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https://github.com/FEX-Emu/xxHash.git
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xxhash can be inlined even if it was previously included
Inlining hash functions is generally beneficial for performance. It becomes extremely beneficial whenever input size is a compile-time constant. To inline xxhash functions, one just needs to include it this way : One potential issue is that "xxhash.h" may have already been included previously, typically as part of another included `*.h` . In which case, the second `#include` statement will have no effect. This patch fixes this situation : now, when XXH_INLINE_ALL is defined, all identifiers are renamed, in order to avoid name collision and confusion with already included indentifiers. The renaming process uses XXH_NAMESPACE. XXH_NAMESPACE must be available (i.e. not already used) for renaming to work. A test has been added in `tests/` to ensure this scenario works correctly.
This commit is contained in:
Yann Collet
parent
8ae09480cf
commit
19cd4ffed3
6
Makefile
6
Makefile
@ -282,9 +282,13 @@ preview-man: man
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test: DEBUGFLAGS += -DDEBUGLEVEL=1
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test: all namespaceTest check test-xxhsum-c c90test test-tools
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.PHONY: test-inline
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test-inline:
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$(MAKE) -C tests test
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.PHONY: test-all
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test-all: CFLAGS += -Werror
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test-all: test test32 clangtest cxxtest usan listL120 trailingWhitespace staticAnalyze
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test-all: test test32 clangtest cxxtest usan test-inline listL120 trailingWhitespace staticAnalyze
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.PHONY: test-tools
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test-tools:
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45
tests/Makefile
Normal file
45
tests/Makefile
Normal file
@ -0,0 +1,45 @@
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CFLAGS += -Wall -Wextra -g
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NM = nm
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GREP = grep
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.PHONY: default
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default: all
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.PHONY: all
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all: test
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.PHONY: test
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test: test_multiinclude
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.PHONY: test_multiinclude
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test_multiinclude:
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@$(MAKE) clean
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# compile without xxhash.o, ensure symbols exist within target
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# note : built using only default rules
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$(MAKE) multiInclude
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@$(MAKE) clean
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# compile with xxhash.o, to detect duplicated symbols
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$(MAKE) multiInclude_withxxhash
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@$(MAKE) clean
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# Note : XXH_INLINE_ALL with XXH_NAMESPACE is currently disabled
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# compile with XXH_NAMESPACE
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# CPPFLAGS=-DXXH_NAMESPACE=TESTN_ $(MAKE) multiInclude_withxxhash
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# no symbol prefixed TESTN_ should exist
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# ! $(NM) multiInclude_withxxhash | $(GREP) TESTN_
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#$(MAKE) clean
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# compile with XXH_NAMESPACE and without xxhash.o
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# CPPFLAGS=-DXXH_NAMESPACE=TESTN_ $(MAKE) multiInclude
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# no symbol prefixed TESTN_ should exist
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# ! $(NM) multiInclude | $(GREP) TESTN_
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#@$(MAKE) clean
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xxhash.o: ../xxhash.c ../xxhash.h
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$(CC) $(CFLAGS) $(CPPFLAGS) $(LDFLAGS) -c -o $@ $<
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multiInclude_withxxhash: multiInclude.o xxhash.o
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$(CC) $(CFLAGS) $(CPPFLAGS) $(LDFLAGS) -o $@ $^
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clean:
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@$(RM) *.o
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@$(RM) multiInclude multiInclude_withxxhash
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58
tests/multiInclude.c
Normal file
58
tests/multiInclude.c
Normal file
@ -0,0 +1,58 @@
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/*
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* test_multiinclude
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* test program, just to validate including multiple times in any order
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*
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* Copyright (C) Yann Collet 2013-present
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*
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* GPL v2 License
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*
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* This program is free software; you can redistribute it and/or modify
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* it under the terms of the GNU General Public License as published by
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* the Free Software Foundation; either version 2 of the License, or
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* (at your option) any later version.
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*
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* This program is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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* GNU General Public License for more details.
