1050 lines
31 KiB
C
1050 lines
31 KiB
C
/* crc32.c -- compute the CRC-32 of a data stream
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* Copyright (C) 1995-2022 Mark Adler
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* For conditions of distribution and use, see copyright notice in zlib.h
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*
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* This interleaved implementation of a CRC makes use of pipelined multiple
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* arithmetic-logic units, commonly found in modern CPU cores. It is due to
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* Kadatch and Jenkins (2010). See doc/crc-doc.1.0.pdf in this distribution.
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*/
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/* @(#) $Id$ */
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/*
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Note on the use of DYNAMIC_CRC_TABLE: there is no mutex or semaphore
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protection on the static variables used to control the first-use generation
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of the crc tables. Therefore, if you #define DYNAMIC_CRC_TABLE, you should
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first call get_crc_table() to initialize the tables before allowing more than
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one thread to use crc32().
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MAKECRCH can be #defined to write out crc32.h. A main() routine is also
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produced, so that this one source file can be compiled to an executable.
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*/
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#ifdef MAKECRCH
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# include <stdio.h>
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# ifndef DYNAMIC_CRC_TABLE
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# define DYNAMIC_CRC_TABLE
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# endif /* !DYNAMIC_CRC_TABLE */
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#endif /* MAKECRCH */
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#include "zutil.h" /* for Z_U4, Z_U8, z_crc_t, and FAR definitions */
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/*
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A CRC of a message is computed on N braids of words in the message, where
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each word consists of W bytes (4 or 8). If N is 3, for example, then three
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running sparse CRCs are calculated respectively on each braid, at these
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indices in the array of words: 0, 3, 6, ..., 1, 4, 7, ..., and 2, 5, 8, ...
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This is done starting at a word boundary, and continues until as many blocks
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of N * W bytes as are available have been processed. The results are combined
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into a single CRC at the end. For this code, N must be in the range 1..6 and
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W must be 4 or 8. The upper limit on N can be increased if desired by adding
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more #if blocks, extending the patterns apparent in the code. In addition,
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crc32.h would need to be regenerated, if the maximum N value is increased.
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N and W are chosen empirically by benchmarking the execution time on a given
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processor. The choices for N and W below were based on testing on Intel Kaby
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Lake i7, AMD Ryzen 7, ARM Cortex-A57, Sparc64-VII, PowerPC POWER9, and MIPS64
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Octeon II processors. The Intel, AMD, and ARM processors were all fastest
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with N=5, W=8. The Sparc, PowerPC, and MIPS64 were all fastest at N=5, W=4.
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They were all tested with either gcc or clang, all using the -O3 optimization
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level. Your mileage may vary.
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*/
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/* Define N */
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#ifdef Z_TESTN
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# define N Z_TESTN
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#else
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# define N 5
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#endif
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#if N < 1 || N > 6
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# error N must be in 1..6
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#endif
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/*
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z_crc_t must be at least 32 bits. z_word_t must be at least as long as
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z_crc_t. It is assumed here that z_word_t is either 32 bits or 64 bits, and
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that bytes are eight bits.
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*/
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/*
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Define W and the associated z_word_t type. If W is not defined, then a
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braided calculation is not used, and the associated tables and code are not
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compiled.
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*/
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#ifdef Z_TESTW
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# if Z_TESTW-1 != -1
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# define W Z_TESTW
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# endif
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#else
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# ifdef MAKECRCH
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# define W 8 /* required for MAKECRCH */
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# else
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# if defined(__x86_64__) || defined(__aarch64__)
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# define W 8
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# else
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# define W 4
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# endif
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# endif
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#endif
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#ifdef W
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# if W == 8 && defined(Z_U8)
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typedef Z_U8 z_word_t;
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# elif defined(Z_U4)
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# undef W
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# define W 4
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typedef Z_U4 z_word_t;
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# else
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# undef W
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# endif
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#endif
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/* If available, use the ARM processor CRC32 instruction. */
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#if defined(__aarch64__) && defined(__ARM_FEATURE_CRC32) && W == 8
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# define ARMCRC32
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#endif
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#if defined(W) && (!defined(ARMCRC32) || defined(DYNAMIC_CRC_TABLE))
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/*
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Swap the bytes in a z_word_t to convert between little and big endian. Any
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self-respecting compiler will optimize this to a single machine byte-swap
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instruction, if one is available. This assumes that word_t is either 32 bits
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or 64 bits.
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*/
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local z_word_t byte_swap(z_word_t word) {
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# if W == 8
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return
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(word & 0xff00000000000000) >> 56 |
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(word & 0xff000000000000) >> 40 |
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(word & 0xff0000000000) >> 24 |
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(word & 0xff00000000) >> 8 |
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(word & 0xff000000) << 8 |
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(word & 0xff0000) << 24 |
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(word & 0xff00) << 40 |
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(word & 0xff) << 56;
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# else /* W == 4 */
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return
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(word & 0xff000000) >> 24 |
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(word & 0xff0000) >> 8 |
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(word & 0xff00) << 8 |
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(word & 0xff) << 24;
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# endif
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}
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#endif
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#ifdef DYNAMIC_CRC_TABLE
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/* =========================================================================
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* Table of powers of x for combining CRC-32s, filled in by make_crc_table()
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* below.
