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author | Guilherme Felipe <guilhermefelipecgs@gmail.com> | 2019-01-03 22:30:03 -0200 |
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committer | Guilherme Felipe <guilhermefelipecgs@gmail.com> | 2019-01-03 22:35:20 -0200 |
commit | e64391f47bf95ab4cdb65683623979ee6790836e (patch) | |
tree | c85c2c9a80d04e338cf39d0fed3fdba2d0291b29 /thirdparty/zstd/compress/hist.h | |
parent | b1e3215f3a316cfaf518747f7dafba4cc0d8d291 (diff) |
Update zstd to 1.3.8
Diffstat (limited to 'thirdparty/zstd/compress/hist.h')
-rw-r--r-- | thirdparty/zstd/compress/hist.h | 95 |
1 files changed, 95 insertions, 0 deletions
diff --git a/thirdparty/zstd/compress/hist.h b/thirdparty/zstd/compress/hist.h new file mode 100644 index 0000000000..8b389358dc --- /dev/null +++ b/thirdparty/zstd/compress/hist.h @@ -0,0 +1,95 @@ +/* ****************************************************************** + hist : Histogram functions + part of Finite State Entropy project + Copyright (C) 2013-present, Yann Collet. + + BSD 2-Clause License (http://www.opensource.org/licenses/bsd-license.php) + + Redistribution and use in source and binary forms, with or without + modification, are permitted provided that the following conditions are + met: + + * Redistributions of source code must retain the above copyright + notice, this list of conditions and the following disclaimer. + * Redistributions in binary form must reproduce the above + copyright notice, this list of conditions and the following disclaimer + in the documentation and/or other materials provided with the + distribution. + + THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS + "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT + LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR + A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT + OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, + SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT + LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, + DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY + THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT + (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE + OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. + + You can contact the author at : + - FSE source repository : https://github.com/Cyan4973/FiniteStateEntropy + - Public forum : https://groups.google.com/forum/#!forum/lz4c +****************************************************************** */ + +/* --- dependencies --- */ +#include <stddef.h> /* size_t */ + + +/* --- simple histogram functions --- */ + +/*! HIST_count(): + * Provides the precise count of each byte within a table 'count'. + * 'count' is a table of unsigned int, of minimum size (*maxSymbolValuePtr+1). + * Updates *maxSymbolValuePtr with actual largest symbol value detected. + * @return : count of the most frequent symbol (which isn't identified). + * or an error code, which can be tested using HIST_isError(). + * note : if return == srcSize, there is only one symbol. + */ +size_t HIST_count(unsigned* count, unsigned* maxSymbolValuePtr, + const void* src, size_t srcSize); + +unsigned HIST_isError(size_t code); /**< tells if a return value is an error code */ + + +/* --- advanced histogram functions --- */ + +#define HIST_WKSP_SIZE_U32 1024 +#define HIST_WKSP_SIZE (HIST_WKSP_SIZE_U32 * sizeof(unsigned)) +/** HIST_count_wksp() : + * Same as HIST_count(), but using an externally provided scratch buffer. + * Benefit is this function will use very little stack space. + * `workSpace` is a writable buffer which must be 4-bytes aligned, + * `workSpaceSize` must be >= HIST_WKSP_SIZE + */ +size_t HIST_count_wksp(unsigned* count, unsigned* maxSymbolValuePtr, + const void* src, size_t srcSize, + void* workSpace, size_t workSpaceSize); + +/** HIST_countFast() : + * same as HIST_count(), but blindly trusts that all byte values within src are <= *maxSymbolValuePtr. + * This function is unsafe, and will segfault if any value within `src` is `> *maxSymbolValuePtr` + */ +size_t HIST_countFast(unsigned* count, unsigned* maxSymbolValuePtr, + const void* src, size_t srcSize); + +/** HIST_countFast_wksp() : + * Same as HIST_countFast(), but using an externally provided scratch buffer. + * `workSpace` is a writable buffer which must be 4-bytes aligned, + * `workSpaceSize` must be >= HIST_WKSP_SIZE + */ +size_t HIST_countFast_wksp(unsigned* count, unsigned* maxSymbolValuePtr, + const void* src, size_t srcSize, + void* workSpace, size_t workSpaceSize); + +/*! HIST_count_simple() : + * Same as HIST_countFast(), this function is unsafe, + * and will segfault if any value within `src` is `> *maxSymbolValuePtr`. + * It is also a bit slower for large inputs. + * However, it does not need any additional memory (not even on stack). + * @return : count of the most frequent symbol. + * Note this function doesn't produce any error (i.e. it must succeed). + */ +unsigned HIST_count_simple(unsigned* count, unsigned* maxSymbolValuePtr, + const void* src, size_t srcSize); |