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*
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* You should have received a copy of the GNU General Public License along
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* with this program; if not, write to the Free Software Foundation, Inc.,
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* 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
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*
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* You can contact the author at :
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* - xxHash homepage : http://www.xxhash.com
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* - xxHash source repository : https://github.com/Cyan4973/xxHash
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*/
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#include <stdio.h> // printf
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/* normal include, gives access to public symbols */
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#include "../xxhash.h"
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/* advanced include, gives access to experimental symbols */
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/* note : without specific effort, experimental symbols might be unavailable */
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#define XXH_STATIC_LINKING_ONLY
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#include "../xxhash.h"
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/* inlining : re-define all symbols, keep them private to the unit.
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* note : without specific efforts, symbol names will collide
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* note 2 : no linking to xxhash.o, so that link stage will fail if inline is ignored */
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#define XXH_INLINE_ALL
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#include "../xxhash.h"
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int main(void)
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{
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XXH3_state_t state; /* part of experimental */
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XXH3_64bits_reset(&state);
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const char input[] = "Hello World !";
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XXH3_64bits_update(&state, input, sizeof(input));
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XXH64_hash_t const h = XXH3_64bits_digest(&state);
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printf("hash '%s' : %0llx \n", input, (unsigned long long)h);
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return 0;
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}
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2
xxh3.h
2
xxh3.h
@ -1654,7 +1654,7 @@ XXH_PUBLIC_API XXH128_hash_t XXH3_128bits_digest (const XXH3_state_t* state)
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/* 128-bit utility functions */
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#include <string.h> /* memcmp */
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#include <string.h> /* memcmp, memcpy */
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/* return : 1 is equal, 0 if different */
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XXH_PUBLIC_API int XXH128_isEqual(XXH128_hash_t h1, XXH128_hash_t h2)
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2
xxhash.c
2
xxhash.c
@ -33,7 +33,7 @@
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*/
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/* xxhash.c only instantiates functions defined in xxhash.h
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/* xxhash.c instantiates functions defined in xxhash.h
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*/
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#define XXH_STATIC_LINKING_ONLY /* access advanced declarations */
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75
xxhash.h
75
xxhash.h
@ -73,29 +73,29 @@ XXH32 6.8 GB/s 6.0 GB/s
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extern "C" {
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#endif
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#ifndef XXHASH_H_5627135585666179
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#define XXHASH_H_5627135585666179 1
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/* ****************************
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* API modifier
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******************************/
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/** XXH_INLINE_ALL (and XXH_PRIVATE_API)
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* This build macro includes xxhash functions in `static` mode
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* in order to inline them, and remove their symbol from the public list.
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* Inlining offers great performance improvement on small keys,
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* Implement requested xxhash functions directly in the unit.
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* Inlining offers great performance improvement on small inputs,
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* and dramatic ones when length is expressed as a compile-time constant.
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* See https://fastcompression.blogspot.com/2018/03/xxhash-for-small-keys-impressive-power.html .
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* It also removes all symbols from the public list.
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* Methodology :
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* #define XXH_INLINE_ALL
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* #include "xxhash.h"
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* `xxhash.c` is automatically included.
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* It's not useful to compile and link it as a separate object.