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*/
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local z_crc_t FAR x2n_table[32];
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#else
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/* =========================================================================
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* Tables for byte-wise and braided CRC-32 calculations, and a table of powers
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* of x for combining CRC-32s, all made by make_crc_table().
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*/
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# include "crc32.h"
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#endif
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/* CRC polynomial. */
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#define POLY 0xedb88320 /* p(x) reflected, with x^32 implied */
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/*
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Return a(x) multiplied by b(x) modulo p(x), where p(x) is the CRC polynomial,
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reflected. For speed, this requires that a not be zero.
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*/
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local z_crc_t multmodp(z_crc_t a, z_crc_t b) {
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z_crc_t m, p;
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m = (z_crc_t)1 << 31;
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p = 0;
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for (;;) {
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if (a & m) {
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p ^= b;
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if ((a & (m - 1)) == 0)
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break;
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}
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m >>= 1;
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b = b & 1 ? (b >> 1) ^ POLY : b >> 1;
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}
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return p;
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}
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/*
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Return x^(n * 2^k) modulo p(x). Requires that x2n_table[] has been
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initialized.
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*/
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local z_crc_t x2nmodp(z_off64_t n, unsigned k) {
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z_crc_t p;
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p = (z_crc_t)1 << 31; /* x^0 == 1 */
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while (n) {
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if (n & 1)
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p = multmodp(x2n_table[k & 31], p);
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n >>= 1;
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k++;
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}
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return p;
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}
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#ifdef DYNAMIC_CRC_TABLE
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/* =========================================================================
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* Build the tables for byte-wise and braided CRC-32 calculations, and a table
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* of powers of x for combining CRC-32s.
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*/
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local z_crc_t FAR crc_table[256];
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#ifdef W
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local z_word_t FAR crc_big_table[256];
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local z_crc_t FAR crc_braid_table[W][256];
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local z_word_t FAR crc_braid_big_table[W][256];
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local void braid(z_crc_t [][256], z_word_t [][256], int, int);
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#endif
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#ifdef MAKECRCH
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local void write_table(FILE *, const z_crc_t FAR *, int);
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local void write_table32hi(FILE *, const z_word_t FAR *, int);
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local void write_table64(FILE *, const z_word_t FAR *, int);
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#endif /* MAKECRCH */
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/*
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Define a once() function depending on the availability of atomics. If this is
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compiled with DYNAMIC_CRC_TABLE defined, and if CRCs will be computed in
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multiple threads, and if atomics are not available, then get_crc_table() must
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be called to initialize the tables and must return before any threads are
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allowed to compute or combine CRCs.
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*/
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/* Definition of once functionality. */
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typedef struct once_s once_t;
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/* Check for the availability of atomics. */
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#if defined(__STDC__) && __STDC_VERSION__ >= 201112L && \
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!defined(__STDC_NO_ATOMICS__)
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#include <stdatomic.h>
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/* Structure for once(), which must be initialized with ONCE_INIT. */
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struct once_s {
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atomic_flag begun;
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atomic_int done;
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};
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#define ONCE_INIT {ATOMIC_FLAG_INIT, 0}
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/*
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Run the provided init() function exactly once, even if multiple threads
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invoke once() at the same time. The state must be a once_t initialized with
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ONCE_INIT.
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*/
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local void once(once_t *state, void (*init)(void)) {
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if (!atomic_load(&state->done)) {
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if (atomic_flag_test_and_set(&state->begun))
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while (!atomic_load(&state->done))
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;
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else {
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init();
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atomic_store(&state->done, 1);
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}
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}
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}
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#else /* no atomics */
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/* Structure for once(), which must be initialized with ONCE_INIT. */
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struct once_s {
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volatile int begun;
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volatile int done;
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};
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#define ONCE_INIT {0, 0}
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/* Test and set. Alas, not atomic, but tries to minimize the period of
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vulnerability. */
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local int test_and_set(int volatile *flag) {
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int was;
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was = *flag;
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*flag = 1;
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return was;
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}
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/* Run the provided init() function once. This is not thread-safe. */
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local void once(once_t *state, void (*init)(void)) {
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if (!state->done) {
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if (test_and_set(&state->begun))
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while (!state->done)
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;
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else {
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init();
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state->done = 1;
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}
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}
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}
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#endif
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/* State for once(). */
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local once_t made = ONCE_INIT;
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/*
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Generate tables for a byte-wise 32-bit CRC calculation on the polynomial:
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x^32+x^26+x^23+x^22+x^16+x^12+x^11+x^10+x^8+x^7+x^5+x^4+x^2+x+1.
