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85923c8f30
Update zlib-ng to 2.2.1 #26113 Release: https://github.com/zlib-ng/zlib-ng/releases/tag/2.2.1 ARM diagnostics patch: https://github.com/zlib-ng/zlib-ng/pull/1774 ### Pull Request Readiness Checklist See details at https://github.com/opencv/opencv/wiki/How_to_contribute#making-a-good-pull-request - [x] I agree to contribute to the project under Apache 2 License. - [x] To the best of my knowledge, the proposed patch is not based on a code under GPL or another license that is incompatible with OpenCV - [x] The PR is proposed to the proper branch - [ ] There is a reference to the original bug report and related work - [ ] There is accuracy test, performance test and test data in opencv_extra repository, if applicable Patch to opencv_extra has the same branch name. - [ ] The feature is well documented and sample code can be built with the project CMake
53 lines
1.8 KiB
C
53 lines
1.8 KiB
C
/* slide_hash.c -- slide hash table C implementation
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*
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* Copyright (C) 1995-2024 Jean-loup Gailly and 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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#include "zbuild.h"
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#include "deflate.h"
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/* ===========================================================================
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* Slide the hash table when sliding the window down (could be avoided with 32
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* bit values at the expense of memory usage). We slide even when level == 0 to
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* keep the hash table consistent if we switch back to level > 0 later.
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*/
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static inline void slide_hash_c_chain(Pos *table, uint32_t entries, uint16_t wsize) {
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#ifdef NOT_TWEAK_COMPILER
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table += entries;
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do {
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unsigned m;
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m = *--table;
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*table = (Pos)(m >= wsize ? m-wsize : 0);
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/* If entries is not on any hash chain, prev[entries] is garbage but
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* its value will never be used.
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*/
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} while (--entries);
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#else
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{
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/* As of I make this change, gcc (4.8.*) isn't able to vectorize
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* this hot loop using saturated-subtraction on x86-64 architecture.
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* To avoid this defect, we can change the loop such that
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* o. the pointer advance forward, and
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* o. demote the variable 'm' to be local to the loop, and
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* choose type "Pos" (instead of 'unsigned int') for the
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* variable to avoid unnecessary zero-extension.
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*/
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unsigned int i;
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Pos *q = table;
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for (i = 0; i < entries; i++) {
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Pos m = *q;
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Pos t = (Pos)wsize;
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*q++ = (Pos)(m >= t ? m-t: 0);
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}
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}
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#endif /* NOT_TWEAK_COMPILER */
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}
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Z_INTERNAL void slide_hash_c(deflate_state *s) {
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uint16_t wsize = (uint16_t)s->w_size;
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slide_hash_c_chain(s->head, HASH_SIZE, wsize);
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slide_hash_c_chain(s->prev, wsize, wsize);
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}
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