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* Do not compile and link xxhash.o as a separate object (not useful)
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*/
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#if defined(XXH_INLINE_ALL) || defined(XXH_PRIVATE_API)
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# ifndef XXH_STATIC_LINKING_ONLY
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# define XXH_STATIC_LINKING_ONLY
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# endif
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#if (defined(XXH_INLINE_ALL) || defined(XXH_PRIVATE_API)) \
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&& !defined(XXH_INLINE_ALL_31684351384)
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/* this section should be traversed only once */
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# define XXH_INLINE_ALL_31684351384
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/* give access to advanced API, required to compile implementations */
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# undef XXH_STATIC_LINKING_ONLY /* avoid macro redef */
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# define XXH_STATIC_LINKING_ONLY
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/* make functions private */
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# undef XXH_PUBLIC_API
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# if defined(__GNUC__)
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# define XXH_PUBLIC_API static __inline __attribute__((unused))
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# elif defined (__cplusplus) || (defined (__STDC_VERSION__) && (__STDC_VERSION__ >= 199901L) /* C99 */)
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@ -103,10 +103,48 @@ extern "C" {
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# elif defined(_MSC_VER)
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# define XXH_PUBLIC_API static __inline
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# else
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/* this version may generate warnings for unused static functions */
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/* note : this version may generate warnings for unused static functions */
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# define XXH_PUBLIC_API static
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# endif
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#else
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/* prefix all names, to avoid symbol duplicates with potential library */
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# ifdef XXH_NAMESPACE
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# error "XXH_INLINE_ALL with XXH_NAMESPACE is not supported"
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# /* Note : Alternative is to #undef all symbols (it's a pretty large list).
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* If doing nothing : it compiles, but functions are actually Not inlined.
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* */
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# endif
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# define XXH_NAMESPACE XXH_INLINE_
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/* some identifiers are not symbols,
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* they must nonetheless be renamed to avoid double declaration
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* Alternative : do not redeclare them,
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* which requires some #ifdef, and is more dispersed in the file
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* while renaming can be achieved in a single place */
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# define XXH_IPREF(Id) XXH_INLINE_ ## Id
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# define XXH_OK XXH_IPREF(XXH_OK)
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# define XXH_ERROR XXH_IPREF(XXH_ERROR)
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# define XXH_errorcode XXH_IPREF(XXH_errorcode)
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# define XXH32_canonical_t XXH_IPREF(XXH32_canonical_t)
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# define XXH64_canonical_t XXH_IPREF(XXH64_canonical_t)
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# define XXH128_canonical_t XXH_IPREF(XXH128_canonical_t)
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# define XXH32_state_s XXH_IPREF(XXH32_state_s)
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# define XXH32_state_t XXH_IPREF(XXH32_state_t)
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# define XXH64_state_s XXH_IPREF(XXH64_state_s)
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# define XXH64_state_t XXH_IPREF(XXH64_state_t)
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# define XXH3_state_s XXH_IPREF(XXH3_state_s)
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# define XXH3_state_t XXH_IPREF(XXH3_state_t)
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# define XXH128_hash_t XXH_IPREF(XXH128_hash_t)
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/* Ensure header is parsed again, even if it was previously included */
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# undef XXHASH_H_5627135585666179
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# undef XXHASH_H_STATIC_13879238742
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#endif /* XXH_INLINE_ALL || XXH_PRIVATE_API */
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#ifndef XXHASH_H_5627135585666179
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#define XXHASH_H_5627135585666179 1
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/* specific declaration modes for Windows */
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#if !defined(XXH_INLINE_ALL) && !defined(XXH_PRIVATE_API)
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# if defined(WIN32) && defined(_MSC_VER) && (defined(XXH_IMPORT) || defined(XXH_EXPORT))
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# ifdef XXH_EXPORT
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# define XXH_PUBLIC_API __declspec(dllexport)
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@ -116,7 +154,7 @@ extern "C" {
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# else
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# define XXH_PUBLIC_API /* do nothing */
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# endif
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#endif /* XXH_INLINE_ALL || XXH_PRIVATE_API */
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#endif
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/*! XXH_NAMESPACE, aka Namespace Emulation :
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*
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@ -577,9 +615,14 @@ XXH_PUBLIC_API XXH128_hash_t XXH128_hashFromCanonical(const XXH128_canonical_t*
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#endif /* defined(XXH_STATIC_LINKING_ONLY) && !defined(XXHASH_H_STATIC_13879238742) */
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/* ======================================================================== */
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/* ======================================================================== */
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/* ======================================================================== */
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/*-**********************************************************************
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* xxHash implementation
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* -**********************************************************************
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* Functions implementation used to be hosted within xxhash.c .
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* However, code inlining requires to place implementation in the header file.
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* As a consequence, xxhash.c used to be included within xxhash.h .
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