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Polynomials over GF(2) are represented in binary, one bit per coefficient,
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with the lowest powers in the most significant bit. Then adding polynomials
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is just exclusive-or, and multiplying a polynomial by x is a right shift by
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one. If we call the above polynomial p, and represent a byte as the
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polynomial q, also with the lowest power in the most significant bit (so the
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byte 0xb1 is the polynomial x^7+x^3+x^2+1), then the CRC is (q*x^32) mod p,
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where a mod b means the remainder after dividing a by b.
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This calculation is done using the shift-register method of multiplying and
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taking the remainder. The register is initialized to zero, and for each
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incoming bit, x^32 is added mod p to the register if the bit is a one (where
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x^32 mod p is p+x^32 = x^26+...+1), and the register is multiplied mod p by x
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(which is shifting right by one and adding x^32 mod p if the bit shifted out
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is a one). We start with the highest power (least significant bit) of q and
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repeat for all eight bits of q.
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The table is simply the CRC of all possible eight bit values. This is all the
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information needed to generate CRCs on data a byte at a time for all
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combinations of CRC register values and incoming bytes.
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*/
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local void make_crc_table(void) {
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unsigned i, j, n;
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z_crc_t p;
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/* initialize the CRC of bytes tables */
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for (i = 0; i < 256; i++) {
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p = i;
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for (j = 0; j < 8; j++)
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p = p & 1 ? (p >> 1) ^ POLY : p >> 1;
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crc_table[i] = p;
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#ifdef W
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crc_big_table[i] = byte_swap(p);
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#endif
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}
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/* initialize the x^2^n mod p(x) table */
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p = (z_crc_t)1 << 30; /* x^1 */
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x2n_table[0] = p;
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for (n = 1; n < 32; n++)
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x2n_table[n] = p = multmodp(p, p);
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#ifdef W
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/* initialize the braiding tables -- needs x2n_table[] */
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braid(crc_braid_table, crc_braid_big_table, N, W);
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#endif
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#ifdef MAKECRCH
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{
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/*
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The crc32.h header file contains tables for both 32-bit and 64-bit
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z_word_t's, and so requires a 64-bit type be available. In that case,
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z_word_t must be defined to be 64-bits. This code then also generates
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and writes out the tables for the case that z_word_t is 32 bits.
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*/
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#if !defined(W) || W != 8
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# error Need a 64-bit integer type in order to generate crc32.h.
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#endif
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FILE *out;
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int k, n;
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z_crc_t ltl[8][256];
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z_word_t big[8][256];
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out = fopen("crc32.h", "w");
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if (out == NULL) return;
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/* write out little-endian CRC table to crc32.h */
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fprintf(out,
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"/* crc32.h -- tables for rapid CRC calculation\n"
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" * Generated automatically by crc32.c\n */\n"
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"\n"
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"local const z_crc_t FAR crc_table[] = {\n"
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" ");
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write_table(out, crc_table, 256);
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fprintf(out,
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"};\n");
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/* write out big-endian CRC table for 64-bit z_word_t to crc32.h */
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fprintf(out,
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"\n"
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"#ifdef W\n"
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"\n"
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"#if W == 8\n"
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"\n"
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"local const z_word_t FAR crc_big_table[] = {\n"
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" ");
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write_table64(out, crc_big_table, 256);
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fprintf(out,
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"};\n");
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/* write out big-endian CRC table for 32-bit z_word_t to crc32.h */
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fprintf(out,
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"\n"
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"#else /* W == 4 */\n"
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"\n"
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"local const z_word_t FAR crc_big_table[] = {\n"
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" ");
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write_table32hi(out, crc_big_table, 256);
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fprintf(out,
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"};\n"
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"\n"
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"#endif\n");
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/* write out braid tables for each value of N */
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for (n = 1; n <= 6; n++) {
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fprintf(out,
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"\n"
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"#if N == %d\n", n);
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/* compute braid tables for this N and 64-bit word_t */
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braid(ltl, big, n, 8);
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/* write out braid tables for 64-bit z_word_t to crc32.h */
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fprintf(out,
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"\n"
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"#if W == 8\n"
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"\n"
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"local const z_crc_t FAR crc_braid_table[][256] = {\n");
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for (k = 0; k < 8; k++) {
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fprintf(out, " {");
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write_table(out, ltl[k], 256);
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fprintf(out, "}%s", k < 7 ? ",\n" : "");
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}
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fprintf(out,
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"};\n"
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"\n"
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"local const z_word_t FAR crc_braid_big_table[][256] = {\n");
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for (k = 0; k < 8; k++) {
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fprintf(out, " {");
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write_table64(out, big[k], 256);
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fprintf(out, "}%s", k < 7 ? ",\n" : "");
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}
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fprintf(out,
|
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"};\n");
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|
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/* compute braid tables for this N and 32-bit word_t */
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braid(ltl, big, n, 4);
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/* write out braid tables for 32-bit z_word_t to crc32.h */
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fprintf(out,
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"\n"
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"#else /* W == 4 */\n"
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"\n"
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"local const z_crc_t FAR crc_braid_table[][256] = {\n");
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for (k = 0; k < 4; k++) {
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fprintf(out, " {");
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write_table(out, ltl[k], 256);
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fprintf(out, "}%s", k < 3 ? ",\n" : "");
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}
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fprintf(out,
|
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"};\n"
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"\n"
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"local const z_word_t FAR crc_braid_big_table[][256] = {\n");
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for (k = 0; k < 4; k++) {
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fprintf(out, " {");
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write_table32hi(out, big[k], 256);
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fprintf(out, "}%s", k < 3 ? ",\n" : "");
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}
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fprintf(out,
|
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"};\n"
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"\n"
|
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"#endif\n"
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"\n"
|
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"#endif\n");
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}
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fprintf(out,
|
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"\n"
|
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"#endif\n");
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|
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/* write out zeros operator table to crc32.h */
|
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fprintf(out,
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"\n"
|
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"local const z_crc_t FAR x2n_table[] = {\n"
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" ");
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write_table(out, x2n_table, 32);
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fprintf(out,
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"};\n");
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fclose(out);
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}
|
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#endif /* MAKECRCH */
|
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}
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|
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#ifdef MAKECRCH
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|
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/*
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Write the 32-bit values in table[0..k-1] to out, five per line in
|
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hexadecimal separated by commas.
