +} + +uint16_t crcspeed16native(uint16_t table[8][256], uint16_t crc, void *buf, + size_t len) { + uint64_t n = 1; + + return *(char *)&n ? crcspeed16little(table, crc, buf, len) + : crcspeed16big(table, crc, buf, len); +} + +/* Initialize CRC lookup table in architecture-dependent manner. */ +void crcspeed64native_init(crcfn64 fn, uint64_t table[8][256]) { + uint64_t n = 1; + + *(char *)&n ? crcspeed64little_init(fn, table) + : crcspeed64big_init(fn, table); +} + +void crcspeed16native_init(crcfn16 fn, uint16_t table[8][256]) { + uint64_t n = 1; + + *(char *)&n ? crcspeed16little_init(fn, table) + : crcspeed16big_init(fn, table); +} -- cgit v1.2.3