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bbcddb127a
This commit only replaces the bundled source and does not include any ZFS integration changes. Because the build depends on integration adjustments, it will fail until the accompanying integration commit is applied. Upstream release: https://github.com/facebook/zstd/releases/tag/v1.5.7 Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov> Signed-off-by: Alexander Moch <mail@alexmoch.com> Closes #18089
83 lines
3.7 KiB
C
83 lines
3.7 KiB
C
/* ******************************************************************
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* hist : Histogram functions
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* part of Finite State Entropy project
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* Copyright (c) Meta Platforms, Inc. and affiliates.
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*
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* You can contact the author at :
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* - FSE source repository : https://github.com/Cyan4973/FiniteStateEntropy
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* - Public forum : https://groups.google.com/forum/#!forum/lz4c
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*
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* This source code is licensed under both the BSD-style license (found in the
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* LICENSE file in the root directory of this source tree) and the GPLv2 (found
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* in the COPYING file in the root directory of this source tree).
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* You may select, at your option, one of the above-listed licenses.
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****************************************************************** */
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/* --- dependencies --- */
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#include "../common/zstd_deps.h" /* size_t */
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/* --- simple histogram functions --- */
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/*! HIST_count():
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* Provides the precise count of each byte within a table 'count'.
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* 'count' is a table of unsigned int, of minimum size (*maxSymbolValuePtr+1).
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* Updates *maxSymbolValuePtr with actual largest symbol value detected.
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* @return : count of the most frequent symbol (which isn't identified).
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* or an error code, which can be tested using HIST_isError().
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* note : if return == srcSize, there is only one symbol.
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*/
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size_t HIST_count(unsigned* count, unsigned* maxSymbolValuePtr,
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const void* src, size_t srcSize);
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unsigned HIST_isError(size_t code); /**< tells if a return value is an error code */
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/* --- advanced histogram functions --- */
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#define HIST_WKSP_SIZE_U32 1024
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#define HIST_WKSP_SIZE (HIST_WKSP_SIZE_U32 * sizeof(unsigned))
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/** HIST_count_wksp() :
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* Same as HIST_count(), but using an externally provided scratch buffer.
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* Benefit is this function will use very little stack space.
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* `workSpace` is a writable buffer which must be 4-bytes aligned,
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* `workSpaceSize` must be >= HIST_WKSP_SIZE
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*/
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size_t HIST_count_wksp(unsigned* count, unsigned* maxSymbolValuePtr,
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const void* src, size_t srcSize,
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void* workSpace, size_t workSpaceSize);
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/** HIST_countFast() :
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* same as HIST_count(), but blindly trusts that all byte values within src are <= *maxSymbolValuePtr.
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* This function is unsafe, and will segfault if any value within `src` is `> *maxSymbolValuePtr`
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*/
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size_t HIST_countFast(unsigned* count, unsigned* maxSymbolValuePtr,
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const void* src, size_t srcSize);
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/** HIST_countFast_wksp() :
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* Same as HIST_countFast(), but using an externally provided scratch buffer.
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* `workSpace` is a writable buffer which must be 4-bytes aligned,
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* `workSpaceSize` must be >= HIST_WKSP_SIZE
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*/
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size_t HIST_countFast_wksp(unsigned* count, unsigned* maxSymbolValuePtr,
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const void* src, size_t srcSize,
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void* workSpace, size_t workSpaceSize);
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/*! HIST_count_simple() :
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* Same as HIST_countFast(), this function is unsafe,
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* and will segfault if any value within `src` is `> *maxSymbolValuePtr`.
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* It is also a bit slower for large inputs.
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* However, it does not need any additional memory (not even on stack).
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* @return : count of the most frequent symbol.
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* Note this function doesn't produce any error (i.e. it must succeed).
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*/
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unsigned HIST_count_simple(unsigned* count, unsigned* maxSymbolValuePtr,
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const void* src, size_t srcSize);
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/*! HIST_add() :
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* Lowest level: just add nb of occurrences of characters from @src into @count.
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* @count is not reset. @count array is presumed large enough (i.e. 1 KB).
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@ This function does not need any additional stack memory.
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*/
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void HIST_add(unsigned* count, const void* src, size_t srcSize);
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