|
|
*/
|
|
local void write_table(FILE *out, const z_crc_t FAR *table, int k) {
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int n;
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|
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for (n = 0; n < k; n++)
|
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fprintf(out, "%s0x%08lx%s", n == 0 || n % 5 ? "" : " ",
|
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(unsigned long)(table[n]),
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n == k - 1 ? "" : (n % 5 == 4 ? ",\n" : ", "));
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|
}
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|
|
/*
|
|
Write the high 32-bits of each value in table[0..k-1] to out, five per line
|
|
in hexadecimal separated by commas.
|
|
*/
|
|
local void write_table32hi(FILE *out, const z_word_t FAR *table, int k) {
|
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int n;
|
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|
|
for (n = 0; n < k; n++)
|
|
fprintf(out, "%s0x%08lx%s", n == 0 || n % 5 ? "" : " ",
|
|
(unsigned long)(table[n] >> 32),
|
|
n == k - 1 ? "" : (n % 5 == 4 ? ",\n" : ", "));
|
|
}
|
|
|
|
/*
|
|
Write the 64-bit values in table[0..k-1] to out, three per line in
|
|
hexadecimal separated by commas. This assumes that if there is a 64-bit
|
|
type, then there is also a long long integer type, and it is at least 64
|
|
bits. If not, then the type cast and format string can be adjusted
|
|
accordingly.
|
|
*/
|
|
local void write_table64(FILE *out, const z_word_t FAR *table, int k) {
|
|
int n;
|
|
|
|
for (n = 0; n < k; n++)
|
|
fprintf(out, "%s0x%016llx%s", n == 0 || n % 3 ? "" : " ",
|
|
(unsigned long long)(table[n]),
|
|
n == k - 1 ? "" : (n % 3 == 2 ? ",\n" : ", "));
|
|
}
|
|
|
|
/* Actually do the deed. */
|
|
int main(void) {
|
|
make_crc_table();
|
|
return 0;
|
|
}
|
|
|
|
#endif /* MAKECRCH */
|
|
|
|
#ifdef W
|
|
/*
|
|
Generate the little and big-endian braid tables for the given n and z_word_t
|
|
size w. Each array must have room for w blocks of 256 elements.
|
|
*/
|
|
local void braid(z_crc_t ltl[][256], z_word_t big[][256], int n, int w) {
|
|
int k;
|
|
z_crc_t i, p, q;
|
|
for (k = 0; k < w; k++) {
|
|
p = x2nmodp((n * w + 3 - k) << 3, 0);
|
|
ltl[k][0] = 0;
|
|
big[w - 1 - k][0] = 0;
|
|
for (i = 1; i < 256; i++) {
|
|
ltl[k][i] = q = multmodp(i << 24, p);
|
|
big[w - 1 - k][i] = byte_swap(q);
|
|
}
|
|
}
|
|
}
|
|
#endif
|
|
|
|
#endif /* DYNAMIC_CRC_TABLE */
|
|
|
|
/* =========================================================================
|
|
* This function can be used by asm versions of crc32(), and to force the
|
|
* generation of the CRC tables in a threaded application.
|
|
*/
|
|
const z_crc_t FAR * ZEXPORT get_crc_table(void) {
|
|
#ifdef DYNAMIC_CRC_TABLE
|
|
once(&made, make_crc_table);
|
|
#endif /* DYNAMIC_CRC_TABLE */
|
|
return (const z_crc_t FAR *)crc_table;
|
|
}
|
|
|
|
/* =========================================================================
|
|
* Use ARM machine instructions if available. This will compute the CRC about
|
|
* ten times faster than the braided calculation. This code does not check for
|
|
* the presence of the CRC instruction at run time. __ARM_FEATURE_CRC32 will
|
|
* only be defined if the compilation specifies an ARM processor architecture
|
|
* that has the instructions. For example, compiling with -march=armv8.1-a or
|
|
* -march=armv8-a+crc, or -march=native if the compile machine has the crc32
|
|
* instructions.
