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57 lines
2.2 KiB
C
57 lines
2.2 KiB
C
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/* crc32_braid_comb.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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#include "zutil.h"
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#include "crc32_braid_p.h"
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#include "crc32_braid_tbl.h"
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#include "crc32_braid_comb_p.h"
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/* ========================================================================= */
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static uint32_t crc32_combine_(uint32_t crc1, uint32_t crc2, z_off64_t len2) {
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return multmodp(x2nmodp(len2, 3), crc1) ^ crc2;
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}
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static uint32_t crc32_combine_gen_(z_off64_t len2) {
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return x2nmodp(len2, 3);
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}
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static uint32_t crc32_combine_op_(uint32_t crc1, uint32_t crc2, const uint32_t op) {
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return multmodp(op, crc1) ^ crc2;
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}
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/* ========================================================================= */
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#ifdef ZLIB_COMPAT
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unsigned long Z_EXPORT PREFIX(crc32_combine)(unsigned long crc1, unsigned long crc2, z_off_t len2) {
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return (unsigned long)crc32_combine_((uint32_t)crc1, (uint32_t)crc2, len2);
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}
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unsigned long Z_EXPORT PREFIX4(crc32_combine)(unsigned long crc1, unsigned long crc2, z_off64_t len2) {
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return (unsigned long)crc32_combine_((uint32_t)crc1, (uint32_t)crc2, len2);
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}
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unsigned long Z_EXPORT PREFIX(crc32_combine_gen)(z_off_t len2) {
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return crc32_combine_gen_(len2);
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}
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unsigned long Z_EXPORT PREFIX4(crc32_combine_gen)(z_off64_t len2) {
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return crc32_combine_gen_(len2);
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}
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unsigned long Z_EXPORT PREFIX(crc32_combine_op)(unsigned long crc1, unsigned long crc2, const unsigned long op) {
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return (unsigned long)crc32_combine_op_((uint32_t)crc1, (uint32_t)crc2, (uint32_t)op);
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}
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#else
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uint32_t Z_EXPORT PREFIX4(crc32_combine)(uint32_t crc1, uint32_t crc2, z_off64_t len2) {
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return crc32_combine_(crc1, crc2, len2);
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}
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uint32_t Z_EXPORT PREFIX(crc32_combine_gen)(z_off64_t len2) {
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return crc32_combine_gen_(len2);
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}
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uint32_t Z_EXPORT PREFIX(crc32_combine_op)(uint32_t crc1, uint32_t crc2, const uint32_t op) {
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return crc32_combine_op_(crc1, crc2, op);
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}
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#endif
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/* ========================================================================= */
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