|
|
*/
|
|
#ifdef ARMCRC32
|
|
|
|
/*
|
|
Constants empirically determined to maximize speed. These values are from
|
|
measurements on a Cortex-A57. Your mileage may vary.
|
|
*/
|
|
#define Z_BATCH 3990 /* number of words in a batch */
|
|
#define Z_BATCH_ZEROS 0xa10d3d0c /* computed from Z_BATCH = 3990 */
|
|
#define Z_BATCH_MIN 800 /* fewest words in a final batch */
|
|
|
|
unsigned long ZEXPORT crc32_z(unsigned long crc, const unsigned char FAR *buf,
|
|
z_size_t len) {
|
|
z_crc_t val;
|
|
z_word_t crc1, crc2;
|
|
const z_word_t *word;
|
|
z_word_t val0, val1, val2;
|
|
z_size_t last, last2, i;
|
|
z_size_t num;
|
|
|
|
/* Return initial CRC, if requested. */
|
|
if (buf == Z_NULL) return 0;
|
|
|
|
#ifdef DYNAMIC_CRC_TABLE
|
|
once(&made, make_crc_table);
|
|
#endif /* DYNAMIC_CRC_TABLE */
|
|
|
|
/* Pre-condition the CRC */
|
|
crc = (~crc) & 0xffffffff;
|
|
|
|
/* Compute the CRC up to a word boundary. */
|
|
while (len && ((z_size_t)buf & 7) != 0) {
|
|
len--;
|
|
val = *buf++;
|
|
__asm__ volatile("crc32b %w0, %w0, %w1" : "+r"(crc) : "r"(val));
|
|
}
|
|
|
|
/* Prepare to compute the CRC on full 64-bit words word[0..num-1]. */
|
|
word = (z_word_t const *)buf;
|
|
num = len >> 3;
|
|
len &= 7;
|
|
|
|
/* Do three interleaved CRCs to realize the throughput of one crc32x
|
|
instruction per cycle. Each CRC is calculated on Z_BATCH words. The
|
|
three CRCs are combined into a single CRC after each set of batches. */
|
|
while (num >= 3 * Z_BATCH) {
|
|
crc1 = 0;
|
|
crc2 = 0;
|
|
for (i = 0; i < Z_BATCH; i++) {
|
|
val0 = word[i];
|
|
val1 = word[i + Z_BATCH];
|
|
val2 = word[i + 2 * Z_BATCH];
|
|
__asm__ volatile("crc32x %w0, %w0, %x1" : "+r"(crc) : "r"(val0));
|
|
__asm__ volatile("crc32x %w0, %w0, %x1" : "+r"(crc1) : "r"(val1));
|
|
__asm__ volatile("crc32x %w0, %w0, %x1" : "+r"(crc2) : "r"(val2));
|
|
}
|
|
word += 3 * Z_BATCH;
|
|
num -= 3 * Z_BATCH;
|
|
crc = multmodp(Z_BATCH_ZEROS, crc) ^ crc1;
|
|
crc = multmodp(Z_BATCH_ZEROS, crc) ^ crc2;
|
|
}
|
|
|
|
/* Do one last smaller batch with the remaining words, if there are enough
|
|
to pay for the combination of CRCs. */
|
|
last = num / 3;
|
|
if (last >= Z_BATCH_MIN) {
|
|
last2 = last << 1;
|
|
crc1 = 0;
|
|
crc2 = 0;
|
|
for (i = 0; i < last; i++) {
|
|
val0 = word[i];
|
|
val1 = word[i + last];
|
|
val2 = word[i + last2];
|
|
__asm__ volatile("crc32x %w0, %w0, %x1" : "+r"(crc) : "r"(val0));
|
|
__asm__ volatile("crc32x %w0, %w0, %x1" : "+r"(crc1) : "r"(val1));
|
|
__asm__ volatile("crc32x %w0, %w0, %x1" : "+r"(crc2) : "r"(val2));
|
|
}
|
|
word += 3 * last;
|
|
num -= 3 * last;
|
|
val = x2nmodp(last, 6);
|
|
crc = multmodp(val, crc) ^ crc1;
|
|
crc = multmodp(val, crc) ^ crc2;
|
|
}
|
|
|
|
/* Compute the CRC on any remaining words. */
|
|
for (i = 0; i < num; i++) {
|
|
val0 = word[i];
|
|
__asm__ volatile("crc32x %w0, %w0, %x1" : "+r"(crc) : "r"(val0));
|
|
}
|
|
word += num;
|
|
|
|
/* Complete the CRC on any remaining bytes. */
|
|
buf = (const unsigned char FAR *)word;
|
|
while (len) {
|
|
len--;
|
|
val = *buf++;
|
|
__asm__ volatile("crc32b %w0, %w0, %w1" : "+r"(crc) : "r"(val));
|
|
}
|
|
|
|
/* Return the CRC, post-conditioned. */
|
|
return crc ^ 0xffffffff;
|
|
}
|
|
|
|
#else
|
|
|
|
#ifdef W
|
|
|
|
/*
|
|
Return the CRC of the W bytes in the word_t data, taking the
|
|
least-significant byte of the word as the first byte of data, without any pre
|
|
or post conditioning. This is used to combine the CRCs of each braid.
|
|
*/
|
|
local z_crc_t crc_word(z_word_t data) {
|
|
int k;
|
|
for (k = 0; k < W; k++)
|
|
data = (data >> 8) ^ crc_table[data & 0xff];
|
|
return (z_crc_t)data;
|
|
}
|
|
|
|
local z_word_t crc_word_big(z_word_t data) {
|
|
int k;
|
|
for (k = 0; k < W; k++)
|
|
data = (data << 8) ^
|
|
crc_big_table[(data >> ((W - 1) << 3)) & 0xff];
|
|
return data;
|
|
}
|
|
|
|
#endif
|
|
|
|
/* ========================================================================= */
|
|
unsigned long ZEXPORT crc32_z(unsigned long crc, const unsigned char FAR *buf,
|
|
z_size_t len) {
|
|
/* Return initial CRC, if requested. */
|
|
if (buf == Z_NULL) return 0;
|
|
|
|
#ifdef DYNAMIC_CRC_TABLE
|
|
once(&made, make_crc_table);
|
|
#endif /* DYNAMIC_CRC_TABLE */
|
|
|
|
/* Pre-condition the CRC */
|
|
crc = (~crc) & 0xffffffff;
|
|
|
|
#ifdef W
|
|
|
|
/* If provided enough bytes, do a braided CRC calculation. */
|
|
if (len >= N * W + W - 1) {
|
|
z_size_t blks;
|
|
z_word_t const *words;
|
|
unsigned endian;
|
|
int k;
|
|
|
|
/* Compute the CRC up to a z_word_t boundary. */
|
|
while (len && ((z_size_t)buf & (W - 1)) != 0) {
|
|
len--;
|
|
crc = (crc >> 8) ^ crc_table[(crc ^ *buf++) & 0xff];
|
|
}
|
|
|
|
/* Compute the CRC on as many N z_word_t blocks as are available. */
|
|
blks = len / (N * W);
|
|
len -= blks * N * W;
|
|
words = (z_word_t const *)buf;
|
|
|
|
/* Do endian check at execution time instead of compile time, since ARM
|
|
processors can change the endianness at execution time. If the
|
|
compiler knows what the endianness will be, it can optimize out the
|
|
check and the unused branch. */
|
|
endian = 1;
|
|
if (*(unsigned char *)&endian) {
|
|
/* Little endian. */
|
|
|
|
z_crc_t crc0;
|
|
z_word_t word0;
|
|
#if N > 1
|
|
z_crc_t crc1;
|
|
z_word_t word1;
|
|
#if N > 2
|
|
z_crc_t crc2;
|
|
z_word_t word2;
|
|
#if N > 3
|
|
z_crc_t crc3;
|
|
z_word_t word3;
|
|
#if N > 4
|
|
z_crc_t crc4;
|
|
z_word_t word4;
|
|
#if N > 5
|
|
z_crc_t crc5;
|
|
z_word_t word5;
|
|
#endif
|
|
#endif
|
|
#endif
|
|
#endif
|
|
#endif
|
|
|
|
/* Initialize the CRC for each braid. */
|
|
crc0 = crc;
|
|
#if N > 1
|
|
crc1 = 0;
|
|
#if N > 2
|
|
crc2 = 0;
|
|
#if N > 3
|
|
crc3 = 0;
|
|
#if N > 4
|
|
crc4 = 0;
|
|
#if N > 5
|
|
crc5 = 0;
|
|
#endif
|
|
#endif
|
|
#endif
|
|
#endif
|
|
#endif
|
|
|
|
/*
|
|
Process the first blks-1 blocks, computing the CRCs on each braid
|
|
independently.
|
|
*/
|
|
while (--blks) {
|
|
/* Load the word for each braid into registers. */
|
|
word0 = crc0 ^ words[0];
|
|
#if N > 1
|
|
word1 = crc1 ^ words[1];
|
|
#if N > 2
|
|
word2 = crc2 ^ words[2];
|
|
#if N > 3
|
|
word3 = crc3 ^ words[3];
|
|
#if N > 4
|
|
word4 = crc4 ^ words[4];
|
|
#if N > 5
|
|
word5 = crc5 ^ words[5];
|
|
#endif
|
|
#endif
|
|
#endif
|
|
#endif
|
|
#endif
|
|
words += N;
|
|
|
|
/* Compute and update the CRC for each word. The loop should
|
|
get unrolled. */
|
|
crc0 = crc_braid_table[0][word0 & 0xff];
|
|
#if N > 1
|
|
crc1 = crc_braid_table[0][word1 & 0xff];
|
|
#if N > 2
|
|
crc2 = crc_braid_table[0][word2 & 0xff];
|
|
#if N > 3
|
|
crc3 = crc_braid_table[0][word3 & 0xff];
|
|
#if N > 4
|
|
crc4 = crc_braid_table[0][word4 & 0xff];
|
|
#if N > 5
|
|
crc5 = crc_braid_table[0][word5 & 0xff];
|
|
#endif
|
|
#endif
|
|
#endif
|
|
#endif
|
|
#endif
|
|
for (k = 1; k < W; k++) {
|
|
crc0 ^= crc_braid_table[k][(word0 >> (k << 3)) & 0xff];
|
|
#if N > 1
|
|
crc1 ^= crc_braid_table[k][(word1 >> (k << 3)) & 0xff];
|
|
#if N > 2
|
|
crc2 ^= crc_braid_table[k][(word2 >> (k << 3)) & 0xff];
|
|
#if N > 3
|
|
crc3 ^= crc_braid_table[k][(word3 >> (k << 3)) & 0xff];
|
|
#if N > 4
|
|
crc4 ^= crc_braid_table[k][(word4 >> (k << 3)) & 0xff];
|
|
#if N > 5
|
|
crc5 ^= crc_braid_table[k][(word5 >> (k << 3)) & 0xff];
|
|
#endif
|
|
#endif
|
|
#endif
|
|
#endif
|
|
#endif
|
|
}
|
|
}
|
|
|
|
/*
|
|
Process the last block, combining the CRCs of the N braids at the
|
|
same time.
|
|
*/
|
|
crc = crc_word(crc0 ^ words[0]);
|
|
#if N > 1
|
|
crc = crc_word(crc1 ^ words[1] ^ crc);
|
|
#if N > 2
|
|
crc = crc_word(crc2 ^ words[2] ^ crc);
|
|
#if N > 3
|
|
crc = crc_word(crc3 ^ words[3] ^ crc);
|
|
#if N > 4
|
|
crc = crc_word(crc4 ^ words[4] ^ crc);
|
|
#if N > 5
|
|
crc = crc_word(crc5 ^ words[5] ^ crc);
|
|
#endif
|
|
#endif
|
|
#endif
|
|
#endif
|
|
#endif
|
|
words += N;
|
|
}
|
|
else {
|
|
/* Big endian. */
|
|
|
|
z_word_t crc0, word0, comb;
|
|
#if N > 1
|
|
z_word_t crc1, word1;
|
|
#if N > 2
|
|
z_word_t crc2, word2;
|
|
#if N > 3
|
|
z_word_t crc3, word3;
|
|
#if N > 4
|
|
z_word_t crc4, word4;
|
|
#if N > 5
|
|
z_word_t crc5, word5;
|
|
#endif
|
|
#endif
|
|
#endif
|
|
#endif
|
|
#endif
|
|
|
|
/* Initialize the CRC for each braid. */
|
|
crc0 = byte_swap(crc);
|
|
#if N > 1
|
|
crc1 = 0;
|
|
#if N > 2
|
|
crc2 = 0;
|
|
#if N > 3
|
|
crc3 = 0;
|
|
#if N > 4
|
|
crc4 = 0;
|
|
#if N > 5
|
|
crc5 = 0;
|
|
#endif
|
|
#endif
|
|
#endif
|
|
#endif
|
|
#endif
|
|
|
|
/*
|
|
Process the first blks-1 blocks, computing the CRCs on each braid
|
|
independently.
|
|
*/
|
|
while (--blks) {
|
|
/* Load the word for each braid into registers. */
|
|
word0 = crc0 ^ words[0];
|
|
#if N > 1
|
|
word1 = crc1 ^ words[1];
|
|
#if N > 2
|
|
word2 = crc2 ^ words[2];
|
|
#if N > 3
|
|
word3 = crc3 ^ words[3];
|
|
#if N > 4
|
|
word4 = crc4 ^ words[4];
|
|
#if N > 5
|
|
word5 = crc5 ^ words[5];
|
|
#endif
|
|
#endif
|
|
#endif
|
|
#endif
|
|
#endif
|
|
words += N;
|
|
|
|
/* Compute and update the CRC for each word. The loop should
|
|
get unrolled. */
|
|
crc0 = crc_braid_big_table[0][word0 & 0xff];
|
|
#if N > 1
|
|
crc1 = crc_braid_big_table[0][word1 & 0xff];
|
|
#if N > 2
|
|
crc2 = crc_braid_big_table[0][word2 & 0xff];
|
|
#if N > 3
|
|
crc3 = crc_braid_big_table[0][word3 & 0xff];
|
|
#if N > 4
|
|
crc4 = crc_braid_big_table[0][word4 & 0xff];
|
|
#if N > 5
|
|
crc5 = crc_braid_big_table[0][word5 & 0xff];
|
|
#endif
|
|
#endif
|
|
#endif
|
|
#endif
|
|
#endif
|
|
for (k = 1; k < W; k++) {
|
|
crc0 ^= crc_braid_big_table[k][(word0 >> (k << 3)) & 0xff];
|
|
#if N > 1
|
|
crc1 ^= crc_braid_big_table[k][(word1 >> (k << 3)) & 0xff];
|
|
#if N > 2
|
|
crc2 ^= crc_braid_big_table[k][(word2 >> (k << 3)) & 0xff];
|
|
#if N > 3
|
|
crc3 ^= crc_braid_big_table[k][(word3 >> (k << 3)) & 0xff];
|
|
#if N > 4
|
|
crc4 ^= crc_braid_big_table[k][(word4 >> (k << 3)) & 0xff];
|
|
#if N > 5
|
|
crc5 ^= crc_braid_big_table[k][(word5 >> (k << 3)) & 0xff];
|
|
#endif
|
|
#endif
|
|
#endif
|
|
#endif
|
|
#endif
|
|
}
|
|
}
|
|
|
|
/*
|
|
Process the last block, combining the CRCs of the N braids at the
|
|
same time.
|
|
*/
|
|
comb = crc_word_big(crc0 ^ words[0]);
|
|
#if N > 1
|
|
comb = crc_word_big(crc1 ^ words[1] ^ comb);
|
|
#if N > 2
|
|
comb = crc_word_big(crc2 ^ words[2] ^ comb);
|
|
#if N > 3
|
|
comb = crc_word_big(crc3 ^ words[3] ^ comb);
|
|
#if N > 4
|
|
comb = crc_word_big(crc4 ^ words[4] ^ comb);
|
|
#if N > 5
|
|
comb = crc_word_big(crc5 ^ words[5] ^ comb);
|
|
#endif
|
|
#endif
|
|
#endif
|
|
#endif
|
|
#endif
|
|
words += N;
|
|
crc = byte_swap(comb);
|
|
}
|
|
|
|
/*
|
|
Update the pointer to the remaining bytes to process.
|
|
*/
|
|
buf = (unsigned char const *)words;
|
|
}
|
|
|
|
#endif /* W */
|
|
|
|
/* Complete the computation of the CRC on any remaining bytes. */
|
|
while (len >= 8) {
|
|
len -= 8;
|
|
crc = (crc >> 8) ^ crc_table[(crc ^ *buf++) & 0xff];
|
|
crc = (crc >> 8) ^ crc_table[(crc ^ *buf++) & 0xff];
|
|
crc = (crc >> 8) ^ crc_table[(crc ^ *buf++) & 0xff];
|
|
crc = (crc >> 8) ^ crc_table[(crc ^ *buf++) & 0xff];
|
|
crc = (crc >> 8) ^ crc_table[(crc ^ *buf++) & 0xff];
|
|
crc = (crc >> 8) ^ crc_table[(crc ^ *buf++) & 0xff];
|
|
crc = (crc >> 8) ^ crc_table[(crc ^ *buf++) & 0xff];
|
|
crc = (crc >> 8) ^ crc_table[(crc ^ *buf++) & 0xff];
|
|
}
|
|
while (len) {
|
|
len--;
|
|
crc = (crc >> 8) ^ crc_table[(crc ^ *buf++) & 0xff];
|
|
}
|
|
|
|
/* Return the CRC, post-conditioned. */
|
|
return crc ^ 0xffffffff;
|
|
}
|
|
|
|
#endif
|
|
|
|
/* ========================================================================= */
|
|
unsigned long ZEXPORT crc32(unsigned long crc, const unsigned char FAR *buf,
|
|
uInt len) {
|
|
return crc32_z(crc, buf, len);
|
|
}
|
|
|
|
/* ========================================================================= */
|
|
uLong ZEXPORT crc32_combine64(uLong crc1, uLong crc2, z_off64_t len2) {
|
|
#ifdef DYNAMIC_CRC_TABLE
|
|
once(&made, make_crc_table);
|
|
#endif /* DYNAMIC_CRC_TABLE */
|
|
return multmodp(x2nmodp(len2, 3), crc1) ^ (crc2 & 0xffffffff);
|
|
}
|
|
|
|
/* ========================================================================= */
|
|
uLong ZEXPORT crc32_combine(uLong crc1, uLong crc2, z_off_t len2) {
|
|
return crc32_combine64(crc1, crc2, (z_off64_t)len2);
|
|
}
|
|
|
|
/* ========================================================================= */
|
|
uLong ZEXPORT crc32_combine_gen64(z_off64_t len2) {
|
|
#ifdef DYNAMIC_CRC_TABLE
|
|
once(&made, make_crc_table);
|
|
#endif /* DYNAMIC_CRC_TABLE */
|
|
return x2nmodp(len2, 3);
|
|
}
|
|
|
|
/* ========================================================================= */
|
|
uLong ZEXPORT crc32_combine_gen(z_off_t len2) {
|
|
return crc32_combine_gen64((z_off64_t)len2);
|
|
}
|
|
|
|
/* ========================================================================= */
|
|
uLong ZEXPORT crc32_combine_op(uLong crc1, uLong crc2, uLong op) {
|
|
return multmodp(op, crc1) ^ (crc2 & 0xffffffff);
|
|
}
|